Numerical study on cavitation flow and induced pressure fluctuation characteristics of centrifugal pump

Abstract

In order to reveal the variation law between cavitation process and pressure pulsation characteristics of centrifugal pump, the internal flow characteristics and pressure pulsation characteristics of centrifugal pump during cavitation development are studied in this paper. First, select the standard k- ε with good coincidence between external characteristics and test data under rated conditions model for calculation after compare the standard k- ε, RNG k- ε and SST k- ω. Then, based on the unsteady calculation results, the characteristics of the internal flow before and after the cavitation critical point, the frequency domain characteristics of the pressure pulsation on the volute wall and at the impeller inlet monitoring points in different cavitation stages are compared and analyzed. Finally, root mean square (RMS) is used to study the change trend of pressure fluctuation energy intensity with cavitation process. The research results show that the prediction accuracy of the characteristic points of RMS change curve of pressure fluctuation for cavitation is higher than that of the traditional 3% head drop point. Using the energy characteristics of pressure fluctuation can more accurately and timely determine the occurrence of cavitation.