Heat and mass transfer in wet porous media in presence of evaporation—condensation

Bouddour, A.; Auriault, Jean‐Louis; Mhamdi-Alaoui, M.; Bloch, Jean‐Francis

doi:10.1016/s0017-9310(98)00002-7

Cited by 89 publications

(39 citation statements)

References 16 publications

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“…Thus, it may partly contribute to the observed diurnal variation of soil moisture, but it cannot cause such a significant R. Therefore, compared with previous studies on water distillation in soil (Bittelli et al 2008;Bouddour et al 1998), this study is based more on field observations. The most intense condensation in shallow soil is suggested to occur in the early morning (from 0800 to 1000 LST) in the Jinta oasis.…”

Section: Discussionmentioning

confidence: 99%

“…The process of water distillation within soil is suggested to be important when the soil temperature gradient is steep (Bouddour et al 1998;De Vries 1958;De Vries and Philip 1986;Deru and Kirkpatrick 2002;Philip and De Vries 1957) and is closely connected with soil hydrothermal variations (Johnson et al 2003;Ren et al 2008;Shao and Irannejad 1999;Yang et al 2005). A mass-heat coupled model should be able to provide a full description of the movement of liquid and gaseous water, as well as their phase transition, and indeed, some of the reported results from such models seem to be comparative with laboratory observations (Gao 2005;Gao et al 2003;Henry 2007Henry , 2008Li and Sun 2008;Olivella et al 2000;Poutou et al 2004;Saito et al 2006;Sakai et al 2009;Simunek et al 2008).…”

Section: Introductionmentioning

confidence: 99%

“…However, it should be noted that, usually, only the calculated/simulated soil temperature, moisture, heat flux, or chemical tracer content, rather than the rate of water distillation itself, can be compared with observations (Grifoll et al 2005;Heitman and Horton 2011;Sakai et al 2009;Scanlon 1992Scanlon , 1994Scanlon and Milly 1994). Among these studies, only a few considered the potential effect of water distillation on the heat or mass transfer within soil (Bittelli et al 2008;Bouddour et al 1998). …”

Section: Introductionmentioning

confidence: 99%

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Internal evaporation and condensation characteristics in the shallow soil layer of an oasis

Han

Lü

et al. 2015

Theor Appl Climatol

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The surface energy balance was analyzed using observations from the Jinta oasis experiment in the summer of 2005. A negative imbalance energy flux was found during daytime that could not be attributed to the soil heat storage process. Rather, the imbalance was related to the evaporation within the soil. The soil heat storage rate and the soil moisture variability always showed similar variations at a depth of 0.05 m between 0800 and 1000 (local standard time), while the observed imbalanced energy flux was very small, which implied that water vapor condensation occurred within the soil. Therefore, the distillation in shallow soil can be derived using reliable surface energy flux observations. In order to show that the importance of internal evaporation and condensation in the shallow soil layer, the soil temperatures at the depths of 0.05, 0.10, and 0.20 m were reproduced using a onedimensional thermal diffusion equation, with the observed soil temperature at the surface and at 0.40 m as the boundary conditions. It was found that the simulated soil temperature improves substantially in the shallow layer when the water distillation is added as a sink/source term, even after the soil effective thermal conductivity has been optimized. This result demonstrates that the process of water distillation may be a dominant cause of both the temperature and moisture variability in the shallow soil layer.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Internal evaporation and condensation characteristics in the shallow soil layer of an oasis

Han

Lü

et al. 2015

Theor Appl Climatol

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“…The mathematical foundations can be found in [22][23][24] and have been applied to a large variety of problems including composite materials modeling 25, porous media [26][27][28][29] , and climatic and geomechanic modeling 30 . Their major advantage is that they can provide effective properties of a relatively large heterogeneous medium for which application of direct numerical simulations is too intensive.…”

