γ-Re_θt转捩模型在跨声速涡轮叶栅中的应用

In order to understand the flow characteristic and accurately predict the heat transfer coefficient of turbine cascades at transonic condition, according to the experimental freestream turbulence intensity and its decay rate of zero pressure gradient test cases, a simple method for estimating free-stream viscosity ratio for γ-Re_θt transition model has been given, to ensure the reasonable turbulence intensity near the blade leading edge and improve the predictive accuracy of heat transfer. It does not need many times of trial calculation. The flow and heat transfer over turbine cascades of MARK II and VKI has been studied with laminar model, shear stress transport (SST) low Reynolds model andγ-Re_θt transition model which had default viscosity ratio and reasonable viscosity ratio, by using computational fluids dynamics software CFX. The comparative analyses for numerical results and experimental data indicate that γ-Re_θt transition model is better than the others and also indicate that setting proper free-stream viscosity ratio can accurately predict the boundary layer transition position and can effectively improve theγ-Re_θt transition model’s prediction accuracy of heat transfer coefficient. When the inlet turbulence intensity is high, the relative error of heat transfer coefficient on the pressure side will be reduced by more than 30% compared to using the default viscosity ratio, control about 7%.