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A pore network model of drying with capillary liquid rings

Vorhauer, Nicole and Tsotsas, Evangelos and Prat, Marc A pore network model of drying with capillary liquid rings. (2015) In: 7th International Conference on Porous Media & Annual Meeting, 18 May 2015 - 21 May 2015 (Padoue, Italy). (Unpublished)

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Abstract

Modelling of drying processes without adjustable parameters is still a challenge. As emphasized in several previous works,e.g. [1-3], this might be due to the impact of liquid films trapped in the corners of the pore space. In this study, we present and analyse a drying experiment with a micromodel which clearly shows the presence of corner films. In contrast with previous works, however, the corner films do not form a system of interconnected films extending over large regions. They rather form isolated capillary rings surrounding the solid blocks of the device. These capillay rings can be regarded as a quasi-two dimensional version of liquid bridges often observed in the contact regions between grains in soils and packings of particles, [4]. These capillary rings essentially remain confined in the two-phase region. As a result, their impact on drying rate is much smaller than in the systems favouring films hydraulically connected over long distances. The capillary liquid ring formation is taken into account in a pore network model of drying [5]. This model leads to a satisfactory agreement with the experiment provided that the lateral pinning of liquid phase observed in the experiment is included in the model. This model enriches the family of pore network models of drying and can be considered as a step toward the modelling of secondary capillary effects in drying in more complex geometry, such as a random packing of particles. The consideration of capillary rings in drying is important not only for a better prediction of evaporation rates but also for situations where the liquid phase contains particles or dissolved salt for example. For example, in the presence of salt, capillary rings are special locations where crystallization will take place as a result of ring evaporation. Since the capillary rings are likely to form in the contact regions between grains, they might play a role in the damages induced by the crystallization process.

Item Type:Conference or Workshop Item (Paper)
Additional Information:Thanks to INTERPORE(International Society for Porous Media) https://www.interpore.org/
Audience (conference):International conference without published proceedings
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Other partners > Otto Von Guericke Universität Magdeburg - OVGU (GERMANY)
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Deposited On:27 Jan 2017 08:27

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