Numerical and experimental study of viscosity effects on an electric submersible pump

This study systematically investigates the performance and internal flow field characteristics of the 387 series three-stage electric submersible pump under varying viscosities. By integrating experimental data with numerical simulations, the research focuses on analyzing the effects of medium viscosity on the pump's hydraulic performance, efficiency, power, and energy losses. Additionally, the turbulence suppression effect under high-viscosity conditions is thoroughly examined through numerical simulations. The results show that as viscosity increases, both the pump head and efficiency decline significantly, while total entropy generation rises substantially. Specifically, the pump efficiency drops from 48.32% to 3.2% as viscosity increases from 20 to 696 mPa·s, with a notable rise in total entropy production. The proportion of entropy generation due to direct dissipation and wall effects gradually increases under high-viscosity conditions. Vortex structure analysis reveals that under high-viscosity conditions, vortex intensity weakens and fluid rotation decreases, while wall shear effects and viscous dissipation become significantly stronger, emerging as the primary sources of energy loss. The distribution of wall entropy generation is concentrated at the inlet and outlet of the impeller blades, the leading edge of the guide vanes, and near the inlet and outlet of the impeller and guide vane backplates, highlighting the dominant role of viscous dissipation under high-viscosity conditions. These findings provide valuable theoretical and practical insights for optimizing the performance and enhancing the efficiency of electric submersible pumps in high-viscosity.