Application of multiscale methodology for transonic turbine blade tip cooling design

Recent research suggests that the cooling flow at transonic turbine tip has several unique flow features such as the strong interaction with the base flow, the acceleration at divergent duct, the strong shock boundary layer interaction, and the weak correlation between aerodynamic loss and the heat transfer. These flow features require the cooling design to be considered together with the tip geometry shaping. However, due to the large disparity of the length scales between the cooling holes and the turbine blade, the combination of the cooling design and the tip geometry shaping tends to be too computationally expensive. This study adopts the multiscale method in a commercial solver to provide a fast and accurate solution for the turbine tip cooling design. The method uses source terms added on the coarse mesh to generate the solution that is close to the one obtained with a well-resolved mesh. The source terms are found to present not only the influence of the mesh resolution but also the flow injection. The multiscale results have been validated against the experimental data and the fine mesh results. The agreement shows the potential for this method to be used in cases with large length scale disparity.