A Numerical Investigation of Perforated Inlet Baffle Configurations on Flow Behavior in a Rectangular Oil / Water Separator using CFD 10.32526/ennrj/24/20250221
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Abstract
Gravity separation tanks are generally utilized to separate water and oil in treatment applications. The operating behavior of such tanks is likely to be sensitive to tank operation, as these factors will largely determine whether or not oil droplets stratify easily and float independently of water. Within the present investigations, the influences of several holes in the baffles on water and oil separation within a rectangular tank were explored through the utilization of a numerical model and the consequent simulation of fluid flow. Moreover, in order to ensure the credibility of the simulations, validation was carried out through utilization of a model based on work already conducted experimentally. FLOW-3D (version 11.04) software was applied to model a steady-state, incompressible flow within a two-dimensional (x-z) domain using the Reynolds Averaged-Navier-Stokes (RANS) equations. The RNG k-ε turbulence model was adopted to approximate the hydraulic behavior, while the volume of fluid (VOF) approach was employed to capture the air-water interface. In addition, the FAVOR (Fractional Area/Volume Obstacle Representation) technique was used to represent the geometric details of the perforated baffles. 2 perforated baffle geometry cases were explored: differing in the number of holes but with the same hole diameter in both cases. Performance was strongly validated through operational uniformity based on the standard deviation of horizontal velocity within the tank, and the flow field pattern was utilized to determine the characterization of the streamlines and recirculation areas. A kinetic energy analysis was carried out to illustrate turbulence in the flow approximation. The results indicated that an inlet baffle with fewer holes had significantly enhanced operating uniformity and lower turbulence compared with more holes, and correspondingly, these flow field patterns depicted more streamlined movement and lower recirculation areas.
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