Study on the hydraulic performance of geothermal electric submersible pump under gas-liquid flow

Abstract

Electric submersible pumps (ESP) are important devices for lifting geothermal water from geothermal wells to the ground. Due to the harsh condition and large discharge of ESP, the operation stability of the pump has become the focus of research. The entrance of gas-liquid flow is a common phenomenon of the geothermal well pump that could cause a decrease in efficiency and strong pressure pulsation. In this paper, the numerical simulation method is used to study the hydraulic performance of a two-stage ESP of a geothermal well with different gas volume fractions (GVF). Combined with the two-phase entropy production diagnostic method, the loss distribution and its causes are studied. The study found that with the increase of GVF , a surge occurred and the pump head and efficiency decreased significantly. The inlet and outlet of the impeller and guide vane are the areas with the most severe hydraulic loss. The change of the flow angle caused by the two-phase flow is the main cause of significantly increasing incidence loss at the inlet area. And the turbulent dissipation enhanced by the wake vortex shedding is accounted for the significant loss at the outlet region.