CORRELATIONS OF GASEOUS FLOW AND DIFFUSIONAL PERMEABILITIES IN POROUS BODIES

Flow and diffusional permeabilities of gases in various unconsolidated and consolidated porous bodies were measured in the pressure range of 6–760 mmHg. From experimental and theoretical considerations a new method is proposed to obtain the tortuosity factors q or the values of ε/q from flow permeability data. The values are compared with those obtained by the usual diffusion method to obtain good agreement between them. A single value of tortuosity factor q (or ε/q) was found to be valid for the whole diffusion region and the viscous flow region for such consolidated or unconsolidated porous body as was used in the study, considered to be relatively homogeneous and monodispersed. Dimensionless flow and diffusional permeabilities are well correlated by the theoretical and empirical equations as a function of the modified Knudsen number. © 1979, The Society of Chemical Engineers, Japan. All rights reserved.