Papers by Author: Hassen Beji

Abstract: This paper aims to provide a better understanding of the gypsum hydric behavior used as coating during imbibition in liquid water. Firstly, we want to describe hydric transfer by determining sorptivity and hydraulic diffusivity of coating gypsum. Secondly, we evaluate the impact of the hemp fibers addition on hydric parameters. Experimentally, hydraulic diffusivity will be obtained by an overall measure of the moisture content (mc) in a defined sample volume, and the sorptivity describes capacity absorption. Through numerical simulation, hydraulic diffusivity will be determined by a local measure of the mc.

Abstract: A glass wool media is commonly classified as a medium made up of many capillaries. They might, however, be considered analogous to a network of tubes as a bundle of capillaries. The capillary pressure of such a medium would be dependent on the amount of fluid held within the bundles. But, this very simple picture of porous media does not capture all the characteristics of this imbibition. We have determined capillaries radii by using Washburn and Laplace relations. Laplace radius can also be obtained by 3 approaches: using White’s relation and using Jurin’s law with visualized height and with weight. We have observed a single value of capillary radius cannot be used to determine the infiltration height as a function of time. This mechanism of capillary infiltration can be controlled by pores of more than one size and pores are interconnected.

Abstract: A two dimensional mathematical model has been developed to simulate the coupled heat and mass transfer in a porous medium undergoing a strong exothermic reaction. The problem has received a lot of interest due to its relevance in a wide variety of engineering applications such heat pipes, nuclear reactors, drying technologies, catalytic reactors and others. The fluid flow is modelled via the Darcy-Brinkman-Forchheimer equation. This model is solved numerically by the finite volume method, and the code is validated by comparing with previously published works. The influence of the exothermic chemical reaction on the heat and mass transfer in the porous medium is discussed. The effects of pertinent parameters such as the Biot number, the Reynolds number and the Frank-Kamenetskii number were analyzed. Quantitative and qualitative results are presented. Comparisons with other works in the literature are performed and excellent agreement between the results is obtained.