Numerical Simulation for Gas Diffusion in Fractal Reconstructed Anisotropic Porous Building Materials

Gas diffusion in porous media are great importance in many science and engineering fields. In this paper, lattice Boltzmann method is applied to simulate the gas diffusion in the fractal reconstructed porous building materials. The isotropic porous materials are reconstructed by the random midpoint displacement (RMD) algorithm. In addition, the filtering and linear spatial transforms are introduced to reconstructed anisotropic porous materials which conform to the typical characteristics of porous building materials. The two-point correlation function and fractal dimension of anisotropic porous media present uniform with the anisotropic strength varied from 0 to 0.6. Lattice Boltzmann method is developed to study the gas diffusion behaviors in the reconstructed anisotropic porous materials with different fractal dimension. The effective diffusion coefficients along different directions of anisotropic porous materials are analyzed.