周期扰动下低压压气机旋转失速先兆辩识

Identification on Rotating Stall Precursor of a Low-Pressure Compressor via Periodic Perturbations

关键词:  压气机  进气畸变  旋转失速  空间模态  数值模拟

Key words:  Compressor  Inlet distortion  Rotating stall  Spatial mode  Numerical simulation

摘要:

为了尽早预测压气机旋转失速的发生，通过在进口施加进气周期干扰以达到识别旋转失速先兆的目的。以一台单级低速低压轴流压气机为研究对象，通过全周数值模拟再现了压气机旋转失速现象。在旋转进气畸变扰动下，具体分析不同干扰对压气机空间模态随分岔参数变化的影响，并考察幅值灵敏度在识别失速先兆中的作用。结果显示，在各种进气条件下压气机一阶、二阶空间模态的幅值及其灵敏度在各自不稳定边界均表现出明显增大的现象。通过监测一阶模态幅值灵敏度的演化，在进气畸变干扰的条件下，相比均匀进口条件能够提前识别出失速先兆。

Abstract:

A numerical method was investigated for the prediction of imminence of rotating stall in a compressor by using the properties of the response to periodic disturbance conditions. Taking a single stage low speed low-pressure axial compressor as the research object，full annulus，unsteady，three dimensional CFD has been used to simulate the rotating stall phenomenon of the compressor. Based on the CFD data with rotating distorted inflow conditions，the investigation was proposed to study the impact on the spatial mode under the perturbation of rotating distortions with respect to the bifurcation parameter. And the effect was also observed on the identification of rotating stall by using the sensitivity of amplitude of spatial mode. It was shown that both the amplitudes and sensitivity of amplitudes of first and second spatial modes to the variation of the bifurcation parameter increased significantly when approaching instable boundary under different inflow distortions. By monitoring the sensitivity of amplitude of first spatial mod as criterion via the perturbation of inlet distortion，the imminence of rotating stall could be identified better before its inception than with clean inflow condition.