Latest open access articles published in Power Engineering and Engineering Thermophysics at https://www.acadlore.com/journals/PEET https://www.acadlore.com/journals/PEET Acadlore en Creative Commons Attribution(CC - BY) PEET support@acadlore.com https://www.acadlore.com/article/PEET/2026_5_1/peet050101 Reducing aerodynamic noise from rotating fans while preserving their aerodynamic performance remains a major challenge in the design of low-noise flow-control and ventilation systems. Motivated by this challenge, the present study performs a comprehensive numerical investigation of the coupled aerodynamic and aeroacoustic behavior of a rotating fan equipped with straight and serrated trailing-edge blades under both quiescent and inflow operating conditions. The effects of rotational speed, external inflow, and blade trailing-edge geometry on flow structure, pressure distribution, and acoustic response are systematically examined. Simulations are conducted for two rotational speeds and two inlet conditions to isolate rotation-induced mechanisms from inflow-dominated effects governing noise generation and propagation. Aerodynamic results show that under quiescent inflow, the flow field is primarily driven by fan rotation, leading to localized acceleration, non-uniform outlet mass flow, and a strong dependence on rotational speed. The presence of external inflow leads to a more uniform flow field and increased mass flow rates, while reducing the sensitivity to trailing-edge geometry. Moreover, rotational speed emerges as the dominant factor governing both aerodynamic and acoustic responses. Trailing-edge serrations mainly affect low-frequency acoustic behavior at low rotational speeds under quiescent conditions, whereas their influence diminishes at higher speeds and in the presence of inflow. External inflow also raises baseline acoustic levels and modifies the spatial distribution of the acoustic field. Overall, the results highlight the regime-dependent effectiveness of trailing-edge serrations and underscore the importance of accounting for realistic inflow environments in the aerodynamic and aeroacoustic design of low-noise rotating machinery. 01-10-2026 <![CDATA[ Reducing aerodynamic noise from rotating fans while preserving their aerodynamic performance remains a major challenge in the design of low-noise flow-control and ventilation systems. Motivated by this challenge, the present study performs a comprehensive numerical investigation of the coupled aerodynamic and aeroacoustic behavior of a rotating fan equipped with straight and serrated trailing-edge blades under both quiescent and inflow operating conditions. The effects of rotational speed, external inflow, and blade trailing-edge geometry on flow structure, pressure distribution, and acoustic response are systematically examined. Simulations are conducted for two rotational speeds and two inlet conditions to isolate rotation-induced mechanisms from inflow-dominated effects governing noise generation and propagation. Aerodynamic results show that under quiescent inflow, the flow field is primarily driven by fan rotation, leading to localized acceleration, non-uniform outlet mass flow, and a strong dependence on rotational speed. The presence of external inflow leads to a more uniform flow field and increased mass flow rates, while reducing the sensitivity to trailing-edge geometry. Moreover, rotational speed emerges as the dominant factor governing both aerodynamic and acoustic responses. Trailing-edge serrations mainly affect low-frequency acoustic behavior at low rotational speeds under quiescent conditions, whereas their influence diminishes at higher speeds and in the presence of inflow. External inflow also raises baseline acoustic levels and modifies the spatial distribution of the acoustic field. Overall, the results highlight the regime-dependent effectiveness of trailing-edge serrations and underscore the importance of accounting for realistic inflow environments in the aerodynamic and aeroacoustic design of low-noise rotating machinery. ]]> Coupled Computational Fluid Dynamics–Aeroacoustic Analysis of Fan Noise: Influence of Rotational Speed, Inflow, and Blade Serrations leila riahinezhad ahmad nooraeen melika mohammadkhah kamran hassani doi: 10.56578/peet050101 Power Engineering and Engineering Thermophysics 01-10-2026 Power Engineering and Engineering Thermophysics 01-10-2026 2026 5 1 Article 1 10.56578/peet050101 https://www.acadlore.com/article/PEET/2026_5_1/peet050101 https://www.acadlore.com/article/PEET/2025_4_3/peet040305 The integration of hydrogen electrolyzers into weak and very weak electrical grids introduces significant power quality challenges, including harmonic distortion and stability fluctuations. This systematic review and meta-analysis evaluated studies published between 2015 and 2025 to quantify the effectiveness of mitigation strategies for improving total harmonic distortion (THD) performance in grid-connected hydrogen production systems. The methodology followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020, screening 6,189 records and including 12 eligible studies for quantitative synthesis. A random-effects model was applied, using log-ratio effect size computation to assess THD of current or voltage reduction and stability improvements across varying Short Circuit Ratio conditions. Results indicated a pooled effect size of 1.321 and an average THD reduction of 82.53%, with the highest performance observed in moderate short-circuit ratio (SCR) of the grid at the point of common coupling environments. Funnel plot symmetry and Egger’s test (p = 0.243) confirmed minimal publication bias, supporting statistical reliability. The discussion highlights that performance strongly correlates with converter topology, control sophistication, and filtering strategy, with active front-end and grid-forming configurations outperforming passive solutions. The meta-analytic evidence suggests that hydrogen systems can operate effectively in weak grids when supported by harmonics-aware control frameworks. This study concludes that while feasibility has been established, future research should prioritize standardization and cost-effective deployment pathways to enhance the effectiveness of this approach. 09-29-2025 <![CDATA[ <p>The integration of hydrogen electrolyzers into weak and very weak electrical grids introduces significant power quality challenges, including harmonic distortion and stability fluctuations. This systematic review and meta-analysis evaluated studies published between 2015 and 2025 to quantify the effectiveness of mitigation strategies for improving total harmonic distortion (THD) performance in grid-connected hydrogen production systems. The methodology followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020, screening 6,189 records and including 12 eligible studies for quantitative synthesis. A random-effects model was applied, using log-ratio effect size computation to assess THD of current or voltage reduction and stability improvements across varying Short Circuit Ratio conditions. Results indicated a pooled effect size of 1.321 and an average THD reduction of 82.53%, with the highest performance observed in moderate short-circuit ratio (SCR) of the grid at the point of common coupling environments. Funnel plot symmetry and Egger’s test (<em>p</em> = 0.243) confirmed minimal publication bias, supporting statistical reliability. The discussion highlights that performance strongly correlates with converter topology, control sophistication, and filtering strategy, with active front-end and grid-forming configurations outperforming passive solutions. The meta-analytic evidence suggests that hydrogen systems can operate effectively in weak grids when supported by harmonics-aware control frameworks. This study concludes that while feasibility has been established, future research should prioritize standardization and cost-effective deployment pathways to enhance the effectiveness of this approach.</p> ]]> Meta-Analysis of Harmonics and Stability Challenges in Renewable Energy-Driven Sloppy Electrolyzers under Weak Grid Conditions singgih dwi prasetyo doi: 10.56578/peet040305 Power Engineering and Engineering Thermophysics 09-29-2025 Power Engineering and Engineering Thermophysics 09-29-2025 2025 4 3 Article 195 10.56578/peet040305 https://www.acadlore.com/article/PEET/2025_4_3/peet040305 https://www.acadlore.com/article/PEET/2025_4_3/peet040304 Hydraulic fracturing is a core stimulation technology for unconventional oil and gas development, in which proppants play a decisive role in sustaining fracture conductivity. As fracturing operations extend toward deep reservoirs, high-temperature and high-pressure (HTHP) environments, and complex fracture networks, the mechanical response, transport behavior, and coupled interactions among proppants, fracturing fluids, and rock formations exhibit pronounced multiscale and multiphysics characteristics. These coupled processes constitute a fundamental constraint on the long-term stability of fracture conductivity. This review focuses on the formation and evolution of proppant-supported fracture conductivity and systematically examines the material characteristics and applicable conditions of different proppant types. From a multiscale perspective, four core mechanisms governing proppant behavior during hydraulic fracturing are synthesized: physical support and embedment–crushing processes under fracture closure; compaction-induced conductivity degradation within proppant packs; thermofluid-dynamic controls on proppant settling and migration inside fractures; and cooperative transport mechanisms between proppants and fracturing fluids that sustain long-term conductivity. The effects of cyclic loading, HTHP environments, and fluid rheology on the coupled behavior of the proppant–fluid–rock system are further analyzed. Current limitations are identified in predicting mechanical behavior under extreme conditions, constructing multiscale coupled models, and bridging laboratory-scale observations with field-scale performance. Recent progress in multiscale multiphysics modeling and proppant design is summarized, and future research directions at the intersection of engineering thermophysics and energy engineering are outlined. The review provides a theoretical basis for proppant selection, conductivity evaluation, and efficient development of unconventional reservoirs. 09-04-2025 <![CDATA[ Hydraulic fracturing is a core stimulation technology for unconventional oil and gas development, in which proppants play a decisive role in sustaining fracture conductivity. As fracturing operations extend toward deep reservoirs, high-temperature and high-pressure (HTHP) environments, and complex fracture networks, the mechanical response, transport behavior, and coupled interactions among proppants, fracturing fluids, and rock formations exhibit pronounced multiscale and multiphysics characteristics. These coupled processes constitute a fundamental constraint on the long-term stability of fracture conductivity. This review focuses on the formation and evolution of proppant-supported fracture conductivity and systematically examines the material characteristics and applicable conditions of different proppant types. From a multiscale perspective, four core mechanisms governing proppant behavior during hydraulic fracturing are synthesized: physical support and embedment–crushing processes under fracture closure; compaction-induced conductivity degradation within proppant packs; thermofluid-dynamic controls on proppant settling and migration inside fractures; and cooperative transport mechanisms between proppants and fracturing fluids that sustain long-term conductivity. The effects of cyclic loading, HTHP environments, and fluid rheology on the coupled behavior of the proppant–fluid–rock system are further analyzed. Current limitations are identified in predicting mechanical behavior under extreme conditions, constructing multiscale coupled models, and bridging laboratory-scale observations with field-scale performance. Recent progress in multiscale multiphysics modeling and proppant design is summarized, and future research directions at the intersection of engineering thermophysics and energy engineering are outlined. The review provides a theoretical basis for proppant selection, conductivity evaluation, and efficient development of unconventional reservoirs. ]]> Multiscale and Multiphysics Mechanisms of Proppant Fracture Conductivity Evolution in Hydraulic Fracturing fuyong wang qin zhang manlai zhang doi: 10.56578/peet040304 Power Engineering and Engineering Thermophysics 09-04-2025 Power Engineering and Engineering Thermophysics 09-04-2025 2025 4 3 Article 178 10.56578/peet040304 https://www.acadlore.com/article/PEET/2025_4_3/peet040304 https://www.acadlore.com/article/PEET/2025_4_3/peet040303 The digitalization of vehicles has accelerated the adoption of touchscreen-based control systems and with the growing push toward full electrification of national vehicle fleets. Their combined implications for driver distraction, road safety, and the electrical infrastructure required to support large-scale vehicle electrification remain insufficiently addressed. The present study offers an essential cross-sector perspective for contemporary resilience planning by combining human-factors analysis with system-level energy considerations. This study investigates these issues by examining both the human-machine interaction demands imposed by touchscreen-centric interfaces and the energetic and infrastructural consequences of replacing all gasoline-powered passenger cars in Italy with battery electric vehicles. The methodology integrates a numerical model of driver visual distraction with empirical findings from recent eye-gaze studies. Touchscreen interactions are decomposed into phases of visual reorientation, cognitive decision-making, pointing movement, actuation, and refocusing. This framework allows estimation of total eyes-off-road time and the corresponding blind-driving distance. Model outcomes are systematically compared with measured interaction durations from controlled experimental studies. The results show that touchscreen interactions require significantly longer visual engagement than predicted by idealized human-machine interaction models, particularly for multi-step tasks such as navigation and address entry. In parallel, national fuel consumption data are used to approximate the annual distance traveled by gasoline vehicles on Italian motorways and ordinary roads. These distances are converted into electrical energy demand using representative consumption values, and the associated average and installed charging powers are computed for fast-charging, slow public charging, and universal home-charging scenarios. From an energy-system perspective, replacing all gasoline vehicles with electric vehicles would require charging power levels that exceed the current Italian peak electrical load by a wide margin, especially under a full home-charging configuration. Overall, the findings suggest that touchscreen-based interfaces lead to significant increases in driver workload, while large-scale fleet electrification imposes substantial demands on the national power system. These results underscore the need for safer interface designs and for electrification strategies that incorporate human, infrastructural, and system-level constraints. 08-13-2025 <![CDATA[ The digitalization of vehicles has accelerated the adoption of touchscreen-based control systems and with the growing push toward full electrification of national vehicle fleets. Their combined implications for driver distraction, road safety, and the electrical infrastructure required to support large-scale vehicle electrification remain insufficiently addressed. The present study offers an essential cross-sector perspective for contemporary resilience planning by combining human-factors analysis with system-level energy considerations. This study investigates these issues by examining both the human-machine interaction demands imposed by touchscreen-centric interfaces and the energetic and infrastructural consequences of replacing all gasoline-powered passenger cars in Italy with battery electric vehicles. The methodology integrates a numerical model of driver visual distraction with empirical findings from recent eye-gaze studies. Touchscreen interactions are decomposed into phases of visual reorientation, cognitive decision-making, pointing movement, actuation, and refocusing. This framework allows estimation of total eyes-off-road time and the corresponding blind-driving distance. Model outcomes are systematically compared with measured interaction durations from controlled experimental studies. The results show that touchscreen interactions require significantly longer visual engagement than predicted by idealized human-machine interaction models, particularly for multi-step tasks such as navigation and address entry. In parallel, national fuel consumption data are used to approximate the annual distance traveled by gasoline vehicles on Italian motorways and ordinary roads. These distances are converted into electrical energy demand using representative consumption values, and the associated average and installed charging powers are computed for fast-charging, slow public charging, and universal home-charging scenarios. From an energy-system perspective, replacing all gasoline vehicles with electric vehicles would require charging power levels that exceed the current Italian peak electrical load by a wide margin, especially under a full home-charging configuration. Overall, the findings suggest that touchscreen-based interfaces lead to significant increases in driver workload, while large-scale fleet electrification imposes substantial demands on the national power system. These results underscore the need for safer interface designs and for electrification strategies that incorporate human, infrastructural, and system-level constraints. ]]> Human-Factors and Power-System Implications of Consumer Electronics-Oriented Vehicle Design and Full-Electric Fleet Deployment luca piancastelli doi: 10.56578/peet040303 Power Engineering and Engineering Thermophysics 08-13-2025 Power Engineering and Engineering Thermophysics 08-13-2025 2025 4 3 Article 168 10.56578/peet040303 https://www.acadlore.com/article/PEET/2025_4_3/peet040303 https://www.acadlore.com/article/PEET/2025_4_3/peet040302 This study highlights how the analysis of the long-term performance of solar reflective materials used both as roofing and flooring solutions to mitigate urban overheating has recently become more important. European and Italian legislations focus just on initial properties, but actual energy efficiency depends on durability over time. The objective is the development and the validation of characterization methodologies that consider performance degradation due to aging, providing reliable guidance for designers and policy makers. This study integrates standard thermophysical characterization methods with natural and accelerated aging protocols. Solar reflectance (SR) measurements can be performed by using ultraviolet-visible-near-infrared spectrophotometer, solar spectrum reflectometer and pyranometer/albedometer, while thermal emissivity can be measured with infrared emissometers. Natural aging was implemented at the Energy Efficiency Laboratory structure of the University of Modena and Reggio Emilia, operational since 2017. Accelerated methods include the standard protocol for surface soiling and an innovative method for biological growth. The analysis reveals significant degradations in SR, with reductions of between 10% and 40% after three years of natural exposure. Bituminous membranes show the most marked degradation, while ceramic materials present the best stability. Accelerated methods show interesting correlations with natural aging. The doubling of the standard accelerated cycle, designed on North American climatic conditions, is more representative of European climatic conditions characterized by greater air pollution. It must be recalled that evaluation based just on initial performance significantly underestimates long-term behaviour. The results suggest the need to update regulations by introducing requirements based on post-ageing performance. New materials design should be focus on durability by integrating into new materials both self-cleaning properties and improved stability over time. While, during design process, materials with certified long-term stability, analyzed through durability and degradation analysis should be considered in energy and economic assessments. 08-13-2025 <![CDATA[ <p>This study highlights how the analysis of the long-term performance of solar reflective materials used both as roofing and flooring solutions to mitigate urban overheating has recently become more important. European and Italian legislations focus just on initial properties, but actual energy efficiency depends on durability over time. The objective is the development and the validation of characterization methodologies that consider performance degradation due to aging, providing reliable guidance for designers and policy makers. This study integrates standard thermophysical characterization methods with natural and accelerated aging protocols. Solar reflectance (SR) measurements can be performed by using ultraviolet-visible-near-infrared spectrophotometer, solar spectrum reflectometer and pyranometer/albedometer, while thermal emissivity can be measured with infrared emissometers. Natural aging was implemented at the Energy Efficiency Laboratory structure of the University of Modena and Reggio Emilia, operational since 2017. Accelerated methods include the standard protocol for surface soiling and an innovative method for biological growth. The analysis reveals significant degradations in SR, with reductions of between 10% and 40% after three years of natural exposure. Bituminous membranes show the most marked degradation, while ceramic materials present the best stability. Accelerated methods show interesting correlations with natural aging. The doubling of the standard accelerated cycle, designed on North American climatic conditions, is more representative of European climatic conditions characterized by greater air pollution. It must be recalled that evaluation based just on initial performance significantly underestimates long-term behaviour. The results suggest the need to update regulations by introducing requirements based on post-ageing performance. New materials design should be focus on durability by integrating into new materials both self-cleaning properties and improved stability over time. While, during design process, materials with certified long-term stability, analyzed through durability and degradation analysis should be considered in energy and economic assessments.</p> ]]> Characterization and Durability of Cool Materials: Standard Methodologies for the Evaluation of Thermal Performance of New and Aged Products chiara ferrari marco puglia nicolò morselli simone pedrazzi giulio allesina mauro a. corticelli paolo tartarini alberto muscio doi: 10.56578/peet040302 Power Engineering and Engineering Thermophysics 08-13-2025 Power Engineering and Engineering Thermophysics 08-13-2025 2025 4 3 Article 160 10.56578/peet040302 https://www.acadlore.com/article/PEET/2025_4_3/peet040302 https://www.acadlore.com/article/PEET/2025_4_3/peet040301 Urban Heat Island (UHI) effects are increasingly recognised as a major challenge for climate resilience, urban sustainability, and public health. Buildings play a dual role: they are highly vulnerable to overheating while simultaneously contributing to urban heat through energy use and anthropogenic emissions. This review explores the modelling of UHI phenomena across scales, from single-building dynamic energy simulations to Urban Building Energy Models capable of capturing interactions between the built environment and the urban microclimate. Particular attention is given to the drivers of UHI formation, the development of modelling tools such as Urban Weather Generator (UWG), and the growing need for harmonised methodologies and standards, including recent World Meteorological Organization (WMO) guidance. The article highlights the link between scientific evidence and regulatory frameworks, from European climate adaptation strategies to national and regional policies promoting passive cooling, reflective materials, and climate resilience planning. By bridging fundamentals, modelling advances, and policy implications, the paper aims to provide an integrated perspective on how UHI research can inform effective mitigation strategies and support the transition toward sustainable, resilient, and carbon-neutral cities. 08-13-2025 <![CDATA[ Urban Heat Island (UHI) effects are increasingly recognised as a major challenge for climate resilience, urban sustainability, and public health. Buildings play a dual role: they are highly vulnerable to overheating while simultaneously contributing to urban heat through energy use and anthropogenic emissions. This review explores the modelling of UHI phenomena across scales, from single-building dynamic energy simulations to Urban Building Energy Models capable of capturing interactions between the built environment and the urban microclimate. Particular attention is given to the drivers of UHI formation, the development of modelling tools such as Urban Weather Generator (UWG), and the growing need for harmonised methodologies and standards, including recent World Meteorological Organization (WMO) guidance. The article highlights the link between scientific evidence and regulatory frameworks, from European climate adaptation strategies to national and regional policies promoting passive cooling, reflective materials, and climate resilience planning. By bridging fundamentals, modelling advances, and policy implications, the paper aims to provide an integrated perspective on how UHI research can inform effective mitigation strategies and support the transition toward sustainable, resilient, and carbon-neutral cities. ]]> Modelling Urban Heat Islands for Resilient Cities: From Building Energy Models to Standards and Policy Frameworks vincenzo corrado ilaria ballarini mamak p. tootkaboni doi: 10.56578/peet040301 Power Engineering and Engineering Thermophysics 08-13-2025 Power Engineering and Engineering Thermophysics 08-13-2025 2025 4 3 Article 149 10.56578/peet040301 https://www.acadlore.com/article/PEET/2025_4_3/peet040301 https://www.acadlore.com/article/PEET/2025_4_2/peet040205 Repurposing deep abandoned oil and gas wells for advanced adiabatic compressed air energy storage (AA-CAES) has attracted increasing attention; however, reliable performance assessment is challenged by the complex thermal behaviour induced by the large aspect ratio of deep wells and the long-term interaction between the gas column and surrounding formations. In particular, simplified heat transfer assumptions commonly adopted in existing models may lead to non-negligible deviations in capacity and efficiency predictions. To address this issue, a coupled thermodynamic framework is established that accounts for gas column gravity effects, geothermal temperature gradients, and unsteady heat conduction in the surrounding rock. Different wellbore heat transfer boundary representations and operational strategies are systematically examined to clarify their influence on the thermal and energetic performance of deep-well AA-CAES systems. The analysis indicates that under low mass flow rate conditions, the extended wellbore length promotes effective heat exchange between the compressed air and the surrounding rock, restricting the average temperature variation along the wellbore and leading to compression and expansion processes that deviate markedly from ideal adiabatic behaviour. When a constant wall temperature boundary is employed to represent long-term formation heat transfer, the predicted storage capacity is reduced by 6.12% compared with conventional adiabatic assumptions. In addition, sliding-pressure operation exhibits superior adaptability to the thermal characteristics of deep wells, increasing the round-trip efficiency (RTE) from 48.82% to 60.99 relative to constant-pressure operation. At low flow rates, extended thermal relaxation further enhances heat dissipation, resulting in a modest increase in effective energy storage density (ESD). These results highlight the role of surrounding rock formations as a distributed thermal buffer and underscore the importance of incorporating realistic heat transfer modelling and appropriate operational strategies in the thermodynamic design of deep-well AA-CAES systems. 