EFFECTIVE DIFFUSION COEFFICIENT OF GAS IN POROUS MATERIALS AND GRANULAR BEDS

Abstract

To predict the effective diffusion coefficient of a porous material, a theoretical equation was derived by using a pore model. However, it cannot be applied to a granular bed of single pore structure.
From this point of view, the tortuosity factor is introduced into the expression of the effective diffusion coefficient and calculated from penetration experiments of gas in porous materials. As a result, for a granular bed, in the region of large void fraction, the effective diffusion coefficient may be estimated by the presented equation. It may be applied to the diffusion of gas in porous materials.