Investigation of gas–liquid two-phase flow in a three-stage rotodynamic multiphase pump via numerical simulation and visualization experiment

To investigate the gas–liquid two-phase flow in a three-stage multiphase pump, numerical simulations and visualization experiments were performed. A mixture of air and water was selected as the medium. A three-dimensional flow field of the three-stage multiphase pump designed by authors was simulated employing the commercial computational fluid dynamics software ANSYS-CFX to solve the Navier–Stokes equations for steady flow and unsteady flow. The differential pressure of each stage and change characteristic of gas volume fraction under various inlet gas volume fraction were compared via steady simulations. The distribution characteristics of pressure and gas volume fraction in three stages were studied, and the movement of gas pockets in impellers was discovered via unsteady simulations as well. Four types of flow patterns were observed during the visualization experiments with the increasing inlet gas volume fraction. The results of the experiment reveal that the positions and characteristics of the gas pocket were similar to the results from the unsteady simulations, which verify the reliability of the simulations.