The present numerical study investigated a novel film cooling scheme that combines a cylindrical hole with an upstream Barchan-dune ramp and a triangular tab over the hole. Simulations revealed that this arrangement can induce an additional anti-kidney vortex pair on the outside of the original primary kidney vortices to suppress the penetration of the high-temperature mainstream by the cooling flow, increasing cooling effectiveness. Compared with schemes employing only a triangular tab or a Barchan-dune ramp, the novel film cooling scheme achieved superior cooling performance. An optimum parameter design is determined through the Taguchi method. Three parameters were investigated, namely, the Barchan-dune-shaped ramp height, triangular tab length, and blowing ratio, under various incoming temperatures. Analysis of variance revealed that the blowing ratio has the greatest influence on cooling effectiveness. An average cooling effectiveness of 34.1% was achieved by the optimum parameter design.
關聯:
International Journal of Heat and Fluid Flow 100, p.109118