Thrust in Electrical Submersible Pumps (ESPs) is a very important factor that affects pumps' performance. Thrust forces in pumps can increase the friction losses and reduce the overall pump efficiency and lifetime. Pump designers have to design pumps to handle thrust generated in the operating range whether by adding up-thrust protection, down-thrust protection, or sometimes both kinds of protections if the operating range includes both up and down thrust.

Hydraulic thrust mainly depends on the hydrodynamic forces generated inside ESPs. These hydrodynamic forces depend on many factors like blade loading, seal geometries, seal diameters, seal engagement, and balance holes location and sizes. Not only is the thrust magnitude important to predict, but also the shape of the thrust curve plays an important role in defining the operating range. If the thrust curve is flat, then this means a wider operating range for the pump.

Currently, no model is available to predict or design for thrust curve. Engineers use an iterative process of manufacturing and testing trying to reach the optimum seal configuration and balance holes geometry for better thrust and pump performance.

In this paper, a detailed CFD model of a mixed flow multistage ESP is presented including all seal elements and balance holes to be able to predict hydraulic thrust. Thrust curve is predicted for the first time using CFD analysis. Different seal geometries and balance holes configuration is also modeled to study the effect of geometry change on thrust curve. The model is validated using experimental test results. Also, other design parameters like the shape of the head curve, pump efficiency, and gas handling capability were controlled early in the design phase using CFD analysis.

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