Numerical study on the effects of slot injection configuration and endwall alignment mode on the film cooling performance of vane endwall

In the pursuit of superior gas turbine engine, turbines are designed to operate with high inlet temperatures and result in high level of heat transfer to the endwall of the first stage vane. Film cooling is an effective cooling method, and widely used in the endwall cooling. The present research aims to numerically investigate the effects of the slot injection configuration and the endwall alignment mode on the film cooling performance of the endwall. Three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations were solved to perform the simulation with shear stress transport (SST) k - omega turbulence model. The turbulence model was validated by comparison with the experimental data. The results indicate that the coolant coverage enlarges with the decrease of the slot width. The case with half width filleted" slot achieves a higher film cooling level at most areas of the endwall than that of the case with half width sharp-edged slot, except the vane leading edge-endwall junction region. In addition, the filleted slot reduces the separation bubble and the horseshoe vortex obviously in mainstream passage. The end wall alignment mode also has significant effect on the adiabatic film cooling level of the endwall surface. The case with h = 1/4 . W obtains the maximum enhancement of film cooling level in the vane leading edge-endwall region, particularly in the region between slot exit and upstream of stagnation. However, the conventional case with h = 0 achieves the highest adiabatic film cooling level in the regions downstream from the stagnation. In addition, the low turbulence level induced by coolant jet is associated with high adiabatic film cooling level of the endwall in mainstream regions for all investigated cases. (C) 2016 Elsevier Ltd. All rights reserved.