07-04-2025 <![CDATA[ <p>Repurposing deep abandoned oil and gas wells for advanced adiabatic compressed air energy storage (AA-CAES) has attracted increasing attention; however, reliable performance assessment is challenged by the complex thermal behaviour induced by the large aspect ratio of deep wells and the long-term interaction between the gas column and surrounding formations. In particular, simplified heat transfer assumptions commonly adopted in existing models may lead to non-negligible deviations in capacity and efficiency predictions. To address this issue, a coupled thermodynamic framework is established that accounts for gas column gravity effects, geothermal temperature gradients, and unsteady heat conduction in the surrounding rock. Different wellbore heat transfer boundary representations and operational strategies are systematically examined to clarify their influence on the thermal and energetic performance of deep-well AA-CAES systems. The analysis indicates that under low mass flow rate conditions, the extended wellbore length promotes effective heat exchange between the compressed air and the surrounding rock, restricting the average temperature variation along the wellbore and leading to compression and expansion processes that deviate markedly from ideal adiabatic behaviour. When a constant wall temperature boundary is employed to represent long-term formation heat transfer, the predicted storage capacity is reduced by 6.12% compared with conventional adiabatic assumptions. In addition, sliding-pressure operation exhibits superior adaptability to the thermal characteristics of deep wells, increasing the round-trip efficiency (RTE) from 48.82% to 60.99 relative to constant-pressure operation. At low flow rates, extended thermal relaxation further enhances heat dissipation, resulting in a modest increase in effective energy storage density (ESD). These results highlight the role of surrounding rock formations as a distributed thermal buffer and underscore the importance of incorporating realistic heat transfer modelling and appropriate operational strategies in the thermodynamic design of deep-well AA-CAES systems.</p> ]]> Thermodynamic Performance of Advanced Adiabatic Compressed Air Energy Storage in Deep Wells Considering Unsteady Wellbore–Rock Heat Transfer dongjin xu zhiwen xu shuqi niu feipeng he yukai guo yong wang xiangyang luo wenping liu doi: 10.56578/peet040205 Power Engineering and Engineering Thermophysics 07-04-2025 Power Engineering and Engineering Thermophysics 07-04-2025 2025 4 2 Article 131 10.56578/peet040205 https://www.acadlore.com/article/PEET/2025_4_2/peet040205 https://www.acadlore.com/article/PEET/2025_4_2/peet040204 The combustion behavior of blended petroleum–biofuel mixtures has increasingly been investigated as interest grows in low-toxicity, biodegradable, and energy-dense biomass-derived fuels. Among higher alkanols, n-butanol is recognized for its favorable physicochemical properties and its compatibility with gasoline-range hydrocarbons (HC) such as iso-octane. In this context, a systematic evaluation of laminar flame propagation and instability characteristics is essential for understanding the combustion performance and operational safety of blended fuels. In the present study, the laminar burning velocity (LBV) and cellular instability of premixed iso-octane/n-butanol/air flames were quantified for a wide range of equivalence ratios (0.7–1.5) at an initial temperature of 423 K and ambient pressure. It was observed that the LBV increased consistently with the addition of n-butanol, whereas the Markstein length (Lb) decreased. Analysis of cellular structures revealed that diffusive-thermal instability strengthened monotonically as the equivalence ratio increased, resulting in more unstable flame propagation under fuel-rich conditions. In contrast, the hydrodynamic instability exhibited a non-monotonic trend, first intensifying and subsequently diminishing with increasing equivalence ratio. The critical Peclet number decreased continuously across the equivalence-ratio range, while the critical flame radius varied non-monotonically. The incorporation of n-butanol was found to enhance both diffusive-thermal and hydrodynamic instabilities and to reduce the critical Peclet number and critical flame radius. These findings underscore the need for careful control of combustion stability in practical applications involving iso-octane/n-butanol mixtures and provide fundamental insight into the flame-structure evolution associated with next-generation alternative fuels. 06-19-2025 <![CDATA[ <p>The combustion behavior of blended petroleum–biofuel mixtures has increasingly been investigated as interest grows in low-toxicity, biodegradable, and energy-dense biomass-derived fuels. Among higher alkanols, n-butanol is recognized for its favorable physicochemical properties and its compatibility with gasoline-range hydrocarbons (HC) such as iso-octane. In this context, a systematic evaluation of laminar flame propagation and instability characteristics is essential for understanding the combustion performance and operational safety of blended fuels. In the present study, the laminar burning velocity (LBV) and cellular instability of premixed iso-octane/n-butanol/air flames were quantified for a wide range of equivalence ratios (0.7–1.5) at an initial temperature of 423 K and ambient pressure. It was observed that the LBV increased consistently with the addition of n-butanol, whereas the Markstein length (<em>L_b</em>) decreased. Analysis of cellular structures revealed that diffusive-thermal instability strengthened monotonically as the equivalence ratio increased, resulting in more unstable flame propagation under fuel-rich conditions. In contrast, the hydrodynamic instability exhibited a non-monotonic trend, first intensifying and subsequently diminishing with increasing equivalence ratio. The critical Peclet number decreased continuously across the equivalence-ratio range, while the critical flame radius varied non-monotonically. The incorporation of n-butanol was found to enhance both diffusive-thermal and hydrodynamic instabilities and to reduce the critical Peclet number and critical flame radius. These findings underscore the need for careful control of combustion stability in practical applications involving iso-octane/n-butanol mixtures and provide fundamental insight into the flame-structure evolution associated with next-generation alternative fuels.</p> ]]> Laminar Burning Velocity and Cellular Instability of Iso-Octane/N-Butanol–Air Premixed Flames shanshan chen doi: 10.56578/peet040204 Power Engineering and Engineering Thermophysics 06-19-2025 Power Engineering and Engineering Thermophysics 06-19-2025 2025 4 2 Article 121 10.56578/peet040204 https://www.acadlore.com/article/PEET/2025_4_2/peet040204 https://www.acadlore.com/article/PEET/2025_4_2/peet040203 This study investigates the design and performance of altitude test benches for piston engines with power outputs up to 200 kW. The primary objective is to generate controlled depressions within an enclosed engine bay to reproduce atmospheric conditions corresponding to altitudes ranging from sea level to 14,000 m. Three configurations are examined: an ejector–diffuser system derived from National Advisory Committee for Aeronautics (NACA) principles, a Venturi device powered by an auxiliary diesel engine (Cursor 13), and a centrifugal turbocharger (Holset HY55V) mechanically coupled to the same auxiliary engine. Computational Fluid Dynamics (CFD) simulations are performed to evaluate the pressure and velocity distributions within the test chamber and its associated flow components. The ejector-diffuser arrangement achieves a moderate pressure reduction but exhibits flow separation in the diffuser at large expansion angles, limiting its efficiency. The Venturi system achieves a greater vacuum level, reducing the chamber pressure to approximately 76 kPa, equivalent to an altitude of around 2,500 m. The turbocharger-based configuration demonstrates the highest performance, achieving a chamber pressure of approximately 15 kPa—equivalent to an altitude of 14,000 m—through appropriate adjustment of compressor rotational speed and intake valve opening. This configuration also ensures a faster transient response and enhanced stability of airflow and pressure distribution. The results highlight the importance of proper integration between auxiliary propulsion systems, component sizing, and boundary condition definition to achieve accurate altitude simulation. The proposed approach demonstrates that combining a variable-speed compressor with active flow control enables flexible reproduction of both steady-state and transient operating conditions. The findings provide practical guidelines for developing cost-effective, reliable, and versatile altitude test benches suitable for experimental evaluation and calibration of high-power piston engines under simulated high-altitude environments. 06-02-2025 <![CDATA[ This study investigates the design and performance of altitude test benches for piston engines with power outputs up to 200 kW. The primary objective is to generate controlled depressions within an enclosed engine bay to reproduce atmospheric conditions corresponding to altitudes ranging from sea level to 14,000 m. Three configurations are examined: an ejector–diffuser system derived from National Advisory Committee for Aeronautics (NACA) principles, a Venturi device powered by an auxiliary diesel engine (Cursor 13), and a centrifugal turbocharger (Holset HY55V) mechanically coupled to the same auxiliary engine. Computational Fluid Dynamics (CFD) simulations are performed to evaluate the pressure and velocity distributions within the test chamber and its associated flow components. The ejector-diffuser arrangement achieves a moderate pressure reduction but exhibits flow separation in the diffuser at large expansion angles, limiting its efficiency. The Venturi system achieves a greater vacuum level, reducing the chamber pressure to approximately 76 kPa, equivalent to an altitude of around 2,500 m. The turbocharger-based configuration demonstrates the highest performance, achieving a chamber pressure of approximately 15 kPa—equivalent to an altitude of 14,000 m—through appropriate adjustment of compressor rotational speed and intake valve opening. This configuration also ensures a faster transient response and enhanced stability of airflow and pressure distribution. The results highlight the importance of proper integration between auxiliary propulsion systems, component sizing, and boundary condition definition to achieve accurate altitude simulation. The proposed approach demonstrates that combining a variable-speed compressor with active flow control enables flexible reproduction of both steady-state and transient operating conditions. The findings provide practical guidelines for developing cost-effective, reliable, and versatile altitude test benches suitable for experimental evaluation and calibration of high-power piston engines under simulated high-altitude environments. ]]> CFD-Based Analysis and Optimization of Depressurization Systems for Engine Test Benches of Small Propeller Aircraft luca piancastelli doi: 10.56578/peet040203 Power Engineering and Engineering Thermophysics 06-02-2025 Power Engineering and Engineering Thermophysics 06-02-2025 2025 4 2 Article 110 10.56578/peet040203 https://www.acadlore.com/article/PEET/2025_4_2/peet040203 https://www.acadlore.com/article/PEET/2025_4_2/peet040202 This paper discussed the possibilities of using the developed Dignet Energy Platform (DEP) for modeling and optimization of bioenergy production. The DEP presents a set of software tools based on a mathematical model to calculate the desired output and the profitability of investments in a renewable energy source based on input parameters. By using Multi-Criteria Decision Analysis (MCDA), the DEP selects an optimal variant of energy or fuel production from biomass. This tool enables the simplification of complex and biomass energy production-related calculations while facilitating the customization of each individual element in the bioenergy production process. The user could use a simple procedure to “simulate” the production parameters and choose the best option from a set of biomass-based projects. Criteria describing the various projects were selected by the users and calculated by the DEP. These criteria helped select the appropriate optimal project by multi-criteria optimization. In this paper, several chains of biomass fuel/heat/electricity production applicable to the settings in the Republic of Croatia and the region were analyzed. Results in this research provided selection of optimal chains for the production of solid fuels and energy, including heat and combined heat and power (CHP) from different categories of biomass. The DEP is proved to be a practical and effective tool in selecting the optimal project of biomass energy production. 05-19-2025 <![CDATA[ This paper discussed the possibilities of using the developed Dignet Energy Platform (DEP) for modeling and optimization of bioenergy production. The DEP presents a set of software tools based on a mathematical model to calculate the desired output and the profitability of investments in a renewable energy source based on input parameters. By using Multi-Criteria Decision Analysis (MCDA), the DEP selects an optimal variant of energy or fuel production from biomass. This tool enables the simplification of complex and biomass energy production-related calculations while facilitating the customization of each individual element in the bioenergy production process. The user could use a simple procedure to “simulate” the production parameters and choose the best option from a set of biomass-based projects. Criteria describing the various projects were selected by the users and calculated by the DEP. These criteria helped select the appropriate optimal project by multi-criteria optimization. In this paper, several chains of biomass fuel/heat/electricity production applicable to the settings in the Republic of Croatia and the region were analyzed. Results in this research provided selection of optimal chains for the production of solid fuels and energy, including heat and combined heat and power (CHP) from different categories of biomass. The DEP is proved to be a practical and effective tool in selecting the optimal project of biomass energy production. ]]> Calculation and Optimization of Biomass Energy Production by the Dignet Energy Platform srđan vasković petar gvero nermin montel ivan marijanović doi: 10.56578/peet040202 Power Engineering and Engineering Thermophysics 05-19-2025 Power Engineering and Engineering Thermophysics 05-19-2025 2025 4 2 Article 98 10.56578/peet040202 https://www.acadlore.com/article/PEET/2025_4_2/peet040202 https://www.acadlore.com/article/PEET/2025_4_2/peet040201 Greenhouses are energy-intensive agricultural systems, where the sustainable design of natural ventilation could markedly reduce energy demand while maintaining optimal conditions for plant growth. The performance of natural ventilation arises from a multifaceted interaction among several determinants, including the geometric configuration of the greenhouse, prevailing environmental conditions, and the structural characteristics of ventilation openings and ducts. This study employed computational fluid dynamics (CFD) to assess the influence of roof inlet design on airflow distribution, regulation of canopy temperature, and energy performance in a single-span greenhouse measuring 20 × 10 × 6 meters. Six ventilation configurations were evaluated by varying the quantity and shape of roof inlets: three large inlets and ten smaller inlets, each with rectangular, oval, or circular geometries. The plant canopy was modeled as a porous medium to realistically capture aerodynamic resistance. Mesh independence was validated using outlet mass flux, and simulations were conducted under steady-state natural ventilation conditions. Key performance indicators included airflow velocity, temperature distribution, ventilation rate, wall shear stress (WSS), air changes per hour (ACH), and estimated annual energy saving. Results of the analysis revealed that circular and oval inlets enhanced air mixing and reduced thermal gradients within the canopy, whereas rectangular inlets generated localized recirculation zones and elevated WSS, resulting in lower energy efficiency. The inlet geometry and quantity played a critical role in the sustainable design of greenhouse ventilation. By integrating CFD-based airflow analysis with energy-saving assessments, this study offered a practical framework to guide greenhouse operators in optimizing ventilation strategies that balance productivity, thermal comfort, and long-term energy sustainability. 05-19-2025 <![CDATA[ Greenhouses are energy-intensive agricultural systems, where the sustainable design of natural ventilation could markedly reduce energy demand while maintaining optimal conditions for plant growth. The performance of natural ventilation arises from a multifaceted interaction among several determinants, including the geometric configuration of the greenhouse, prevailing environmental conditions, and the structural characteristics of ventilation openings and ducts. This study employed computational fluid dynamics (CFD) to assess the influence of roof inlet design on airflow distribution, regulation of canopy temperature, and energy performance in a single-span greenhouse measuring 20 × 10 × 6 meters. Six ventilation configurations were evaluated by varying the quantity and shape of roof inlets: three large inlets and ten smaller inlets, each with rectangular, oval, or circular geometries. The plant canopy was modeled as a porous medium to realistically capture aerodynamic resistance. Mesh independence was validated using outlet mass flux, and simulations were conducted under steady-state natural ventilation conditions. Key performance indicators included airflow velocity, temperature distribution, ventilation rate, wall shear stress (WSS), air changes per hour (ACH), and estimated annual energy saving. Results of the analysis revealed that circular and oval inlets enhanced air mixing and reduced thermal gradients within the canopy, whereas rectangular inlets generated localized recirculation zones and elevated WSS, resulting in lower energy efficiency. The inlet geometry and quantity played a critical role in the sustainable design of greenhouse ventilation. By integrating CFD-based airflow analysis with energy-saving assessments, this study offered a practical framework to guide greenhouse operators in optimizing ventilation strategies that balance productivity, thermal comfort, and long-term energy sustainability. ]]> Design of Greenhouse Ventilation Systems with Computational Fluid Dynamics: Balancing Performance and Energy Sustainability leila riahinezhad ahmad nooraeen melika mohammadkhah doi: 10.56578/peet040201 Power Engineering and Engineering Thermophysics 05-19-2025 Power Engineering and Engineering Thermophysics 05-19-2025 2025 4 2 Article 86 10.56578/peet040201 https://www.acadlore.com/article/PEET/2025_4_2/peet040201 https://www.acadlore.com/article/PEET/2025_4_1/peet040105 Heating, ventilation, and air-conditioning (HVAC) systems have been identified as major contributors to global energy consumption, underscoring the urgency of optimizing their performance for economic and environmental sustainability. This review presents a comprehensive examination of the thermofluid behavior, mathematical modeling techniques, and optimization strategies employed in HVAC systems. Particular emphasis is placed on the development and implementation of dynamic and steady-state models that enable predictive analysis and performance forecasting. The inherently nonlinear and time-varying nature of HVAC systems has necessitated the adoption of advanced computational approaches, including artificial intelligence (AI), machine learning (ML), genetic algorithm (GA), and simulated annealing (SA), to enhance system responsiveness and occupant comfort. AI- and ML- based control strategies have been shown to improve adaptability to real-time environmental and occupancy changes, thereby increasing operational efficiency. However, these approaches are often constrained by high data requirements and computational complexity. Multi-objective optimization frameworks have been proposed to balance energy efficiency with environmental impact, yet challenges remain regarding precision, scalability, and the seamless integration of emerging technologies. The application of digital twin technology has recently gained traction as a viable solution for real-time simulation and virtual testing, offering a non-intrusive means of performance evaluation and system tuning. It is suggested that the future of HVAC optimization lies in the convergence of classical thermodynamic and fluid dynamic modeling with intelligent control architectures, enabling the development of adaptive systems capable of autonomous decision-making. This integrated modeling paradigm is anticipated to support advancements in energy-aware design, occupant-centric climate control, and sustainable building operation. Through this synthesis of traditional and data-driven methodologies, new pathways were proposed for achieving robust, scalable, and intelligent HVAC systems that respond efficiently to evolving environmental and user-specific demands. 03-30-2025 <![CDATA[ Heating, ventilation, and air-conditioning (HVAC) systems have been identified as major contributors to global energy consumption, underscoring the urgency of optimizing their performance for economic and environmental sustainability. This review presents a comprehensive examination of the thermofluid behavior, mathematical modeling techniques, and optimization strategies employed in HVAC systems. Particular emphasis is placed on the development and implementation of dynamic and steady-state models that enable predictive analysis and performance forecasting. The inherently nonlinear and time-varying nature of HVAC systems has necessitated the adoption of advanced computational approaches, including artificial intelligence (AI), machine learning (ML), genetic algorithm (GA), and simulated annealing (SA), to enhance system responsiveness and occupant comfort. AI- and ML- based control strategies have been shown to improve adaptability to real-time environmental and occupancy changes, thereby increasing operational efficiency. However, these approaches are often constrained by high data requirements and computational complexity. Multi-objective optimization frameworks have been proposed to balance energy efficiency with environmental impact, yet challenges remain regarding precision, scalability, and the seamless integration of emerging technologies. The application of digital twin technology has recently gained traction as a viable solution for real-time simulation and virtual testing, offering a non-intrusive means of performance evaluation and system tuning. It is suggested that the future of HVAC optimization lies in the convergence of classical thermodynamic and fluid dynamic modeling with intelligent control architectures, enabling the development of adaptive systems capable of autonomous decision-making. This integrated modeling paradigm is anticipated to support advancements in energy-aware design, occupant-centric climate control, and sustainable building operation. Through this synthesis of traditional and data-driven methodologies, new pathways were proposed for achieving robust, scalable, and intelligent HVAC systems that respond efficiently to evolving environmental and user-specific demands. ]]> Optimization of HVAC Systems: Advances in Thermofluid Performance Modeling and Intelligent Control Strategies ebtehal s. hussain saja mohammed suhael doi: 10.56578/peet040105 Power Engineering and Engineering Thermophysics 03-30-2025 Power Engineering and Engineering Thermophysics 03-30-2025 2025 4 1 Article 58 10.56578/peet040105 https://www.acadlore.com/article/PEET/2025_4_1/peet040105 https://www.acadlore.com/article/PEET/2025_4_1/peet040104 Understanding thermal transport phenomena in porous structures is of fundamental importance across diverse sectors, including energy systems, construction, electronics, and biomedical engineering. In contrast to conventional dense solids, porous materials exhibit distinct thermal behaviors due to the intrinsic discontinuity between solid phases, pore geometry, and interfacial interactions. In this review, current advances in the understanding of heat transfer mechanisms—namely conduction, convection, and radiation—within porous media were systematically analyzed, with particular emphasis on the influence of porosity, pore morphology, and material composition on effective thermal conductivity. Both open- and closed-cell architectures were examined, and their respective roles in thermal transport were clarified in relation to practical applications. The predictive capability of numerical models was shown to improve significantly through the incorporation of local thermal equilibrium (LTE) and local thermal non-equilibrium (LTNE) models, as well as homogenization techniques. State-of-the-art experimental techniques employed for characterizing thermal transport in porous materials at micro- and nanoscales were also discussed, including steady-state and transient plane source (TPS) methods, along with high-resolution imaging techniques such as X-ray Computed Tomography (XCT) and electron microscopy. Emerging computational strategies, particularly the integration of reinforcement learning and machine learning (ML) algorithms into numerical and analytical models, were identified as promising tools for optimizing the thermal performance of porous structures. Furthermore, recent progress in the development of functional nanostructured and composite porous materials has enabled enhanced performance in applications such as thermal insulation, energy storage, and medical device design. Nonetheless, several critical challenges persist, particularly in experimental reproducibility, accurate model development, and the bridging of multi-scale effects. The strategic integration of artificial intelligence (AI) and data-driven design methodologies is anticipated to play a transformative role in advancing the next generation of porous materials for sustainable thermal management solutions. The findings underscore the necessity of porous structures in accelerating low-carbon technologies and achieving energy-efficient thermal transport systems. 03-30-2025 <![CDATA[ Understanding thermal transport phenomena in porous structures is of fundamental importance across diverse sectors, including energy systems, construction, electronics, and biomedical engineering. In contrast to conventional dense solids, porous materials exhibit distinct thermal behaviors due to the intrinsic discontinuity between solid phases, pore geometry, and interfacial interactions. In this review, current advances in the understanding of heat transfer mechanisms—namely conduction, convection, and radiation—within porous media were systematically analyzed, with particular emphasis on the influence of porosity, pore morphology, and material composition on effective thermal conductivity. Both open- and closed-cell architectures were examined, and their respective roles in thermal transport were clarified in relation to practical applications. The predictive capability of numerical models was shown to improve significantly through the incorporation of local thermal equilibrium (LTE) and local thermal non-equilibrium (LTNE) models, as well as homogenization techniques. State-of-the-art experimental techniques employed for characterizing thermal transport in porous materials at micro- and nanoscales were also discussed, including steady-state and transient plane source (TPS) methods, along with high-resolution imaging techniques such as X-ray Computed Tomography (XCT) and electron microscopy. Emerging computational strategies, particularly the integration of reinforcement learning and machine learning (ML) algorithms into numerical and analytical models, were identified as promising tools for optimizing the thermal performance of porous structures. Furthermore, recent progress in the development of functional nanostructured and composite porous materials has enabled enhanced performance in applications such as thermal insulation, energy storage, and medical device design. Nonetheless, several critical challenges persist, particularly in experimental reproducibility, accurate model development, and the bridging of multi-scale effects. The strategic integration of artificial intelligence (AI) and data-driven design methodologies is anticipated to play a transformative role in advancing the next generation of porous materials for sustainable thermal management solutions. The findings underscore the necessity of porous structures in accelerating low-carbon technologies and achieving energy-efficient thermal transport systems. ]]> Thermal Transport in Porous Structures: Mechanisms, Modeling Approaches, and Future Directions duraid thamer mahmood doi: 10.56578/peet040104 Power Engineering and Engineering Thermophysics 03-30-2025 Power Engineering and Engineering Thermophysics 03-30-2025 2025 4 1 Article 42 10.56578/peet040104 https://www.acadlore.com/article/PEET/2025_4_1/peet040104 https://www.acadlore.com/article/PEET/2025_4_1/peet040103 The stagnation point flow behavior of a micropolar nanofluid over an inclined stretching surface was numerically investigated. The formulation accounts for the combined effects of Brownian motion, thermophoresis, thermal radiation, velocity slip, and the presence of internal heat generation or absorption. The governing system of non-linear partial differential equations was transformed into a set of coupled ordinary differential equations through the application of appropriate similarity transformations. These transformed equations were solved numerically to analyze the behavior of the fluid near the stagnation region, where both the stretching velocity of the surface and the external free stream velocity are assumed to vary linearly with distance from the stagnation point. Special attention was paid to the influence of dimensionless parameters on key physical quantities, including skin friction coefficient, energy transfer, and Sherwood number. It was observed that increasing the stagnation point parameter leads to a reduction in skin friction, while the inclination angle demonstrates an opposing effect on heat and mass transfer rates. Data extracted from graphical results was tabulated to provide quantitative insights into the impact of varying parameters. The findings offer significant implications for microscale heat and mass transfer systems, particularly in processes involving inclined geometries and nanoparticle-enhanced fluids under magnetohydrodynamic (MHD) effects. 