Numerical research on performance failure caused by gas blocking in multiphase mixed-transport pump under non-uniform inflow conditions

Abstract

The helical-axial multiphase mixed-transport pump fails due to gas blocking caused by gas-liquid separation caused by cavitation under complex conditions with high gas volume fraction. This is an urgent engineering problem that needs to be addressed in the application of this pump. In order to simulate the flow structure characteristics in the channel, two types of non-uniform inflow boundary conditions were introduced. The bubble structure, velocity, and pressure under different inflow conditions were compared and analyzed, and the variation patterns affected by non-uniform boundary conditions were obtained. At the same time, the internal flow characteristics and mechanisms of multiphase mixed-transport pump are analyzed based on the velocity changes at the inlet of the impeller and the pressure fluctuations at the outlet of the guide vanes, leading to the intensification of gas-liquid separation and eventually the development of gas blocking. Research has shown that through programmatic control of the inlet boundary conditions, a linear change in inlet pressure has a more significant effect on the intensification of gas-liquid separation in the flow channel of the mixed-transport pump than a sinusoidal change, ultimately leading to significant performance failure when generating gas blocking. The research conclusion provides reference value for solving gas blocking in engineering applications of helical-axial multiphase mixed-transport pump.