Effects of molecular mass on the diffusion coefficient in a multiphase lattice Boltzmann model

We introduce a simplified expression for the diffusion coefficient (D) of a multicomponent Lattice Boltzmann model. For dilute solutions, this expression is reduced to have dependence only on the molecular mass and relaxation time of the solute. By altering the molecular mass, the value of D can be varied by several orders of magnitude, thus, providing an additional parameter for use in tuning LB model values to physical systems. The ability to adjust the values of molecular mass can also be used to decrease simulation times. This is advantageous as it allows application of the LB model to solve problems that previously required prohibitive computational resources. The capability to model a wide range of diffusion coefficients and decrease simulation times is illustrated in a simple case study.