Flow Pattern Prediction in Electrical Submersible Pump (ESP) Under Gassy Flow Conditions Using Transient Multiphase CFD Methods With Visualization Experimental Validation

This paper presents a numerical study of flow pattern recognition inside the rotating impeller of electrical submersible pump (ESP) using the transient multiphase CFD simulations. Based on the previous experimental facility for visualizing flow patterns in an ESP, the entire flow domain is constructed. The high-quality structured mesh comprising hexahedral grids is generated using multi-block technique in ANSYS ICEM. Mesh independence is confirmed by comparing numerical results with catalog curves. For transient two-phase simulation, the realized RNG k-ε turbulence model with volume of fluid (VOF) and Eulerian multiphase models is successfully implemented in ANSYS Fluent solver. The sliding mesh technique is applied to interfaces where rotating and stationary parts interact. By incorporating the same boundary conditions as experimental study, two different cases with fixed liquid flow rates and varying gas flow rates are selected to conduct CFD simulations. The comparison of numerical results against experimental visualizations shows that the two-fluid Eulerian model is superior to VOF model in simulating gas/liquid flow in a rotating ESP. The single-phase simulation results match catalog curves of ESP, which validates the numerical methodology. For gas-liquid simulations, the simulated flow patterns with Eulerian model agree well with visualization experiments. The distinct flow patterns prevailing inside the rotating ESP impeller are captured by CFD simulations, including dispersed bubble flow, bubbly flow, and intermittent flow.