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Numerical modeling of kinetic interphase mass transfer during air sparging using a dual‐media approach
Author(s) -
Falta Ronald W.
Publication year - 2000
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 - 10.1029/2000wr900220
Subject(s) - air sparging , mass transfer , sparging , porous medium , plume , secondary air injection , interphase , mechanics , environmental science , multiphase flow , materials science , chemistry , contamination , environmental remediation , porosity , thermodynamics , geology , geotechnical engineering , physics , ecology , genetics , biology
A dual‐media multiphase flow approach is proposed for modeling the local interphase mass transfer that occurs during in situ air sparging. The method is applied to two‐ or three‐phase flow in porous media to simulate the small gas channels that form during air sparging, allowing resolution of the local diffusive mass transfer of contaminants between the flowing gas phase and nearby stagnant liquid‐filled zones. This approach provides a good match with laboratory column experiments in which dissolved trichloroethylene (TCE) is removed by air sparging, and it is shown that the simulation results are very sensitive to the nature of the local mass transfer regime. The numerical model is then applied to hypothetical field air‐sparging cases involving either a dissolved plume of TCE or a TCE nonaqueous phase liquid source. In these simulations the local mass transfer appears to play a much smaller role than in the laboratory‐scale tests, and significant deviations from local equilibrium simulations only occur when the mass transfer rates are reduced below the calibrated laboratory‐scale values.