Conjugate heat transfer analysis of transonic internally cooled turbine blades

The conjugate heat transfer (CHT) method was employed to predict the thermal properties of two types of transonic internally cooled turbine blades, linear cascade and annular cascade. Firstly, the NASA turbine vane MARK II was simulated. It was linear cascade cooled internally by air flowing through ten round and radially-oriented channels. Different simulations with laminar model, turbulence model and transition model were discussed, and the CHT method turned out to be feasible and reliable after comparing with the experiment results. Then SST model was applied to simulate a three dimensional annular cascade with and without transition model respectively, which was high pressure stage stator cooled by polygon channels. The results show that reasonable turbulence model must be employed to obtain accurate temperature distribution with consideration of transition. Heat boundary condition also has an impact on the aerodynamic flow such as the separation and reattachment. And the effects of shock wave, separation, passage vortex and corner vortex on the temperature distribution are significant. In addition, internal cooling is important to lower the blade temperature, and numerical results can be referred to improve the cooling structure.