03-30-2025 <![CDATA[ The stagnation point flow behavior of a micropolar nanofluid over an inclined stretching surface was numerically investigated. The formulation accounts for the combined effects of Brownian motion, thermophoresis, thermal radiation, velocity slip, and the presence of internal heat generation or absorption. The governing system of non-linear partial differential equations was transformed into a set of coupled ordinary differential equations through the application of appropriate similarity transformations. These transformed equations were solved numerically to analyze the behavior of the fluid near the stagnation region, where both the stretching velocity of the surface and the external free stream velocity are assumed to vary linearly with distance from the stagnation point. Special attention was paid to the influence of dimensionless parameters on key physical quantities, including skin friction coefficient, energy transfer, and Sherwood number. It was observed that increasing the stagnation point parameter leads to a reduction in skin friction, while the inclination angle demonstrates an opposing effect on heat and mass transfer rates. Data extracted from graphical results was tabulated to provide quantitative insights into the impact of varying parameters. The findings offer significant implications for microscale heat and mass transfer systems, particularly in processes involving inclined geometries and nanoparticle-enhanced fluids under magnetohydrodynamic (MHD) effects. ]]> Numerical Analysis of Micropolar Nanofluid Flow near a Stagnation Point over an Inclined Stretching Surface pennelli saila kumari shaik mohammed ibrahim prathi vijaya kumar giulio lorenzini doi: 10.56578/peet040103 Power Engineering and Engineering Thermophysics 03-30-2025 Power Engineering and Engineering Thermophysics 03-30-2025 2025 4 1 Article 30 10.56578/peet040103 https://www.acadlore.com/article/PEET/2025_4_1/peet040103 https://www.acadlore.com/article/PEET/2025_4_1/peet040102 Solid oxide fuel cell/gas turbine (SOFC/GT) hybrid systems have been recognized as a promising solution in the pursuit of high-efficiency and low-emission power generation, offering electrical efficiencies exceeding 60% and notable fuel flexibility. However, the substantial amount of high-temperature exhaust gas (typically in the range of 700–800 K) released during operation has presented ongoing challenges in effective thermal energy recovery, thereby constraining further improvements in overall system efficiency. In recent years, various waste heat recovery technologies have been explored for their applicability to SOFC/GT systems. Among the most studied are the supercritical carbon dioxide (SCO₂) cycle, the transcritical carbon dioxide cycle (TRCC), the organic Rankine cycle (ORC), the Kalina cycle (KC), and the steam cycle (ST). In this review, the thermodynamic principles, performance metrics, and thermal integration compatibility associated with each technology were critically examined. In addition, a novel waste heat recovery configuration optimized for SOFC–GT hybrid systems was proposed and discussed. This approach was conceptually validated to enhance total system efficiency and to facilitate the development of advanced combined heat and power (CHP) systems. The results contribute to the broader efforts in clean energy system design and offer technical insights into the next generation of high-performance, low-emission power technologies. 03-30-2025 <![CDATA[ <p>Solid o<span>xide fuel cell/gas turbine (SOFC/GT) hybrid systems have been recognized as a promising solution in the pursuit of high-efficiency and low-emission power generation, offering electrical efficiencies exceeding 60% and notable fuel flexibility. However, the substantial amount of high-temperature exhaust gas (typically in the range of 700–800 K) released during operation has presented ongoing challenges in effective thermal energy recovery, thereby constraining further improvements in overall system efficiency. In recent years, various waste heat recovery technologies have been explored for their applicability to SOFC/GT systems. Among the most studied are the supercritical carbon dioxide (SCO₂) cycle, the transcritical carbon dioxide cycle (TRCC), the organic Rankine cycle (ORC), the Kalina cycle (KC), and the steam cycle (ST). In this review, the thermodynamic principles, performance metrics, and thermal integration compatibility associated with each technology were critically examined. In addition, a novel waste heat recovery configuration optimized for SOFC–GT hybrid systems was proposed and discussed. This approach was conceptually validated to enhance total system efficiency and to facilitate the development of advanced combined heat and power (CHP) systems. The results contribute to the broader efforts in clean energy system design and offer technical insights into the next generation of high-performance, low-emission power technologies.</span></p> ]]> Advances in Waste Heat Recovery Technologies for SOFC/GT Hybrid Systems luqi zhao hua li ningze jiang tianlong hong yan mao yuyao wang doi: 10.56578/peet040102 Power Engineering and Engineering Thermophysics 03-30-2025 Power Engineering and Engineering Thermophysics 03-30-2025 2025 4 1 Article 12 10.56578/peet040102 https://www.acadlore.com/article/PEET/2025_4_1/peet040102 https://www.acadlore.com/article/PEET/2025_4_1/peet040101 Phase change materials (PCMs), an innovative class of functional materials, exhibit the ability to store or release thermal energy through reversible transformations at specific phase transition temperatures, which have been extensively employed in aerospace, military, construction, and refrigeration industries. As oil and gas exploration and development word-widely advance into deeper formations, extremely high-temperature and high-pressure conditions in these environments impose significant challenges on drilling fluids and down-hole instruments, limiting the progress of deep hydrocarbon exploration. To address the technical challenges related to the high-temperature resistant stability of drilling fluids in deep formations, this study investigates the integration of PCMs into drilling fluids. Through theoretical analysis and experimental simulations, the feasibility of utilizing the "phase change heat storage principle" of PCMs to reduce circulating drilling fluid temperatures in boreholes was demonstrated. The results indicate that three selected PCMs exhibit phase transition temperatures in the range of 120–145℃ and phase change latent heat of 90.3–280.6 J/g, showcasing excellent phase change heat storage properties. The materials were found to be compatible with drilling fluids. At a PCM concentration of 12%, the rheological and filtration properties of the drilling fluids still met operational requirements. Incorporating PCMs into drilling fluids effectively reduced the circulating temperature in boreholes, with a more pronounced cooling effect observed at higher PCM concentrations. At a concentration of 12%, the circulating temperature of drilling fluids was reduced by up to 20℃. Additionally, the PCMs demonstrated good reusability, consistently undergoing the "heat storage and release" phase change process, thereby satisfying the circulating cooling demands of drilling fluids. The findings provide a robust reference for PCM integration in high-temperature drilling fluids, particularly in ultra-deep wells with extreme thermal conditions. 03-30-2025 <![CDATA[ <p>Phase change materials (PCMs), an innovative class of functional materials, exhibit the ability to store or release thermal energy through reversible transformations at specific phase transition temperatures, which have been extensively employed in aerospace, military, construction, and refrigeration industries. As oil and gas exploration and development word-widely advance into deeper formations, extremely high-temperature and high-pressure conditions in these environments impose significant challenges on drilling fluids and down-hole instruments, limiting the progress of deep hydrocarbon exploration. To address the technical challenges related to the high-temperature resistant stability of drilling fluids in deep formations, this study investigates the integration of PCMs into drilling fluids. Through theoretical analysis and experimental simulations, the feasibility of utilizing the "phase change heat storage principle" of PCMs to reduce circulating drilling fluid temperatures in boreholes was demonstrated. The results indicate that three selected PCMs exhibit phase transition temperatures in the range of 120–145℃ and phase change latent heat of 90.3–280.6 J/g, showcasing excellent phase change heat storage properties. The materials were found to be compatible with drilling fluids. At a PCM concentration of 12%, the rheological and filtration properties of the drilling fluids still met operational requirements. Incorporating PCMs into drilling fluids effectively reduced the circulating temperature in boreholes, with a more pronounced cooling effect observed at higher PCM concentrations. At a concentration of 12%, the circulating temperature of drilling fluids was reduced by up to 20℃. Additionally, the PCMs demonstrated good reusability, consistently undergoing the "heat storage and release" phase change process, thereby satisfying the circulating cooling demands of drilling fluids. The findings provide a robust reference for PCM integration in high-temperature drilling fluids, particularly in ultra-deep wells with extreme thermal conditions.</p> ]]> Study and Application of Phase Change Materials for Temperature Reduction in High-Temperature Deep-Well Drilling Fluids junyi liu ye xia doi: 10.56578/peet040101 Power Engineering and Engineering Thermophysics 03-30-2025 Power Engineering and Engineering Thermophysics 03-30-2025 2025 4 1 Article 1 10.56578/peet040101 https://www.acadlore.com/article/PEET/2025_4_1/peet040101 https://www.acadlore.com/article/PEET/2024_3_4/peet030405 The enhancement of heat transfer continues to be a critical objective across various high-performance applications, including electronics cooling, automotive thermal systems, and renewable energy systems. Among emerging passive and active strategies, oscillating fin technology has attracted growing interest due to its potential to disrupt thermal boundary layers and augment convective heat transfer. In this review, a systematic analysis of 120 peer-reviewed studies indexed in Scopus, Web of Science, and Google Scholar was conducted, employing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology to ensure transparency and reproducibility. Search terms such as “oscillating fins,” “heat transfer enhancement,” “numerical simulations,” and “experimental techniques” were used to capture the breadth of relevant literature. Emphasis was placed on the interplay between oscillation parameters—namely frequency, amplitude, and mode of oscillation—and fin geometry, with particular focus on their influence on local and average heat transfer coefficients. Numerical methodologies, including Computational Fluid Dynamics (CFD) and Finite Element Thermal Analysis (FETA), were utilized extensively to characterize fluid motion and thermal gradients around oscillating structures. The reliability of these simulations was critically assessed in light of experimental validations, with instrumentation precision and laboratory conditions considered as key metrics of model fidelity. Challenges related to continuous fin movement, mechanical fatigue, and manufacturing constraints were also identified. To address these issues, recent developments in fatigue-resistant composite materials and advanced fabrication techniques—such as additive manufacturing—were reviewed. Furthermore, the incorporation of novel materials, including porous metals, nanofluids, and piezoelectric components, was explored for their synergistic effects on thermal performance and system durability. This review not only consolidates the current understanding of oscillating fin mechanisms but also highlights gaps in knowledge and opportunities for future research in the development of high-efficiency thermal management systems. 12-30-2024 <![CDATA[ The enhancement of heat transfer continues to be a critical objective across various high-performance applications, including electronics cooling, automotive thermal systems, and renewable energy systems. Among emerging passive and active strategies, oscillating fin technology has attracted growing interest due to its potential to disrupt thermal boundary layers and augment convective heat transfer. In this review, a systematic analysis of 120 peer-reviewed studies indexed in Scopus, Web of Science, and Google Scholar was conducted, employing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology to ensure transparency and reproducibility. Search terms such as “oscillating fins,” “heat transfer enhancement,” “numerical simulations,” and “experimental techniques” were used to capture the breadth of relevant literature. Emphasis was placed on the interplay between oscillation parameters—namely frequency, amplitude, and mode of oscillation—and fin geometry, with particular focus on their influence on local and average heat transfer coefficients. Numerical methodologies, including Computational Fluid Dynamics (CFD) and Finite Element Thermal Analysis (FETA), were utilized extensively to characterize fluid motion and thermal gradients around oscillating structures. The reliability of these simulations was critically assessed in light of experimental validations, with instrumentation precision and laboratory conditions considered as key metrics of model fidelity. Challenges related to continuous fin movement, mechanical fatigue, and manufacturing constraints were also identified. To address these issues, recent developments in fatigue-resistant composite materials and advanced fabrication techniques—such as additive manufacturing—were reviewed. Furthermore, the incorporation of novel materials, including porous metals, nanofluids, and piezoelectric components, was explored for their synergistic effects on thermal performance and system durability. This review not only consolidates the current understanding of oscillating fin mechanisms but also highlights gaps in knowledge and opportunities for future research in the development of high-efficiency thermal management systems. ]]> Advances in Oscillating Fin Technologies for Heat Transfer Enhancement: A Review of Numerical and Experimental Approaches dheya ghanim mutasher doi: 10.56578/peet030405 Power Engineering and Engineering Thermophysics 12-30-2024 Power Engineering and Engineering Thermophysics 12-30-2024 2024 3 4 Article 279 10.56578/peet030405 https://www.acadlore.com/article/PEET/2024_3_4/peet030405 https://www.acadlore.com/article/PEET/2024_3_4/peet030404 The thermal performance and energy efficiency of Photovoltaic Thermal (PVT) systems were investigated through the integration of Phase Change Materials (PCMs) combined with distinct container configurations. Two types of PCMs—paraffin wax, an organic material, and Polyethylene Glycol 1000 (PEG-1000), a polymer-based alternative—were embedded within two container designs: a plain container and a baffled container. To evaluate the impact of PCM selection and container geometry on system performance, a series of numerical simulations were conducted using Computational Fluid Dynamics (CFD) in ANSYS Fluent under varying solar irradiance levels of 300, 600, 900, and 1200 W/m². The results revealed that PCM integration significantly mitigates the operating temperature of PV cells, contributing to enhanced thermal stability and electrical conversion efficiency. At the highest irradiance of 1200 W/m², the plain paraffin configuration attained a minimum cell temperature of 27.4℃ and achieved the highest electrical efficiency of 11.7%. Conversely, the baffled PEG-1000 configuration exhibited a slightly higher peak temperature of 28.1℃ with a corresponding efficiency of 11.18%. Although the baffled container promoted improved internal heat distribution, the plain configuration demonstrated superior overall thermal regulation. These findings underscore the critical influence of PCM thermal properties and container geometry on the operational sustainability of PVT systems. This study provides new insights into PCM-container coupling strategies, offering a valuable framework for the development of high-efficiency, sustainable solar energy systems. 12-30-2024 <![CDATA[ <p>The thermal performance and energy efficiency of Photovoltaic Thermal (PVT) systems were investigated through the integration of Phase Change Materials (PCMs) combined with distinct container configurations. Two types of PCMs—paraffin wax, an organic material, and Polyethylene Glycol 1000 (PEG-1000), a polymer-based alternative—were embedded within two container designs: a plain container and a baffled container. To evaluate the impact of PCM selection and container geometry on system performance, a series of numerical simulations were conducted using Computational Fluid Dynamics (CFD) in ANSYS Fluent under varying solar irradiance levels of 300, 600, 900, and 1200 W/m². The results revealed that PCM integration significantly mitigates the operating temperature of PV cells, contributing to enhanced thermal stability and electrical conversion efficiency. At the highest irradiance of 1200 W/m², the plain paraffin configuration attained a minimum cell temperature of 27.4℃ and achieved the highest electrical efficiency of 11.7%. Conversely, the baffled PEG-1000 configuration exhibited a slightly higher peak temperature of 28.1℃ with a corresponding efficiency of 11.18%. Although the baffled container promoted improved internal heat distribution, the plain configuration demonstrated superior overall thermal regulation. These findings underscore the critical influence of PCM thermal properties and container geometry on the operational sustainability of PVT systems. This study provides new insights into PCM-container coupling strategies, offering a valuable framework for the development of high-efficiency, sustainable solar energy systems.</p> ]]> Enhancing the Sustainability of PVT Systems through Optimized PCM Selection and Container Configuration: A CFD Approach royb fathur rizal misbahul munir doi: 10.56578/peet030404 Power Engineering and Engineering Thermophysics 12-30-2024 Power Engineering and Engineering Thermophysics 12-30-2024 2024 3 4 Article 266 10.56578/peet030404 https://www.acadlore.com/article/PEET/2024_3_4/peet030404 https://www.acadlore.com/article/PEET/2024_3_4/peet030403 The transition from outdated biomass boiler systems to modern, efficient district heating technologies represents a critical pathway toward sustainable energy production. In this study, the replacement of obsolete solid biomass-fueled boilers with a new wood chip-based heating system in the district heating plant of Pale, Bosnia and Herzegovina, was analyzed under real-world operational conditions. Historical operational data, including annual fuel consumption, were obtained directly from the facility. The degree-day method was applied to evaluate the thermal efficiency of the former heating system and to estimate the annual fuel demand for the newly installed wood chip-based infrastructure. A key component of this transition involves the reliability and efficiency of the wood chip supply chain. Therefore, the logistical feasibility of securing a continuous, local, and renewable wood chip fuel source was examined, including the assessment of storage capacity and supply chain resilience. Furthermore, a scenario-based simulation was conducted to project the cost of heat production under varying fuel price conditions and market dynamics. Through this integrated approach, a replicable methodology was proposed for replacing legacy biomass heating systems with environmentally sustainable, economically viable district heating technologies based on locally sourced wood chips. The findings offer a practical roadmap for municipalities aiming to achieve energy transition targets through the adoption of locally available renewable energy sources, with particular emphasis on operational feasibility, fuel logistics, and cost-effectiveness. 12-30-2024 <![CDATA[ <p>The transition from outdated biomass boiler systems to modern, efficient district heating technologies represents a critical pathway toward sustainable energy production. In this study, the replacement of obsolete solid biomass-fueled boilers with a new wood chip-based heating system in the district heating plant of Pale, Bosnia and Herzegovina, was analyzed under real-world operational conditions. Historical operational data, including annual fuel consumption, were obtained directly from the facility. The degree-day method was applied to evaluate the thermal efficiency of the former heating system and to estimate the annual fuel demand for the newly installed wood chip-based infrastructure. A key component of this transition involves the reliability and efficiency of the wood chip supply chain. Therefore, the logistical feasibility of securing a continuous, local, and renewable wood chip fuel source was examined, including the assessment of storage capacity and supply chain resilience. Furthermore, a scenario-based simulation was conducted to project the cost of heat production under varying fuel price conditions and market dynamics. Through this integrated approach, a replicable methodology was proposed for replacing legacy biomass heating systems with environmentally sustainable, economically viable district heating technologies based on locally sourced wood chips. The findings offer a practical roadmap for municipalities aiming to achieve energy transition targets through the adoption of locally available renewable energy sources, with particular emphasis on operational feasibility, fuel logistics, and cost-effectiveness.</p> ]]> Operational Analysis and Optimization of a District Heating Plant Using Wood Chips srđan vasković ljubiša tanić petar gvero azrudin husika doi: 10.56578/peet030403 Power Engineering and Engineering Thermophysics 12-30-2024 Power Engineering and Engineering Thermophysics 12-30-2024 2024 3 4 Article 254 10.56578/peet030403 https://www.acadlore.com/article/PEET/2024_3_4/peet030403 https://www.acadlore.com/article/PEET/2024_3_4/peet030402 The present paper emphasizes finding the solution for a fuzzy fractional heat conduction equation using the homotopy analysis transform method (HATM). The HATM combines two powerful, well-known methods: homotopy analysis method and the Laplace transform method. The approximate solution of the fuzzy fractional heat conduction equation is obtained by using HATM. Comparison with existing methods shows that the results obtained using the proposed method are in good agreement with the exact solutions available in the literature. All the numerical computations justify the proposed method is very efficient, effective, and simple for obtaining an approximate solution of the fuzzy time-fractional heat conduction equation. 12-30-2024 <![CDATA[ <p>The present paper emphasizes finding the solution for a fuzzy fractional heat conduction equation using the homotopy analysis transform method (HATM). The HATM combines two powerful, well-known methods: homotopy analysis method and the Laplace transform method. The approximate solution of the fuzzy fractional heat conduction equation is obtained by using HATM. Comparison with existing methods shows that the results obtained using the proposed method are in good agreement with the exact solutions available in the literature. All the numerical computations justify the proposed method is very efficient, effective, and simple for obtaining an approximate solution of the fuzzy time-fractional heat conduction equation.</p> ]]> Numerical Solution of Time-Fractional Heat Conduction Problem in a Fuzzy Environment shreya mukherjee amit kumar doi: 10.56578/peet030402 Power Engineering and Engineering Thermophysics 12-30-2024 Power Engineering and Engineering Thermophysics 12-30-2024 2024 3 4 Article 244 10.56578/peet030402 https://www.acadlore.com/article/PEET/2024_3_4/peet030402 https://www.acadlore.com/article/PEET/2024_3_4/peet030401 A novel approach for analyzing fluid flow dynamics and static pressure distributions within a convergent-divergent nozzle was presented, integrating soft computing techniques with computational fluid dynamics (CFD) simulations performed using Ansys Fluent. The study differs from traditional CFD approaches by leveraging soft computing methods to optimize simulation parameters and enhance the accuracy of predictions. Four distinct fluids—air, hydrogen, nitrogen, and helium—were analyzed across a range of inlet velocities (1 m/s to 5 m/s). The study systematically evaluates the influence of boundary conditions and flow models, including both viscous and inviscid conditions, on the flow patterns and static pressure distributions. The results highlight the substantial impact of fluid density and viscosity on the flow dynamics, particularly for lighter gases such as hydrogen and helium. These gases exhibit higher velocities and less pronounced pressure gradients due to their lower density and viscosity compared to denser fluids like air and nitrogen. Soft computing techniques improve the reliability of these findings by enhancing the predictive capability of the CFD model, allowing for more precise insights into complex fluid behaviors. The implications of these findings are significant across multiple engineering domains, such as aerospace propulsion, chemical processing, and energy systems, where optimizing fluid flow characteristics is critical. The integration of soft computing with CFD provides a robust framework for more accurate modelling of low-density, high-velocity flows and offers valuable insights for the design of more efficient systems. This study underscores the potential of advanced computational techniques in advancing both fluid dynamics research and engineering applications. 12-30-2024 <![CDATA[ <p>A novel approach for analyzing fluid flow dynamics and static pressure distributions within a convergent-divergent nozzle was presented, integrating soft computing techniques with computational fluid dynamics (CFD) simulations performed using Ansys Fluent. The study differs from traditional CFD approaches by leveraging soft computing methods to optimize simulation parameters and enhance the accuracy of predictions. Four distinct fluids—air, hydrogen, nitrogen, and helium—were analyzed across a range of inlet velocities (1 m/s to 5 m/s). The study systematically evaluates the influence of boundary conditions and flow models, including both viscous and inviscid conditions, on the flow patterns and static pressure distributions. The results highlight the substantial impact of fluid density and viscosity on the flow dynamics, particularly for lighter gases such as hydrogen and helium. These gases exhibit higher velocities and less pronounced pressure gradients due to their lower density and viscosity compared to denser fluids like air and nitrogen. Soft computing techniques improve the reliability of these findings by enhancing the predictive capability of the CFD model, allowing for more precise insights into complex fluid behaviors. The implications of these findings are significant across multiple engineering domains, such as aerospace propulsion, chemical processing, and energy systems, where optimizing fluid flow characteristics is critical. The integration of soft computing with CFD provides a robust framework for more accurate modelling of low-density, high-velocity flows and offers valuable insights for the design of more efficient systems. This study underscores the potential of advanced computational techniques in advancing both fluid dynamics research and engineering applications.