Abstract
To characterize the micro-flow and predict the apparent permeability of porous media, a modified lattice Boltzmann method considering the volume diffusion effect was presented based on Klimontovich's kinetic equation and Enskog equation-based lattice Boltzmann Bhatnagar-Gross- Krook (LBGK) model. For comparison purposes, simulations of gas flow in the periodic body-centered cubic and tube were carried out initially. The simulation results show a good agreement with empirical correlations in the literatures. The porous structures were reconstructed using the QSGS (Quartet Structure Generation Set) method. Then, with the modified effective viscosity and the second-order slip boundary condition, a series of numerical simulations of gas flow in the reconstructed porous media with different mean Knudsen numbers was carried out based on the proposed model. The correction factor under different Knudsen number was predicted and compared with the Beskok & Karniadakis-Civan's correction. The present work provides a promising tool for handling the micro gas flow with complex geometries and boundaries.
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