Gas Dispersion and Immobile Gas Content in Granular Porous Media:: Effect of Particle Size Nonuniformity
2010 (English)In: Soil science, ISSN 0038-075X, E-ISSN 1538-9243, Vol. 175, no 9, 426-431 p.Article in journal (Refereed) Published
Gas dispersion is an important process often controlling gastransport in porous media. At present, however, relatively little is knownabout the relationship between gas dispersion and porous media physicalproperties. In this study, gas dispersion and mobile gas content in porousmedia were measured as a function of medium average particle diameter,particle size range, and pore gas velocity. A set of natural granular mediaconsisting of sand and gravel with uniform particle size distributionscovering average particle diameters from 0.5 to 14 mm was used. Cleansand and gravel were used to obtain media with specific particle sizedistributions via mechanical sieving. Gas dispersion and mobile gas contentwere measured by column tracer experiments using atmospheric airand nitrogen as tracer gases. Gas dispersion coefficients, gas dispersivities,and mobile gas contents were determined by fitting the advectiondispersionequation to the measured gas breakthrough curves. The resultsshowed that gas dispersivity decreased with increasing mean particle diameterand increased with increasing particle size range (width of particlesize distribution). Thus, the largest dispersivities were observed for mediawith a small mean particle diameter and a wide particle size distribution.A model concept for predicting gas dispersivity from mean particle diameterand particle size range was proposed. The mobile gas contentincreased with increasing pore gas velocity but was independent of eitherparticle size range or mean particle diameter.
Place, publisher, year, edition, pages
2010. Vol. 175, no 9, 426-431 p.
IdentifiersURN: urn:nbn:se:uu:diva-179766DOI: 10.1097/SS.0b013e3181f0edafOAI: oai:DiVA.org:uu-179766DiVA: diva2:546191