离心风机吸力侧旋转失速和进口涡流特征诊断

Feather Diagnosis of Suction-Side Rotating Stall and Inlet Vortex in Centrifugal Fans

针对离心式风机进口涡流和吸力侧旋转失速的低频耦合问题，采用谐波小波变换方法，对4-73No8D型风机吸力侧旋转失速和进口涡流的脉动信号进行了时频分析和特征诊断。结果表明．二者均出现在10～50Hz范围内．吸力侧旋转失速的流量一频率关系是一条平坦的曲线．而进口涡流频率与流量成一定斜率的线性关系，且二者在耦合发展过程中存在时频信号分离现象。该方法能够有效诊断离心风机的非稳态流问题。

To diagnose the centrifugal fans coupling fault between suction surface flow separation and the inlet vortex at low frequency scope, the Harmonic Wavelet was used for time-frequency analysis and feature extraction to the pulsation from suction surface rotating stall and inlet vortex at 4-73No8D fans. Experimental study shows: they both appear at 10-50Hz, the suction surface rotating stall flow-frequency relation is a flat curve, the inlet vortex flow-frequency is a gradient linear relation, the time-frequency signal separation phenomena can be found in the course of coupling development. The effectiveness of the method is showed in the fault diagnosis of fans unsteady flows.