基于小波变换的离心压气机旋转失速先兆时频分析

THE TIME-FREQUENCY ANALYSIS OF ROTATING STALL INCEPTION IN THE CENTRIFUGAL COMPRESSOR BASED ON WAVELET

本文采用连续小波变换的方法，对跨音离心压气机机壳壁面动态压力及叶片应变信号进行了时频分析。结果表明，在失速前的先兆阶段存在着两种特征截然不同的先兆成分。即连续增强成分和间断扰动成分。间断扰动成分和间断失速段的失速团具有相近的特性．压力信号中间断失速段的失速团频率比在连续失速段的失速团频率高，而叶片应力信号中则相反，并计算得出连续失速段的失速团比间断失速段的失速团数目少。在间断失速段，压力信号的频率阶跃以及叶片应变信号的频率衰减现象，对应于扰动能量聚集而使失速团数目减少的过程。

This paper presents time-frequency analysis of the rotating stall inception in a centrifugal compressor by means of wavelet transform. The data was acquired form a blade-mounted semi-conductor strain gage and an array of pressure transducers positioned at different locations along the flow path on the shroud wall. It is found that there were two types of rotating stall, intermittent and continuous, and there are two different types of stall precursor, the progressive-amplitude continuous precursor and the intermittent precursor. The behavior of the intermittent disturbance was similar to that of the intermittent stall, but the pressure ocillation frequency of the intermittent stall is lower than that of latter, and their gage frequency is reversed. And the number of stall cell was more than that of intermittent disturbances. During the inception of the intermittent stall, the frequency stepping-up of pressure signal and the frequency decaying of gage signal correspond to the process of the energy congregating and the stall cell number decreasing.