Conjugate Heat Transfer Simulation of Overall Cooling Performance for Cratered Film Cooling Holes

Abstract

Film cooling is widely applied as an effective way to maintain the turbine blade temperature at an acceptable level. The present paper investigates the overall cooling effectiveness and flow structure by performing conjugate heat transfer simulations for the flat-plate baseline cylindrical and three cratered film-cooling holes. The flow and heat transfer in the fluid domain is obtained using the Shear Stress Transport turbulence model, and the solid conductivity is considered by solving the Laplace equation. Four blowing ratios ranging from 0.5 to 2.0 are studied. The numerical results show that the concentric elliptic cratered hole yields a slightly higher overall cooling effectiveness than the baseline cylindrical hole, but the two contoured cratered holes exhibit great improvements due to the generation of the anti-kidney-shaped vortex pair. The area-averaged overall cooling effectiveness has improved by 5.58–65.30% for the contoured cratered hole. The variation of Biot number results in small change in the area-averaged overall cooling effectiveness. However, the area-averaged overall cooling effectiveness uniformity coefficient depends on the Biot number.

Keywords

• film cooling
• conjugate heat transfer
• cratered hole
• overall cooling effectiveness
• numerical simulation