Modeling of Combined Creaming and Flocculation in Emulsions

A computer model is presented which simulates the simultaneous creaming and flocculation of emulsions. A cubic lattice model is used, with particles bonding together and breaking apart according to predefined probabilities. Creaming and diffusion are included, with different rates for different sizes of floc. Results are presented in the form of concentration profiles as a function of height, and as the variation of the pseudo-fractal dimension of the particle networks formed. In the numerical simulations, an increase in creaming rate was observed before a particle network formed which prevented further creaming. A sharp serum interface was seen. In the presence of bond breakage, creaming proceeded for a longer period and a more compact network was formed. These results explain some features observed experimentally in creaming and flocculating emulsions, but do not reproduce the rapid serum development seen in some cases.