To study the flow characteristics of gravity based separation between oil and water using CFD AWWA D100 tool. Also, suggest an optimum design for the fixed oil skimmer based on the study.
For multi-phase modeling, there are two approaches for the numerical calculation: the Euler-Lagrange approach and the Euler-Euler approach. In this study for design of internals in the Water balance tank, Euler-Lagrange approach is employed, since the dispersed secondary phase volume fraction is very low. The simulation uses Euler- Lagrange approach to model oil droplets. The oil droplet trajectories are computed individually at specified intervals during the water phase calculation.
It is observed, the flow inside the tank makes a circular pattern where the flow velocities are higher at the periphery of the Skim Tank and the velocities reduce as the flow moves radially towards the center of the tank. This kind of flow pattern increases the residence time of oil particles inside the tank, hence improving the flow separation efficiency of the ITS Tanks. The size of nozzles, orientation and other internals are sufficient to meet design guarantee for the Skim Tank.