The analysis of interactional mechanism between hub corner stall and tip leakage flow in an axial-flow compressor stator

Taking a certain single-stage axial-flow compressor as the subject investigated, the interstage and outlet aerodynamic parameters were measured with pneumatic probes. Moreover, full three-dimensional numerical simulations were carried out to investigate the internal flow field of the stator with and without tip clearance. The overall performance and the spanwise distribution of the interstage and outlet parameters with tip clearance were predicted, and the results agreed well with the experimental data. The flow field near the endwall with tip clearance was compared with that without tip clearance, and it was found that the hub-suction surface corner stall was the main flow characteristic near the endwall. In the case without tip clearance, there existed a ring-like vortex structure near the hub-suction surface corner region, which consisted of multi-vortex system, and the vortex could induce a large amount of overturning flow on the suction surface. The introduction of tip clearance destroyed the formation of ring-like vortex structure, however a streamwise leakage vortex were formed at the hub-suction surface corner region. Meanwhile, the intensity of the spanwise separation vortex at the outlet of the passage was greatly increased. Both the leakage vortex and the increased separation vortex at the outlet edge enlarged the range of high total pressure loss under the 30% span at near stall condition.