Phase field computations for ternary fluid flows

We present a new phase field model for three-component immiscible liquid flows with surface tension. In the phase field approach, the classical sharp-interface between the two immiscible fluids is replaced by a transition region across which the properties of fluids change continuously. The proposed method incorporates a chemical potential which can eliminate the unphysical phase field profile and a continuous surface tension force formulation from which we can calculate the pressure field directly from the governing equations. The capabilities of the method are demonstrated with several examples. We compute the ternary phase separation via spinodal decomposition, equilibrium phase field profiles, pressure field distribution, and a three-interface contact angle resulting from a spreading liquid lens on an interface. The numerical results show excellent agreement with analytical solutions.