Implementation of gas diffusion in the discrete element model

摘要

In this paper, particle scale diffusion is implemented in the discrete element model. We focus on the question of how to calibrate the particle scale diffusion coefficient. Theoretical relation between micro- and macro-diffusion coefficients is derived for the regular 2-D packing. Then this relation is validated in several numerical tests where the macroscopic diffusion coefficient is determined numerically based on the half-time of a desorption scheme. To further test the coupled model, we simulate the diffusion and desorption in the circular sample. The numerical results match the analytical solution very well.