Phase field simulation of liquid phase separation with fluid flow

A phase-field theory of binary liquid phase separation coupled to fluid flow is presented. The respective Cahn–Hilliard-type and Navier–Stokes equations are solved numerically. We incorporate composition and temperature dependent capillary forces. The free energies of the bulk liquid phases are taken from the regular solution model. In the simulations, we observe Marangoni motion, and direct and indirect hydrodynamic interactions between the droplets. We find that coagulation is dramatically accelerated by flow effects. Possible extension of the model to solidification is discussed.