The Relationship of Spike Stall and Hub Corner Separation in Axial Compressor

Abstract

AbstractThe onset of spike stall induced by the interaction of hub corner separation flow with the tip leakage flow is investigated in detail by numerical method in this paper. The time resolved results indicate that the remarkable radial secondary flow from hub to tip near the trailing edge is formed when the compressor approaching rotating stall. The radial secondary flow is unstable and cross-passages propagates, which flows in and away out of the tip region periodically. The disturbance caused by radial secondary flow will influence the tip leakage flow directly by reforming the vortexes in blade tip region. A secondary vortex which comes from the radial migration of corner separation and is induced by the tip leakage vortex appears in the tip region. The simulation result demonstrates that the generation of the secondary vortex is an important symbol of blockage growth in the tip region at the stall inception phase. The disturbance produced by secondary vortex is an incentive of the leading edge overflow and the intensity of secondary vortex could be used as a criterion of rotating stall before leading edge spillage.