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.