Consistent lattice Boltzmann model for multicomponent mixtures
Abstract
A new lattice Boltzmann model for multicomponent ideal gas mixtures is presented. The model development consists of two parts. First, a new kinetic model for Stefan Maxwell diffusion amongst the species is proposed and realized as a lattice Boltzmann equation on the standard discrete velocity set. Second, a compressible lattice Boltzmann model for the momentum and energy of the mixture is established. Both parts are consistently coupled through mixture composition, momentum, pressure, energy and enthalpy whereby a passive scalar advectiondiffusion coupling is obviated, unlike in previous approaches. The proposed model is realized on the standard threedimensional lattices and is validated with a set of benchmarks highlighting various physical aspects of compressible mixtures. StefanMaxwell diffusion is tested against experiment and theory of uphill diffusion of argon and methane in a ternary mixture with hydrogen. The speed of sound is measured in various binary and ternary compositions. We further validate the StefanMaxwell diffusion coupling with hydrodynamics by simulating diffusion in opposed jets and the threedimensional KelvinHelmholtz instability of shear layers in a twocomponent mixture. Apart from the multicomponent compressible mixture, the proposed lattice Boltzmann model also provides an extension of the lattice Boltzmann equation to the compressible flow regime on the standard threedimensional lattice.
 Publication:

arXiv eprints
 Pub Date:
 April 2020
 arXiv:
 arXiv:2004.11286
 Bibcode:
 2020arXiv200411286S
 Keywords:

 Physics  Fluid Dynamics;
 Physics  Computational Physics
 EPrint:
 J. Fluid Mech. 909 (2021) A1