Stall inception of low-speed axial-flow compressor with inlet distortion

Stall inception of a 2-stage low speed axial-flow compressor with both of uniform and distorted inlet flow was investigated.The inlet distortion has three kinds,including 1 × 90° single wave,2 × 90° double wave,and 1 × 90° rotating single wave.The results show that the stall inception of this compressor is modal-wave type in both uniform and fixed-distortion inlet flow,and neither of modal-wave and spike can be detected in rotating distortion inlet flow.First,the stall inception phenomenon with uniform inlet is studied when the rotor speed is of 600 r/min and 800 r/min,and modal wave disturbance can be found before stall occurs.In the developing process,speed of the stall cell does not change,and it equals to 42% of rotor speed.The result shows that variation of speed does not change the stall onset phenomenon.Second,the stall onset processes with different distortion equipments are inspected.The results show that the distortion may affect the characteristic of stall inception.In fixed screen experiment,the results reveal that the modal wave appears before stall.The early stall cell rotates fast,which will become full developed stall cell whose speed will steady after few rotations.The full developed stall cell in this fixed distortion is 43% of rotor speed,almost the same with the uniform inlet flow.