Effects of serial and parallel pore nonuniformities : Results from two models of the porous structure

• Published in: Transport in porous media Vol. 25; no. 3; pp. 335 - 350
• Main Authors: NILSSON, L, STENSTRÖM, S
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01-12-1996
• Subjects: Cauchy-Schwarz-Bunjakovskij inequality; Chemical Engineering; computational fluid dynamics; Earth sciences; Earth, ocean, space; effective diffusivity; Engineering and Technology; Exact sciences and technology; Hydrogeology; Hydrology. Hydrogeology; Kemiteknik; permeability; pore-size distribution; specific; surface area; Teknik; models; thickness; porosity; permeability; diffusivity; transport; specific surface; boundary conditions; fluid dynamics; porous media
• ISSN: 0169-3913; 1573-1634
• DOI: 10.1007/BF00140987

The effects of parallel-type and serial-type pore nonuniformities on the effective diffusivity and the permeability of a porous material were evaluated, constant porosity and constant specific surface area being assumed. Two structural models were considered. In the first model, the porous structure was described as a bundle of cylindrical capillaries penetrating the whole thickness of the material and in the other it was described instead as a collection of randomly distributed obstacles hindering transport. Both models predicted that parallel-type pore nonuniformities produce an increase in permeability compared with uniform structures having the same porosity and specific surface area. Both models also predicted that the increase in permeability due to parallel-type pore nonuniformities would be larger than the increase in effective diffusivity. Regarding serial-type pore nonuniformities, both models predicted a decrease in permeability and that this decrease would be greater than the decrease in effective diffusivity. The predicted changes in effective diffusivity due to nonuniformities of the sample differed for the two structural models.