</p> ]]> Analysis of Fluid Velocity and Static Pressure Dynamics in a Convergent-Divergent Nozzle: Integration of Soft Computing Techniques with CFD nindia nova novena zainal arifin catur harsito abram anggit mahadi mochamad subchan mauludin rafiel carino syahroni yuki trisnoaji singgih dwi prasetyo doi: 10.56578/peet030401 Power Engineering and Engineering Thermophysics 12-30-2024 Power Engineering and Engineering Thermophysics 12-30-2024 2024 3 4 Article 209 10.56578/peet030401 https://www.acadlore.com/article/PEET/2024_3_4/peet030401 https://www.acadlore.com/article/PEET/2024_3_3/peet030305 In this study, we investigate the heat and mass transfer characteristics of an unsteady mixed convection magnetohydrodynamic (MHD) flow of Casson fluid through a porous medium in the presence of thermal diffusion and heat source effects. The flow is considered between isothermal inclined plates, incorporating the influences of Joule heating and viscous dissipation. Using dimensionless variables, the governing partial differential equations are transformed into their dimensionless form. The resulting dimensionless equations are solved empirically through the perturbation methodology. The effects of various critical parameters on the velocity, temperature, and concentration distributions within the boundary layer are analyzed with the aid of graphical representations. Additionally, numerical values of skin friction, Nusselt number, and Sherwood number near the plate are examined for different parameter values and presented in tabular form. The findings provide a deeper understanding of heat and mass transfer mechanisms in MHD flows through porous media, which are relevant to various industrial and engineering applications. 09-29-2024 <![CDATA[ In this study, we investigate the heat and mass transfer characteristics of an unsteady mixed convection magnetohydrodynamic (MHD) flow of Casson fluid through a porous medium in the presence of thermal diffusion and heat source effects. The flow is considered between isothermal inclined plates, incorporating the influences of Joule heating and viscous dissipation. Using dimensionless variables, the governing partial differential equations are transformed into their dimensionless form. The resulting dimensionless equations are solved empirically through the perturbation methodology. The effects of various critical parameters on the velocity, temperature, and concentration distributions within the boundary layer are analyzed with the aid of graphical representations. Additionally, numerical values of skin friction, Nusselt number, and Sherwood number near the plate are examined for different parameter values and presented in tabular form. The findings provide a deeper understanding of heat and mass transfer mechanisms in MHD flows through porous media, which are relevant to various industrial and engineering applications. ]]> Analysis of Heat and Mass Transfer in Unsteady Magnetohydrodynamic MHD Casson Fluid Flow over Isothermal Inclined Plates with Thermal Diffusion and Heat Source Effects sivaramakrishna valiveti madhavi jetti madhavi reddy yallalla raghunath kodi giulio lorenzini doi: 10.56578/peet030305 Power Engineering and Engineering Thermophysics 09-29-2024 Power Engineering and Engineering Thermophysics 09-29-2024 2024 3 3 Article 195 10.56578/peet030305 https://www.acadlore.com/article/PEET/2024_3_3/peet030305 https://www.acadlore.com/article/PEET/2024_3_3/peet030304 The concept of heat commodification is proposed as a sustainable solution for global energy management, with heat being treated as a tradable commodity in an international market. In such a market, heat would be assigned a value based on factors such as available enthalpy, heat grade (temperature), and the time at which it is delivered. Heat, as the currency of this market, would allow for a decentralized and dynamic exchange system. A central heat market could be established, extending down to individual households where excess heat—such as waste heat from household appliances—could be stored and traded locally, potentially through a peer-to-peer model or a virtual marketplace. A key innovation in this system would be the development of modular heat storage solutions, analogous to gas bottles, that allow consumers to store excess heat and exchange it within the market. These “heat packets" would be rechargeable with heat, as opposed to gas, and could be traded both physically or digitally. To ensure inclusivity and sustainability, it is suggested that these heat packets be based on nature-inspired storage materials that can efficiently store renewable or waste heat with minimal environmental impact. Specifically, thermochemical storage media, such as salt, would be employed to facilitate charging and discharging processes using water as a trigger. Such solid-state storage systems would allow heat to be stored indefinitely with minimal heat loss to the environment, even in lower temperature conditions. This paradigm shift could enable the cross-continental transport of heat packets, revolutionizing the global energy market. The proposed system would also eliminate the need for electricity grids and reduce inefficiencies associated with energy conversion, as heat can be stored and utilized directly for both heating and cooling applications. Furthermore, the reliance on heat-driven refrigeration systems would obviate the need for electricity-driven heat pumps or chillers. This approach offers a potential solution to global energy challenges by facilitating a sustainable and efficient heat exchange network on a global scale. 09-29-2024 <![CDATA[ <p>The concept of heat commodification is proposed as a sustainable solution for global energy management, with heat being treated as a tradable commodity in an international market. In such a market, heat would be assigned a value based on factors such as available enthalpy, heat grade (temperature), and the time at which it is delivered. Heat, as the currency of this market, would allow for a decentralized and dynamic exchange system. A central heat market could be established, extending down to individual households where excess heat—such as waste heat from household appliances—could be stored and traded locally, potentially through a peer-to-peer model or a virtual marketplace. A key innovation in this system would be the development of modular heat storage solutions, analogous to gas bottles, that allow consumers to store excess heat and exchange it within the market. These “heat packets" would be rechargeable with heat, as opposed to gas, and could be traded both physically or digitally. To ensure inclusivity and sustainability, it is suggested that these heat packets be based on nature-inspired storage materials that can efficiently store renewable or waste heat with minimal environmental impact. Specifically, thermochemical storage media, such as salt, would be employed to facilitate charging and discharging processes using water as a trigger. Such solid-state storage systems would allow heat to be stored indefinitely with minimal heat loss to the environment, even in lower temperature conditions. This paradigm shift could enable the cross-continental transport of heat packets, revolutionizing the global energy market. The proposed system would also eliminate the need for electricity grids and reduce inefficiencies associated with energy conversion, as heat can be stored and utilized directly for both heating and cooling applications. Furthermore, the reliance on heat-driven refrigeration systems would obviate the need for electricity-driven heat pumps or chillers. This approach offers a potential solution to global energy challenges by facilitating a sustainable and efficient heat exchange network on a global scale.</p> ]]> Heat Commodification for a Sustainable Energy Future kamel hooman doi: 10.56578/peet030304 Power Engineering and Engineering Thermophysics 09-29-2024 Power Engineering and Engineering Thermophysics 09-29-2024 2024 3 3 Article 189 10.56578/peet030304 https://www.acadlore.com/article/PEET/2024_3_3/peet030304 https://www.acadlore.com/article/PEET/2024_3_3/peet030303 Water-cooled heat sinks are efficient cooling solutions for high-heat dissipation applications in industrial and electronic systems. This study investigates water-cooled heat sinks' thermal and hydrodynamic performance through Computational Fluid Dynamics (CFD) simulations. The fluid flow distribution, heat transfer characteristics, and thermal efficiency of various cooling channel geometries were examined under controlled conditions, including a mass flow rate of 0.05 kg/s, an inlet fluid temperature of 22℃, and a convection film coefficient of 80 W/m²℃ between the fluid and heat sink. Additionally, the convection coefficient between the heat sink body and its fins to the environment was set at 10 W/m²℃, with an ambient temperature of 22℃ and a heat flux of 10,000 W/m² applied to the heat sink's base. The analysis reveals that the coolant channel geometry, flow velocity, and the materials' thermophysical properties strongly influence the system's thermal performance and pressure drop. The optimized channel configuration significantly enhanced the heat dissipation efficiency, achieving an increase of 49.1% and a temperature reduction of 59℃. Furthermore, a thermal efficiency of 40.97% and an overall system efficiency of 45.04% were attained. These findings highlight the substantial role of optimized channel geometries in enhancing the performance of water-cooled heat sinks, leading to more efficient and effective cooling systems. The study demonstrates that CFD simulations can be a powerful tool in identifying key design parameters that maximize heat transfer efficiency in water-cooled heat sinks. 09-29-2024 <![CDATA[ <p>Water-cooled heat sinks are efficient cooling solutions for high-heat dissipation applications in industrial and electronic systems. This study investigates water-cooled heat sinks' thermal and hydrodynamic performance through Computational Fluid Dynamics (CFD) simulations. The fluid flow distribution, heat transfer characteristics, and thermal efficiency of various cooling channel geometries were examined under controlled conditions, including a mass flow rate of 0.05 kg/s, an inlet fluid temperature of 22℃, and a convection film coefficient of 80 W/m²℃ between the fluid and heat sink. Additionally, the convection coefficient between the heat sink body and its fins to the environment was set at 10 W/m²℃, with an ambient temperature of 22℃ and a heat flux of 10,000 W/m² applied to the heat sink's base. The analysis reveals that the coolant channel geometry, flow velocity, and the materials' thermophysical properties strongly influence the system's thermal performance and pressure drop. The optimized channel configuration significantly enhanced the heat dissipation efficiency, achieving an increase of 49.1% and a temperature reduction of 59℃. Furthermore, a thermal efficiency of 40.97% and an overall system efficiency of 45.04% were attained. These findings highlight the substantial role of optimized channel geometries in enhancing the performance of water-cooled heat sinks, leading to more efficient and effective cooling systems. The study demonstrates that CFD simulations can be a powerful tool in identifying key design parameters that maximize heat transfer efficiency in water-cooled heat sinks.</p> ]]> Thermal and Hydrodynamic Performance Analysis of Water-Cooled Heat Sinks Using Aluminum and Structural Steel Materials daffa’ fuad hanan gilang maulana lazuardi yuki trisnoaji singgih dwi prasetyo mochamad subchan mauludin catur harsito abram anggit mahadi zainal arifin doi: 10.56578/peet030303 Power Engineering and Engineering Thermophysics 09-29-2024 Power Engineering and Engineering Thermophysics 09-29-2024 2024 3 3 Article 176 10.56578/peet030303 https://www.acadlore.com/article/PEET/2024_3_3/peet030303 https://www.acadlore.com/article/PEET/2024_3_3/peet030302 To investigate the variation in the diffusion patterns of natural gas leaks in the Floating Production Storage and Offloading (FPSO) system, with the aim of formulating appropriate emergency response strategies and minimizing accident losses, a study was conducted on the gas leak issues of oil and gas processing equipment in the FPSO upper module. A consequence prediction and assessment model was established based on Computational Fluid Dynamics (CFD) methods. Sixteen working conditions and one control working condition were developed to simulate the diffusion characteristics of combustible gas leaks. The simulations provided insights into the gas leakage patterns under different conditions and identified the most hazardous scenario for gas leaks in the FPSO upper module. The results indicate that the density and shape of the equipment within the upper module significantly influence the diffusion outcome. After a leak, high concentrations of combustible gas were observed near the crude oil heat exchanger skid in Industrial Zone II. The effects of individual factors on gas diffusion were significant, and the interactions among multiple factors were complex. Wind speed had a more pronounced effect on longitudinal gas diffusion compared to wind direction and leak aperture, while wind direction significantly influenced lateral gas diffusion. The leak aperture, on the other hand, had a more substantial impact on vertical gas diffusion. 09-19-2024 <![CDATA[ <p>To investigate the variation in the diffusion patterns of natural gas leaks in the Floating Production Storage and Offloading (FPSO) system, with the aim of formulating appropriate emergency response strategies and minimizing accident losses, a study was conducted on the gas leak issues of oil and gas processing equipment in the FPSO upper module. A consequence prediction and assessment model was established based on Computational Fluid Dynamics (CFD) methods. Sixteen working conditions and one control working condition were developed to simulate the diffusion characteristics of combustible gas leaks. The simulations provided insights into the gas leakage patterns under different conditions and identified the most hazardous scenario for gas leaks in the FPSO upper module. The results indicate that the density and shape of the equipment within the upper module significantly influence the diffusion outcome. After a leak, high concentrations of combustible gas were observed near the crude oil heat exchanger skid in Industrial Zone II. The effects of individual factors on gas diffusion were significant, and the interactions among multiple factors were complex. Wind speed had a more pronounced effect on longitudinal gas diffusion compared to wind direction and leak aperture, while wind direction significantly influenced lateral gas diffusion. The leak aperture, on the other hand, had a more substantial impact on vertical gas diffusion.</p> ]]> Diffusion Characteristics of Combustible Gas Leaks in the FPSO Upper Module longting wang yaonan wu zhen long zimo liu zhihui liu zhang shi yanqun yu doi: 10.56578/peet030302 Power Engineering and Engineering Thermophysics 09-19-2024 Power Engineering and Engineering Thermophysics 09-19-2024 2024 3 3 Article 158 10.56578/peet030302 https://www.acadlore.com/article/PEET/2024_3_3/peet030302 https://www.acadlore.com/article/PEET/2024_3_3/peet030301 The thermal behavior and fluid dynamics of Nano-Enhanced Phase Change Materials (NEPCM) in enclosed systems have been investigated using numerical simulations, focusing on the effects of time-varying temperature profiles and nanoparticle concentration. The analysis reveals that the inclusion of nanoparticles significantly enhances the fluid flow velocity and streamlining within the enclosure, particularly for aluminium oxide (Al2O3), copper oxide (CuO), and zinc oxide (ZnO) nanoparticles. The results indicate that an increase in nanoparticle concentration leads to an acceleration in fluid flow and improved heat transfer efficiency, with distinct phase change dynamics observed across different concentrations. The study demonstrates that nanomaterials hold substantial potential for enhancing the thermal performance of NEPCM systems. These enhancements can contribute to greater efficiency in thermal energy storage (TES) and heat transfer processes, particularly in industrial applications requiring energy optimization. The findings align with previous research, emphasizing the positive correlation between nanoparticle concentration and velocity streamlining. This work provides valuable insights for the future exploration of different nanoparticle types and concentrations, paving the way for the development of more efficient NEPCM systems in advanced thermal systems. 09-14-2024 <![CDATA[ <p><span>The thermal behavior and fluid dynamics of Nano-Enhanced Phase Change Materials (NEPCM) in enclosed systems have been investigated using numerical simulations, focusing on the effects of time-varying temperature profiles and nanoparticle concentration. The analysis reveals that the inclusion of nanoparticles significantly enhances the fluid flow velocity and streamlining within the enclosure, particularly for aluminium oxide (Al</span>_{<span>2</span>}<span>O</span>_{<span>3</span>}<span>), copper oxide (CuO), and zinc oxide (ZnO) nanoparticles. The results indicate that an increase in nanoparticle concentration leads to an acceleration in fluid flow and improved heat transfer efficiency, with distinct phase change dynamics observed across different concentrations. The study demonstrates that nanomaterials hold substantial potential for enhancing the thermal performance of NEPCM systems. These enhancements can contribute to greater efficiency in thermal energy storage (TES) and heat transfer processes, particularly in industrial applications requiring energy optimization. The findings align with previous research, emphasizing the positive correlation between nanoparticle concentration and velocity streamlining. This work provides valuable insights for the future exploration of different nanoparticle types and concentrations, paving the way for the development of more efficient NEPCM systems in advanced thermal systems.</span></p> ]]> Numerical Analysis of Time-Varying Temperature Profiles and Nanoparticle Concentration Effects on Nano-Enhanced Phase Change Materials in Enclosed Systems mohammed abdulritha khazaa alireza daneh-dezfuli laith jaafer habeeb doi: 10.56578/peet030301 Power Engineering and Engineering Thermophysics 09-14-2024 Power Engineering and Engineering Thermophysics 09-14-2024 2024 3 3 Article 148 10.56578/peet030301 https://www.acadlore.com/article/PEET/2024_3_3/peet030301 https://www.acadlore.com/article/PEET/2024_3_2/peet030205 The performance of open-type refrigerated display cabinets has been rigorously examined through the development and application of two comprehensive block schemes, which integrate numerical simulations with experimental research. Central to these schemes is the use of a simplified two-dimensional, time-dependent computational fluid dynamics (CFD) model, designed to evaluate and optimize airflow patterns, thermal behavior, and energy efficiency within the cabinets. The numerical simulations, validated against experimental data, demonstrate that the strategic design and configuration of air curtains and internal components significantly mitigate the impact of ambient air, thereby reducing temperature fluctuations that are critical for maintaining food quality and safety. The application of these block schemes has been shown to enhance energy efficiency and reduce electrical consumption, contributing to operational cost savings. The strong correlation between CFD results and experimental findings underscores the reliability of these models for accurately representing real-world conditions. Future investigations could benefit from exploring additional geometric configurations and incorporating more advanced CFD techniques to further refine the performance of refrigerated display systems. This integrated approach offers a robust framework for improving the operational effectiveness and food preservation capabilities of open-type refrigerated display cabinets. 06-29-2024 <![CDATA[ The performance of open-type refrigerated display cabinets has been rigorously examined through the development and application of two comprehensive block schemes, which integrate numerical simulations with experimental research. Central to these schemes is the use of a simplified two-dimensional, time-dependent computational fluid dynamics (CFD) model, designed to evaluate and optimize airflow patterns, thermal behavior, and energy efficiency within the cabinets. The numerical simulations, validated against experimental data, demonstrate that the strategic design and configuration of air curtains and internal components significantly mitigate the impact of ambient air, thereby reducing temperature fluctuations that are critical for maintaining food quality and safety. The application of these block schemes has been shown to enhance energy efficiency and reduce electrical consumption, contributing to operational cost savings. The strong correlation between CFD results and experimental findings underscores the reliability of these models for accurately representing real-world conditions. Future investigations could benefit from exploring additional geometric configurations and incorporating more advanced CFD techniques to further refine the performance of refrigerated display systems. This integrated approach offers a robust framework for improving the operational effectiveness and food preservation capabilities of open-type refrigerated display cabinets. ]]> Optimizing the Performance of Open-Type Refrigerated Display Cabinets: Block Schemes and Key Tasks tadas vengalis doi: 10.56578/peet030205 Power Engineering and Engineering Thermophysics 06-29-2024 Power Engineering and Engineering Thermophysics 06-29-2024 2024 3 2 Article 134 10.56578/peet030205 https://www.acadlore.com/article/PEET/2024_3_2/peet030205 https://www.acadlore.com/article/PEET/2024_3_2/peet030204 The study aimed to compare the effects of thermal stratification ($S$), anisotropic parameters ($k^*$ and $\theta$), and buoyancy force distribution parameter ($m^*$) on natural convection in fluids characterized by high and low Prandtl numbers. The second-order coupled partial differential equations governing the problem were initially converted into ordinary differential equations through the Laplace transform technique. The D'Alembert method was then applied to systematically decouple these equations without altering their original order. Subsequently, the closed-form solutions in the Laplace domain were transformed into their respective time domains using a numerical scheme based on the Riemann sum algorithm. The research established that reverse flow is feasible under certain conditions, occurring more rapidly in fluids with lower Prandtl numbers. Additionally, it was observed that an increase in $k^*$ and $S$ reduces skin friction on the bounding plates, whereas an increase in $\theta$ enhances skin friction on both channel walls. 06-29-2024 <![CDATA[ <p>The study aimed to compare the effects of thermal stratification ($S$), anisotropic parameters ($k^*$ and $\theta$), and buoyancy force distribution parameter ($m^*$) on natural convection in fluids characterized by high and low Prandtl numbers. The second-order coupled partial differential equations governing the problem were initially converted into ordinary differential equations through the Laplace transform technique. The D'Alembert method was then applied to systematically decouple these equations without altering their original order. Subsequently, the closed-form solutions in the Laplace domain were transformed into their respective time domains using a numerical scheme based on the Riemann sum algorithm. The research established that reverse flow is feasible under certain conditions, occurring more rapidly in fluids with lower Prandtl numbers. Additionally, it was observed that an increase in $k^*$ and $S$ reduces skin friction on the bounding plates, whereas an increase in $\theta$ enhances skin friction on both channel walls.</p> ]]> Natural Convection Flow in a Thermally Stratified Fluid Through an Asymmetrically Heated and Cooled Vertical Channel with Anisotropic Porous Material basant k. jha muhammad k. musa abiodun o. ajibade doi: 10.56578/peet030204 Power Engineering and Engineering Thermophysics 06-29-2024 Power Engineering and Engineering Thermophysics 06-29-2024 2024 3 2 Article 116 10.56578/peet030204 https://www.acadlore.com/article/PEET/2024_3_2/peet030204 https://www.acadlore.com/article/PEET/2024_3_2/peet030203 The provision of fresh, drinkable water is essential for human survival. Solar stills, devices that utilize solar energy to produce pure water, face the disadvantage of low productivity. This study proposes a novel solar still design aimed at enhancing thermal performance through the incorporation of stepped types and additional modifications, such as the integration of magnets, to further augment thermal efficiency. Experimental evaluations were conducted outdoors under the climatic conditions of Thi-Qar throughout the year 2023. The findings indicate that solar stills with the innovative stepped design achieved a productivity increase of 39.329% and 31.745%, respectively, compared to conventional designs. Furthermore, the inclusion of magnets resulted in an additional enhancement of 136.2% in productivity compared to the same design without magnets. Solar evaporation is highly regarded for passive water desalination due to its abundant resources, high efficiency, and lack of carbon emissions. Recent advancements have seen the development of bio-inspired solar evaporators that efficiently harvest solar energy and convert it into heat. However, challenges persist regarding the relatively low freshwater production rate and harvesting efficiency. Key areas for improvement include the absorption properties of the evaporator material and the evaporation efficiency of saline water. Water evaporation primarily occurs at the top surface of saline water, with the rate significantly influenced by the temperature difference between the evaporating surface and the surrounding atmosphere. To achieve a substantial temperature difference, broad-band solar absorbers with advanced microstructures have been designed to enhance solar absorptance and minimize heat loss via radiation on evaporating surfaces. Despite the development of sophisticated photothermal materials and evaporators, practical solar evaporation under simple fabrication processes remains elusive. 06-24-2024 <![CDATA[ <p>The provision of fresh, drinkable water is essential for human survival. Solar stills, devices that utilize solar energy to produce pure water, face the disadvantage of low productivity. This study proposes a novel solar still design aimed at enhancing thermal performance through the incorporation of stepped types and additional modifications, such as the integration of magnets, to further augment thermal efficiency. Experimental evaluations were conducted outdoors under the climatic conditions of Thi-Qar throughout the year 2023. The findings indicate that solar stills with the innovative stepped design achieved a productivity increase of 39.329% and 31.745%, respectively, compared to conventional designs. Furthermore, the inclusion of magnets resulted in an additional enhancement of 136.2% in productivity compared to the same design without magnets. Solar evaporation is highly regarded for passive water desalination due to its abundant resources, high efficiency, and lack of carbon emissions. Recent advancements have seen the development of bio-inspired solar evaporators that efficiently harvest solar energy and convert it into heat. However, challenges persist regarding the relatively low freshwater production rate and harvesting efficiency. Key areas for improvement include the absorption properties of the evaporator material and the evaporation efficiency of saline water. Water evaporation primarily occurs at the top surface of saline water, with the rate significantly influenced by the temperature difference between the evaporating surface and the surrounding atmosphere. To achieve a substantial temperature difference, broad-band solar absorbers with advanced microstructures have been designed to enhance solar absorptance and minimize heat loss via radiation on evaporating surfaces. Despite the development of sophisticated photothermal materials and evaporators, practical solar evaporation under simple fabrication processes remains elusive.</p> ]]> Experimental Evaluation of Stepped Solar Stills Augmented with Magnets as Granular Porous Media alaa m. lafta karima e. amori mustafa m. mansour doi: 10.56578/peet030203 Power Engineering and Engineering Thermophysics 06-24-2024 Power Engineering and Engineering Thermophysics 06-24-2024 2024 3 2 Article 103 10.56578/peet030203 https://www.acadlore.com/article/PEET/2024_3_2/peet030203 https://www.acadlore.com/article/PEET/2024_3_2/peet030202 The increasing shift towards sustainable and net-zero targets has heightened interest in substituting hydrogen for natural gas in gas turbines and combined cycle power plants. This study investigates the compressibility of hydrogen within gas compressors, situated upstream of gas turbines, particularly when blended with various gases. Emphasis was placed on the inherent properties of hydrogen, including its behavior under compression, susceptibility to material embrittlement, and the influence of its gas characteristics on compressor performance. An extensive examination of prevalent compression methods, notably centrifugal compressors, was conducted to evaluate their efficacy in managing hydrogen at varying blend ratios. Issues related to material compatibility and safety were highlighted, alongside the formulation of reliable compression processes crucial for hydrogen-rich gas mixtures. Operational challenges posed by different hydrogen fuel proportions were identified, with proposed solutions including the implementation of precision control systems or the introduction of innovative materials. The study culminates in a discussion on prospective research directions and necessary technologies for effective hydrogen-rich gasification compression technology. The findings offer critical insights for ongoing initiatives aimed at enhancing and promoting hydrogen compression technology, facilitating the integration of hydrogen into existing infrastructures and supporting the sustainable development of the energy sector. 