Microscopic modeling of mass transfer in LLE systems using VOF approach

Liquid-liquid extraction is one of the main separation processes which has many applications in different industries. Among different influencing parameters on Liquid-liquid performance, the surface tension effect was investigated in the present study. The mass transfer of a single droplet was simulated using the volume of fluid approach coupled with a single-field mass transfer approach.  Due to the high computational time, the moving reference frame approach was supplemented to computational codes in parallel processing mode assuming static droplet and moving zone. The results showed that with the reduction of surface tension coefficient, while the other parameters were kept constant, the regime change from spherical to oscillating occurred, the velocity decreased. In addition, along with an additional reduction in the surface tension coefficient, the droplet breakage happened. Despite a considerable reduction in terminal velocity, the reduction in mass transfer was not observed due to the interfacial area increase which enhanced mass transfer while velocity reduction negatively disturbed it. The concentration contour plots of droplets in various surface tension coefficients were reported in different droplet regimes starting from circulating to breakup.