Stall Inception Analysis on Axial Compressors With Different Rotor Loading Distributions Under Radial Inlet Distortions

Stability studies were conducted on a single-stage, low-speed compressor with different rotor loading-distribution designs under a uniform inlet, 10% intensity, and 20% intensity total tip pressure distortion inlet conditions via numerical calculations, theoretical model predictions, and experimental methods. The steady numerical performance was in basic agreement with experimentally measured performance. The theoretical prediction model showed an error within 1.5%, which is less than that of the steady numerical calculation. The total tip pressure distortion reduced flow stability. Conversely, the design of moving the rotor loading axially rearward significantly improved the flow stability. The blade loading analysis showed that the radial distortion caused a radial redistribution of rotor loading. The increase in the rotor-tip loading due to tip distortion was the main reason for the reduced flow stability. In contrast, the design of moving the rotor loading axially rearward reduced the rotor-tip leading-edge loading, enhancing the flow stability. Moreover, an analysis of the unsteady flow validated the findings of the blade loading analyses. It was found that the periodic evolution of the tip leakage vortex (TLV) had an adverse effect on flow stability. In addition, the modified rotors could prevent the tip leakage flow (TLF) from spilling from the leading edge and prevent the interaction of different diffusing regions, decreasing the probability of flow separation.