Research on stagnation zone based on RTD method and improvement of coupled fluid-solid heat transfer considering mesh morphing

The permanent magnet synchronous motor (PMSM) is sealed inside the compressor, and the heat dissipation space is narrow. High temperature will affect the normal operation of the PMSM. Based on the heat transfer theory and hydromechanics theory, the fluid and temperature fields of a 560 kW PMSM for a compressor are numerically calculated, and the temperature distribution of each component of the PMSM is revealed. The rheological properties of the cooling medium are diagnosed from the perspective of fluid residence time. The location of the stagnation zone is clarified and its volume fraction is analyzed. In order to reduce the volume fraction of the stagnation zone, the shape of the fluid field is optimized based on the mesh morphing optimization method. After optimization, the volume fraction of the stagnation zone is reduced from 0.187 to 0.125, and the temperature of each component of the PMSM is reduced at different degree. Finally, the temperature rise test of a 560 kW PMSM for a compressor is carried out, and the test data are compared with the calculated results to verify the correctness of the calculated results.