Analysis of flow and phase interaction characteristics in a gas-liquid two-phase pump

Abstract

To analyze the characteristics of internal flow and phase interaction in a gas-liquid two-phase pump, the influence of Inlet Gas Void Fraction (IGVF), discharge coefficient, and medium viscosity were investigated using medium combinations of air-water and air-crude. Simulations were performed using ANSYS_CFX at different IGVFs and various values of discharge coefficient. Structured grid for the full flow passage was generated using ICEM_CFD and TurboGrid. Under conditions of IGVF = 0% (pure water) and IGVF = 15%, the reliability of numerical method was proved by means of the comparison with the experimental data of external characteristic. The results for air-water combination showed a uniform gas distribution in the inlet pipe, and formation of a stratified structure in the outlet pipe. The gas in impeller gathered at the hub because of the rotation of the impeller, also, the interphase forces increased with the increased IGVF. For the two medium combinations, the drag force was the largest interphase force, followed by added mass and lift forces, and then the turbulent dispersion force was the least, which can be neglected. Because of the larger viscosity of crude than that of water, the variation trend of interphase forces in the impeller is relatively smooth along the flow direction when the medium combination was air-crude.