Study on the multiphase unsteady flow characteristics of asymmetric multiphase rotor pumps

Existing multiphase pumps face challenges in transporting more than two phases, including high costs and energy consumption. To address the challenges of multiphase transportation in oilfields, a new multiphase rotor pump has been developed to reduce energy consumption and enhance efficiency. This study employs computational fluid dynamics technology, validated by experiments. Using dynamic mesh technology and the Eulerian multiphase flow model, the study analyzes the effects of pulsation characteristics, turbulent kinetic energy dissipation, gas content, bubble diameter, solid content, and particle diameter on pump performance. The results indicate that: (a) Compared to single-phase media, the pump's performance slightly decreases when transporting multiphase media, but the volumetric efficiency remains above 74%, indicating good media compatibility. Transport efficiency follows the order: η single-phase > η three-phase > η two-phase . (b) During transport, gas–solid mixtures tend to separate, with the gas phase primarily on the rotor surface and the solid phase along the pump chamber walls. Increasing the gas volume fraction reduces pump performance, but when the bubble diameter exceeds the meshing clearance, it can improve transport efficiency. Variations in sand content positively impact the pump's transport capacity. (c) Turbulent kinetic energy dissipation for single-phase, two-phase, and three-phase media is concentrated at the clearance and outlet. The dissipation intensity for multiphase media is greater than that for single-phase media and increases with the gas volume fraction. The solid phase shows minimal sensitivity to turbulent kinetic energy dissipation. The findings provide a reference for designing asymmetric multiphase rotor pumps and their use in petroleum transportation.