Evaluation of RANS Turbulence Models for Prediction of Lateral Film Cooling Effectiveness at Low Blowing Ratios

Abstract

Accuracy of numerical predictions of film cooling performance is vital to investigate for designing and analyzing film cooling technology. Three RANS turbulence models of Standard k-$\varepsilon$ (SKE), Standard k-$\omega$ (SKW) and Shear Stress Transport methods (SST k-$\omega$) were selected and used to simulate low blowing ratio cases ($\mathrm{M} < 1$). The three blowing ratio of 0.2, 0.5 and 0.7 were produced using an inclined cylindrical hole of 30 degree made on a flat plate. ANSYS CFX solver was used to simulate the selected experimental cases with density ratio (DR) of 1.8. The numerical results of the three turbulence models under the blowing rate of 0.2 have not captured the lateral distribution of coolant correctly. SKW under the blowing rate of 0.5 have accurately predicted the effectiveness in mixing region. Centerline adiabatic effectiveness generated by SKW model was in a good agreement with experimental results for the blowing rate of 0.5. For the blowing rate of 0.2, the centerline effectiveness were best predicted by the SST model while SKW and SKE models can be used to predict the adiabatic effectiveness with considerable accuracy in lateral direction in the region of $\mathrm{X}/\mathrm{D} < 10$.