Modelling the Film Cooling of a Modern High-Pressure Turbine Nozzle Guide Vane in 3D CFD

Abstract In this paper, a reduced order film cooling model previously investigated on single cylindrical and laid back fan-shaped cooling holes is extended with a model variant for trailing edge cooling slots. The extended model is evaluated on a modern HPT NGV combining these cooling features and paired with either an eddy viscosity model or a differential RSM. To simulate a worst-case scenario during the maximum take-off operating point, a hot streak from the combustion chamber with a maximum temperature of about 2230 K is directly impinging on this NGV. Compared to resolved RANS simulations, the model performs better on the NGV than on single holes. In particular, the grid dependency is significantly reduced. The model error and grid dependence peak at the leading edge and decrease downstream of the showerhead. When an average film cooling efficiency is considered, three cells per cooling hole diameter were sufficient to approach grid convergence. A more accurate turbulence model also reduced the model error of the film cooling model, with an absolute error in the averaged film cooling effectiveness of 0.2 at the leading edge and 0.1 at the suction and pressure sides of the NGV.