Study on Rotating Stall of Multistage Compressor Using Wavelets

Abstract

Abstract Rotating stall in the high speed compressor can lead to violent disruption of flow, damage to the blade structures and, eventually, engine shutdown. To investigate the mechanism of stall inception and stall propagation in multi-stage compressor, the onset and transient behavior of rotating stall in a transonic 2-stage compressor are simulated based on the in-house software ASPAC. Many sampling points are placed to monitor the flow variation. The analysis results of circumferential sampling points indicate that, the spectral characteristics of circumferential sampling points in steady state and unstable state are similar, the pressure pulsation is similar, but there exist phase difference. In the transition state, the main frequency is similar and the secondary frequency is slightly different, the 17th blade channel at the blade top of rotor 2 produces a disturbance with lower frequency and higher amplitude before other channels, which triggers the stall disturbance. The analysis results of axial sampling points show that the blade row interference frequency exists in the whole flow change process, and the disturbance of adjacent blade rows is dominant. The stall disturbance starts with rotor 2. This initial disturbance soon spreads to its adjacent stator 1 and stator 2. Rotor 1 is finally affected and enters into unstable state at about the 12th revolution.