Numerical analysis and experimental research of shroud casing boundary layer removal on a counter-rotating compressor

Domain scaling method is used in the unsteady numerical simulation of a dual-stage axial counter-rotating compressor. Numerical results show that tip leakage vortex over Rotor 2(R2) is the main source of flow blockage in high spanwise and high entropy zone in the tip region, which makes outlet guide vanes in the downstream endure a serious flow condition. Shroud casing boundary layer removal in the high entropy core over rotor tip can make the flow field better and improve the characteristic of compressor. Based on the results of numerical calculation, we redesign and machine the aspirated shroud casing, meanwhile set up boundary layer suction and control system. Experiment is carried out at 1.0% suction rate through R2 tip region shroud casing at 80% corrected rotating speed. Results indicate that boundary layer suction through shroud casing should be used under the massflow with the highest efficiency in original characteristic. Boundary layer suction can better the efficiency and improve the loading level in this flow area. Else it has a negative influence.