  The Multiparticle Collision Dynamics technique (MPC) for hydrodynamics
simulations is generalized to binary fluid mixtures and multiphase flows, by
coupling the particle-based fluid dynamics to a Ginzburg-Landau free-energy
functional for phase-separating binary fluids. To describe fluids with a
non-ideal equation of state, an additional density-dependent term is
introduced. The new approach is verified by applying it to thermodynamics near
the critical demixing point, and interface fluctuations of droplets. The
interfacial tension obtained from the analysis of the capillary wave spectrum
agrees well with the results based on the Laplace-Young equation.
Phase-separation dynamics follows the Lifshitz-Slyozov law.