06-19-2024 <![CDATA[ <p>The increasing shift towards sustainable and net-zero targets has heightened interest in substituting hydrogen for natural gas in gas turbines and combined cycle power plants. This study investigates the compressibility of hydrogen within gas compressors, situated upstream of gas turbines, particularly when blended with various gases. Emphasis was placed on the inherent properties of hydrogen, including its behavior under compression, susceptibility to material embrittlement, and the influence of its gas characteristics on compressor performance. An extensive examination of prevalent compression methods, notably centrifugal compressors, was conducted to evaluate their efficacy in managing hydrogen at varying blend ratios. Issues related to material compatibility and safety were highlighted, alongside the formulation of reliable compression processes crucial for hydrogen-rich gas mixtures. Operational challenges posed by different hydrogen fuel proportions were identified, with proposed solutions including the implementation of precision control systems or the introduction of innovative materials. The study culminates in a discussion on prospective research directions and necessary technologies for effective hydrogen-rich gasification compression technology. The findings offer critical insights for ongoing initiatives aimed at enhancing and promoting hydrogen compression technology, facilitating the integration of hydrogen into existing infrastructures and supporting the sustainable development of the energy sector.</p> ]]> Challenges in Compressing Hydrogen-Blended Gas for Gas Turbine Power Plants daido fujita takahiko miyazaki doi: 10.56578/peet030202 Power Engineering and Engineering Thermophysics 06-19-2024 Power Engineering and Engineering Thermophysics 06-19-2024 2024 3 2 Article 92 10.56578/peet030202 https://www.acadlore.com/article/PEET/2024_3_2/peet030202 https://www.acadlore.com/article/PEET/2024_3_2/peet030201 As populations expand and cities grow, the horizontal development of sustainable initiatives, coupled with the preservation of natural resources and the shift towards agricultural ventures, has led to an increased necessity for road lighting to mitigate traffic accidents. The burgeoning field of photovoltaic (PV) energy is significantly altering the energy paradigm, gaining prominence within regional energy mixes and power systems. This study presents an examination of various off-grid solar PV system designs for the illumination of the Kuwaiti roundabout, highlighting the distinct differences among these approaches. Through mathematical modeling and subsequent validation via PVsyst software, the focus is placed on sophisticated light emitting diode (LED) street lighting systems featuring automatic controls powered by solar energy. LEDs, acclaimed for their energy efficiency and longevity, are progressively supplanting traditional lighting technologies worldwide. This investigation explores multiple system configurations, transitioning from centralized systems employing sodium flashlights to autonomous systems with LED lamps. Key challenges such as power consumption, spatial limitations, and network load considerations are addressed. Innovative solutions including dual-voltage lamps and charge controllers are introduced, pinpointing optimal design strategies for roadway applications, which have implications for sustainable urban lighting paradigms. Additionally, the proposal of a solar-powered searchlight underscores potential cost-effectiveness, reflecting the continuous evolution of solar lighting technologies. Collectively, the findings underscore the crucial role of comprehensive design considerations in achieving efficient and sustainable lighting solutions within urban settings. 06-12-2024 <![CDATA[ <p>As populations expand and cities grow, the horizontal development of sustainable initiatives, coupled with the preservation of natural resources and the shift towards agricultural ventures, has led to an increased necessity for road lighting to mitigate traffic accidents. The burgeoning field of photovoltaic (PV) energy is significantly altering the energy paradigm, gaining prominence within regional energy mixes and power systems. This study presents an examination of various off-grid solar PV system designs for the illumination of the Kuwaiti roundabout, highlighting the distinct differences among these approaches. Through mathematical modeling and subsequent validation via PVsyst software, the focus is placed on sophisticated light emitting diode (LED) street lighting systems featuring automatic controls powered by solar energy. LEDs, acclaimed for their energy efficiency and longevity, are progressively supplanting traditional lighting technologies worldwide. This investigation explores multiple system configurations, transitioning from centralized systems employing sodium flashlights to autonomous systems with LED lamps. Key challenges such as power consumption, spatial limitations, and network load considerations are addressed. Innovative solutions including dual-voltage lamps and charge controllers are introduced, pinpointing optimal design strategies for roadway applications, which have implications for sustainable urban lighting paradigms. Additionally, the proposal of a solar-powered searchlight underscores potential cost-effectiveness, reflecting the continuous evolution of solar lighting technologies. Collectively, the findings underscore the crucial role of comprehensive design considerations in achieving efficient and sustainable lighting solutions within urban settings.</p> ]]> Photovoltaic Solar Energy for Street Lighting: A Case Study at Kuwaiti Roundabout, Gaza Strip, Palestine hala j. el-khozondar ahmed a. asfour yasser f. nassar saleh w. shaheen mahmoud f. el-zaety rifa j. el-khozondar mohamed m. khaleel abdussalm a. ahmed abdulgader h. alsharif doi: 10.56578/peet030201 Power Engineering and Engineering Thermophysics 06-12-2024 Power Engineering and Engineering Thermophysics 06-12-2024 2024 3 2 Article 77 10.56578/peet030201 https://www.acadlore.com/article/PEET/2024_3_2/peet030201 https://www.acadlore.com/article/PEET/2024_3_1/peet030105 An evaluation of renewable energy system (RES) adoption in Hopedale, Newfoundland and Labrador, was conducted with the focus on developing a robust hybrid microgrid system. Situated in a remote area distinguished by its severe weather and rich cultural history, Hopedale primarily relies on diesel generators for energy, presenting unique challenges including high energy costs and significant environmental impacts. The current reliance on three diesel generators for electrical needs underscores the necessity for a shift towards sustainable energy. Hybrid Optimization of Multiple Energy Resources (HOMER) Pro simulations were employed in this study to analyze a proposed system integrating solar and wind power, battery storage, and an additional diesel generator. The system's design aims to reduce dependency on fossil fuels amidst increasing environmental concerns and fossil fuel limitations. The environmental performance and cost-effectiveness of combining solar and wind energy with battery storage and a diesel backup were assessed. The hybrid system's potential to decrease carbon emissions by over 50% compared to the existing diesel-only setup is demonstrated, suggesting a substantial reduction in greenhouse gas emissions. Although the economic Levelized Cost of Energy (LCOE) of \$0.182 per kWh is higher than the traditional diesel cost of $0.16 per kWh, it represents a strategic commitment to environmental sustainability. A Net Present Cost (NPC) of \$14.6 million was predicted for the system, encompassing Capital Expenditure (CAPEX), Operational Expenditure (OPEX), and replacement cost over 25 years. Significant reductions in environmental impact and notable operational savings were anticipated. These findings contribute valuable insights into the benefits of hybrid microgrids for remote communities, offering a model for energy resilience, cost savings, and reduced carbon footprints. Thus, the study adds significant information to the ongoing discourse on sustainable energy solutions for isolated locations. 03-30-2024 <![CDATA[ <p>An evaluation of renewable energy system (RES) adoption in Hopedale, Newfoundland and Labrador, was conducted with the focus on developing a robust hybrid microgrid system. Situated in a remote area distinguished by its severe weather and rich cultural history, Hopedale primarily relies on diesel generators for energy, presenting unique challenges including high energy costs and significant environmental impacts. The current reliance on three diesel generators for electrical needs underscores the necessity for a shift towards sustainable energy. Hybrid Optimization of Multiple Energy Resources (HOMER) Pro simulations were employed in this study to analyze a proposed system integrating solar and wind power, battery storage, and an additional diesel generator. The system's design aims to reduce dependency on fossil fuels amidst increasing environmental concerns and fossil fuel limitations. The environmental performance and cost-effectiveness of combining solar and wind energy with battery storage and a diesel backup were assessed. The hybrid system's potential to decrease carbon emissions by over 50% compared to the existing diesel-only setup is demonstrated, suggesting a substantial reduction in greenhouse gas emissions. Although the economic Levelized Cost of Energy (LCOE) of \$0.182 per kWh is higher than the traditional diesel cost of $0.16 per kWh, it represents a strategic commitment to environmental sustainability. A Net Present Cost (NPC) of \$14.6 million was predicted for the system, encompassing Capital Expenditure (CAPEX), Operational Expenditure (OPEX), and replacement cost over 25 years. Significant reductions in environmental impact and notable operational savings were anticipated. These findings contribute valuable insights into the benefits of hybrid microgrids for remote communities, offering a model for energy resilience, cost savings, and reduced carbon footprints. Thus, the study adds significant information to the ongoing discourse on sustainable energy solutions for isolated locations.</p> ]]> Enhancing Sustainability in Hopedale, Newfoundland and Labrador, Through Hybrid Microgrid System Design afreen maliat siddhanth kotian samaneh shirinnezhad davoud ghahremanlou doi: 10.56578/peet030105 Power Engineering and Engineering Thermophysics 03-30-2024 Power Engineering and Engineering Thermophysics 03-30-2024 2024 3 1 Article 58 10.56578/peet030105 https://www.acadlore.com/article/PEET/2024_3_1/peet030105 https://www.acadlore.com/article/PEET/2024_3_1/peet030104 To elucidate the relationship between the flow rate of an engine’s piston cooling nozzle and its internal structure, a structural model of the piston cooling nozzle and a three-dimensional model of the internal flow field were established through an analysis of the nozzle's structural characteristics and operational conditions. Flow field simulations were conducted using Fluent software, yielding velocity and pressure distribution maps as well as flow rate data within the fluid domain of the piston cooling nozzle. Additionally, the variation in flow rate with changes in the nozzle throat length and diameter was investigated. It was found that the flow rate decreases linearly with an increase in nozzle throat length, while it exhibits a nonlinear increase with an increase in throat diameter. Compared to changes in throat length, modifications in throat diameter have a more significant impact on the flow rate of the piston cooling nozzle. An analytical expression for the flow rate as a function of throat diameter was also derived, providing valuable insights and guidance for the engineering design of nozzles. 03-30-2024 <![CDATA[ To elucidate the relationship between the flow rate of an engine’s piston cooling nozzle and its internal structure, a structural model of the piston cooling nozzle and a three-dimensional model of the internal flow field were established through an analysis of the nozzle's structural characteristics and operational conditions. Flow field simulations were conducted using Fluent software, yielding velocity and pressure distribution maps as well as flow rate data within the fluid domain of the piston cooling nozzle. Additionally, the variation in flow rate with changes in the nozzle throat length and diameter was investigated. It was found that the flow rate decreases linearly with an increase in nozzle throat length, while it exhibits a nonlinear increase with an increase in throat diameter. Compared to changes in throat length, modifications in throat diameter have a more significant impact on the flow rate of the piston cooling nozzle. An analytical expression for the flow rate as a function of throat diameter was also derived, providing valuable insights and guidance for the engineering design of nozzles. ]]> Enhanced Design of Piston Cooling Nozzles via Computational Fluid Dynamics xianren zeng jiahui zhang linmei li jiaxiang zuo doi: 10.56578/peet030104 Power Engineering and Engineering Thermophysics 03-30-2024 Power Engineering and Engineering Thermophysics 03-30-2024 2024 3 1 Article 45 10.56578/peet030104 https://www.acadlore.com/article/PEET/2024_3_1/peet030104 https://www.acadlore.com/article/PEET/2024_3_1/peet030103 In this study, an exact solution is developed to elucidate the effects of radially varying temperature-dependent heat sources/sinks (RVTDHS) and magnetic fields on natural convection flow between two vertically oriented concentric cylinders, where heating is administered through both isoflux (constant heat flux) and isothermal (constant wall temperature) conditions. The energy equation incorporates a temperature-dependent heat source/sink term, postulated to vary inversely with the radial coordinate. Through the application of suitable transformations, exact expressions for temperature distributions and fluid velocities as functions of the radial coordinate, the ratio of radii, the heat source/sink parameter, and the Hartmann number (representing magnetic field strength) are derived. Findings indicate that the presence of a radially varying heat source/sink notably influences temperature distribution, velocity profile, skin friction, and mass flux, with the heat source elevating fluid temperature. Consequently, this adjustment shortens the range over which isothermal heating supersedes isoflux heating. Conversely, in the presence of a heat sink, isothermal heating remains predominant over isoflux heating irrespective of the annular gap's size. These results not only provide deeper insights into the dynamics of magnetohydrodynamics (MHD) free-convection flows in engineering and geophysical applications but also enhance the understanding of how magnetic fields and heat sources/sinks can be strategically manipulated to control such flows. 03-14-2024 <![CDATA[ In this study, an exact solution is developed to elucidate the effects of radially varying temperature-dependent heat sources/sinks (RVTDHS) and magnetic fields on natural convection flow between two vertically oriented concentric cylinders, where heating is administered through both isoflux (constant heat flux) and isothermal (constant wall temperature) conditions. The energy equation incorporates a temperature-dependent heat source/sink term, postulated to vary inversely with the radial coordinate. Through the application of suitable transformations, exact expressions for temperature distributions and fluid velocities as functions of the radial coordinate, the ratio of radii, the heat source/sink parameter, and the Hartmann number (representing magnetic field strength) are derived. Findings indicate that the presence of a radially varying heat source/sink notably influences temperature distribution, velocity profile, skin friction, and mass flux, with the heat source elevating fluid temperature. Consequently, this adjustment shortens the range over which isothermal heating supersedes isoflux heating. Conversely, in the presence of a heat sink, isothermal heating remains predominant over isoflux heating irrespective of the annular gap's size. These results not only provide deeper insights into the dynamics of magnetohydrodynamics (MHD) free-convection flows in engineering and geophysical applications but also enhance the understanding of how magnetic fields and heat sources/sinks can be strategically manipulated to control such flows. ]]> Influence of Radially Varying Magnetic Fields and Heat Sources/Sinks on MHD Free-Convection Flow Within a Vertical Concentric Annulus michael o. oni basant k. jha junaid m. abba olaife h adebayo doi: 10.56578/peet030103 Power Engineering and Engineering Thermophysics 03-14-2024 Power Engineering and Engineering Thermophysics 03-14-2024 2024 3 1 Article 27 10.56578/peet030103 https://www.acadlore.com/article/PEET/2024_3_1/peet030103 https://www.acadlore.com/article/PEET/2024_3_1/peet030102 High-entropy alloy (HEA) is currently regarded as materials with the most superior comprehensive properties, possessing capabilities not found in traditional alloys. This is particularly attributed to the characteristic presence of multiple principal elements, endowing the alloys with exceptional performance across various aspects, thus becoming a focal point of both current and future research endeavors. The performance of HEA is derived from phase transition. This review summarizes the intrinsic phase transition of HEA itself and the enhancement of HEA performance through the addition of particulate phases. Starting from the definition of HEA, the common definitions are introduced, leading to the design principles of HEA and the prediction of solid solution phases. The influence of different elements on the structural changes of HEA solid solution phases is explained through lattice distortion phase transition and segregation phase transition methods. The patterns of phase transition induced by large atomic elements are summarized, and the development process of segregation phase transition by small atomic elements is presented, offering references for future research on HEA. Furthermore, the concept of solubility of elements in HEA is introduced, based on the phase transition caused by large and small atomic elements, providing a more accurate basis for the design and preparation of HEA. The common hard particles used to enhance the performance of HEA are discussed, revealing how direct addition of particles can lead to decomposition and the uncertainty of the effects of elements on HEA performance. The significance of encapsulation techniques in enhancing the performance of high-quality HEA is proposed. 02-04-2024 <![CDATA[ High-entropy alloy (HEA) is currently regarded as materials with the most superior comprehensive properties, possessing capabilities not found in traditional alloys. This is particularly attributed to the characteristic presence of multiple principal elements, endowing the alloys with exceptional performance across various aspects, thus becoming a focal point of both current and future research endeavors. The performance of HEA is derived from phase transition. This review summarizes the intrinsic phase transition of HEA itself and the enhancement of HEA performance through the addition of particulate phases. Starting from the definition of HEA, the common definitions are introduced, leading to the design principles of HEA and the prediction of solid solution phases. The influence of different elements on the structural changes of HEA solid solution phases is explained through lattice distortion phase transition and segregation phase transition methods. The patterns of phase transition induced by large atomic elements are summarized, and the development process of segregation phase transition by small atomic elements is presented, offering references for future research on HEA. Furthermore, the concept of solubility of elements in HEA is introduced, based on the phase transition caused by large and small atomic elements, providing a more accurate basis for the design and preparation of HEA. The common hard particles used to enhance the performance of HEA are discussed, revealing how direct addition of particles can lead to decomposition and the uncertainty of the effects of elements on HEA performance. The significance of encapsulation techniques in enhancing the performance of high-quality HEA is proposed. ]]> Progress in High-Entropy Alloy Performance Enhancement xinsheng wang jifeng luo rongbin ma kai wang doi: 10.56578/peet030102 Power Engineering and Engineering Thermophysics 02-04-2024 Power Engineering and Engineering Thermophysics 02-04-2024 2024 3 1 Article 12 10.56578/peet030102 https://www.acadlore.com/article/PEET/2024_3_1/peet030102 https://www.acadlore.com/article/PEET/2024_3_1/peet030101 This study conducts a numerical investigation into the heat transfer enhancement of $\mathrm{Fe}_3 \mathrm{O}_4$-distilled water nanofluid within a magnetically influenced environment. The research is centered on the analysis of the impact of varying magnetic field strengths on the heat transfer characteristics in a controlled tube setting. The tube, possessing an inner diameter of 25.4 mm and a length of 210 mm, serves as the medium for the flow of nanofluid, initially at 300 K. The influence of magnetism on the nanofluid's thermal boundary layer and the formation of fluid vortices is meticulously examined, leveraging the application of magnetic fields ranging from one to three Teslas. In this context, the study observes the behavior of magnetic particles under these fields, revealing their attraction or repulsion, subsequently inducing turbulence and modifying flow patterns. It is noted that increased flow velocities tend to shield the magnetic field's thermal effects. A key focus is placed on the Nusselt number and $\mathrm{Y}^{+}$ as indicators of heat transfer efficiency, both of which demonstrate significant variations with changes in the magnetic field strength and fluid velocity. The Nusselt number, in particular, escalates to a peak value of 128.7 when exposed to a 0.1 m/s flow velocity and a magnetic field of 3 Teslas. The findings suggest an interrelation between increased magnetic field strengths and the entrance of the fluid into a turbulent state, thereby facilitating an efficient temperature transfer to the fluid. Notably, this research sheds light on the prospect of using ferrofluid-based cooling systems in electrical equipment, highlighting the potential of magnetically manipulated nanofluids to enhance heat transfer capabilities. The investigation delineates how the interplay between magnetic fields, fluid velocity, and nanofluid properties can be optimized for improved thermal management in various applications. 02-02-2024 <![CDATA[ <p>This study conducts a numerical investigation into the heat transfer enhancement of $\mathrm{Fe}_3 \mathrm{O}_4$-distilled water nanofluid within a magnetically influenced environment. The research is centered on the analysis of the impact of varying magnetic field strengths on the heat transfer characteristics in a controlled tube setting. The tube, possessing an inner diameter of 25.4 mm and a length of 210 mm, serves as the medium for the flow of nanofluid, initially at 300 K. The influence of magnetism on the nanofluid's thermal boundary layer and the formation of fluid vortices is meticulously examined, leveraging the application of magnetic fields ranging from one to three Teslas. In this context, the study observes the behavior of magnetic particles under these fields, revealing their attraction or repulsion, subsequently inducing turbulence and modifying flow patterns. It is noted that increased flow velocities tend to shield the magnetic field's thermal effects. A key focus is placed on the Nusselt number and $\mathrm{Y}^{+}$ as indicators of heat transfer efficiency, both of which demonstrate significant variations with changes in the magnetic field strength and fluid velocity. The Nusselt number, in particular, escalates to a peak value of 128.7 when exposed to a 0.1 m/s flow velocity and a magnetic field of 3 Teslas. The findings suggest an interrelation between increased magnetic field strengths and the entrance of the fluid into a turbulent state, thereby facilitating an efficient temperature transfer to the fluid. Notably, this research sheds light on the prospect of using ferrofluid-based cooling systems in electrical equipment, highlighting the potential of magnetically manipulated nanofluids to enhance heat transfer capabilities. The investigation delineates how the interplay between magnetic fields, fluid velocity, and nanofluid properties can be optimized for improved thermal management in various applications.</p> ]]> Numerical Analysis of Heat Transfer Enhancement Using Fe₃O₄ Nanofluid Under Variable Magnetic Fields asaad abdulnabi lazim alireza daneh-dezfuli laith jaafer habeeb doi: 10.56578/peet030101 Power Engineering and Engineering Thermophysics 02-02-2024 Power Engineering and Engineering Thermophysics 02-02-2024 2024 3 1 Article 1 10.56578/peet030101 https://www.acadlore.com/article/PEET/2024_3_1/peet030101 https://www.acadlore.com/article/PEET/2023_2_4/peet020405 In the realm of renewable energy, the optimization of solar water heating (SWH) systems stands paramount for addressing the escalating energy demands. This investigation delves into the pivotal role of design configurations in augmenting the efficiency of SWH systems, with a focus on diverse climatic and locational contexts. Employing the k-omega turbulence model within the ANSYS software framework, a meticulous evaluation of three distinct design configurations, namely, tube-over-plate, tube-under-plate, and tube-in-line-with-plate, is presented. The essence of this study lies not merely in delineating the intrinsic characteristics of these configurations but in a comparative assessment of their efficiencies to ascertain the most efficacious design for superior SWH performance. The adoption of the k-omega turbulence model is instrumental in capturing the intricate fluid dynamics that significantly influence SWH efficiency. The findings reveal that the tube-under-plate configuration exhibits remarkable efficiency, while the tube-in-line-with-plate arrangement demonstrates comparably effective performance. These insights represent a substantial contribution to the advancement of water heating technology, paving the way for more effective and sustainable energy solutions. 12-29-2023 <![CDATA[ In the realm of renewable energy, the optimization of solar water heating (SWH) systems stands paramount for addressing the escalating energy demands. This investigation delves into the pivotal role of design configurations in augmenting the efficiency of SWH systems, with a focus on diverse climatic and locational contexts. Employing the k-omega turbulence model within the ANSYS software framework, a meticulous evaluation of three distinct design configurations, namely, tube-over-plate, tube-under-plate, and tube-in-line-with-plate, is presented. The essence of this study lies not merely in delineating the intrinsic characteristics of these configurations but in a comparative assessment of their efficiencies to ascertain the most efficacious design for superior SWH performance. The adoption of the k-omega turbulence model is instrumental in capturing the intricate fluid dynamics that significantly influence SWH efficiency. The findings reveal that the tube-under-plate configuration exhibits remarkable efficiency, while the tube-in-line-with-plate arrangement demonstrates comparably effective performance. These insights represent a substantial contribution to the advancement of water heating technology, paving the way for more effective and sustainable energy solutions. ]]> Efficiency Optimization in Solar Water Heaters: A Comparative CFD Study of Design Configurations zvawanda paul peace-maker masukume doi: 10.56578/peet020405 Power Engineering and Engineering Thermophysics 12-29-2023 Power Engineering and Engineering Thermophysics 12-29-2023 2023 2 4 Article 238 10.56578/peet020405 https://www.acadlore.com/article/PEET/2023_2_4/peet020405 https://www.acadlore.com/article/PEET/2023_2_4/peet020404 This investigation examines the effects of varied nanoparticle concentrations, such as zinc oxide (ZnO), copper oxide (CuO), and aluminum oxide (Al2O3), on the mass fraction and melting characteristics within nano-enhanced phase change materials (NEPCMs). Employing numerical simulations via ANSYS-FLUENT, the study explores these dynamics within a square enclosure subjected to distinct thermal gradients. The enclosure, measuring 10cm×10cm, incorporates a heat-supplying wall, partitioned into quarters, each exhibiting a unique temperature gradient. This setup provides a comprehensive understanding of boundary conditions relevant to NEPCM behavior. The focus lies on a comparative analysis of NEPCM’s thermal properties under varying nanoparticle concentrations: 0.1, 0.3, and 0.5 weight percent. A low-temperature wall, lined with paraffin wax and integrated with these nanomaterials, facilitates the assessment of their impact on the phase change materials (PCMs). Remarkably, an inverse relationship is observed between nanoparticle concentration and mass fraction, ranging from 0.86 to 0.08. This finding underscores the significant role of nanoparticle integration in modulating NEPCM properties. Among the nanoparticles studied, CuO emerges as the most efficacious in enhancing melting due to its low density and high thermal conductivity. The temperature distribution profile within the paraffin wax shifts from a dispersed state to a more uniform and curved pattern upon nanoparticle incorporation. Such a transformation indicates an improved thermal response of the NEPCM system. The implications of this study are manifold, extending to the design and optimization of thermal energy storage systems. These insights are particularly valuable for applications in energy conservation within buildings, solar energy equipment, transportation, and storage solutions. The research elucidates the criticality of selecting appropriate nanoparticle concentrations for achieving desired phase change properties in NEPCM-based systems. Furthermore, it contributes to a deeper understanding of how nanoparticle characteristics influence the thermal behavior of PCMs, thus offering a guide for future innovations in this field. 