Lattice Boltzmann simulation of multicomponent noncontinuum diffusion in fractal porous structures.
A lattice Boltzmann method (LBM) of multicomponent diffusion is developed to examine multicomponent, noncontinuum mass diffusion in porous media. An additional collision interaction is proposed to mimic the Knudsen diffusion caused by the collision interaction between gas molecules and solid pore walls. Using the improved LBM model, the ternary mixtures diffusion is simulated in fractal porous structures which are reconstructed by the random midpoint displacement algorithm. The effects of fractal characteristics and Knudsen diffusion resistance on the multicomponent diffusion in porous structures are investigated and discussed. The results indicate that the smaller fractal dimension enhances the diffusion rate of gas mixtures in fractal porous structures. When the dimensionless Knudsen diffusion coefficient is less than 20, the presence of Knudsen diffusion resistance reduces the rate of mass diffusion in porous structures obviously, especially for the species with larger molecular weight.
Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, People's Republic of China.
Qiang
Q
Ma
Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096, People's Republic of China.|IIUSE, Southeast University, Nanjing 210096, People's Republic of China.
Zhenqian
Z
Chen