Hydrodynamics of Binary Fluid Mixtures - An Augmented Multiparticle Collison Dynamics Approach

TL;DR

This paper extends the Multiparticle Collision Dynamics method to simulate binary fluid mixtures and multiphase flows, incorporating phase separation and interface dynamics, verified through thermodynamics and droplet fluctuation analyses.

Contribution

It introduces a generalized MPC approach coupling particle dynamics with a Ginzburg-Landau functional for binary fluids, including a density-dependent term for non-ideal equations of state.

Findings

Interfacial tension matches Laplace-Young predictions.

Phase separation follows Lifshitz-Slyozov law.

Method accurately captures interface fluctuations.

Abstract

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.