NUMERICAL STUDY OF INTERNAL FLOW STRUCTURES WITHIN HYDROCYCLONES WITH PARABOLIC AND HYPERBOLIC SWIRL CHAMBERS

In this work we examine the internal flow structures within hydrocyclones used for liquid-liquid separation, especially those used for the removal of oil droplets from water. The internal flow structures and patterns are greatly influenced by the geometric shape of the swirl chamber. The effects of parabolic and hyperbolic wall profiles of the swirl chamber on the reverse flow vortex core, short circuit flows, and the separation efficiency are investigated numerically by solving the Reynolds Average Navier-Stokes equations closed by an equation of change for the Reynolds stress. Droplets (forming the dispersed phase) trajectories are predicted by solving a kinematic equation of motion and force balance. Internal flow structures for different geometric conditions have partially motivated the redesign of the hydrocyclone geometry so as to support a longer and stable reverse flow vortex core and for greater separation efficiency. Results indicate that both the parabolic and hyperbolic swirl chambers provide improved separation efficiency. However, the hyperbolic swirl chamber has a greater potential for the reduction of effective length of the hydrocyclone with maintaining the same separation. efficiency.