[en] This paper deals with the moisture exchanges occurring between soils and the surrounding atmosphere. Convective drying tests are performed on Awans silts at different drying temperatures and air relative humidities in order to reproduce the natural drying conditions. The experiments improve the understanding of the vapour transfers kinetics between the soil samples and the atmosphere. The experimental results are analysed assuming that the transfers take place in a boundary layer existing at the surface of the porous medium. The influence of the thermal conditions on the evaporation is also taken into account. In our model, coupled vapour and energy exchanges are controlled by mass and heat transfer coefficients
characterizing the boundary layer. These coefficients are determined from the drying experiments. The modelling of the drying tests in non-isothermal conditions is performed in order to validate the formulation of the vapour and heat exchanges. The numerical results present a good agreement with the kinetic of the materials desaturation determined during the tests. The analysis of the moisture transport mechanisms into the sample and at the boundary shows that at the beginning of the test, the drying is first achieved by the transport of moisture in its liquid form and its evaporation at the sample outer boundary in contact with the atmosphere. In a second step, vapour diffusion becomes predominant into the sample and it corresponds to the most important decrease of relative humidity.
Gerard, Pierre ; Université de Liège - ULiège > Département Argenco : Secteur GEO3 > Mécanique des sols et des roches & infrastructures - Géomécanique et géologie de l'ingénieur
Léonard, Angélique ; Université de Liège - ULiège > Département de chimie appliquée > Génie chimique - Procédés et développement durable
Masekanya, Jean-Pierre
Charlier, Robert ; Université de Liège - ULiège > Département Argenco : Secteur GEO3 > Géomécanique et géologie de l'ingénieur
Collin, Frédéric ; Université de Liège - ULiège > Département Argenco : Secteur GEO3 > Géomécanique et géologie de l'ingénieur
Language :
English
Title :
Study of the soil-atmosphere moisture exchanges through convective drying tests in non-isothermal conditions
Publication date :
2010
Journal title :
International Journal for Numerical and Analytical Methods in Geomechanics
ISSN :
0363-9061
eISSN :
1096-9853
Publisher :
John Wiley & Sons, New York, United States - New York
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