Eventos Anais de eventos
ENCIT 2016
16th Brazilian Congress of Thermal Sciences and Engineering
General model to predict performance degradation in centrifugal pumps.
Submission Author:
Edgar Ofuchi , PR
Co-Authors:
Ana Leticia Lima Santos, Thiago Sirino, Henrique Stel, Rigoberto Morales
Presenter: Edgar Ofuchi
doi://10.26678/ABCM.ENCIT2016.CIT2016-0561
Abstract
Electrical Submersible Pump (ESP) system is an artificial lift technique used by petroleum industry whenever the oil production of a given well must be restored. However, when centrifugal pumps operate with viscous oil, its performance is lower when compared with the performance of the centrifugal pump operating with water. In addition, several ESP models have semi-axial impellers and specific speeds that do not strictly match into the range of pumps normally used in literature to evaluate performance degradation. These issues are considered in this investigation through a numerical study of the flow in two different multistage, mixed-flow type ESPs. Dimensionless numbers such as the Reynolds number and specific speed are used to compare data for different operating conditions and between both ESPs analyzed. This investigation is carried out numerically by using a Computational Fluid Dynamics (CFD) package, where the flow inside three ESP stages is considered and modeled using a multi-block, transient rotor-stator technique. Head curves for several operating conditions are compared with manufacturer’s curves and experimental data for a three-stage ESP, showing good agreement for a wide range of fluid viscosities and rotational speeds. Results suggest that performance degradation is directly related to the Reynolds number and specific speed. With the results a general model to predict performance degradation in centrifugal pumps is proposed. This model correlate data from both pumps fairly well and could probably be extended for similar ESPs. Such a procedure could then be an alternative to estimate performance degradation over methods still used by the petroleum industry that may not be quite suitable for mixed-flow ESPs. In general, results and conclusions from this work can also be useful to bring more information about the flow of highly viscous fluids in pumps, especially in mixed-flow, multistage ESPs, which are still scarce in literature.
Keywords
centrifugal pump, performance degradation, general model, CFD
