Multidisciplinary design optimization based on parameterized free-form deformation for single turbine

In a traditional multidisciplinary design optimization loop for complex-shaped structures, the regeneration of structure geometry and its associated analysis grids may be unsuccessful or of poor quality, which will reduce the result validity and efficiency of multidisciplinary design optimization. In this Paper, an improved multidisciplinary design optimization method based on parameterized free-form mesh deformation is proposed. Using this method, the analysis grid can be directly updated with high quality instead of regenerating the geometry model when design variables change during optimization. To achieve the mesh deformation of a blade in a single turbine stage, three-dimensional control volume needs to be constructed using two-dimensional control planes at different blade heights, where the control points in the two-dimensional control plane are arranged and parameterized according to the definition of profile design variables. The grids for both computational fluid dynamics and structural analysis are controlled by the same control volume to ensure grid consistency on the fluid-structure interface. Results for an example single turbine stage show that the proposed method can guarantee good controllability and high grid quality when updating design variables in optimization loop. Multidisciplinary design optimization for the single turbine stage is performed, and the optimization results indicate a significant improvement of isentropic efficiency and turbine blade fatigue life. Therefore, the proposed multidisciplinary design optimization method based on parameterized mesh deformation provides an efficient tool for the design of complex and high-performance engineering structures.