Relating gas dispersion in porous media to medium tortuosity and anisotropy ratio

Lorenzo Pugliese*, Tjalfe G. Poulsen, Rune R. Andreasen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Gas dispersion in a set of three different porous materials with similar particle size, as a function of material tortuosity and anisotropy ratio, was investigated. The materials were packed with different spatial orientations of the individual particles so as to create media with different tortuosity and anisotropy ratios. Three different media (slate chips, wood chips, and pebbles) and four particle orientations have been used to generate a total of nine different porous media mimicking single porosity, dual porosity isotropic, anisotropic, aggregated, or granular materials. Resulting values of tortuosity and anisotropy ratio for each medium were determined via measurements of gas permeability and molecular gas diffusion coefficient. These values were then compared to measured values of gas dispersivity for each medium. The results showed that dispersivity is inversely proportional to tortuosity but directly proportional to anisotropy ratio and that the relations were approximately linear within the range of tortuosities and anisotropy ratios investigated. Wood chips (dual porosity material) yielded higher values of gas dispersivity compared to slate chips (single porosity material). A likely reason is in part the difference in pore structure between the materials and in part a difference in particle surface roughness (which was highest for wood chips) both of which affects dispersion.

Original languageEnglish
Pages (from-to)4101-4118
Number of pages18
JournalWater, Air, and Soil Pollution
Volume223
Issue number7
DOIs
StatePublished - Sep 2012
Externally publishedYes

Keywords

  • Anisotropy ratio
  • Gas permeability
  • Mechanical dispersion
  • Particle orientation
  • Particle shape
  • Porous medium tortuosity

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