Process fundamentals of membrane emulsification : simulation with CFD

Membrane emulsification is a process in which a to-be-dispersed phase is pressed through a membrane; the droplets formed are carried away with the continuous phase. To design a suitable membrane setup, more insight into the formation of the droplets at the membrane surface is needed. Therefore, the formation of one droplet from a cylindrical pore was calculated using computational fluid dynamics. From the resulting droplet diameter (33 m; pore diameter, 5 m) and the calculated droplet shape, the maximum membrane porosity was calculated to be 1.5°to prevent coalescence of droplets growing on neighboring pores. Due to the deformation of the droplet and the formation of the neck, the pressure drop over the pore and the velocity of oil in the pore varied in time. During necking, the velocity in the pore decreased sharply. After detachment of the first droplet, no satellite droplets were formed, but a small oil volume remained attached at the pore, forming a new droplet.