Mathematical Simulation of the Two-Phase Flow for Oil-Water Separation in Hydrocyclones

Hydrocyclones are devices used on offshore petroleum platforms to separate the water-oil system. They are applied in the second stage of separation, and their use in the first stage is also a viable option, as gravitational separators are inconveniently heavy, require too much space, and prolong the process. Dimensioning an innovative hydrocyclone can be made easier by computational simulation of the flow within the device, which can yield the geometry necessary for the targeted separation. A mathematical model of a current hydrocyclone was developed and validated, which should be adapted to fit the dimensions required for the new device. Steady-state Computational Fluid Dynamics simulations were performed with hexahedral meshes, the Reynolds Stress turbulence model, and the Eulerian-Eulerian multiphase approach. Average velocity and pressure were applied as boundary conditions at the inlets and outlets, respectively. The obtained mean velocity profiles follow the axisymmetric flow pattern observed in the actual device. A visual comparison with another mathematical model of the same hydrocyclone confirms such similarity. This likeness to the physical model validates the proposed model, although improvements remain to be implemented in future studies.