Numerical simulation and experimental study on gas–liquid two-phase unsteady flow in a centrifugal pump during the transition process

Abstract

In order to study the transition process of the gas-liquid two-phase flow in the centrifugal pump, the model pump was studied experimentally. At the same time, the Eulerian-Eulerian heterogeneous flow model and the SST k- ω turbulence model were used to simulate the transition process of the gas-liquid two-phase flow in the pump. The two-phase flow transition process in the pump was studied in detail by using the numerical model verified by experimental results. The flow law of the transition process in the pump was revealed. The judgment criterion for the end of the gas-liquid two-phase flow transition process in the pump was determined. The results show that the gas volume fraction at the pump outlet is more accurate than the outlet pressure. After 0.45 s, the gas volume fraction at the pump outlet does not change with time. It can be regarded as the end of the transition process. The average gas volume fraction at each monitoring point increases rapidly with time, then decreases slowly, and finally reaches stability. The average pressure at each monitoring point first drops rapidly, then rises slightly, and finally reaches a stable value. Along the radial direction of the section VIII in the volute, the amplitude of the gas velocity fluctuation gradually decreases, and the gas velocity gradually changes from greater than the liquid velocity to less than the liquid velocity since the driving effect of the impeller becomes weak. This study is of great significance to further improve the structural design of the gas-liquid two-phase flow pump and improve the stability of the pump operation.