离心泵流动空化噪声测试

Measurement of cavitation noise in centrifugal pump

选择3个流量工况(80,92,100 m3/h)对离心泵进行空化试验,利用TST6200动态采集系统、Noise A 2.10噪声测试软件和灵敏度为-210 d B的水听器构成的噪声测试系统采集空化噪声信号,并利用照相机同时拍摄3个流量工况下水流中空泡的变化过程.采用功率谱法对空化噪声信号进行频域分析和处理,将整个频域分为高中低3个频段,统计各频段信号的平均功率,得到信号功率随汽蚀余量之间的关系曲线.研究结果表明:离心泵流动空化信号的特征主要集中在低频段,而在中高频段没有明显特征;利用功率谱法对空化噪声信号进行分析和处理,得到的结果能够很好地反映离心泵流动空化的发展过程;选择了2个功率带分别作为判断离心泵空化初生和临界空化时的阈值,利用该阈值可以对离心泵空化进行实时监测.

Cavitation experiments were carried out to tackle cavitation problem of a centrifugal pump in the paper by making use of TST6200 dynamic acquisition system, NoiseA 2.10 noise test software and a hydrophone with -210 dB sensitivity under three flow conditions （80, 92, 100 m3/h）. At the same time, the variation histories of vapour cavity in the stream were recorded by using a camera under three flow conditions. The recorded cavitation noise signals were analysed in frequency domain by adopting power spectrum method. The averaged powers of signal in three frequency bands were determined and the relationships between the signal power and the net positive suction head available were obtained. It is shown that the characteristics of cavitation signal in the centrifugal pump are mainly involved in the low frequency band, but not obviously demonstrated in the medium and high frequency bands. The re- suits in the frequency domain can reflect the development of cavitation in the pump. The specified power in the two bands can be used as the thresholds respectively for cavitation inception and critical cavitation. By means of them, the cavitation in a centrifugal pump can be monitored in real time.