Moisture transport in shrinking gels during saturated drying

Achanta, Srinivas; Okos, Martin R.; Cushman, John H.; Kessler, David P.

doi:10.1002/aic.690430818

Cited by 61 publications

(48 citation statements)

References 16 publications

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“…the ratio of the characteristic relaxation time to the characteristic diffusion time, is small, indicating that the elastic contribution is sufficient to describe the hydro-mechanical coupling [22]. Mechanical properties can be found in [12].…”

Section: Mechanical Equilibrium Equationmentioning

confidence: 87%

Convective Drying of Gels: Comparison Between Simulated and Experimental Moisture Profiles Obtained by X-ray Microtomography

et al. 2010

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Abstract:In this work, internal moisture profiles obtained either by simulation or experimentally during the convective drying of resorcinol-formaldehyde gels are compared. Such a comparison constitutes an attractive way to validate drying simulation models. X-ray microtomography, a powerful 3D imaging technique, coupled to image analysis is used to determine the internal moisture profiles in a non destructive way. A thermo-hygro-mechanical coupled model is used to simulate the moisture profiles developing during drying. Resorcinol-formaldehyde gels are used because their degree of shrinkage can be easily controlled. Results show a fairly good agreement between experimental and simulated profiles, especially at high moisture contents.

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Section: Mechanical Equilibrium Equationmentioning

confidence: 87%

Convective Drying of Gels: Comparison Between Simulated and Experimental Moisture Profiles Obtained by X-ray Microtomography

et al. 2010

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“…In many practical applications, swelling systems can be unsaturated, e.g., in the case of drying of wood and food materials (Datta 2007;Perre and Turner 1999), and transport in soils (Carminati et al 2008;Purandara et al 2008). The swelling behavior of a porous medium (saturated or unsaturated) results from interactions at different spatial scales, and therefore, researchers have developed multiscale thermomechanical models to study heat and mass transport in multiphase swelling porous systems (Achanta 1995;Bennethum and Cushman 1996b;Murad et al 1995;Murad and Cushman 1996, 2000Bennethum et al 2000;Schrefler 2002;Singh et al 2003a,b;Weinstein et al 2008). Approaches used to develop macroscopic theories can be broadly classified into three categories-averaging or macroscopization theories, theory of mixtures, and hybrid theories of the first two.…”

Section: Introductionmentioning

confidence: 99%

A Model for Flow and Deformation in Unsaturated Swelling Porous Media

et al. 2009

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A thermomechanical theory for multiphase transport in unsaturated swelling porous media is developed on the basis of Hybrid Mixture Theory (saturated systems can also be modeled as a special case of this general theory). The aim is to comprehensively and non-empirically describe the effect of viscoelastic deformation on fluid transport (and vice versa) for swelling porous materials. Three phases are considered in the system: the swelling solid matrix s, liquid l, and air a. The Coleman-Noll procedure is used to obtain the restrictions on the form of the constitutive equations. The form of Darcy's law for the fluid phase, which takes into account both Fickian and non-Fickian transport, is slightly different from the forms obtained by other researchers though all the terms have been included. When the fluid phases interact with the swelling solid porous matrix, deformation occurs. Viscoelastic large deformation of the solid matrix is investigated. A simple form of differential-integral equation is obtained for the fluid transport under isothermal conditions, which can be coupled with the deformation of the solid matrix to solve for transport in an unsaturated system. The modeling theory thus developed, which involves two-way coupling of the viscoelastic solid deformation and fluid transport, can be applied to study the processing of biopolymers, for example, soaking of foodstuffs and stress-crack predictions. Moreover, extension and modification of this modeling theory can be applied to study a vast variety of problems, such as drying of gels, consolidation of clays, drug delivery, and absorption of liquids in diapers.

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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%

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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Moisture transport in shrinking gels during saturated drying

Cited by 61 publications

References 16 publications

Convective Drying of Gels: Comparison Between Simulated and Experimental Moisture Profiles Obtained by X-ray Microtomography

Convective Drying of Gels: Comparison Between Simulated and Experimental Moisture Profiles Obtained by X-ray Microtomography

A Model for Flow and Deformation in Unsaturated Swelling Porous Media

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

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