Effect of open crack on axial compressor performance

Abstract

To investigate the effects and mechanisms of rotor open crack on axial compressor performance, a steady 3D single-passage numerical simulation is used on NASA Stage 35. The results show that the crack leakage flow can affect the compressor performance, and the crack at the middle span has the most serious effect. At 100% rotating speed, there is a 1.2% decrease in peak total pressure ratio and a 0.36% decrease in peak efficiency. Besides, the stability margin is reduced by 26.9% relatively. The effect of crack is not only limited to the span range near it, and the main phenomena of cracks at different spans are various, concentrating in the aspects of vortex structure and stator passage flow. From peak efficiency to near stall condition, the effect of crack leakage flow is gradually strengthened, which leads to the flow blockage and reduces the working flow range of compressor. With the decrement of rotating speed, the reduction of stability margin increases gradually, but the influence span range of crack at low-speed narrows.