Mechanism investigation of aerodynamic effect on the inlet flow distortion in a transonic axial-flow compressor

An inlet flow distortion with plugboard was simulated. The flow-field characteristics, circumferential distribution of shock wave and stall mechanism were analyzed in detail. Experiment and numerical simulation were conducted. The experimental and numerical simulation results show that the positive and negative pre-rotation were generated in front of the compressor at different circumferential respectively, and the circumferential distribution of velocity in front of the rotor constantly changed along axial direction. The axial velocity of distortion sector was larger near the rotor leading edge. The air flow was under positive pre-rotation in non-shock wave region at transition sector A where the rotor was rotated into the low pressure sector. It was under negative pre-rotation in strong shock wave region at transition sector B where the rotor was rotated out of the low pressure sector. The leakage vortex of transition sectors was stronger than any other sectors. So the transition sectors were the regions where unstable flow occurred in advance.