Measurement of cavitation noise in centrifugal pump
QING Biao1,2, YU Bo2, LAN Wei3, HU Jinheng2
1.Yingxiuwan Hydropower Plant, State Grid Sichuan Province Electric Power Company, Chengdu, Sichuan 611830, China; 2.School of Energy and Power Engineering, Xihua University, Chengdu, Sichuan 610039, China; 3.State Grid Chongqing Electric Power Company, Chongqing, 401120, China
Cavitation experiments are carried out to tackle cavitation problem a centrifugal pump in the paper by making use of TST6200 dynamic acquisition system, NoiseA2.10 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 are recorded by using a camera under these flow conditions. The recorded cavitation noise signals are analysed in frequency domain by adopting power spectrum method. The averaged powers of signal in three frequency bands are determined and the relationships between the signal powers and the net positive suction head available are 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 results in the frequency domain can reflect the development of cavitation in the pump. The specified powers 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.
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