caa a22 4500 463163087 CHVBK 20180406164753.0 cr unu---uuuuu 170326e20070201xx s 000 0 eng 10.1007/s11242-006-0028-6 doi (NATIONALLICENCE)springer-10.1007/s11242-006-0028-6 Equivalent diffusion coefficient and equivalent diffusion accessible porosity of a stratified porous medium [Elektronische Daten] [Marijke Huysmans, Alain Dassargues] Diffusion is an important transport process in low permeability media, which play an important role in contamination and remediation of natural environments. The calculation of equivalent diffusion parameters has however not been extensively explored. In this paper, expressions of the equivalent diffusion coefficient and the equivalent diffusion accessible porosity normal to the layering in a layered porous medium are derived based on analytical solutions of the diffusion equation. The expressions show that the equivalent diffusion coefficient changes with time. It is equal to the power average with p = −0.5 for small times and converges to the harmonic average for large times. The equivalent diffusion accessible porosity is the harmonic average of the porosities of the individual layers for all times. The expressions are verified numerically for several test cases. Springer Science+Business Media B.V., 2007 Diffusion nationallicence Equivalent parameters nationallicence Low permeability media nationallicence C (kg/m3) : solute concentration in the liquid phase nationallicence D ( m 2/ s ) : effective diffusion coefficient (as defined by Gillham et al. 1984) nationallicence D eq (m2/s) : equivalent diffusion coefficient nationallicence L (m) : layer thickness nationallicence n (-) : diffusion accessible porosity nationallicence n eq (-) : equivalent diffusion accessible porosity nationallicence R (-) : retardation factor nationallicence t (s) : time nationallicence x (m) : distance from the top of the first layer nationallicence X̅ p : power average with power = p nationallicence Huysmans Marijke Hydrogeology and Engineering Geology Group, Department of Geology-Geography, Katholieke Universiteit Leuven, Redingenstraat 16, 3000, Leuven, Belgium aut Dassargues Alain Hydrogeology and Engineering Geology Group, Department of Geology-Geography, Katholieke Universiteit Leuven, Redingenstraat 16, 3000, Leuven, Belgium aut Transport in Porous Media Kluwer Academic Publishers 66/3(2007-02-01), 421-438 0169-3913 66:3<421 2007 66 11242 https://doi.org/10.1007/s11242-006-0028-6 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s11242-006-0028-6 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Huysmans Marijke Hydrogeology and Engineering Geology Group, Department of Geology-Geography, Katholieke Universiteit Leuven, Redingenstraat 16, 3000, Leuven, Belgium aut NATIONALLICENCE 700 1- Dassargues Alain Hydrogeology and Engineering Geology Group, Department of Geology-Geography, Katholieke Universiteit Leuven, Redingenstraat 16, 3000, Leuven, Belgium aut NATIONALLICENCE 773 0- Transport in Porous Media Kluwer Academic Publishers 66/3(2007-02-01), 421-438 0169-3913 66:3<421 2007 66 11242 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer