The parametric study of an electrical submersible pump rotary gas separator under two-phase flow condition

The performance of the electric submersible pump (ESP) significantly affected by Gas Void Fraction (GVF). Thus, using of a Rotary Gas Separator (RGS) is a suitable solution for this issue. The performance of the RGS is function of different parameters such as geometry of impeller, rotating speed, boundary conditions, media viscosity and GVF. In this study, the influences of GVF, viscosity, and flow rate on vortex and paddle wheel gas separator have been studied. For this purpose, commercial CFD software has been implemented. As results show, paddle wheel geometry is more efficient in comparison to the vortex gas separator in same conditions. Nevertheless, low efficient region occurs in high flow rates. In other words in flow rates higher than 1000 bpd efficiency of separator is lower than 50% which means that only the natural separation occurs in RGS equipment. Paddle wheel separator is more sensitive to GVF increase in high viscosities and the dropdown of efficiency in viscosity of 10 cp is about 20 in percent. The opposite happens with vortex gas separator in which the separation efficiency is more sensitive to increase of GVF of liquid stream in lower viscosities.