Flow pattern in a horizontal primary separator

Abstract

It is important in any gravity separator to provide uniform flow conditions between the inlet and the outlets. In this study, two-dimensional Computational Fluid Dynamics (CFD) modelling was used to reveal the problems of a conventional primary gravity separator at the bulk liquid flow zone particularly. Internal device in the form of simple perforated baffle was incorporated to the separator and its effect on improving the uniformity of flow was investigated. A CFD commercial package, ANSYS was used as the simulation tool. The modelling effort concentrated on the inlet and momentum breaker zone and the bulk liquid flow zone. The problem was first simulated in its simplest form, leaving out baffle in order to understand its underlying transport phenomena. The observed results were then discussed and interpreted according to the law of physics. After the fundamental model was successfully developed, it facilitated the optimisation of hole spacing and diameter of a baffle on a separator’s performance. Derived Standard Deviation (SD) for the horizontal velocity along the locations at specific position was used as an indicator to the uniformity of flow and the relative severity of recirculation.