Characterization of a centrifugal pump impeller under two-phase flow conditions

Multiphase pumping is an area of primary interest, particularly for the petroleum industry, where fair amount of gas can be found in oil wells production. This study presents the results of numerical simulations carried out in a centrifugal pump impeller of an Electrical Submersible Pump (Ns = 2063) conveying an air–water mixture. The results include the impeller head and the relative flow angle at the outlet (β2) as a function of the liquid flow rate, as well as the phases distribution within the impeller. A sensibility analysis with regard to the Gas-Void Fraction (GVF) and the bubble diameter was also included. The deterioration of the head reported by other investigators (in the case of two-phase flow) is reproduced and substantiated by means of the forces acting on bubbles within centrifugal impellers. Finally, comparison with experimental data is excellent, which demonstrate that Computational Fluid Dynamics (CFD) is a useful tool in the analysis of turbomachinery.