A two-fluid BGK lattice Boltzmann model for ideal mixtures
In the present work, a lattice Boltzmann model for binary mixtures is formally derived from a two-fluid kinetic model of Maxwell molecules by discretizing the Boltzmann equation. In this model, collisions among the same and different species are treated separately, as non-linear BGK terms, enabling the independent management of the fluid viscosities and the binary diffusion coefficient. The velocity space is discretized, in accordance with a quadrature method based on prescribed abscissas. A Chapman-Enskog analysis is performed for deriving the macroscopic mass and momentum transport equations. The model is verified against theoretical solutions for the concentration and velocity step problems.
binary mixtures lattice boltzmann method mass diffusion