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| Titel |
Modeling evaporation processes in a saline soil from saturation to oven dry conditions |
| VerfasserIn |
M. Gran, J. Carrera, S. Olivella, M. W. Saaltink |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 15, no. 7 ; Nr. 15, no. 7 (2011-07-04), S.2077-2089 |
| Datensatznummer |
250012880
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| Publikation (Nr.) |
 copernicus.org/hess-15-2077-2011.pdf |
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| Zusammenfassung |
| Thermal, suction and osmotic gradients interact during evaporation from a
salty soil. Vapor fluxes become the main water flow mechanism under very dry
conditions. A coupled nonisothermal multiphase flow and reactive transport
model was developed to study mass and energy transfer mechanisms during an
evaporation experiment from a sand column. Very dry and hot conditions,
including the formation of a salt crust, necessitate the modification of the
retention curve to represent oven dry conditions. Experimental observations
(volumetric water content, temperature and concentration profiles) were
satisfactorily reproduced using mostly independently measured parameters,
which suggests that the model can be used to assess the underlying processes.
Results show that evaporation concentrates at a very narrow front and is
controlled by heat flow, and limited by salinity and liquid and vapor fluxes.
The front divides the soil into a dry and saline portion above and a moist
and diluted portion below. Vapor diffusses not only upwards but also
downwards from the evaporation front, as dictated by temperature gradients.
Condensation of this downward flux causes dilution, so that salt
concentration is minimum and lower than the initial one, just beneath the
evaporation front. While this result is consistent with observations, it
required adopting a vapor diffusion enhancement factor of 8. |
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