离心式压缩机声共振分析与试验验证

Acoustic Resonance Analysis for Centrifugal Compressor and Experiment Verification

声共振是离心式压缩机叶片破坏失效的一个重要原因,但是当前国内对其理论研究却非常有限,特别缺少有效的试验验证。为有效研究声共振的影响,首先从压缩机声腔的仿真分析入手,应用LMS Virtual.Lab Acoustics仿真软件对压缩机声腔的声模态进行计算,获取其特征频率及对应的振型。通过改变叶片的通过频率来改变气流的激振频率,当叶片通过频率与空腔声模态频率相近时将产生声共振。采用压缩机模型级试验台进行验证,进行压缩机声腔的压力脉动测试,获取不同转速下的叶片通过频率对应的特征幅值,声共振造成压力脉动幅值将成倍增加,进而产生较强的破坏作用。验证了声共振将造成的压缩机内部压力脉动大幅度增加,为大型离心式压缩机组的叶片状态监测与破坏抑制提供依据。

Acoustic resonance is an important factor leading to blade fatigue for centrifugal compressor.But the investigation is limited in this area.It is especially without effective experimental testing to verify it.To investigate on the effect of acoustic resonance,LMS Virtual.Lab Acoustics simulation software is used to determine the acoustic modes based on the acoustic cavity of centrifugal compressor.Its acoustic modes frequency and modes of pressure distribution can be obtained.Fluid excitation frequency can be different by adjusting blade passing frequency.Acoustic resonance will happen when the blade passing frequency is close to acoustic mode.Model level testing rig of centrifugal compressor is used to verify the simulation analysis.Pressure pulsation of acoustic cavity is monitored.The frequency amplitudes for different blade passing frequency are determined.The pressure pulsation will be up to several times when the acoustic resonance occurs according to experiment analysis.It will lead to serious damage for the centrifugal compressor.This research verifies the pressure pulsation increasing for compressor as acoustic resonance.It can contribute to blade condition monitoring and the prohibition failure of centrifugal compressor.