实验探究周向进气畸变对局部喘振型跨声速轴流压气机进气的影响

To explore the mechanism of stall point shift in detail，a series of experiments are conducted to explore the effects of circumferential inlet distortions on compressor instability evolutions with three different distortion intensities. During the experiments，the high-response dynamic test points are mounted to measure static pressures at rotor tips and total pressures at stator trailing edges，and an additional test point is set on the wall of the plenum to detect the system response. The results demonstrate that the decrease of mass flow rate near rotating stall under circumferential inlet distortions is due to that it is the occurrence of spike-type stall inception that leads to the flow instability instead of that of the partial surge. The instability inception of partial surge occurs under uniform inlet conditions and it is in the form of axisymmetric low-frequency disturbances localized in the stator hub region. The low-frequency disturbance still can appear under circumferential inlet distortions but the propagation characteristic of axisymmetric is suppressed. Therefore，the low-frequency disturbance cannot be further developed，and the final compressor instability is caused by the spike-type inception at the rotor tip. In conclusion，circumferential inlet distortion can change the stall route so as to extend the stalled operation point.