Effect of variable speed conditions on the internal flow characteristics of a multiphase pump

Abstract

The multiphase pump is an important device in the mixing and transmission technology for oil and gas. It simplifies the entire process of oil and gas extraction and transmission. In actual engineering, the gas volume fraction (GVF) of the fluid being transported is constantly changing, and this change has an important impact on the internal flow characteristics of the pump. The multiphase pump also needs to change the operating speed to adapt to this change to keep its internal flow field and external characteristics in a good operating range. In this work, the internal flow characteristics of the pump unit under different velocity conditions for the bullet flow type are compared and analyzed. It can be concluded that the higher the rotational speed, the better the pressure increment performance. The lower efficiency of the multiphase pump under high-speed conditions is mainly caused by the increase in the velocity difference between gas and liquid phases in the back area of the guide vane outlet, which leads to an increase in a vortex. Unlike the design point condition, the efficiency curves of the two high-speed conditions show an increasing trend in the design flow interval from 0.1 times to 1.2 times. It shows that an increase in speed causes the high-efficiency zone of the multiphase pump to shift to the high-flow rate zone. Finally, an experimental investigation of the variable velocity condition was performed to verify the validity of the numerical simulation.