Numerical investigation of the non-condensable gas effect on predicting the cavitation performance of a centrifugal pump

Abstract

Improving the prediction accuracy of cavitation performance of pumps is a research hotspot. The non-condensable gas effect has been included in some existing cavitation models. However, the amount of the non-condensable gas in water still needs discussing since it will affect the vaporization process. In this paper, Zwart-Gerber-Belamri model was used to calculate the cavitation performance of a three-blade centrifugal pump with water temperature of 10 °C and a corresponding cavitation experiment was carried out to verify the numerical model. Numerical results respectively with five volume fractions of the non-condensable gas were analyzed. Compared to the recommended default value, the head drop curve obtained with a much lower volume fraction of the non-condensable gas agrees better with the experimental result. Comparison and analysis of the cavitation patterns as well as the flow field indicates that the default volume fraction of the non-condensable gas which was proposed at 25 °C overestimates the interphase mass transfer rate at 10 °C Reasonably setting the volume fraction of non-condensable gas in the cavitation model will achieve more accurate cavitation pattern, and then the head drop curve of pump can be predicted more precisely.