Electrical submersible pump (ESP) is one of the most widely used artificial lift methods in the petroleum industry. It is crucial to study the wear in ESP stages with sand production, which can severely reduce pump performance and life span. Usually, experiments and simulation studies were conducted for simple flow geometry such as direct impingement and pipe elbow. Various erosion equations and models were developed for different material and affecting factors. However, the predictions of these erosion models for complex flow geometry need to be evaluated in order to make a proper selection. This study will compare the wear patterns and erosion rates of six different erosion models in three ESPs by using commercial Computational Fluid Dynamics (CFD) software ANSYS Fluent. The results will offer engineers a brief guidance of erosion model selection for complicated flow domain.
In this paper, stages of three ESPs, DN1750, TE2700 and Flex31, are modeled. For each pump, the flow domain of two stages are selected and high-quality structured meshes, comprising around 1.2 to 1.8 million hexahedral grids per stage, are generated by ICEM or Turbogrid. Six erosion models, Ahlert (1994), Haugen (1995), Zhang (2007), Oka (2007), Mansouri (2014) and DNV (2015), are simulated under pump best efficiency point.
Among six selected erosion models, Ahlert (1994) gives a much higher wear rate than others, while DNV predicts lowest, Besides, the impact angle functions show that all models, except Haugen (1995), assume steel to be a ductile material. Furthermore, the erosion pattern, location, and distribution of all three pumps are different, which indicates different solid particle handling capabilities and failure reasons of radial type and mixed type ESPs.