The Application of Non-axisymmetric Endwall Contouring and Blade Profile Optimization in a Counter-rotating Compressor

摘要

Non-axisymmetric endwall contouring is an effective way to mitigate secondary flow loss and to improve the performance of turbines. However, the application of non-axisymmetric endwall on eliminating separation vortex in axial flow compressors is relatively rare. The investigation rig is a dual-stage counter-rotating compressor which is at a high attack angle and has large separation vortex at the outlet guide vane (OGV) tip at near stall condition. In order to eliminate the 3D separation vortex, investigation has been done to optimize the OGV tip profile by a 3 dimension numerical simulation optimization platform, and the shroud endwall of OGV is optimization designed with non-axisymmetric endwall afterwards. Both the profile optimization and contoured endwall design are applied at near stall condition. Results show a 0.4% increase of the efficiency of the whole compressor after profile optimization. Optimized non-axisymmetric endwall is different with existing shapes, which consists of a 'hill' near the suction surface and a 'valley' near the pressure surface of the blade. The flow field of peak efficiency slightly improves after profile optimization and non-axisymmetric endwall contouring. Increased circumferential pressure gradient at OGV tip can effectively reduce the boundary layer thickness.