FRACTAL MODEL OF GAS DIFFUSION THROUGH POROUS FIBROUS MATERIALS WITH ROUGH SURFACES

Abstract

Fractal model of gas diffusion through porous fibrous materials with rough surfaces is derived, in which the porous structure is simplified to be composed of a bundle of tortuous capillaries whose pore size distribution and surface roughness follow the fractal scaling laws. The analytical expression for gas relative diffusion coefficient is a function of the relative roughness, fiber radius and the other microstructural parameters (porosity, the fractal dimension for pore size distribution and tortuosity, the maximum and minimum pore diameter and the characteristic length). The proposed fractal model is validated by comparison with available experimental data and correlations. At the same time, the effect of microstructural parameters of porous fibrous materials on gas diffusion has been studied in detail. It is believed that the current model may be extended to porous materials other than fibrous materials.