Application of the two-phase three-component computational model to predict cavitating flow in a centrifugal pump and its validation

To improve the numerical simulation accuracy of predicting the cavitating flow in centrifugal pumps, a new developed cavitating flow computational model, named two-phase three-component computational model, is proposed. To evaluate its performance, the comparisons are carried out among CFX default cavitating flow computational model, the optimal computational model and the proposed model, concerning a centrifugal pump. Meanwhile, the experiments are conducted to validate the calculations, including pump head drop test and cavitating flow visualization at the pump inlet. The results show that the two-phase three-component computational model has better performance both on predicting pump head drop and bubble structure. It is observed in the current work that the sheet cavity firstly occurs on the leading edge of the suction side of the impeller. With the cavitation number decreasing, the cavity length grows rapidly along the suction side towards impeller outlet. Simultaneously, the cavity starts to extend to the pressure side. Based on the analysis of the blade pressure load on the blade surface and total pressure coefficient distribution in the channel, it is found that the cavitation has great effect on blade pressure load. Besides, the total pressure coefficient drops mainly take place on the upstream, that is to say, the growth of cavitation affects downstream rarely.