Section: Homogenizationmentioning

confidence: 99%

Homogenization of mesoscopic theories: Effective properties of model membranes

2002

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A new mathematical framework is introduced for modeling diffusion in nanoporous materials or on surfaces exhibiting heterogeneity in properties over large length scales while retaining molecular scale information typically captured by molecular simulations only. This framework entails first the use of newly developed mesoscopic equations derived rigorously from underlying master equations by coarse-graining statistical mechanics techniques. Homogenization techniques are then employed to derive the leading-order effective mesoscopic models that are subsequently solved by spectral methods. These solutions are also compared to direct numerical simulations for selected two-dimensional model membranes with defects, when attractive adsorbate-adsorbate interactions affect particle diffusion. It has been found that not only the density but also the dispersion of defects significantly alters the macroscopic behavior in terms of fluxes and concentration patterns, especially when phase transitions can occur. It is also shown that homogenization techniques could potentially offer a promising alternative to direct numerical simulations, when complex, large-scale heterogeneities are present. Implications for various applications, including heterogeneous catalysts, materials growth, and separations using membranes, are also discussed. * Corresponding author. INTRODUCTIONThe introduction of Monte Carlo (MC) techniques 1 in conjunction with the rapidly increasing computational power have revolutionized our understanding about the mesoscopic structure, thermodynamic, and transport properties of a large spectrum of problems for which molecular interactions are important. Examples include bulk liquids, solids, surface reconstruction phenomena, protein folding, and crystallization 2-6 . Aside from equilibrium problems, MC methods, especially on a lattice, have been successfully employed for irreversible problems such as crystal growth and catalytic reactions [7][8][9][10][11][12] . MC simulations solve directly an underlying master equation, and given sufficient information about transition probabilities, they provide its exact solution.Despite the enormous progress achieved so far, MC simulations are computationally very intensive and limited to relatively small time and length scales. The issue of length scales is not restrictive when only microscopic inhomogeneities are present as a result, for example, of intermolecular forces. These can typically be captured adequately via periodic boundary conditions and sufficiently large simulation boxes. However, there are three broad classes of problems, which are currently intractable by MC simulations due to macroscopic inhomogeneities. The first class includes systems that exhibit mesoscopic or macroscopic patterns as a result of self-regulation mechanisms. Examples include Turing patterns 13 and patterns resulting from the competition of microphase separation, driven by attractive interactions, and chemical reaction 14,15 . The second class encompasses forced systems that opera...

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“…This is assumed to happen starting from time t = 0 and frying is described as a coupling between heat transfer (conduction and convection) and vapour migration in an undeformable porous medium (see [1] and [8]). …”

Section: Introductionmentioning

confidence: 99%

A mathematical model of frying processes

Mancini¹,

Yang²,

Primicerio³

2007

Atti Accad. Naz. Lincei Cl. Sci. Fis. Mat. Natur.

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We present a mathematical model for the process of frying a rather thick sample of an indeformable porous material saturated with water (e.g. a potato slice).The model is based on thermodynamical arguments and results in a initial-boundary value problem for a system of equations satisfied by the temperature and vapour content, with a free boundary separating the region saturated with water and the vapour region.We provide some results of numerical simulations.In questo lavoro viene presentato un modello per il processo di frittura per immersione. Si considera il processo applicato ad un campione il cui spessore sia sufficientemente grande da rendere trascurabili le deformazioni dovute alla cottura come accade, per esempio, nelle comuni patatine fritte.Lo sviluppo del modelloè basato su considerazioni termodinamiche ed ha la forma di un sistema di equazioni differenziali alle derivate parziali con frontiera libera, quest'ultima rappresentata dal fronte di desaturazione dovuta alla vaporizzazione dell'acqua contenuta nel campione (modellato come un mezzo poroso non deformabile). Le incognite del sistema rappersentano la temperatura all'interno del campione ed il vapore contenuto.

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Heat and mass transfer in wet porous media in presence of evaporation—condensation

Cited by 89 publications

References 16 publications

Internal evaporation and condensation characteristics in the shallow soil layer of an oasis

Internal evaporation and condensation characteristics in the shallow soil layer of an oasis

Homogenization of mesoscopic theories: Effective properties of model membranes

A mathematical model of frying processes

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