关键词: 轴流压气机；叶顶泄漏涡；二次泄漏涡；失速先兆；数值模拟；涡动力学

Abstract: In order to study the stall mechanism based on the vorticity dynamics in a single-rotor axial compressor，unsteady numerical simulation was performed using a scale adaptive hybrid Reynolds-average Navier-Stokes/large eddy (RANS/LES) method based on shear stress transport(SST) turbulence model. The results show that the rotor tip blockage caused by the breakdown of tip leakage vortex，secondary leakage vortex and induced vortex is responsible for the internal flow instability of the axial compressor at the design speed of 3kr/min. The angle between the tip leakage vortex trajectory and the axial direction increases from 70° to 76° as the compressor runs toward the small mass flow condition from near chock condition. At the same time the starting point of secondary leakage vortex moves upstream，which accelerates the tip leakage vortex movement to rotor leading-edge. The axial momentum of tip leakage vortex is almost same as that of the mainstream and tip leakage vortex moves to rotor leading-edge at near-stall condition. As the compressor’s mass flow decreases，the axial momentum of mainstream reduces. The axial momentum of the tip leakage vortex can not be suppressed and tip leakage vortex spillages to leading-edge of the rotor. As a result，spike-type stall precursor is induced.

Key words: Axial compressor；Tip leakage vortex；Secondary leakage vortex；Stall precursor；Numerical simulation；Vorticity dynamics