Numerical Analysis of Performance Degradation in Multistage Electric Submersible Pumps

Edgar M. Ofuchi¹; Henrique Stel¹; Thiago Sirino¹; Rafael Dunaiski¹; Rigoberto E. M. Morales¹

¹ Federal University of Technology-Paraná - UTFPR

doi:10.20906/CPS/COB-2015-2519

Resumo

When handling oils, centrifugal pumps experiment a performance degradation that affects head, flow rate and efficiency. This degradation is related to a decrease of the pump Reynolds number, which in turn is a function of the impeller speed and fluid viscosity. The effect of the Reynolds number on performance, as well as its relation with other pump dimensionless numbers are still quite unexplored in literature. These issues are addressed in this study through an investigation of the performance degradation in multistage Electric Submersible Pumps (ESPs). Numerical simulations are conducted using two different semi-axial ESPs operating with a wide range of conditions and viscosities. A multi-block, transient rotor-stator technique with the aid of a Computational Fluid Dynamics (CFD) software was used to solve the flow numerically. Dimensional analysis of the flow was adopted to manage the numerical results and correlate performance degradation of both pumps. Such procedure consolidated data for both ESPs fairly well. This resulted in a methodology to correct the pumps head and flow rate as a function of the Reynolds number and a dimensionless specific speed. Results suggest that the approach presented could be also extended for other ESP models, which would be useful for the petroleum industry.

Palavras-chave: ESP; Performance Degradation; CFD; Reynolds; Specific speed