Multi-size Numerical Simulation of Bubbles on Gas-liquid Two-Phase Flow in a Centrifugal Pump

Abstract

In order to further understand the distribution and motion of gas phase in the gas-liquid two-phase flow inside a centrifugal pump, the numerical simulation on gas-liquid two-phase flow in the centrifugal pump was carried out and the CFD method was verified by experiment test. The MUSIG model was used as the multiphase flow model, coupled with the Prince-Blanch model and the Luo-Svendson model to describe the bubble breaking and coalescence process. The influence of inlet gas volume fraction and liquid flow rate on the gas-liquid two-phase flow inside centrifugal pump was investigated. The results show that the proportion of large bubbles in impeller is higher than that in volute. Large bubbles are mainly at the suction chamber inlet and impeller inlet, and small bubbles are mainly at the impeller outlet and volute outlet. From suction chamber, impeller to the volute, the average diameter of bubbles decreases in turn. With the increase of inlet gas volume fraction, the proportion of small bubbles in the pump decreases. Also, the flow pattern inside the pump gradually changes from bubble flow to gas pocket flow and the average diameter of bubbles in each flow passage component increases. With the increase of liquid flow rate, the proportion of small bubbles in the pump increases. Meanwhile, the flow pattern gradually changes from gas pocket flow to bubble flow and the average diameter of bubbles in each flow passage component decreases.