Conjugate heat transfer simulation of air-cooled turbine based on Gama-Theta transition model

The finite volume method was adopted to solve the N-S equation based on unstructured meshes. The scheme of convective flux was AUSM+, and the method for calculating gradient was weighted least squares method. The LUSGS implicit method was applied with precondition and reordering of grids. The conjugate heat transfer(CHT) simulation platform, which coupled with the heat conduction equation, was established. The direct-coupled method was adopted, and the temperature was transmitted between interfaces by the interpolation method, which can maintain the conservation of flux. The γ-Rē_θt transition model was used in the calculation of the flow field in order to study the impact of transition on the CHT. The numerical results were compared with experimental data of the 5411 and the 4311 experimental condition of MARKII blade. It indicates that the transition model has little effect on pressure distribution and agrees well with the experimental ones. It can be seen from the distribution of intermittency that γ-Rē_θt transition model successfully predicts transition process from laminar to turbulent flow. The eddy viscosity calculated in laminar region agrees better with the real flow. Because the eddy viscosity has great influence on heat transfer simulation, the γ-Rē_θt transition model effectively improves the accuracy of heat transfer simulation in laminar and transition area, and the temperature and heat transfer coefficient agree better with the experimental results. However, because the model is coupled with the SST model, due to limitations of the model SST, a greater simulation error was produced in the shock and boundary layer interaction region.