Study on pressure pulsations and transient fluid forces in centrifugal pump under different degrees of cavitation

Abstract

At the early stage of cavitation, the external characteristics and vibration noise of centrifugal pump have not changed significantly, but the flow conditions in the pump have changed markedly. In order to carry out in-depth study on the change characteristics of the flow conditions in centrifugal pump under different degrees of cavitation at the early stage of cavitation, in this paper, the quantitative relation between cavitation degree and pressure pulsation and fluid force was established by means of numerical calculation combined with test and by analyzing the changes in pressure pulsations and fluid forces in the pump under different degrees of cavitation degree. Studies have shown that the pressure pulsation amplitude and range value at the main frequency (shaft frequency and blade frequency) increases with the cavitation degree. The RMS value of pressure pulsation in each frequency band is positively correlated with cavitation development. In case of severe cavitation, the pressure pulsations in high frequency bands are greatly affected by cavitation. The radial force on pump volute and impeller fluctuates more significantly with the increase of cavitation degree.