Numerical Investigation on Sand Erosion Phenomenon of Coated and Uncoated Vanes in Low-Pressure Gas Turbine

For energy saving and less environmental impact, efficient energy utilization is of importance. In a gasturbine engine, its performance increases as increasing temperature of the turbine inlet flow. However, turbine components are required to be protected from the high temperature flows. Recently, ceramic matrix composite (referred as CMC, hereafter) is expected to be utilized as protecting the gas-turbine components due to the excellent properties of CMC in high temperature conditions: low density, high strength and high rigidity. Therefore, the CMC allows us to increase the inlet temperature and leads to high performance of gas-turbine engines. On the other hand, sand erosion phenomenon is one of serious problems in gas-turbine engines. Sand particles ingested from the engine inlet impinge and erode the wall surfaces, which can cause engine failure. In order to prevent the sand erosion phenomenon, anti-erosion coatings have been developed and adopted for gas-turbines, although the anti-erosion characteristics of the CMC coating have not completely been clarified. The objective of the present paper is to perform numerical simulations of sand erosion phenomenon on the coated and the uncoated T106 CMC vanes in a low-pressure gas turbine. We investigate the flow field, particle trajectories and the eroded shape of the CMC turbine vanes. The results show that the erosion occurs near the leading edge and at the 90 percent axial chord on the pressure surface in both of the coated and uncoated cases. In the uncoated case, the severe erosion phenomenon is observed especially. Accordingly, we have concluded that the coating obviously played an important role in protecting the CMC vanes from sand erosion.