Aerodynamic Design Studies of a Transonic Centrifugal Compressor Impeller Based on Automated 3D-CFD Optimization

A transonic centrifugal compressor is optimized to improve the performance of the impeller by varying the geometry of blades and the meridional contour in the axial range of the main blades. The main objectives are to increase the isentropic efficiency and the operating range. A genetic algorithm controlling an automated process chain is used as the optimization method. To ensure a wide operating range the optimization is performed at three operating points on the 100 % speed line. A method, which is developed to use stationary CFD calculations for predicting the blade tone noise, the strongest component of the compressor noise, is used to reduce the compressor noise emissions. To evaluate the success of the optimization their best members' fitness values will be analyzed experimentally. The optimization procedure is described in detail. The geometrical modifications leading to the aerodynamic and acoustic improvements are discussed. A mechanical stress optimization of the impeller is planned for the near future.