Numerical Investigation of Film Cooling Characterstics in Multi-perforated CMC Plates

With the continuous improvement of the performance of aero-engines, the turbine inlet temperature is increasing, while the cooling air available for combustor liner and turbine blade is reduced. This has led to an increasingly severe operating environment for aero-engine materials and extremely high requirements for their high-temperature performance. Ceramic matrix composite (CMC) material becomes an attractive candidate on hot components due to its light weight and temperature stability. In this study, the overall cooling effectiveness of multi-perforated CMC plates is numerically investigated for three cooling schemes. Meanwhile, corresponding superalloy cases have been conducted for comparison. The study reveals that the blowing ratio has a significant effect on cooling effectiveness, with Scheme S1 being the most effective, followed by Schemes S2 and S3. At a density ratio of 1.52, the cooling effectiveness of CMC material was higher than that of superalloy material, while at DR =2.1, cooling effectiveness for both materials was very close. Lower blowing ratios produced better spanwise coverage of film at the hole outlet, while higher ratios increased the influence distance of the film downstream. Adiabatic cooling effectiveness was found to be poor at the downstream far from the cooling hole, with an uneven distribution. Comparing superalloy and CMC cases showed that the cooling effectiveness distribution along the flow direction of CMC was more uniform than that of superalloy due to its larger in-plane thermal conductivity.