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Computed tomography imaging of air sparging in porous media
Author(s) -
Chen MayRu,
Hinkley Richard E.,
Killough John E.
Publication year - 1996
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 - 10.1029/96wr01136
Subject(s) - air sparging , saturation (graph theory) , porous medium , porosity , air permeability specific surface , mechanics , airflow , tomography , compressibility , permeability (electromagnetism) , materials science , capillary pressure , capillary action , secondary air injection , soil science , geotechnical engineering , geology , optics , thermodynamics , physics , chemistry , composite material , mathematics , ecology , contamination , biology , biochemistry , layer (electronics) , combinatorics , environmental remediation , membrane
This paper describes the use of an X ray computerized tomography scanner for noninvasive, three‐dimensional, high‐resolution imaging of air distribution patterns during air sparging in water‐saturated sandpacks. Experiments were performed in Plexiglas cylindrical cells using well‐defined Ottawa sands. The reconstructed images provide detailed porosity and air saturation distributions previously unavailable. Two classes of behavior were observed. In high‐permeability (106 darcy) uniform sandpacks a relatively few, discrete, and tortuous air pathways were formed. Steady state was rapidly attained, and the intrachannel air saturations were low (0.10). In contrast, low‐permeability (3 darcy) sandpacks increased the breadth of air contact, delayed attainment of steady state, and displayed high air saturations (0.50). The concept of a hydrodynamic stagnation saturation and standard one‐dimensional fractional flow theory proved useful in explaining the experiments. Numerical simulation confirms the explanations, even when capillary pressure and compressibility effects are included.