12-23-2023 <![CDATA[ <p><span>This investigation examines the effects of varied nanoparticle concentrations, such as zinc oxide (ZnO), copper oxide (CuO), and aluminum oxide (Al</span>_{<span>2</span>}<span>O</span>_{<span>3</span>}<span>), on the mass fraction and melting characteristics within nano-enhanced phase change materials (NEPCMs). Employing numerical simulations via ANSYS-FLUENT, the study explores these dynamics within a square enclosure subjected to distinct thermal gradients. The enclosure, measuring 10cm×10cm, incorporates a heat-supplying wall, partitioned into quarters, each exhibiting a unique temperature gradient. This setup provides a comprehensive understanding of boundary conditions relevant to NEPCM behavior. The focus lies on a comparative analysis of NEPCM’s thermal properties under varying nanoparticle concentrations: 0.1, 0.3, and 0.5 weight percent. A low-temperature wall, lined with paraffin wax and integrated with these nanomaterials, facilitates the assessment of their impact on the phase change materials (PCMs). Remarkably, an inverse relationship is observed between nanoparticle concentration and mass fraction, ranging from 0.86 to 0.08. This finding underscores the significant role of nanoparticle integration in modulating NEPCM properties. Among the nanoparticles studied, CuO emerges as the most efficacious in enhancing melting due to its low density and high thermal conductivity. The temperature distribution profile within the paraffin wax shifts from a dispersed state to a more uniform and curved pattern upon nanoparticle incorporation. Such a transformation indicates an improved thermal response of the NEPCM system. The implications of this study are manifold, extending to the design and optimization of thermal energy storage systems. These insights are particularly valuable for applications in energy conservation within buildings, solar energy equipment, transportation, and storage solutions. The research elucidates the criticality of selecting appropriate nanoparticle concentrations for achieving desired phase change properties in NEPCM-based systems. Furthermore, it contributes to a deeper understanding of how nanoparticle characteristics influence the thermal behavior of PCMs, thus offering a guide for future innovations in this field.</span></p> ]]> Influence of Nanoparticle Concentrations on Heat Transfer in Nano-Enhanced Phase Change Materials mohammed abdulritha khazaal alireza daneh-dezfuli laith jaafer habeeb doi: 10.56578/peet020404 Power Engineering and Engineering Thermophysics 12-23-2023 Power Engineering and Engineering Thermophysics 12-23-2023 2023 2 4 Article 228 10.56578/peet020404 https://www.acadlore.com/article/PEET/2023_2_4/peet020404 https://www.acadlore.com/article/PEET/2023_2_4/peet020403 In the domain of compact flat plate heat exchangers, enhancing efficiency remains a pivotal challenge, primarily due to the low thermal conductivity characteristic of the gas phase. This investigation explores efficiency improvements in such exchangers by the integration of modified delta-wing longitudinal vortex generators (LVGs). The focus is centered on geometric modifications and alterations in the size ratios of the traditional delta-wing design as documented in pertinent literature. The geometric modifications include partial surface removal and elevation from the attachment surface, as well as a combination of these approaches. Concurrently, size ratio alterations involve a systematic reduction in the overall dimensions of the modified LVGs to 75%, 50%, and 25% of their initial size. Employing ANSYS Fluent, the study conducts numerical simulations to evaluate air flow at various Reynolds numbers ($Re$ = 2,000 – 10,000). Analyses include examining temperature progression along the axial distance, mapping temperature contours, and applying the Q-criterion for in-depth understanding. Performance evaluation of each modification was undertaken by calculating the thermal enhancement factor (TEF) in relation to a baseline scenario of two unmodified flat plates, utilizing the Nusselt number and the friction factor for comprehensive comparison. To ensure reliability, the study demonstrates mesh independence in results and validates the computational model through comparative analysis with established correlations and experimental data from existing literature on delta-wing LVG designs. Findings indicate that geometric modifications of vortex generators, as explored in this research, do not markedly decrease head loss nor significantly enhance system performance. In contrast, size ratio modifications, particularly the reduction of vortex generator dimensions to 75% and 50% of the original size, show an increase in TEF ranging from 3% to 9% compared to the conventional delta-wing design. This underscores the potential of incorporating an array of such modified LVGs on each plate of a flat plate heat exchanger to boost its efficiency significantly. 12-10-2023 <![CDATA[ <p>In the domain of compact flat plate heat exchangers, enhancing efficiency remains a pivotal challenge, primarily due to the low thermal conductivity characteristic of the gas phase. This investigation explores efficiency improvements in such exchangers by the integration of modified delta-wing longitudinal vortex generators (LVGs). The focus is centered on geometric modifications and alterations in the size ratios of the traditional delta-wing design as documented in pertinent literature. The geometric modifications include partial surface removal and elevation from the attachment surface, as well as a combination of these approaches. Concurrently, size ratio alterations involve a systematic reduction in the overall dimensions of the modified LVGs to 75%, 50%, and 25% of their initial size. Employing ANSYS Fluent, the study conducts numerical simulations to evaluate air flow at various Reynolds numbers ($Re$ = 2,000 – 10,000). Analyses include examining temperature progression along the axial distance, mapping temperature contours, and applying the Q-criterion for in-depth understanding. Performance evaluation of each modification was undertaken by calculating the thermal enhancement factor (TEF) in relation to a baseline scenario of two unmodified flat plates, utilizing the Nusselt number and the friction factor for comprehensive comparison. To ensure reliability, the study demonstrates mesh independence in results and validates the computational model through comparative analysis with established correlations and experimental data from existing literature on delta-wing LVG designs. Findings indicate that geometric modifications of vortex generators, as explored in this research, do not markedly decrease head loss nor significantly enhance system performance. In contrast, size ratio modifications, particularly the reduction of vortex generator dimensions to 75% and 50% of the original size, show an increase in TEF ranging from 3% to 9% compared to the conventional delta-wing design. This underscores the potential of incorporating an array of such modified LVGs on each plate of a flat plate heat exchanger to boost its efficiency significantly.</p> ]]> Efficiency Enhancement in Air Heat Exchangers: Analyzing the Impact of Size Ratio and Geometric Modifications on Delta-Wing Vortex Generators pedro popelka álvaro valencia doi: 10.56578/peet020403 Power Engineering and Engineering Thermophysics 12-10-2023 Power Engineering and Engineering Thermophysics 12-10-2023 2023 2 4 Article 212 10.56578/peet020403 https://www.acadlore.com/article/PEET/2023_2_4/peet020403 https://www.acadlore.com/article/PEET/2023_2_4/peet020402 This study explores the durability of plasticized polyvinyl chloride (PVC-P) geomembranes in hydraulic engineering anti-seepage structures, particularly under varying operational temperature conditions. Employing accelerated thermal air aging tests on three distinct PVC-P geomembrane variants, the study assesses their mechanical properties, specifically axial tensile strength, using an electronic universal testing machine. A comprehensive thermal air aging model, based on the Arrhenius equation, has been developed, offering insights into the lifespan prediction of these geomembranes. Results demonstrate that factors such as annual average temperature, plasticizer content, and membrane thickness significantly influence the geomembranes' service life. Post-aging observations include a notable yellowing and increased brittleness of the geomembranes, coupled with a decline in tensile strength and elongation. Elongations exhibit a decreasing trend, aligning with a first-order degradation kinetics equation. Under conditions of 50℃ over a period of 120 days, the elongation of polyvinyl chloride (PVC)-HX, PVC2.0-JT, and PVC2.5-JT geomembranes was reduced to 255.88%, 430.11%, and 434.58%, respectively. Predictions indicate that at an operational temperature of 20℃, the expected lifespans for these geomembranes are 19, 45, and 48 years, with material failure correlating to plasticizer loss rates of 58.2%, 32.5%, and 24.8%, respectively. These findings offer valuable guidance for the selection of geomembrane materials in hydraulic engineering projects, considering various designed service durations. 11-19-2023 <![CDATA[ <p>This study explores the durability of plasticized polyvinyl chloride (PVC-P) geomembranes in hydraulic engineering anti-seepage structures, particularly under varying operational temperature conditions. Employing accelerated thermal air aging tests on three distinct PVC-P geomembrane variants, the study assesses their mechanical properties, specifically axial tensile strength, using an electronic universal testing machine. A comprehensive thermal air aging model, based on the Arrhenius equation, has been developed, offering insights into the lifespan prediction of these geomembranes. Results demonstrate that factors such as annual average temperature, plasticizer content, and membrane thickness significantly influence the geomembranes' service life. Post-aging observations include a notable yellowing and increased brittleness of the geomembranes, coupled with a decline in tensile strength and elongation. Elongations exhibit a decreasing trend, aligning with a first-order degradation kinetics equation. Under conditions of 50℃ over a period of 120 days, the elongation of polyvinyl chloride (PVC)-HX, PVC2.0-JT, and PVC2.5-JT geomembranes was reduced to 255.88%, 430.11%, and 434.58%, respectively. Predictions indicate that at an operational temperature of 20℃, the expected lifespans for these geomembranes are 19, 45, and 48 years, with material failure correlating to plasticizer loss rates of 58.2%, 32.5%, and 24.8%, respectively. These findings offer valuable guidance for the selection of geomembrane materials in hydraulic engineering projects, considering various designed service durations.</p> ]]> Thermal Air Aging and Lifespan Prediction of PVC-P Geomembranes: An Arrhenius Equation-Based Approach xianlei zhang hesong liu shaoshuai ma pengpeng yang doi: 10.56578/peet020402 Power Engineering and Engineering Thermophysics 11-19-2023 Power Engineering and Engineering Thermophysics 11-19-2023 2023 2 4 Article 199 10.56578/peet020402 https://www.acadlore.com/article/PEET/2023_2_4/peet020402 https://www.acadlore.com/article/PEET/2023_2_4/peet020401 In the design of shell and tube heat exchangers encompassing a condensing zone, meticulous attention is required due to the complexities surrounding forced convection in multiphase systems. Despite extensive research, the intricacies within these multiphase systems have remained elusive, rendering the heat transfer coefficient unresolved. In this study, a novel methodology is introduced to elucidate the thermal characteristics of forced convection within the condensing region of shell and tube condensers. An amalgamation of theoretical methods, specifically the Logarithmic Mean Temperature Difference (LMTD), and empirical data sourced from industrial operations forms the foundation of this approach. Upon rigorous analysis employing both Power Law Analysis and Logarithmic Linear Regression, a correlation in terms of ${N_u}=C \cdot {Re}^m \cdot {Pr}^{\mathrm{n}}$ within the condensing region was discerned using Buckingham Pi Theorem. Findings revealed coefficients of C=1.15, m=0.893, and n=13.442. For optimization purposes, the Particle Swarm Optimization (PSO) Algorithm was employed. A focused examination of parameters such as tube length, tube outside diameter, baffle spacing, shell diameter, number of tube passings, and tube wall thickness revealed that by attenuating their values by 30%, 46%, 80.3%, 8%, 50%, and 61.9% respectively, a substantial increase in condenser effectiveness was observed, elevating the value from 0.9473 to 4.299. 10-05-2023 <![CDATA[ <p>In the design of shell and tube heat exchangers encompassing a condensing zone, meticulous attention is required due to the complexities surrounding forced convection in multiphase systems. Despite extensive research, the intricacies within these multiphase systems have remained elusive, rendering the heat transfer coefficient unresolved. In this study, a novel methodology is introduced to elucidate the thermal characteristics of forced convection within the condensing region of shell and tube condensers. An amalgamation of theoretical methods, specifically the Logarithmic Mean Temperature Difference (LMTD), and empirical data sourced from industrial operations forms the foundation of this approach. Upon rigorous analysis employing both Power Law Analysis and Logarithmic Linear Regression, a correlation in terms of ${N_u}=C \cdot {Re}^m \cdot {Pr}^{\mathrm{n}}$ within the condensing region was discerned using Buckingham Pi Theorem. Findings revealed coefficients of C=1.15, m=0.893, and n=13.442. For optimization purposes, the Particle Swarm Optimization (PSO) Algorithm was employed. A focused examination of parameters such as tube length, tube outside diameter, baffle spacing, shell diameter, number of tube passings, and tube wall thickness revealed that by attenuating their values by 30%, 46%, 80.3%, 8%, 50%, and 61.9% respectively, a substantial increase in condenser effectiveness was observed, elevating the value from 0.9473 to 4.299.</p> ]]> Optimization of Shell and Tube Condenser Effectiveness via PSO Algorithm Coupled with Forced Convection Characterization in Multiphase Systems nu rhahida arini allisa dwi putri wahyu nur fadilah abir hasnaoui doi: 10.56578/peet020401 Power Engineering and Engineering Thermophysics 10-05-2023 Power Engineering and Engineering Thermophysics 10-05-2023 2023 2 4 Article 188 10.56578/peet020401 https://www.acadlore.com/article/PEET/2023_2_4/peet020401 https://www.acadlore.com/article/PEET/2023_2_3/peet020305 In this study, a numerical investigation into heat transfer and entropy generation characteristics using confined-slot jet impingement was conducted. Comparisons were drawn between the heat transfer and entropy generation attributes of two wing ribs positioned on the heated impinging target surface and those of a rib-less surface. The influences of variations in the spacing between the stagnation point and the rib (B) of (10-30 mm), ranging from 10 to 30 mm, rib heights (A) between 0.5 to 2 mm, and a Reynolds number of the jet (Re) between 3000 to 8000 on fluid flow, heat transfer, and entropy generation were elucidated. Employing the Finite Volume Method (FVM) managed the continuity, momentum, and energy equations in adherence to the principles of the SIMPLE methodology. Results revealed that the Nusselt number $(\overline{N u})$, pressure drop, and total entropy $\left(\bar{S}_{\text {total }}\right)$ escalated in accordance with Re and A. Conversely, they diminished with reduced spacing from the stagnation point to B. Notably, a superior heat transfer rate was observed when employing a target plate integrated with wing ribs in contrast to a rib-less configuration. Performance Evaluation Criteria (PEC) values were noted to augment with rib height increment. It is demonstrated that the PEC increases as A increases. Also, the lower value of PEC equals 1.044 at A of 2 mm, B of 10 mm, and Re of 8000, while the higher value of the PEC equals 1.68 at A of 2 mm, B of 10 mm, and Re of 3000. The findings suggest that slot-Jet impingement complemented by wing ribs plays a pivotal role in enhancing the cooling efficiency of electronic devices. 09-29-2023 <![CDATA[ <p>In this study, a numerical investigation into heat transfer and entropy generation characteristics using confined-slot jet impingement was conducted. Comparisons were drawn between the heat transfer and entropy generation attributes of two wing ribs positioned on the heated impinging target surface and those of a rib-less surface. The influences of variations in the spacing between the stagnation point and the rib (<em>B</em>) of (10-30 mm), ranging from 10 to 30 mm, rib heights (<em>A</em>) between 0.5 to 2 mm, and a Reynolds number of the jet (<em>Re</em>) between 3000 to 8000 on fluid flow, heat transfer, and entropy generation were elucidated. Employing the Finite Volume Method (FVM) managed the continuity, momentum, and energy equations in adherence to the principles of the SIMPLE methodology. Results revealed that the Nusselt number $(\overline{N u})$, pressure drop, and total entropy $\left(\bar{S}_{\text {total }}\right)$ escalated in accordance with <em>Re</em> and <em>A</em>. Conversely, they diminished with reduced spacing from the stagnation point to<em> B</em>. Notably, a superior heat transfer rate was observed when employing a target plate integrated with wing ribs in contrast to a rib-less configuration. Performance Evaluation Criteria (PEC) values were noted to augment with rib height increment. It is demonstrated that the PEC increases as<em> A</em> increases. Also, the lower value of PEC equals 1.044 at <em>A</em> of 2 mm, <em>B</em> of 10 mm, and <em>Re</em> of 8000, while the higher value of the PEC equals 1.68 at <em>A</em> of 2 mm, <em>B</em> of 10 mm, and <em>Re</em> of 3000. The findings suggest that slot-Jet impingement complemented by wing ribs plays a pivotal role in enhancing the cooling efficiency of electronic devices.</p> ]]> Numerical Examination of Heat Transfer and Entropy Generation in Confined-Slot Jet Impingement Featuring Wing Ribs mohammed abed ahmed saad m. hatem ibrahim k. alabdaly doi: 10.56578/peet020305 Power Engineering and Engineering Thermophysics 09-29-2023 Power Engineering and Engineering Thermophysics 09-29-2023 2023 2 3 Article 173 10.56578/peet020305 https://www.acadlore.com/article/PEET/2023_2_3/peet020305 https://www.acadlore.com/article/PEET/2023_2_3/peet020304 This investigation elucidates the intertwined effects of magnetic fields and porous media on the flow of nanofluids towards a stretching sheet, contemplating variable viscosity and convective boundary conditions. A nanofluid model, incorporating the influences of thermophoresis and Brownian motion, is adopted. Via judicious transformations, the fundamental governing coupled non-linear partial differential equations are condensed, and the consequent transformed equations are numerically resolved employing the Finite Element Method (FEM). Paramount emphasis is accorded to parameters embodying notable physical significance, inclusive of the Prandtl number (Pr), Hartmann number, Lewis number (Le), Brownian motion number (Nb), thermophoresis number (Nt), and permeability parameter. The numerical results acquired, as particular instances of the aforementioned study, are found to be congruent with previously reported findings, substantiating the accuracy and reliability of the proposed methodology. A thorough examination of the collective impact of the selected parameters on flow and heat transfer characteristics has been systematically undertaken, revealing intricate dependencies and fostering a deeper understanding of the complex phenomenon under consideration. This study, hence, paves a pathway towards bolstering the comprehension of flow mechanics in porous media under the influence of magnetic fields, contributing valuable insights to the overarching field of fluid dynamics in nano-engineering applications. 09-29-2023 <![CDATA[ <p>This investigation elucidates the intertwined effects of magnetic fields and porous media on the flow of nanofluids towards a stretching sheet, contemplating variable viscosity and convective boundary conditions. A nanofluid model, incorporating the influences of thermophoresis and Brownian motion, is adopted. Via judicious transformations, the fundamental governing coupled non-linear partial differential equations are condensed, and the consequent transformed equations are numerically resolved employing the Finite Element Method (FEM). Paramount emphasis is accorded to parameters embodying notable physical significance, inclusive of the Prandtl number (<em>Pr</em>), Hartmann number, Lewis number (<em>Le</em>), Brownian motion number (<em>Nb</em>), thermophoresis number (<em>Nt</em>), and permeability parameter. The numerical results acquired, as particular instances of the aforementioned study, are found to be congruent with previously reported findings, substantiating the accuracy and reliability of the proposed methodology. A thorough examination of the collective impact of the selected parameters on flow and heat transfer characteristics has been systematically undertaken, revealing intricate dependencies and fostering a deeper understanding of the complex phenomenon under consideration. This study, hence, paves a pathway towards bolstering the comprehension of flow mechanics in porous media under the influence of magnetic fields, contributing valuable insights to the overarching field of fluid dynamics in nano-engineering applications.</p> ]]> Magnetic Field Impacts on Nanofluid Flow Towards a Stretching Sheet Embedded in a Porous Medium with Considerations of Variable Viscosity and Convective Boundary Conditions murali gundagani venkata narendra babu n doi: 10.56578/peet020304 Power Engineering and Engineering Thermophysics 09-29-2023 Power Engineering and Engineering Thermophysics 09-29-2023 2023 2 3 Article 162 10.56578/peet020304 https://www.acadlore.com/article/PEET/2023_2_3/peet020304 https://www.acadlore.com/article/PEET/2023_2_3/peet020303 In the quest to design a robust model for microwave heating systems with symmetrical octagonal tube cavities (MWHSO), a fuzzy-based approach, specifically the Takagi Sugeno Fuzzy Model, was explored to capture the dynamics of the heating process. To achieve this, the mathematical model was adaptively adjusted according to varying input conditions through the utilization of fuzzy logic. Input data were sourced from two magnetrons, with the system outputs derived from measurements acquired from five temperature sensors placed on the heated object. For performance evaluation, the Root Mean Square Error (RMSE) was employed. A comparison was drawn with the autoregressive model with exogenous variable (ARX), a traditional approach wherein the system's mathematical model remains static. Simulation studies were conducted, treating every probe measurement across all dataset validations as distinct cases. It was found that the T-S Fuzzy model surpassed the ARX40 in performance in 33 of the total cases, accounting for 92.49%. The most notable performance of the fuzzy-based approach was observed at a 180-Watt power input, recording an average RMSE of 0.00574 across the five sensors. In contrast, the ARX-based model registered an RMSE of 0.01256. These findings suggest that the fuzzy-based modeling approach presents a compelling alternative for representing the dynamic heating processes within MWHSO. 09-24-2023 <![CDATA[ <p>In the quest to design a robust model for microwave heating systems with symmetrical octagonal tube cavities (MWHSO), a fuzzy-based approach, specifically the Takagi Sugeno Fuzzy Model, was explored to capture the dynamics of the heating process. To achieve this, the mathematical model was adaptively adjusted according to varying input conditions through the utilization of fuzzy logic. Input data were sourced from two magnetrons, with the system outputs derived from measurements acquired from five temperature sensors placed on the heated object. For performance evaluation, the Root Mean Square Error (RMSE) was employed. A comparison was drawn with the autoregressive model with exogenous variable (ARX), a traditional approach wherein the system's mathematical model remains static. Simulation studies were conducted, treating every probe measurement across all dataset validations as distinct cases. It was found that the T-S Fuzzy model surpassed the ARX40 in performance in 33 of the total cases, accounting for 92.49%. The most notable performance of the fuzzy-based approach was observed at a 180-Watt power input, recording an average RMSE of 0.00574 across the five sensors. In contrast, the ARX-based model registered an RMSE of 0.01256. These findings suggest that the fuzzy-based modeling approach presents a compelling alternative for representing the dynamic heating processes within MWHSO.</p> ]]> Modeling of Microwave Heating Systems with Octagonal Tube Cavities: A Comparative Study of Fuzzy-Based and ARX Approaches dhidik prastiyanto esa apriaskar prima astuti handayani ramadhan destanto viyola lokahita bilqis doi: 10.56578/peet020303 Power Engineering and Engineering Thermophysics 09-24-2023 Power Engineering and Engineering Thermophysics 09-24-2023 2023 2 3 Article 150 10.56578/peet020303 https://www.acadlore.com/article/PEET/2023_2_3/peet020303 https://www.acadlore.com/article/PEET/2023_2_3/peet020302 Helical or spiral coiled heat exchangers, prevalent in industries such as power generation, heat recovery systems, the food sector, and various plant processes, exhibit potential for performance enhancement through optimal fluid selection. Notably, nanofluids, distinguished by their superior thermophysical properties, including enhanced thermal conductivity, viscosity, and convective heat transfer coefficient (HTC), are considered viable candidates. In this study, the thermo-physical attributes of helical coil heat exchangers (HCHEs), when subjected to nanofluids, were meticulously examined. During the design phase, Creo parametric design software was employed to refine the geometric configuration, subsequently enhancing fluid flow dynamics, thereby yielding a design improvement for the HCHE. Subsequent computational fluid dynamics (CFD) simulations of the heat exchanger were conducted via the ANSYS CFX program. A CuO/water nanofluid, at a 1% volume fraction, served as the basis for the CFD analysis, incorporating the Re-Normalisation Group ($k-\varepsilon$) turbulence model. From these simulations, zones exhibiting elevated temperature and pressure were discerned. It was observed that the wall HTC value for the CuO/water mixture surpassed that of pure water by 10.01%. Concurrently, the Nusselt number, when the CuO/water nanofluid was employed, escalated by 6.8% in comparison to utilizing water alone. However, it should be noted that a 5.43% increment in the pressure drop was recorded for the CuO/water nanofluid in contrast to pure water. 