Experimental and Numerical Investigation of Phase Separation with Entrance Mixing

Abstract

In this paper, experimental and numerical methods are used to investigate the separation of an oil / water mixture. An American Petroleum Institute (API) gravity-based separator was built to conduct the experimental studies. The numerical simulations were developed with the same geometry as the experimental setup. The effect of inlet velocity and the oil volume fraction on the separation process is investigated with the new numerical predictions. Validations of the simulation model show that the numerical predictions of the multiphase Volume of Fluid (VOF) model with the laminar viscosity model agree well with the experimental results. The results of oil volume fraction and velocity vector distribution in the separator showed that there was a mixing zone located at the entrance, which had a lower relative oil volume fraction and a higher velocity. The study of the inlet velocity effect on the mixing length of the entrance mixing zone shows that when the fluid in the separator is in the laminar range, the mixing length is less than 40% of the total separator length. However, when the inlet velocity was increased until the fluid in the separator reached the transient range, the mixing length occupied 90% of the total separator length.