Residual wastewater produced during the utilization of high-energy propellants presents a power-driven engineering problem in which reaction efficiency, energy input, and thermophysical stability must be jointly controlled. An integrated, mobile treatment system coupling electrochemical oxidation (ECO) with disc-tube reverse osmosis (DTRO) was designed and assessed from a system-level thermophysical perspective. A model-driven framework was employed to guide the engineering design of the electrochemical reactor, membrane unit, and pipeline network under constraints associated with power input, hydraulic behavior, and structural reliability. The ECO reactor equipped with boron-doped diamond (BDD) electrodes was operated under high-current conditions, and the effects of current density and energy input on degradation behavior were examined. Experimental results show that, at a current density of 70 mA·cm⁻², the integrated system achieved a unsymmetrical dimethylhydrazine (UDMH) removal efficiency of 99.2% within 3 h while maintaining stable thermal and mechanical states. The downstream DTRO unit enabled effective separation of reaction intermediates and residual contaminants, resulting in stable effluent quality during continuous high-load operation. These results demonstrate that the ECO–DTRO configuration constitutes a feasible power-driven treatment pathway for high-energy propellant residues, characterized by controlled energy utilization and satisfactory thermophysical stability, and provides engineering guidance for the design of coupled electrochemical–membrane systems.

An experimental investigation was conducted to evaluate the influence of geometric orientation on the thermal performance of a cylindrical phase change material energy storage system incorporating concentric heat transfer fluid tubes. Three configurations—vertical, inclined, and horizontal—were systematically examined to determine their effects on heat transfer characteristics, melting dynamics, and energy storage capacity. The phase change material was subjected to charging processes using heat transfer fluid inlet temperatures of 60℃, 70℃, and 80℃ at a constant mass flow rate of 1 kg/min, while discharging experiments were performed under identical flow conditions to ensure consistency. It was observed that the melting time was significantly reduced in the vertical configuration, exhibiting a decrease of 29.2% compared to the horizontal arrangement and 19.4% relative to the inclined configuration at an inlet temperature of 80℃. This enhancement was attributed to the intensification of natural convection within the molten phase change material region. Furthermore, at a charging duration of 140 minutes, the total thermal energy stored in the vertical configuration was found to be approximately 4.4%, 17.4%, and 19.4% higher than that of the horizontal configuration for heat transfer fluid inlet temperatures of 60℃, 70℃, and 80℃, respectively. The results demonstrate that the optimization of system orientation plays a critical role in enhancing both the charging rate and storage capacity of phase change material-based thermal energy storage systems. These findings provide valuable design insights for the development of high-efficiency latent heat storage units in renewable energy and thermal management applications.

Solidification-based cold energy storage systems are often limited by the low thermal conductivity of phase change materials (PCMs), which leads to prolonged freezing times and reduced system responsiveness. To address this issue, a numerical study is carried out on the solidification behavior within a cold energy storage unit of complex geometry. Two approaches are considered to improve heat transfer within the storage domain: the dispersion of a ternary hybrid nanoparticle mixture (Ag–TiO$_2$–Al$_2$O$_3$) in water and the incorporation of porous metal foam. Owing to the weak fluid motion during solidification, heat transfer is treated as conduction-dominated, and the governing energy equation is formulated using a transient latent heat method. The problem is solved using the Galerkin finite element approach with adaptive mesh refinement to capture the evolution of the solidification front. The results indicate that the inclusion of metal foam markedly shortens the freezing time, with a reduction of approximately 82.39% compared with the base case. The addition of ternary hybrid nanoparticles also contributes to a reduction in freezing time, although to a lesser extent (about 13.13%). When both techniques are applied simultaneously, a further decrease in solidification duration is observed. The results also show that the contribution of metal foam to heat transfer is significantly greater than that of nanoparticle addition alone. These findings provide a basis for improving the thermal response of cold energy storage systems, particularly in applications where rapid solidification is required.