Multipseudopotential interaction : a lattice Boltzmann scheme for simulation of multiphase flows

Abstract

In this study, a new pseudopotential Lattice Boltzmann (LB) scheme, multipseudopotential interaction (MPI), including boundary conditions is proposed for simulation of two-phase flows. It solves several drawbacks of available schemes such as being thermodynamically inconsistent with practical equations of state (EOSs), being limited to low-density ratios, not having an independently tunable interface width. The lattice interaction potential is described by a series of consistent sub-potentials. In theory, in addition to being intrinsically consistent with thermodynamics, the MPI-LB scheme is stable for a large range of density ratios (up to 106), and tunable for interface width. In engineering applications, the scheme is superior over the previous schemes of reproducing practical EOSs by removing the deficiency of creating unphysical potentials. The scheme is unlimited to implement the practical EOSs which can be expressed in a polynomial format. The scheme is studied and verified regarding liquid vapour circular and flat interfaces, Laplace law, Galilean invariance, and change of viscosity. Furthermore, the scheme is investigated for the effects of different wall boundary conditions on the hydrodynamics of non-ideal single-phase fluids. The suitable boundary condition is chosen based on density variation across the channel, and errors because of domain resolution, relaxation time, and compressibility.