SIMULATION OF DROPLET-FORMATION AND -INTERACTION IN EMULSIFICATION PROCESSES

Emulsification is a key operational step in many processes for production and functionalization of dispersed liquid systems. Within the membrane emulsification process, emulsified droplets are formed from the bulk liquid at the individual pores of a porous solids body or surface. New interface area is produced in this way where the drops may get immediately in contact. This interaction of emulsified droplets may lead to relative movement and deformation (sliding) of the droplets, to droplet repulsion or even droplet coalescence, thus influencing the final emulsion droplet size distribution. Multiphase flow modeling with discrete interface tracking is used here to analyze the droplet formation and the droplet contact behaviour in the membrane emulsification process. A modification of the standard Volume-of-Fluid model (VOF) for multiphase flow is introduced that allows describing droplet interactions on the macroscale (drop size) including droplet contact, coalescence or bouncing. A proof of concept for this multiple entity VOF model is described here for emulsion droplets, where the droplet contact time is used as a criterion for droplet coalescence.