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Effects of pore scale dead‐end air fingers on relative permeabilities for air sparging in soils
Author(s) -
Clayton Wilson S.
Publication year - 1999
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/1999wr900202
Subject(s) - saturation (graph theory) , soil water , air permeability specific surface , air sparging , soil science , moisture , permeability (electromagnetism) , airflow , relative permeability , chemistry , capillary action , environmental science , hydrology (agriculture) , mineralogy , materials science , geotechnical engineering , thermodynamics , geology , porosity , mathematics , composite material , environmental remediation , physics , membrane , ecology , contamination , biology , biochemistry , layer (electronics) , combinatorics
Measurements of relative permeability‐saturation‐capillary head relationships ( k r − S − h c ) during unsteady state displacement of water by air in soil cores reveal several unique behaviors that have not been previously described. Extremely low air relative permeability ( k ra ) was observed, which increased independent of saturation, by up to an order of magnitude to approach Brooks‐Corey k ra ( S ) estimates. These effects were more extreme at faster displacement rates and are inferred to reflect the development and subsequent breakthrough of pore scale dead‐end air fingers, which initially do not conduct air flow. Furthermore, k ra ( h c ) estimates tended to be accurate, and where low k ra ( S ) was observed, h c ( S ) was significantly below moisture retention data. Where k ra ( S ) approximated Brooks‐Corey estimates, h c ( S ) approximated moisture retention data. A calculated backbone (conductive) air saturation, which is the total air saturation minus the dead‐end air saturation, was found to control both k ra and h c . Generally, water relative permeability data followed common functional relationships.