09-20-2023 <![CDATA[ <p>Helical or spiral coiled heat exchangers, prevalent in industries such as power generation, heat recovery systems, the food sector, and various plant processes, exhibit potential for performance enhancement through optimal fluid selection. Notably, nanofluids, distinguished by their superior thermophysical properties, including enhanced thermal conductivity, viscosity, and convective heat transfer coefficient (HTC), are considered viable candidates. In this study, the thermo-physical attributes of helical coil heat exchangers (HCHEs), when subjected to nanofluids, were meticulously examined. During the design phase, Creo parametric design software was employed to refine the geometric configuration, subsequently enhancing fluid flow dynamics, thereby yielding a design improvement for the HCHE. Subsequent computational fluid dynamics (CFD) simulations of the heat exchanger were conducted via the ANSYS CFX program. A CuO/water nanofluid, at a 1% volume fraction, served as the basis for the CFD analysis, incorporating the Re-Normalisation Group ($k-\varepsilon$) turbulence model. From these simulations, zones exhibiting elevated temperature and pressure were discerned. It was observed that the wall HTC value for the CuO/water mixture surpassed that of pure water by 10.01%. Concurrently, the Nusselt number, when the CuO/water nanofluid was employed, escalated by 6.8% in comparison to utilizing water alone. However, it should be noted that a 5.43% increment in the pressure drop was recorded for the CuO/water nanofluid in contrast to pure water.</p> ]]> Computational Analysis of Thermal Performance Augmentation in Helical Coil Heat Exchangers via CuO/Water Nanofluid rafael cavicchioli batista rejeesh charuvila rajendran doi: 10.56578/peet020302 Power Engineering and Engineering Thermophysics 09-20-2023 Power Engineering and Engineering Thermophysics 09-20-2023 2023 2 3 Article 139 10.56578/peet020302 https://www.acadlore.com/article/PEET/2023_2_3/peet020302 https://www.acadlore.com/article/PEET/2023_2_3/peet020301 A hybrid procedure FLT-HPM was proposed in this study, by combining the homotopy perturbation method (HPM) with Fourier transform and Laplace transform which aimed to find an approximate analytical solution to the problem of two-dimensional transient natural convection in a horizontal cylindrical concentric annulus bounded by two isothermal surfaces. The effect of the Grashof number, Prandtl number, and the radius ratio on fluid flow (air) and heat transfer with different values awreas discussed. Moreover, the velocity distributions and the mean Nusselt numbers were studied, and the Nusselt numbers were used to represent local and general heat transfer rates. Finally, the convergence of FLT-HPM was tested theoretically through the proof of some theorems. In addition, these theorems were applied to the results of the new solutions obtained using FLT-HPM. 08-16-2023 <![CDATA[ <p>A hybrid procedure FLT-HPM was proposed in this study, by combining the homotopy perturbation method (HPM) with Fourier transform and Laplace transform which aimed to find an approximate analytical solution to the problem of two-dimensional transient natural convection in a horizontal cylindrical concentric annulus bounded by two isothermal surfaces. The effect of the Grashof number, Prandtl number, and the radius ratio on fluid flow (air) and heat transfer with different values awreas discussed. Moreover, the velocity distributions and the mean Nusselt numbers were studied, and the Nusselt numbers were used to represent local and general heat transfer rates. Finally, the convergence of FLT-HPM was tested theoretically through the proof of some theorems. In addition, these theorems were applied to the results of the new solutions obtained using FLT-HPM.</p> ]]> FLT-HPM for Two-dimensional Transient Natural Convection in a Horizontal Cylindrical Concentric Annulus yasir ahmed abdulameer abdulsattar jaber ali al-saif doi: 10.56578/peet020301 Power Engineering and Engineering Thermophysics 08-16-2023 Power Engineering and Engineering Thermophysics 08-16-2023 2023 2 3 Article 120 10.56578/peet020301 https://www.acadlore.com/article/PEET/2023_2_3/peet020301 https://www.acadlore.com/article/PEET/2023_2_2/peet020205 The development of an effective cooling system is paramount for the optimal design of high altitude Unmanned Aerial Vehicles (UAVs). These vehicles often operate at or near supersonic speeds in thin atmospheric conditions to generate sufficient lift. It is emphasized that the necessity for air-cooling mandates the incorporation of cooling ducts into the initial design, striving for a balance between low-speed, high-density cooling air for efficient heat rejection, minimal drag, or even potential thrust augmentation. The proposition is that dedicated, meticulously optimized cooling air pathways may facilitate superior performance at high altitudes. The abstract further underscores that the longevity and efficiency of solar panels, commonplace in solar-powered UAVs, are substantially temperature-dependent. As such, high-altitude cooling poses a complex challenge. For conventionally fueled jet-powered UAVs, fuel may serve as a viable heat sink, necessitating a design approach that integrates Peltier cells within electronic components. An alternative approach involves the installation of a subsonic Meredith duct within the primary air intake of the main turbo engine. This duct operates by reducing air speed at the face of a high-efficiency air-to-liquid radiator and then expanding the heated air into a nozzle, making the application of radiators feasible, even for supersonic UAVs. The feasibility of deploying the Meredith duct with direct exposure to external air in subsonic UAVs is also explored. This investigation thus sheds light on innovative cooling mechanisms for UAVs operating at high altitudes, potentially leading to improved efficiency and lifespan of critical components. The findings are poised to enhance the understanding of UAV design and operation, contributing to their overall performance and effectiveness. 06-29-2023 <![CDATA[ <p>The development of an effective cooling system is paramount for the optimal design of high altitude Unmanned Aerial Vehicles (UAVs). These vehicles often operate at or near supersonic speeds in thin atmospheric conditions to generate sufficient lift. It is emphasized that the necessity for air-cooling mandates the incorporation of cooling ducts into the initial design, striving for a balance between low-speed, high-density cooling air for efficient heat rejection, minimal drag, or even potential thrust augmentation. The proposition is that dedicated, meticulously optimized cooling air pathways may facilitate superior performance at high altitudes. The abstract further underscores that the longevity and efficiency of solar panels, commonplace in solar-powered UAVs, are substantially temperature-dependent. As such, high-altitude cooling poses a complex challenge. For conventionally fueled jet-powered UAVs, fuel may serve as a viable heat sink, necessitating a design approach that integrates Peltier cells within electronic components. An alternative approach involves the installation of a subsonic Meredith duct within the primary air intake of the main turbo engine. This duct operates by reducing air speed at the face of a high-efficiency air-to-liquid radiator and then expanding the heated air into a nozzle, making the application of radiators feasible, even for supersonic UAVs. The feasibility of deploying the Meredith duct with direct exposure to external air in subsonic UAVs is also explored. This investigation thus sheds light on innovative cooling mechanisms for UAVs operating at high altitudes, potentially leading to improved efficiency and lifespan of critical components. The findings are poised to enhance the understanding of UAV design and operation, contributing to their overall performance and effectiveness.</p> ]]> An Innovative Heat Rejection System for High Altitude Unmanned Aerial Vehicles luca piancastelli doi: 10.56578/peet020205 Power Engineering and Engineering Thermophysics 06-29-2023 Power Engineering and Engineering Thermophysics 06-29-2023 2023 2 2 Article 110 10.56578/peet020205 https://www.acadlore.com/article/PEET/2023_2_2/peet020205 https://www.acadlore.com/article/PEET/2023_2_2/peet020204 This study examines the energy and exergy performance of the Khoy dual fuel combined cycle power plant, focusing on dual pressure heat recovery steam generators (HRSGs). The aim is to identify an optimal design through the development of a thermodynamic model using ASPEN PLUS software. In the simulation, isentropic efficiencies of high-pressure and low-pressure steam turbines, gas turbines, and compressors are assumed to be 0.85, 0.80, 0.85, and 0.85, respectively. Various practical parameters, such as compressor pressure, condenser pressure, high-pressure steam turbine pressure, and outlet and inlet temperatures of superheaters and turbines, are investigated for their effects on energy and exergy efficiencies. The analysis reveals that combustion chamber I and combustion chamber II contribute the highest amounts of exergy destruction, accounting for 21.80% and 21.50% of the total exergy destruction, respectively. These areas are identified as requiring improvement. Based on the findings, an optimal design is presented, resulting in significant enhancements in energy and exergy efficiencies. The energy efficiency experiences a remarkable increase of 8.75%, while the exergy efficiency demonstrates a substantial improvement of 22.04%. This underscores the superiority of the optimized power plant configuration and provides valuable insights for designers, engineers, and power plant operators. In conclusion, this study advances the understanding of the energy and exergy performance of the Khoy dual fuel combined cycle power plant and offers guidance for optimizing its design and operation. 06-29-2023 <![CDATA[ <p>This study examines the energy and exergy performance of the Khoy dual fuel combined cycle power plant, focusing on dual pressure heat recovery steam generators (HRSGs). The aim is to identify an optimal design through the development of a thermodynamic model using ASPEN PLUS software. In the simulation, isentropic efficiencies of high-pressure and low-pressure steam turbines, gas turbines, and compressors are assumed to be 0.85, 0.80, 0.85, and 0.85, respectively. Various practical parameters, such as compressor pressure, condenser pressure, high-pressure steam turbine pressure, and outlet and inlet temperatures of superheaters and turbines, are investigated for their effects on energy and exergy efficiencies. The analysis reveals that combustion chamber I and combustion chamber II contribute the highest amounts of exergy destruction, accounting for 21.80% and 21.50% of the total exergy destruction, respectively. These areas are identified as requiring improvement. Based on the findings, an optimal design is presented, resulting in significant enhancements in energy and exergy efficiencies. The energy efficiency experiences a remarkable increase of 8.75%, while the exergy efficiency demonstrates a substantial improvement of 22.04%. This underscores the superiority of the optimized power plant configuration and provides valuable insights for designers, engineers, and power plant operators. In conclusion, this study advances the understanding of the energy and exergy performance of the Khoy dual fuel combined cycle power plant and offers guidance for optimizing its design and operation.</p> ]]> Energy and Exergy Evaluation of a Dual Fuel Combined Cycle Power Plant: An Optimization Case Study of the Khoy Plant razieh abbasgholi rezaei doi: 10.56578/peet020204 Power Engineering and Engineering Thermophysics 06-29-2023 Power Engineering and Engineering Thermophysics 06-29-2023 2023 2 2 Article 97 10.56578/peet020204 https://www.acadlore.com/article/PEET/2023_2_2/peet020204 https://www.acadlore.com/article/PEET/2023_2_2/peet020203 This paper aimed to analyze the properties of rubber agglomerate panel, a heterogeneous material. After making three adjustments using three classical differential fractional models, namely, the Scott-Blair model, the generalized fractional Maxwell model (FMM), and the 1D standard fractional viscoelastic order for fluids (SFVOF), this paper assessed the number of parameters in those models for rubber agglomerate panel, made from rubber grains and urea thermoplastic elastomer (TPE). Combining data published from an undergraduate thesis with Microsoft Excel software and the solver command, this paper obtained better sample results using four parameters, rather than two or three complicated material function equations. Data of Ribeiro Alves in 2019 came from hardness experiments. Then this paper transformed deformation data into creep compliance in accordance with equation $J(t)=\varepsilon / t$ (mm/s), and obtained graphical adjustment representations, parameter values, and eventually adjustment equations. However, results from the modified FMM and 1D SFVOF were more comparable, and certain hypotheses were investigated to choose the better model. It was determined that the generalized FMM fit the data the best for this time period. With a certain margin of error, this model could be used for constructing new recycled materials and rubber agglomerate panel using Salvadori equipment. However, it is suggested that new and recent materials should be tested in order to solve environmental problems. 05-28-2023 <![CDATA[ <p>This paper aimed to analyze the properties of rubber agglomerate panel, a heterogeneous material. After making three adjustments using three classical differential fractional models, namely, the Scott-Blair model, the generalized fractional Maxwell model (FMM), and the 1D standard fractional viscoelastic order for fluids (SFVOF), this paper assessed the number of parameters in those models for rubber agglomerate panel, made from rubber grains and urea thermoplastic elastomer (TPE). Combining data published from an undergraduate thesis with Microsoft Excel software and the solver command, this paper obtained better sample results using four parameters, rather than two or three complicated material function equations. Data of Ribeiro Alves in 2019 came from hardness experiments. Then this paper transformed deformation data into creep compliance in accordance with equation $J(t)=\varepsilon / t$ (mm/s), and obtained graphical adjustment representations, parameter values, and eventually adjustment equations. However, results from the modified FMM and 1D SFVOF were more comparable, and certain hypotheses were investigated to choose the better model. It was determined that the generalized FMM fit the data the best for this time period. With a certain margin of error, this model could be used for constructing new recycled materials and rubber agglomerate panel using Salvadori equipment. However, it is suggested that new and recent materials should be tested in order to solve environmental problems.</p> ]]> Properties of Heterogeneous Material Using Fractional Models: Rubber Agglomerate Panel bruno manuel ribeiro alves doi: 10.56578/peet020203 Power Engineering and Engineering Thermophysics 05-28-2023 Power Engineering and Engineering Thermophysics 05-28-2023 2023 2 2 Article 86 10.56578/peet020203 https://www.acadlore.com/article/PEET/2023_2_2/peet020203 https://www.acadlore.com/article/PEET/2023_2_2/peet020202 Thermal Energy Storage (TES) system has emerged as a promising solution of energy demand and supply management, which stores excess thermal energy and releases it when energy demand is high, making it an efficient and cost-effective energy storage solution when combined with renewable energy sources, such as solar and wind power. This study aimed to evaluate the thermal performance of TES units using Computational Fluid Dynamics (CFD) simulations in the ANSYS CFX software package. After comparing the heat storage capacity of conventional Phase Change Material (PCM) and iron oxide/paraffin wax composite (2%) using industrial residual water, temperature distribution plots and heat flux data were generated in simulations for both cases. Addition of iron oxide nanoparticles significantly improved the heat absorption performance of TES units. Both materials initially exhibited a higher heat absorption rate, which gradually decreased over time. CFD data analysis revealed that iron oxide/paraffin wax material enhanced heat absorption performance by up to 1.3%, which demonstrated the potential of iron oxide nanoparticles in improving the efficiency of TES system and highlighted the advantages of TES system combined with renewable energy sources. By improving heat absorption properties, the incorporation of iron oxide nanoparticles had the potential to increase the lifespan of TES units and significantly reduced maintenance and replacement expenses. This breakthrough, along with the cost savings and energy efficiency offered by TES technology, may encourage its widespread application, thus reducing reliance on fossil fuels and promoting sustainable energy practices. 05-17-2023 <![CDATA[ <p>Thermal Energy Storage (TES) system has emerged as a promising solution of energy demand and supply management, which stores excess thermal energy and releases it when energy demand is high, making it an efficient and cost-effective energy storage solution when combined with renewable energy sources, such as solar and wind power. This study aimed to evaluate the thermal performance of TES units using Computational Fluid Dynamics (CFD) simulations in the ANSYS CFX software package. After comparing the heat storage capacity of conventional Phase Change Material (PCM) and iron oxide/paraffin wax composite (2%) using industrial residual water, temperature distribution plots and heat flux data were generated in simulations for both cases. Addition of iron oxide nanoparticles significantly improved the heat absorption performance of TES units. Both materials initially exhibited a higher heat absorption rate, which gradually decreased over time. CFD data analysis revealed that iron oxide/paraffin wax material enhanced heat absorption performance by up to 1.3%, which demonstrated the potential of iron oxide nanoparticles in improving the efficiency of TES system and highlighted the advantages of TES system combined with renewable energy sources. By improving heat absorption properties, the incorporation of iron oxide nanoparticles had the potential to increase the lifespan of TES units and significantly reduced maintenance and replacement expenses. This breakthrough, along with the cost savings and energy efficiency offered by TES technology, may encourage its widespread application, thus reducing reliance on fossil fuels and promoting sustainable energy practices.</p> ]]> Heat Absorption Performance Enhancement of TES System Using Iron Oxide/Paraffin Wax Composite abhishek agarwal doi: 10.56578/peet020202 Power Engineering and Engineering Thermophysics 05-17-2023 Power Engineering and Engineering Thermophysics 05-17-2023 2023 2 2 Article 73 10.56578/peet020202 https://www.acadlore.com/article/PEET/2023_2_2/peet020202 https://www.acadlore.com/article/PEET/2023_2_2/peet020201 Unsustainable fossil fuels are mainly used to generate power in compression ignition (CI) engines in industry now. Due to fossil fuel depletion and potential environmental hazards, it is necessary for researchers to find alternative energy resources to adequately substitute hydrocarbon fossil fuels in current engines. A huge number of studies have focused on the use of renewable fuels in CI engines along with conventional petroleum fuels. Therefore, this paper aimed to analyze the effect of gaseous fuels added to CI engines as a supplement, such as H2, biogas and syngas, in dual fuel mode with diesel as an alternative fuel. This paper analyzed several important characteristics, on which engine evaluation of CI engines using gaseous fuel as an additive is based, such as combustion, performance and emissions, and compared them with those of CI engines operating in single-fuel mode. The findings of numerous empirical studies are shown in graphs of particular parameters, which were crucial for investigating and assessing the case. The main conclusions indicated that gaseous fuel enrichment caused slight decline of performance in CI dual-fuel engine but actually improved emissions. In addition, this paper thoroughly analyzed various methods to assess the performance of biogas in CI dual-fuel engines and investigated dangerous emission pollution. 05-10-2023 <![CDATA[ <p>Unsustainable fossil fuels are mainly used to generate power in compression ignition (CI) engines in industry now. Due to fossil fuel depletion and potential environmental hazards, it is necessary for researchers to find alternative energy resources to adequately substitute hydrocarbon fossil fuels in current engines. A huge number of studies have focused on the use of renewable fuels in CI engines along with conventional petroleum fuels. Therefore, this paper aimed to analyze the effect of gaseous fuels added to CI engines as a supplement, such as H₂, biogas and syngas, in dual fuel mode with diesel as an alternative fuel. This paper analyzed several important characteristics, on which engine evaluation of CI engines using gaseous fuel as an additive is based, such as combustion, performance and emissions, and compared them with those of CI engines operating in single-fuel mode. The findings of numerous empirical studies are shown in graphs of particular parameters, which were crucial for investigating and assessing the case. The main conclusions indicated that gaseous fuel enrichment caused slight decline of performance in CI dual-fuel engine but actually improved emissions. In addition, this paper thoroughly analyzed various methods to assess the performance of biogas in CI dual-fuel engines and investigated dangerous emission pollution.</p> ]]> Review of Compression Ignition Engine Powered by Biogas and Hydrogen nhad k frhan al-abboodi huda ridha doi: 10.56578/peet020201 Power Engineering and Engineering Thermophysics 05-10-2023 Power Engineering and Engineering Thermophysics 05-10-2023 2023 2 2 Article 57 10.56578/peet020201 https://www.acadlore.com/article/PEET/2023_2_2/peet020201 https://www.acadlore.com/article/PEET/2023_2_1/peet020105 Turboprop engines are widely used in the commuter or light transport aircraft (LTA) turboprop engines, because they are more fuel efficient than the propeller, which has a low jet velocity, at flight velocities below 0.6 Mach. For short distances, turboprop engines are more fuel efficient than jet engines, because the light weight assures a high power output per unit of weight. In addition, turboprops are known for their efficiency at medium and low altitudes. Turboprop engines require an exhaust stub (or nozzle) to duct the engine exhaust flue gas outboard of the aircraft. The design of these exhaust stubs is dictated primarily by the aircraft configuration. During the exhaust stub design, full flow at bends and in diffusing sections must be realized by following the established practice for the design of internal flow ducts. Otherwise, the flow will separate from the wall, causing unnecessary pressure loss and reducing the effective flow area. This paper discusses some of the many variations in exhaust stub design, and examines how they influence the performance of the engine, the performance of the aircraft, and the manufacturing aspect. The authors carried out a detailed analysis on the influencing parameters, such as the location, orientation, flange dimension, and geometric effective area of exhaust port. On this basis, the authors determined the jet temperature at exhaust stub exit and temperature at exhaust stub exit plane and nacelle midsection were determined at both static and cruise condition, laying the data basis for further analysis on the exhaust temperature effects over the nacelle and aircraft surfaces. 03-29-2023 <![CDATA[ <p>Turboprop engines are widely used in the commuter or light transport aircraft (LTA) turboprop engines, because they are more fuel efficient than the propeller, which has a low jet velocity, at flight velocities below 0.6 Mach. For short distances, turboprop engines are more fuel efficient than jet engines, because the light weight assures a high power output per unit of weight. In addition, turboprops are known for their efficiency at medium and low altitudes. Turboprop engines require an exhaust stub (or nozzle) to duct the engine exhaust flue gas outboard of the aircraft. The design of these exhaust stubs is dictated primarily by the aircraft configuration. During the exhaust stub design, full flow at bends and in diffusing sections must be realized by following the established practice for the design of internal flow ducts. Otherwise, the flow will separate from the wall, causing unnecessary pressure loss and reducing the effective flow area. This paper discusses some of the many variations in exhaust stub design, and examines how they influence the performance of the engine, the performance of the aircraft, and the manufacturing aspect. The authors carried out a detailed analysis on the influencing parameters, such as the location, orientation, flange dimension, and geometric effective area of exhaust port. On this basis, the authors determined the jet temperature at exhaust stub exit and temperature at exhaust stub exit plane and nacelle midsection were determined at both static and cruise condition, laying the data basis for further analysis on the exhaust temperature effects over the nacelle and aircraft surfaces.</p> ]]> Engine Exhaust Stub Sizing for Turboprop Powered Aircraft chikkanayakanahalli anand vinay kumar gottegere narayanappa girdharababu yepuri doi: 10.56578/peet020105 Power Engineering and Engineering Thermophysics 03-29-2023 Power Engineering and Engineering Thermophysics 03-29-2023 2023 2 1 Article 49 10.56578/peet020105 https://www.acadlore.com/article/PEET/2023_2_1/peet020105 https://www.acadlore.com/article/PEET/2023_2_1/peet020104 In an oil-film lubricating system, fit clearance and the different types of lubricating oil can result in changes in the orbit of shaft center, thereby affecting the stability of the system. Subject of this paper is the camshaft lubricating system of airspace engine, to figure out the effects of fit clearance and the type of lubricating oil on the shaft center orbit of camshaft, in this study, a 3D model of the camshaft lubricating system was built for simulation purpose based on Reynolds equation, and the calculation results suggest that, as the fit clearance grows larger, the convergence position of shaft center gradually moves away from the starting position, and the stability of shaft center declines; in terms of the type of lubricating oil, the higher the viscosity of the lubricating oil, the closer of the position of shaft center to the starting point, and the higher the stability. Our research method can be applied to common oil-film lubricating systems and we hope it could provide a theoretical evidence for the selection of fit clearance and type of lubricating oil for such systems. 03-29-2023 <![CDATA[ <p>In an oil-film lubricating system, fit clearance and the different types of lubricating oil can result in changes in the orbit of shaft center, thereby affecting the stability of the system. Subject of this paper is the camshaft lubricating system of airspace engine, to figure out the effects of fit clearance and the type of lubricating oil on the shaft center orbit of camshaft, in this study, a 3D model of the camshaft lubricating system was built for simulation purpose based on Reynolds equation, and the calculation results suggest that, as the fit clearance grows larger, the convergence position of shaft center gradually moves away from the starting position, and the stability of shaft center declines; in terms of the type of lubricating oil, the higher the viscosity of the lubricating oil, the closer of the position of shaft center to the starting point, and the higher the stability. Our research method can be applied to common oil-film lubricating systems and we hope it could provide a theoretical evidence for the selection of fit clearance and type of lubricating oil for such systems.</p> ]]> Effects of Fit Clearance and Viscosity of Lubricating Oil on Shaft Center Orbit of Camshaft zishan zhang yu wang doi: 10.56578/peet020104 Power Engineering and Engineering Thermophysics 03-29-2023 Power Engineering and Engineering Thermophysics 03-29-2023 2023 2 1 Article 42 10.56578/peet020104 https://www.acadlore.com/article/PEET/2023_2_1/peet020104 https://www.acadlore.com/article/PEET/2023_2_1/peet020103 In the process of robot bone grinding, a large amount of heat is generated, which will cause mechanical and thermal damage to bone tissues and nerves. It is necessary to study the influence of cooling and lubrication parameters on the robot bone grinding temperature and establish the prediction models among them. The FE model of single abrasive bone grinding was established to explore the influence of cooling and lubrication parameters on the bone grinding temperature. Response surface design of experiment was carried out to obtain the simulation results, and Design-Expert was used to establish a multiple regression prediction models of grinding temperature under the condition of different cooling and lubrication. Through the variance and response surface comparative analysis of the prediction model, the influence rules of the bone grinding parameters and the cooling and lubrication parameters on the bone grinding temperature was obtained. A robot bone grinding experiment was performed to prove the accuracy of FE simulation and prediction model. The research results show that the relationship between grinding temperature and cooling lubrication parameters obtained by FE simulation, RSM prediction and experiment verification is consistent, and the simulation model and prediction model of cooling and lubrication parameters are proven to be correct and effective. The influence rules and prediction effects obtained in this study will provide a reasonable scheme for doctors to implement robot bone grinding with high efficiency and low damage, and establish the theoretical basis for the effective control of robot bone grinding force thermal damage. 