Transfer Phenomena During the Drying of a Shrinkable Product: Modeling and Simulation

Mihoubi, Daoued; Zagrouba, Féthi; Vaxelaire, Jean; Bellagi, A.; Roques, M.

doi:10.1081/drt-120028216

Cited by 43 publications

(17 citation statements)

References 10 publications

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“…In diffusive approach, some researchers (Chemkhi et al 2004;Kechaou 1989;Kechaou and Roques, 1989;Mihoubi and Bellagi 2008;Mihoubi et al 2004b;Zagrouba 1993) consider the product as an homogeneous medium formed of solid and liquid phases. The mass transfer is described by the law of Fick (Bird et al 2002) involving an effective coefficient of diffusion determined from the confrontation of the experimental and simulated drying kinetics.…”

Section: Introductionmentioning

confidence: 99%

“…In the earlier author's works (Mihoubi 2004;Mihoubi and Bellagi 2008;Mihoubi et al 2004b;Zagrouba et al 2002), the first approach (diffusive model), based on coordinates transformation, has been used to describe the evolutions of moisture content and temperature within the product during air drying. Using both equations of continuity and the Fick law, a relation between solid velocity and moisture gradient was established.…”

Section: Introductionmentioning

confidence: 99%

“…A diffusive approach was used and oppositely, to the previous works (Mihoubi 2004;Mihoubi et al 2004a;Zagrouba et al 2002), the solid velocity was determined from the momentum equation in order to combine mechanical equilibrium to heat and mass transfers. The balance equations were resolved in actual configuration.…”

Section: Introductionmentioning

confidence: 99%

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Stress Generated During Drying of Saturated Porous Media

Mihoubi

Bellagi

2009

Transp Porous Med

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The article is a contribution for the modelling of heat and mass transfers coupled to strain-stress equations during drying of deformable two-phase media. Both unidirectional and bidirectional configurations are examined. In order to compare the results, one assumes the material of a convectively dried clay slab in two configurations. Numerical calculations of the temperature, drying curves variations and the spatio-temporal distributions of moisture, temperature and drying induced stresses are evaluated. A significant difference was observed between the results obtained for both configurations particularly in intensity of the shear stress that caused cracking. List of symbolsMolecular weight of water (kg kmol −1 ) K m Mass transfer coefficient between the product and air (m s −1 ) T Temperature ( • C, K) Re Reynolds number (−) R H Relative humidity (−) Pr Prandtl number (−)

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Stress Generated During Drying of Saturated Porous Media

Mihoubi

Bellagi

2009

Transp Porous Med

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“…In order to take into account these relevant mechanisms, the most common practice is to lump all effects of liquid migration into the diffusion coefficient (Coumans, 1987;Kechaou and Roques, 1990;Katelaars, 1992;Achanta et al, 1997;Zagrouba et al, 2002a;Mihoubi et al, 2004;Chemkhi et al, 2004a;Chemkhi et al, 2005a). In so doing, the diffusion coefficient becomes an effective coefficient.…”

Section: Introductionmentioning

confidence: 99%

“…Zagrouba et al (2002b) and Mihoubi et al (2002) presented the kinetics, the characteristic curve, and the experimental characterisation for the drying of clay. Then Zagrouba et al (2002a), Mihoubi et al (2004), and Chemkhi et al (2004a;2005a) discussed the transfer phenomena during the drying of deformable media using the diffusion model. Finally, Chemkhi et al (2004b;2005b) and Chemkhi and Zagrouba (2005) presented the water sorption equilibrium, the water diffusion coefficient, and some physical and chemical properties of clay material.…”

Section: Introductionmentioning

confidence: 99%

Development of A Darcy-flow model applied to simulate the drying of shrinking media

Chemkhi¹,

Zagrouba

2008

Braz. J. Chem. Eng.

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-A mathematical model is developed to describe the coupling between heat, mass, and momentum transfers and is applied to simulate the drying of saturated and shrinking media. This model is called "the Darcy-flow model", which is based on the fact that the liquid flow is induced by a pressure gradient. The main novelties of the model are that firstly no phenomenological law need be introduced by keeping solid mass conservation and solid volume conservation together and secondly we use the effective stresses notion strongly coupling mechanical behaviour with mass transport. The analysis is limited to the preheating and the constant rate drying periods because shrinkage occurs during these two periods for most materials. Our purpose is to simulate the drying process and to compare the results of the simulations and the experiments done on clay material to demonstrate the consistency of the model developed. One of the important conclusions is that is no correlation between moisture flow and moisture gradient.

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Drying of solids; estimation of the mathematical model parameters

2010

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In order to determine physical meaning of a thin-layer mathematical model parameter, the Page model was modified and tested on numerous experimental data. Applicability of the model was tested on the drying kinetics data, X(t), of 11 different types of the porous materials and dried in a convective, vacuum and/or microwave dryers under the predetermined external process conditions. During the entire drying time the drying kinetics of all the investigated materials and heating methods were successfully correlated with the modified Page model. The evaluated values of a new parameter, t k , corresponded to the time at which diffusion, as a governing mechanism of moisture movement through the material, started. The results were confirmed by the pore size distribution of some materials.Afin de déterminer la signification physique d'un paramètre de modèle mathématique des couches minces, le modèle de Page aété modifié et testé en utilisant de nombreuses données expérimentales. L'applicabilité du modèle aété testée en utilisant les données cinétique de séchage, X (t), de onze différents types de matériau poreux et séchés dans des séchoirsà convection, sous vide et/ouà micro-ondes dans des conditions de traitement externes prédéterminées. Pendant toute la durée du séchage, la cinétique de séchage de tous les matériaux et des méthodes thermiqueś etudiées aété corrélée avec succès avec le modèle modifié de Page. Les valeurs estimées d'un nouveau paramètre, tk, ont corresponduà l'heure où la diffusion,étant le mécanisme fondamental contrôlant le mouvement d'humidité au sein du matériau, a débuté. Les résultats ontété confirmés par la distribution des tailles de pores de certains matériaux.

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Transfer Phenomena During the Drying of a Shrinkable Product: Modeling and Simulation

Cited by 43 publications

References 10 publications

Stress Generated During Drying of Saturated Porous Media

Stress Generated During Drying of Saturated Porous Media

Development of A Darcy-flow model applied to simulate the drying of shrinking media

Drying of solids; estimation of the mathematical model parameters

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