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| Titel |
Mass Transfer Limitations and Non-Locality for Large Scale Reactive Transport |
| VerfasserIn |
Marco Dentz, Philippe Gouze, Jesús Carrera |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250049160
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| Zusammenfassung |
| The correct characterization of large scale reactive transport dynamics is an important issue
for modeling reactive transport on the Darcy scale, specifically in situations in which
reactions are localized, that is when different reactions occur in different portions of the
porous medium. We consider here reactive transport in a porous medium that is characterized
by mass transfer between a mobile and a suite of immobile regions. Chemical and physical
heterogeneities are reflected by distributions of kinetic reaction rate constants and residence
times in the immobile zones. We derive an effective reactive transport equation for the
mobile solute that is characterized by non-local physical mass transfer and reaction
terms. Mass transfer limitations due to physical heterogeneity yield effective kinetic
rate coefficients that can be much smaller than the volumetric average of the local
scale coefficients. These results help to explain and quantify the often reported
discrepancy between observed field reaction rate constants and the ones obtained
under well mixed laboratory conditions. Furthermore, these results indicate that
transport under physical and chemical heterogeneity cannot be upscaled separately. |
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