Surface Roughness Effect on Performance of an Electric Submersible Pump

An electric submersible pump (ESP) is a multistage centrifugal pump widely used in the petroleum industry to transport wellbore fluids to the surface. For a turbulent flow through a pump, the surface roughness plays a vital role as it causes flow separation and increases boundary layer momentum loss. In the present work, a 3D numerical analysis by solving a Reynolds-averaged Navier-Stokes equation with k-ω SST turbulence model for wall bounded steady incompressible flow through a pump was carried out. The geometry was meshed and validated numerically with the experimental data available in the literature. At the design and off-design conditions, the simulations were conducted to study the effect of roughness and its dependence on Reynolds number of the flow. The performance of the pump was compared for a nondimensional roughness factor (K). A hydraulically smooth surface gives a maximum head. A drop in head observed up to the critical surface roughness (K = 0.1), and the head further rises for K > 0.1. The effect of roughness factor increases with increase in Reynolds number.