Convective heat and mass transfer modelling at air–porous material interfaces: Overview of existing methods and relevance

Defraeye, Thijs; Blocken, Bje Bert; Derome, Dominique; Nicolaı̈, Bart; Carmeliet, JE Jan

doi:10.1016/j.ces.2012.02.032

Cited by 59 publications

(40 citation statements)

References 94 publications

(95 reference statements)

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“…One option to take into account properly the change in the external mass transfer would be to avoid using the concept of external mass transfer coefficient by solving explicitly the equations governing the external mass transfer. 8,31,32 This represents a heavy task since these equations should be solved repeatedly together with Eqs. (3) and (10) governing the ion transport and the evolution of saturation in the porous medium.…”

Section: Discussionmentioning

confidence: 99%

Porous medium coffee ring effect and other factors affecting the first crystallisation time of sodium chloride at the surface of a drying porous medium

et al. 2013

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We study the distribution of ions in a drying porous medium up to the formation of first crystals at the surface. The study is based on comparisons between numerical simulations and experiments with packings of glass beads. The experimental configuration, which is representative of many previous drying experiments, is characterized by the formation of an efflorescence fairy ring at the surface of the porous medium. The preferential formation of crystals at the periphery is explained by the combined effect of higher evaporation fluxes at the surface periphery, as in the classical coffee ring problem, and variations in the porosity near the wall bordering the packing. It is shown that both effects have a great impact on the time marking the occurrence of first crystals, which is referred to as the first crystallization time.The experiments indicate that the first crystallization time increases with a decreasing bead size for a given initial ion concentration. This is explained by the variation with bead size of the characteristic size of the near wall region where a preferential desaturation of the sample occurs as a result of the porosity increase near the wall. The study also reveals a significant salt supersaturation effect. This represents a noticeable fact in relation with salt weathering issues. C 2013 AIP Publishing LLC.

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Section: Discussionmentioning

confidence: 99%

Porous medium coffee ring effect and other factors affecting the first crystallisation time of sodium chloride at the surface of a drying porous medium

et al. 2013

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“…II Centro de Ciências Agrárias, Ambientais e Biológica, UFRB, Cruz das Almas, BA, Brasil. alterações visuais como a redução do volume do fruto (KATEKAWA & SILVA, 2007;ZOTARELLI et al, 2011). Otimizar a secagem é fundamental para melhorar a efi ciência sem comprometer a qualidade do produto (DEFRAEYE et al, 2012). As curvas de secagem estipulam o tempo ideal de desidratação.…”

Section: Introductionunclassified

Estabilidade físico-química e microbiológica de banana passa orgânica

et al. 2014

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“…Such models are referred to in literature as conjugate models. Defraeye et al [29] gives a good overview of recent developments in this field of modelling. An early attempt to develop a coupled model was done by Amir et al [30].…”

Section: Numerical Modelling: Coupling Ham With Cfdmentioning

confidence: 99%

Validation of a coupled heat, vapour and liquid moisture transport model for porous materials implemented in CFD

Belleghem

Steeman

Janssen

et al. 2014

Building and Environment

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Moisture-related damage is an important issue when looking at the performance of building envelopes. In order to accurately predict the moisture behaviour of building components, building designers can resort to Heat, Air and Moisture (HAM) models. In this paper a newly developed heat and mass transfer model that is implemented in a 3D finite volume solver, Fluent®, is presented. This allows a simultaneous modelling approach of both the convective conditions surrounding a porous material and the heat and moisture transport in the porous material governed by diffusion. Unlike most HAM models that often confine to constant convective transport coefficients it is now possible to better predict these convective boundary conditions. An important application of the model is the convective drying of porous building materials. Especially during the first drying stage, the drying rate is determined by the convective boundary conditions. The model was validated against a convective drying experiment from literature, in which a saturated ceramic brick sample is dried by flowing dry air over one side of the sample surface. Temperature and relative humidity measurements at different depths in the sample, moisture distribution profiles and mass loss measurements were compared with simulation results. An overall good agreement between the coupled model and the experiments was found, however, the model predicted the constant drying rate period better than the falling rate period. This was improved by adjusting the material properties. The adjustment of the material properties was supported by neutron radiography measurements.

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Convective heat and mass transfer modelling at air–porous material interfaces: Overview of existing methods and relevance

Cited by 59 publications

References 94 publications

Porous medium coffee ring effect and other factors affecting the first crystallisation time of sodium chloride at the surface of a drying porous medium

Porous medium coffee ring effect and other factors affecting the first crystallisation time of sodium chloride at the surface of a drying porous medium

Estabilidade físico-química e microbiológica de banana passa orgânica

Validation of a coupled heat, vapour and liquid moisture transport model for porous materials implemented in CFD

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