Lattice Boltzmann model for interface capturing of multiphase flows based on Allen-Cahn equation

A phase-field-based lattice Boltzmann model is proposed for the interface capturing of multi-phase flows based on the conservative Allen-Cahn equation (ACE). By adopting the improved form of a relaxation matrix and an equilibrium distribution function, the time derivative ∂_t(φu) induced by recovering the diffusion term in ACE is eliminated. The conducted Chapman-Enskog analysis demonstrates that the correct conservative ACE is recovered. Four benchmark cases including Zalesak's disk rotation, vortex droplet, droplet impact on thin film, and Rayleigh-Taylor instability are investigated to validate the proposed model. The numerical results indicate that the proposed model can accurately describe the complex interface deformation.