离心泵水力诱导激振试验研究

摘要

The trend toward large and high speed centrifugal pump brings a great challenge for the safe and stable operation of centrifugal pumps.And fluid force induced vibration of centrifugal pumps is increased significantly.In order to reveal the fluid force induced vibration characteristic of centrifugal pumps,a single-blade centrifugal pump was used as the test pump.Based on the pump performance experiment,two vertically arranged eddy current displacement sensors were used to measure the transient displacement of impeller wear ring when pumping air and water.Time history and frequency spectrum of the displacement of the wear ring and locus of the wear ring displacement were obtained.Fluid force induced vibration characteristics of the centrifugal pump at different flow rates were obtained by using Huake hydraulic machinery tester based on the key phase information of the Hall sensor.The experimental results showed that the time history and frequency spectrum of the displacement of centrifugal pump were similar in both pumping air and water.Waveforms were periodically repeated distortion sinusoids and the dominant frequency was the rotational frequency of impeller.Locus of the wear ring displacement was distorted oval,and there was a mutation when pumping water.Fluid force induced locus of the wear ring displacement under different flow conditions were also distorted oval.And there was a mutation between 210° and 300°,the maximum appeared at around 130°.Fluid force induced vibration was significantly increased at the small flow rates,corresponding to the pump efficiency was significantly reduced,and it became weak at the design flow rate and large flow rates,corresponding to the higher efficiency of the pump.The research result provided a reference for the stable operation of centrifugal pumps and on-line fault diagnosis.%离心泵的水力诱导激振影响泵的安全稳定运行.为了揭示离心泵水力诱导激振特性,以一台单叶片离心泵为试验对象,采用两个垂直布置的涡电流位移传感器测量离心泵空转及抽水时叶轮口环的瞬态位移,获得了叶轮口环瞬态位移的时域图、频域图以及口环位移轨迹图.基于霍尔感应器的键相信息,采用华科水力机械综合测试仪获得了离心泵在不同流量工况的水力诱导激振特性.试验结果表明,离心泵空转及抽水时时域图、频域图相似,波形均为周期性重复的畸变正弦曲线,主频均为叶轮转频,口环位移轨迹图均为畸变的椭圆形,但抽水时口环位移幅值有所减小.离心泵的水力诱导口环位移轨迹图在不同流量工况下均为畸变的椭圆形,在210°～ 300°之间出现一个突变区域,水力诱导激振在小流量工况显著增强,在额定工况及大流量工况水力诱导激振基本不变.