03-23-2023 <![CDATA[ <p>In the process of robot bone grinding, a large amount of heat is generated, which will cause mechanical and thermal damage to bone tissues and nerves. It is necessary to study the influence of cooling and lubrication parameters on the robot bone grinding temperature and establish the prediction models among them. The FE model of single abrasive bone grinding was established to explore the influence of cooling and lubrication parameters on the bone grinding temperature. Response surface design of experiment was carried out to obtain the simulation results, and Design-Expert was used to establish a multiple regression prediction models of grinding temperature under the condition of different cooling and lubrication. Through the variance and response surface comparative analysis of the prediction model, the influence rules of the bone grinding parameters and the cooling and lubrication parameters on the bone grinding temperature was obtained. A robot bone grinding experiment was performed to prove the accuracy of FE simulation and prediction model. The research results show that the relationship between grinding temperature and cooling lubrication parameters obtained by FE simulation, RSM prediction and experiment verification is consistent, and the simulation model and prediction model of cooling and lubrication parameters are proven to be correct and effective. The influence rules and prediction effects obtained in this study will provide a reasonable scheme for doctors to implement robot bone grinding with high efficiency and low damage, and establish the theoretical basis for the effective control of robot bone grinding force thermal damage.</p> ]]> Influence of Cooling and Lubrication Parameters on Robot Bone Grinding Temperature and Prediction Modeling heqiang tian bin tian debao meng qian xu xiaoqing dang doi: 10.56578/peet020103 Power Engineering and Engineering Thermophysics 03-23-2023 Power Engineering and Engineering Thermophysics 03-23-2023 2023 2 1 Article 26 10.56578/peet020103 https://www.acadlore.com/article/PEET/2023_2_1/peet020103 https://www.acadlore.com/article/PEET/2023_2_1/peet020102 Convectional refrigeration is one of the causes of global warming as carbon dioxide is emitted from its refrigerant to the environment. Semiconductor-based refrigeration is one of the alternative technologies that can lower the carbon dioxide emissions to the atmosphere as it uses electron gas instead of a refrigerant as its working fluid. The present work aims to design and construct a semiconductor-based refrigerator and test its performance. The refrigerator was designed to cool 4×10-3 m-3 of water from a temperature of 30℃ to 0℃. The tests performed on the refrigerator were retention time of the temperature of the water, change in the water temperature at different intervals of time, and the cooling rate of the water. The results of the tests indicated that the temperature of the water dropped from its initial value of 30℃ to 0℃ after 225 minutes, and maintained the temperature of 0℃ for 15 minutes. After the refrigerator was switched off, the temperature of 0℃ was retained for approximately 30 minutes, and then took 192 minutes to rise from 0℃ to its initial value of 30℃. The average cooling rate for the duration of 225 minutes was 0.133℃/min. The current work widens the studies on the use of alternative technologies for convectional refrigeration. 03-23-2023 <![CDATA[ <p style="text-align: justify">Convectional refrigeration is one of the causes of global warming as carbon dioxide is emitted from its refrigerant to the environment. Semiconductor-based refrigeration is one of the alternative technologies that can lower the carbon dioxide emissions to the atmosphere as it uses electron gas instead of a refrigerant as its working fluid. The present work aims to design and construct a semiconductor-based refrigerator and test its performance. The refrigerator was designed to cool 4×10^-3 m^-3 of water from a temperature of 30℃ to 0℃. The tests performed on the refrigerator were retention time of the temperature of the water, change in the water temperature at different intervals of time, and the cooling rate of the water. The results of the tests indicated that the temperature of the water dropped from its initial value of 30℃ to 0℃ after 225 minutes, and maintained the temperature of 0℃ for 15 minutes. After the refrigerator was switched off, the temperature of 0℃ was retained for approximately 30 minutes, and then took 192 minutes to rise from 0℃ to its initial value of 30℃. The average cooling rate for the duration of 225 minutes was 0.133℃/min. The current work widens the studies on the use of alternative technologies for convectional refrigeration.</p> ]]> A Semiconductor-Based Refrigeration System for Cooling of Water: Design, Construction, and Performance Tests taiwo o. oni samuel j. aliyu bernard a. adaramola oluwasina l. rominiyi doi: 10.56578/peet020102 Power Engineering and Engineering Thermophysics 03-23-2023 Power Engineering and Engineering Thermophysics 03-23-2023 2023 2 1 Article 15 10.56578/peet020102 https://www.acadlore.com/article/PEET/2023_2_1/peet020102 https://www.acadlore.com/article/PEET/2023_2_1/peet020101 The world is presently confronted with the twin crisis of resource restriction and environmental degradation. The search for solutions that promise a harmonious correlation with sustainable development, energy conservation, efficiency, and environmental preservation has become highly important. The main purpose of innovative studies on fuel refinement and combustion engines is to improve fuel properties by adding fuel additives. In this study, the impact of Titanium dioxide, TiO2, nanoparticles solution blended with diesel fuel on the performance and emission characteristics of four-stroke combustion engine OM 364 EU III, manufactured by IDEM Co and licensed by Daimler Benz, has been investigated. The selection of TiO2 nanoparticles is based on the easy access in the market and the gap recognized; in previous literature, these nanoparticles were added to biodiesel or n-butanol blends. The proposed combined fuel in this study contains 2.5 ppm TiO2 nanoparticles dissolved in 1200 [ml] water and added to 60 [Lit] base diesel fuel. The results of the aforementioned combined fuel have been compared with the base diesel fuel. It has been observed that applying nano-additives improves the mechanical performance of the diesel engine, such as power, torque, brake-specific fuel consumption, and thermal efficiency. Moreover, soot, unburned hydrocarbons, and carbon monoxide have declined by 2.78%, 3.55%, and 3.32%, respectively, due to TiO2 nanoparticles' catalytic effect on fuel combustion. However, the amount of NOx has increased up to 3.09% because of the high cycle temperature. 03-23-2023 <![CDATA[ <p>The world is presently confronted with the twin crisis of resource restriction and environmental degradation. The search for solutions that promise a harmonious correlation with sustainable development, energy conservation, efficiency, and environmental preservation has become highly important. The main purpose of innovative studies on fuel refinement and combustion engines is to improve fuel properties by adding fuel additives. In this study, the impact of Titanium dioxide, TiO₂, nanoparticles solution blended with diesel fuel on the performance and emission characteristics of four-stroke combustion engine OM 364 EU III, manufactured by IDEM Co and licensed by Daimler Benz, has been investigated. The selection of TiO₂ nanoparticles is based on the easy access in the market and the gap recognized; in previous literature, these nanoparticles were added to biodiesel or n-butanol blends. The proposed combined fuel in this study contains 2.5 ppm TiO₂ nanoparticles dissolved in 1200 [ml] water and added to 60 [Lit] base diesel fuel. The results of the aforementioned combined fuel have been compared with the base diesel fuel. It has been observed that applying nano-additives improves the mechanical performance of the diesel engine, such as power, torque, brake-specific fuel consumption, and thermal efficiency. Moreover, soot, unburned hydrocarbons, and carbon monoxide have declined by 2.78%, 3.55%, and 3.32%, respectively, due to TiO₂ nanoparticles' catalytic effect on fuel combustion. However, the amount of NOx has increased up to 3.09% because of the high cycle temperature.</p> ]]> Experimental Investigation on the Effect of TiO₂ Nanoparticles Emulsion in Water on Emissions and Performance Characteristics of DI Diesel Engine razieh abbasgholi rezaei doi: 10.56578/peet020101 Power Engineering and Engineering Thermophysics 03-23-2023 Power Engineering and Engineering Thermophysics 03-23-2023 2023 2 1 Article 1 10.56578/peet020101 https://www.acadlore.com/article/PEET/2023_2_1/peet020101 https://www.acadlore.com/article/PEET/2022_1_1/peet010108 The atmospheric pressure air plasma technology is based on the general principle of transforming the air into an ideal conductor of plasma energy thanks to the application of an electric potential difference able to ionize the molecules. Applying the principle to the human surgery, it comes to be possible to assure an energy transfer from plasma-generator devices to the human tissue in a relatively simple way: passing through the air, with exceptionally limited effects in terms of tissue heating. Such a condition is very useful to assure effective treatments in surgery: less thermal damage, fewer side effects on the patient. This is also what emerged during the use of innovative devices embedding the Airplasma&reg; technology (by Otech Industry S.r.l.), where temperatures on human tissues were measured stably below 50°C. However, the profiles assumed by the temperature along the different electrodes during the operating conditions are rather unclear. This knowledge is essential to improve the efficiency of the electrodes (through their redesign in shapes and materials) as well as to reduce the invasiveness of surgical interventions. The present work had the purpose of characterizing the most common electrodes thanks to temperature measurements carried out by infrared sensors respect to different operating conditions. A simplified finite element model was also developed to support the optimal redesign of electrodes. 10-30-2022 <![CDATA[ <p>The atmospheric pressure air plasma technology is based on the general principle of transforming the air into an ideal conductor of plasma energy thanks to the application of an electric potential difference able to ionize the molecules. Applying the principle to the human surgery, it comes to be possible to assure an energy transfer from plasma-generator devices to the human tissue in a relatively simple way: passing through the air, with exceptionally limited effects in terms of tissue heating. Such a condition is very useful to assure effective treatments in surgery: less thermal damage, fewer side effects on the patient. This is also what emerged during the use of innovative devices embedding the Airplasma&reg; technology (by Otech Industry S.r.l.), where temperatures on human tissues were measured stably below 50°C. However, the profiles assumed by the temperature along the different electrodes during the operating conditions are rather unclear. This knowledge is essential to improve the efficiency of the electrodes (through their redesign in shapes and materials) as well as to reduce the invasiveness of surgical interventions. The present work had the purpose of characterizing the most common electrodes thanks to temperature measurements carried out by infrared sensors respect to different operating conditions. A simplified finite element model was also developed to support the optimal redesign of electrodes.</p> ]]> Measuring Temperatures Generated by Air Plasma Technology cristiano fragassa marco arru filippo capelli ana pavlovic matteo gherardi doi: 10.56578/peet010108 Power Engineering and Engineering Thermophysics 10-30-2022 Power Engineering and Engineering Thermophysics 10-30-2022 2022 1 1 Article 76 10.56578/peet010108 https://www.acadlore.com/article/PEET/2022_1_1/peet010108 https://www.acadlore.com/article/PEET/2022_1_1/peet010107 During the operation of the ground source heat pump (GSHP) system, the operations of the chiller system should be controlled by adjusting the difference between water temperature and wet bulb temperature. Therefore, it is important to consider the control strategy for the switch time (ST) and wet bulb temperature difference (WBTD) of the chiller system. This paper sets up two control strategies, namely, the strategy to control the ST of system operations, and the strategy to control the WBTD. Then, theoretical modeling was carried out to compare the system energy consumption and borehole wall temperature under different strategies. The modeling results were referred to optimize the control strategy for composite GSHP systems. It was found that, under the ST control strategy, the best wet bulb temperature is 2℃, and the best chiller operation hours are 3h; under the WBTD control strategy, the best wet bulb temperature is 3.5℃, and the best WBTD is 1.5℃. In addition, the ST control strategy is superior to the WBTD control strategy, in terms of system energy consumption, borehole wall temperature and initial investment. 10-30-2022 <![CDATA[ <p>During the operation of the ground source heat pump (GSHP) system, the operations of the chiller system should be controlled by adjusting the difference between water temperature and wet bulb temperature. Therefore, it is important to consider the control strategy for the switch time (ST) and wet bulb temperature difference (WBTD) of the chiller system. This paper sets up two control strategies, namely, the strategy to control the ST of system operations, and the strategy to control the WBTD. Then, theoretical modeling was carried out to compare the system energy consumption and borehole wall temperature under different strategies. The modeling results were referred to optimize the control strategy for composite GSHP systems. It was found that, under the ST control strategy, the best wet bulb temperature is 2℃, and the best chiller operation hours are 3h; under the WBTD control strategy, the best wet bulb temperature is 3.5℃, and the best WBTD is 1.5℃. In addition, the ST control strategy is superior to the WBTD control strategy, in terms of system energy consumption, borehole wall temperature and initial investment.</p> ]]> Optimal Operation Control of Composite Ground Source Heat Pump System liang wang shudan deng doi: 10.56578/peet010107 Power Engineering and Engineering Thermophysics 10-30-2022 Power Engineering and Engineering Thermophysics 10-30-2022 2022 1 1 Article 64 10.56578/peet010107 https://www.acadlore.com/article/PEET/2022_1_1/peet010107 https://www.acadlore.com/article/PEET/2022_1_1/peet010106 This paper intends to improve the hydrogen production efficiency of the electrolysis cells, fully utilize wind energy, and ensure the reliability of power supply. For this purpose, the authors put forward a capacity optimization configuration for non-grid-connected wind-hydrogen hybrid energy storage system, in view of the features of hydrogen production efficiency. The working interval of the electrolytic cell was optimized by analyzing the said features. Considering the features of battery charge/discharge, equipment capacity and power, the authors formulated the energy management strategy applicable to six working conditions, established the quantitative multi-objective function of system cost and reliability, and solved the optimization model by the fast non-dominant sorting genetic algorithm (NSGA)-II. In this way, the optimal combination of energy storage capacity was determined. Next, the wind velocity data of a pastoral area in Inner Mongolia was measured, and analyzed in details. The analysis results show that the electrolytic cell always operates in the optimal working area, and the optimized wind-hydrogen system is economic and reliable in power supply. The research provides a reference for practical engineering applications. 10-30-2022 <![CDATA[ <p>This paper intends to improve the hydrogen production efficiency of the electrolysis cells, fully utilize wind energy, and ensure the reliability of power supply. For this purpose, the authors put forward a capacity optimization configuration for non-grid-connected wind-hydrogen hybrid energy storage system, in view of the features of hydrogen production efficiency. The working interval of the electrolytic cell was optimized by analyzing the said features. Considering the features of battery charge/discharge, equipment capacity and power, the authors formulated the energy management strategy applicable to six working conditions, established the quantitative multi-objective function of system cost and reliability, and solved the optimization model by the fast non-dominant sorting genetic algorithm (NSGA)-II. In this way, the optimal combination of energy storage capacity was determined. Next, the wind velocity data of a pastoral area in Inner Mongolia was measured, and analyzed in details. The analysis results show that the electrolytic cell always operates in the optimal working area, and the optimized wind-hydrogen system is economic and reliable in power supply. The research provides a reference for practical engineering applications.</p> ]]> Energy Storage Capacity Optimization of Non-Grid-Connected Wind-Hydrogen Systems: From the Perspective of Hydrogen Production Features xinyu zhang hua li jikang wang doi: 10.56578/peet010106 Power Engineering and Engineering Thermophysics 10-30-2022 Power Engineering and Engineering Thermophysics 10-30-2022 2022 1 1 Article 48 10.56578/peet010106 https://www.acadlore.com/article/PEET/2022_1_1/peet010106 https://www.acadlore.com/article/PEET/2022_1_1/peet010105 Although many fluidized systems are not vertically oriented, little research has been done on fluidization within inclined channels. The fluidization of the gravitational force and the tensile force may be substantially opposing in the vertical system. The theory of gravitational field fluidization, which is related to industrial fluidization processes like coal gasification, iron ore reduction, and catalytic cracking and calls for the use of standing tubes or angled risers, has to be developed in order to encompass various orientations. Without underlying theories, engineers must rely on vertical fluidization equations to build these sloping systems. A significant barrier to improving the design and optimization of new solid circulation systems is the tendency of fluidization. Based on historical developments and theoretical progress, the study presents an overview of recent advancements of liquid-solid fluidized beds in inclined columns. The fluidized bed is investigated as a whole by looking at the governing factors. 10-30-2022 <![CDATA[ <p>Although many fluidized systems are not vertically oriented, little research has been done on fluidization within inclined channels. The fluidization of the gravitational force and the tensile force may be substantially opposing in the vertical system. The theory of gravitational field fluidization, which is related to industrial fluidization processes like coal gasification, iron ore reduction, and catalytic cracking and calls for the use of standing tubes or angled risers, has to be developed in order to encompass various orientations. Without underlying theories, engineers must rely on vertical fluidization equations to build these sloping systems. A significant barrier to improving the design and optimization of new solid circulation systems is the tendency of fluidization. Based on historical developments and theoretical progress, the study presents an overview of recent advancements of liquid-solid fluidized beds in inclined columns. The fluidized bed is investigated as a whole by looking at the governing factors.</p> ]]> Two-Phase Liquid-Solid Hydrodynamics of Inclined Fluidized Beds huda ridha nhad k. frhan al-abboodi doi: 10.56578/peet010105 Power Engineering and Engineering Thermophysics 10-30-2022 Power Engineering and Engineering Thermophysics 10-30-2022 2022 1 1 Article 33 10.56578/peet010105 https://www.acadlore.com/article/PEET/2022_1_1/peet010105 https://www.acadlore.com/article/PEET/2022_1_1/peet010104 Given the geometric nonlinearity of the piezoelectric cantilever beam, this study establishes a distributed parameter model of the nonlinear bi-stable cantilever piezoelectric energy harvester, following the generalized Hamilton variational principle. The analytical expressions of the dynamic response were obtained for the energy harvesting system using Galerkin modal decomposition and the multi-scale method. The investigation focuses on how the performance of the energy harvesting system is influenced by the gap distance between magnets, external excited amplitude, mechanical damping ratio and external load resistance. The calculation results were compared with those obtained neglecting the geometric nonlinearity of the beam. The results show that the system responses contain jump and multiple solutions. The consideration of the geometrical nonlinearity significantly amplified the peak displacement and peak output power of the intra-well and inter-well motions. There is an evident hardening effect of the inter-well motion frequency response curve. By reasonable adjusting the parameters, it is possible to improve the output power of the piezoelectric energy harvesting system and broaden the operating frequency of the system. 10-30-2022 <![CDATA[ <p>Given the geometric nonlinearity of the piezoelectric cantilever beam, this study establishes a distributed parameter model of the nonlinear bi-stable cantilever piezoelectric energy harvester, following the generalized Hamilton variational principle. The analytical expressions of the dynamic response were obtained for the energy harvesting system using Galerkin modal decomposition and the multi-scale method. The investigation focuses on how the performance of the energy harvesting system is influenced by <span style="font-family: 宋体;">t</span>he gap distance between magnets, external excited amplitude, mechanical damping ratio and external load resistance. The calculation results were compared with those obtained neglecting the geometric nonlinearity of the beam. The results show that the system responses contain jump and multiple solutions. The consideration of the geometrical nonlinearity significantly amplified the peak displacement and peak output power of the intra-well and inter-well motions. There is an evident hardening effect of the inter-well motion frequency response curve. By reasonable adjusting the parameters, it is possible to improve the output power of the piezoelectric energy harvesting system and broaden the operating frequency of the system.</p> ]]> Parametric Analysis of Nonlinear Bi-Stable Piezoelectric Energy Harvester Based on Multi-Scale Method dawei man gaozheng xu huaiming xu deheng xu doi: 10.56578/peet010104 Power Engineering and Engineering Thermophysics 10-30-2022 Power Engineering and Engineering Thermophysics 10-30-2022 2022 1 1 Article 19 10.56578/peet010104 https://www.acadlore.com/article/PEET/2022_1_1/peet010104 https://www.acadlore.com/article/PEET/2022_1_1/peet010103 Bilinear and bicubic interpolations were often used in digital elevation models (DEMs), image scaling, and image restoration, with the aid of spatial transform techniques. This paper resorts to bilinear and bicubic interpolations, along with the spatial transform of images, to present the temperature distribution on a plate with a circular hole. The Dirichlet boundary conditions were applied, a rectangular grid was created, and the nodal values were calculated using the finite difference method (FDM). These methods were also employed to represent the mechanical stress distribution on a plate with a circular hole, under the presence of uniaxial stress. In this case, the nodal values were calculated using the analytical method. Experimental results show that bicubic interpolation generated continuous contours, while bilinear interpolation had a discontinuity in some cases. The results were comparative to images for similar cases when solved through ANSYS. 10-30-2022 <![CDATA[ <p>Bilinear and bicubic interpolations were often used in digital elevation models (DEMs), image scaling, and image restoration, with the aid of spatial transform techniques. This paper resorts to bilinear and bicubic interpolations, along with the spatial transform of images, to present the temperature distribution on a plate with a circular hole. The Dirichlet boundary conditions were applied, a rectangular grid was created, and the nodal values were calculated using the finite difference method (FDM). These methods were also employed to represent the mechanical stress distribution on a plate with a circular hole, under the presence of uniaxial stress. In this case, the nodal values were calculated using the analytical method. Experimental results show that bicubic interpolation generated continuous contours, while bilinear interpolation had a discontinuity in some cases. The results were comparative to images for similar cases when solved through ANSYS.</p> ]]> Bilinear and Bicubic Interpolations for Image Presentation of Mechanical Stress and Temperature Distribution manikanta b. pithani shubhashis sanyal anuj k. shukla doi: 10.56578/peet010103 Power Engineering and Engineering Thermophysics 10-30-2022 Power Engineering and Engineering Thermophysics 10-30-2022 2022 1 1 Article 8 10.56578/peet010103 https://www.acadlore.com/article/PEET/2022_1_1/peet010103 https://www.acadlore.com/article/PEET/2022_1_1/peet010102 This study aims to realize continuous, high efficiency defrosting of air-to-air heat pumps using the effect of outdoor warm air recycling, trying to improve the coefficient of performance (COP) and total heat capacity of traditional defrosting methods like hot bypass and Joule heating. The proposed patented method recovers heat from the air change system by mixing the warm discarded air with the incoming air of the external heat exchanger. The fan of the external unit sucks the indoor air with the depression obtained by a Venturi. The warm air is ducted to the Venturi through a hole in the wall. The amount of warm air mixed to the outside air is regulated by a butterfly valve installed on the pipe from the hole to the Venturi. In this way, the air entering the external coil is warm enough to avoid frost. The energy efficiency of the system is assured, for the warm indoor air is heated with the high COP of the heat pump. Our system can achieve defrosting with a limited amount of warm air, and realize a higher overall COP than the best traditional defrosting systems. Finally, the defrosting device can be added as an option to any existing split systems. 10-30-2022 <![CDATA[ <p>This study aims to realize continuous, high efficiency defrosting of air-to-air heat pumps using the effect of outdoor warm air recycling, trying to improve the coefficient of performance (COP) and total heat capacity of traditional defrosting methods like hot bypass and Joule heating. The proposed patented method recovers heat from the air change system by mixing the warm discarded air with the incoming air of the external heat exchanger. The fan of the external unit sucks the indoor air with the depression obtained by a Venturi. The warm air is ducted to the Venturi through a hole in the wall. The amount of warm air mixed to the outside air is regulated by a butterfly valve installed on the pipe from the hole to the Venturi. In this way, the air entering the external coil is warm enough to avoid frost. The energy efficiency of the system is assured, for the warm indoor air is heated with the high COP of the heat pump. Our system can achieve defrosting with a limited amount of warm air, and realize a higher overall COP than the best traditional defrosting systems. Finally, the defrosting device can be added as an option to any existing split systems.</p> ]]> Continuous, High Efficiency Defrosting of Air-to-Air Heat Pumps luca piancastelli doi: 10.56578/peet010102 Power Engineering and Engineering Thermophysics 10-30-2022 Power Engineering and Engineering Thermophysics 10-30-2022 2022 1 1 Article 2 10.56578/peet010102 https://www.acadlore.com/article/PEET/2022_1_1/peet010102 https://www.acadlore.com/article/PEET/2022_1_1/peet010101 10-30-2022 <![CDATA[ ]]> Editorial to the Inaugural Issue luca piancastelli doi: 10.56578/peet010101 Power Engineering and Engineering Thermophysics 10-30-2022 Power Engineering and Engineering Thermophysics 10-30-2022 2022 1 1 Article 1 10.56578/peet010101 https://www.acadlore.com/article/PEET/2022_1_1/peet010101