Open Access

ARTICLE

Application of a Diffusion Model to Predict Drying Kinetics Changes Under Variable Conditions: Experimental and Simulation Study

L. Bennamoun¹, A. Belhamri², A. Ali Mohamed

1 Corresponding aothor. Département de Physique, Institut des Sciences Exactes, Centre Universitaire Larbi Benm’hidi, Oum El Bouaghi, 04000, Algeria, Tel. / Fax: (213) 32 42 41 92, E-mail: lyes_bennamoun@yahoo.ca
2 Département de Génie Climatique, Faculté des Sciences de l’Ingénieur, Université Mentouri, Con-stantine, 25000, Algeria, Tel/Fax: (213) 31819012, E-mail: belhamri_a@yahoo.fr

Fluid Dynamics & Materials Processing 2009, 5(2), 177-192. https://doi.org/10.3970/fdmp.2009.005.177

Abstract

This study focuses on the interplay between drying kinetics (encountered in typical industrial processes and particularly in the context of solar drying) and the possible variation of external (e.g., environmental) conditions. Theoretical models of these behaviours are introduced. Experimental results confirmed by simulation are also presented. Variation of the thermo physical properties of air is taken into account in terms of variation of viscosity, density and coefficient of diffusion. In particular, this coefficient is calculated from experimental data and expressed as a function of the wet bulb air temperature. When external conditions are modified and, as a natural consequence, also the drying kinetics undergo some change, in general, products exhibit a time of response. This response (the principal object of the present study) changes from the kernel of the product to its surface. Two kinds of conditions are simulated in the present work to model such behaviour: a constant flux and a convective flux. It is found that the convective flux is more affected by external conditions than the constant flux. A comparison between sudden and progressive changes of drying conditions is also considered for possible optimisation of the considered processes.

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Keywords

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