Contrast study of the influence of the turbulent flow and transition model on the gas-heat coupled calculation of an air-cooled turbine

Developed was a heat conduction solution-seeking program based on the three-dimensional non-structural grid. Through a contrast with the analytic solutions, it has been verified that the weighted least square method has a higher precision than the Green function method when seeking solutions to the gradient. The heat conduction program with a three-order precision based on the weighted least square method was coupled with the program HIT-3D for calculating the flow field in cascades to accomplish a gas-heat coupled calculation. The 5411 test conditions for MARKII blades were numerically simulated and with the help of the turbulent flow model available in the program HIT-3D, the influence of the transition on the heat transfer calculation was studied. It has been found that the temperature predicted by using the BL model has a greatest difference from the test value, being up to 10% at the transition point. As the software has an ability to simulate the transition, the temperature error in the transition zone calculated by using the BL+AGS transition model, SST-Gama model and q-ω model is relatively small, being around 5%. It can be seen that the turbulent flow models with the transition being taken into account can better predict the temperature on turbine blades.