Gas Dispersion in Granular Porous Media under Air-Dry and Wet Conditions

Muhammad Naveed, Shoichiro Hamamoto, Ken Kawamoto, Toshihiro Sakaki, Manabu Takahashi, Toshiko Komatsu, Lis Wollesen de Jonge, Mathieu Lamande, Per Moldrup

Research output: Contribution to journalArticle

Abstract

Subsurface gaseous-phase transport is governed by three gas transport parameters: the air permeability coefficient (ka), gas diffusion coefficient (DP), and gas dispersion coefficient (DH). Among these, DH is the least understood due to hitherto limited research into the relationship between gas dispersion and soil physical characteristics. In this study, a series of advection–dispersion experiments was performed on granular porous media to identify the effects of soil column dimensions (length and diameter), particle size and shape, dry bulk density, and moisture content on the magnitude of gas dispersion. Glass beads and various sands of different shapes (angular and rounded) with mean particle diameters (d50) ranging from 0.19 to 1.51 mm at both air-dry and variable moisture contents were used as granular porous media. Gas dispersion coefficients and gas dispersivities (α = DH/v, where v is the pore-gas velocity) were determined by fitting the advection–dispersion equation to the measured breakthrough curves. For all test conditions, DH increased linearly with v. The test results showed that neither soil column length nor diameter had significant effect on gas dispersivity. Under air-dry conditions, higher gas dispersivities were observed for media with wider particle size distribution and higher dry bulk density. The minor effect of particle shape on gas dispersivity was found under both air-dry and wet conditions. Under wet conditions, the variations in gas dispersivity were mainly controlled by the air-filled porosity. An empirical model was also proposed for the prediction of gas dispersivity in granular, unsaturated porous media.
Original languageEnglish
Pages (from-to)845-852
Number of pages8
JournalSoil Science Society of America Journal
Volume76
Issue number3
DOIs
Publication statusPublished - 2012
Externally publishedYes

Cite this

Naveed, M., Hamamoto, S., Kawamoto, K., Sakaki, T., Takahashi, M., Komatsu, T., ... Moldrup, P. (2012). Gas Dispersion in Granular Porous Media under Air-Dry and Wet Conditions. Soil Science Society of America Journal, 76(3), 845-852. https://doi.org/10.2136/sssaj2011.0314
Naveed, Muhammad ; Hamamoto, Shoichiro ; Kawamoto, Ken ; Sakaki, Toshihiro ; Takahashi, Manabu ; Komatsu, Toshiko ; de Jonge, Lis Wollesen ; Lamande, Mathieu ; Moldrup, Per. / Gas Dispersion in Granular Porous Media under Air-Dry and Wet Conditions. In: Soil Science Society of America Journal. 2012 ; Vol. 76, No. 3. pp. 845-852.
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abstract = "Subsurface gaseous-phase transport is governed by three gas transport parameters: the air permeability coefficient (ka), gas diffusion coefficient (DP), and gas dispersion coefficient (DH). Among these, DH is the least understood due to hitherto limited research into the relationship between gas dispersion and soil physical characteristics. In this study, a series of advection–dispersion experiments was performed on granular porous media to identify the effects of soil column dimensions (length and diameter), particle size and shape, dry bulk density, and moisture content on the magnitude of gas dispersion. Glass beads and various sands of different shapes (angular and rounded) with mean particle diameters (d50) ranging from 0.19 to 1.51 mm at both air-dry and variable moisture contents were used as granular porous media. Gas dispersion coefficients and gas dispersivities (α = DH/v, where v is the pore-gas velocity) were determined by fitting the advection–dispersion equation to the measured breakthrough curves. For all test conditions, DH increased linearly with v. The test results showed that neither soil column length nor diameter had significant effect on gas dispersivity. Under air-dry conditions, higher gas dispersivities were observed for media with wider particle size distribution and higher dry bulk density. The minor effect of particle shape on gas dispersivity was found under both air-dry and wet conditions. Under wet conditions, the variations in gas dispersivity were mainly controlled by the air-filled porosity. An empirical model was also proposed for the prediction of gas dispersivity in granular, unsaturated porous media.",
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Naveed, M, Hamamoto, S, Kawamoto, K, Sakaki, T, Takahashi, M, Komatsu, T, de Jonge, LW, Lamande, M & Moldrup, P 2012, 'Gas Dispersion in Granular Porous Media under Air-Dry and Wet Conditions' Soil Science Society of America Journal, vol. 76, no. 3, pp. 845-852. https://doi.org/10.2136/sssaj2011.0314

Gas Dispersion in Granular Porous Media under Air-Dry and Wet Conditions. / Naveed, Muhammad; Hamamoto, Shoichiro; Kawamoto, Ken; Sakaki, Toshihiro; Takahashi, Manabu; Komatsu, Toshiko; de Jonge, Lis Wollesen; Lamande, Mathieu; Moldrup, Per.

In: Soil Science Society of America Journal, Vol. 76, No. 3, 2012, p. 845-852.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Gas Dispersion in Granular Porous Media under Air-Dry and Wet Conditions

AU - Naveed, Muhammad

AU - Hamamoto, Shoichiro

AU - Kawamoto, Ken

AU - Sakaki, Toshihiro

AU - Takahashi, Manabu

AU - Komatsu, Toshiko

AU - de Jonge, Lis Wollesen

AU - Lamande, Mathieu

AU - Moldrup, Per

PY - 2012

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AB - Subsurface gaseous-phase transport is governed by three gas transport parameters: the air permeability coefficient (ka), gas diffusion coefficient (DP), and gas dispersion coefficient (DH). Among these, DH is the least understood due to hitherto limited research into the relationship between gas dispersion and soil physical characteristics. In this study, a series of advection–dispersion experiments was performed on granular porous media to identify the effects of soil column dimensions (length and diameter), particle size and shape, dry bulk density, and moisture content on the magnitude of gas dispersion. Glass beads and various sands of different shapes (angular and rounded) with mean particle diameters (d50) ranging from 0.19 to 1.51 mm at both air-dry and variable moisture contents were used as granular porous media. Gas dispersion coefficients and gas dispersivities (α = DH/v, where v is the pore-gas velocity) were determined by fitting the advection–dispersion equation to the measured breakthrough curves. For all test conditions, DH increased linearly with v. The test results showed that neither soil column length nor diameter had significant effect on gas dispersivity. Under air-dry conditions, higher gas dispersivities were observed for media with wider particle size distribution and higher dry bulk density. The minor effect of particle shape on gas dispersivity was found under both air-dry and wet conditions. Under wet conditions, the variations in gas dispersivity were mainly controlled by the air-filled porosity. An empirical model was also proposed for the prediction of gas dispersivity in granular, unsaturated porous media.

U2 - 10.2136/sssaj2011.0314

DO - 10.2136/sssaj2011.0314

M3 - Article

VL - 76

SP - 845

EP - 852

JO - Soil Science Society of America Journal

JF - Soil Science Society of America Journal

SN - 0361-5995

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ER -