Irreversibility Analysis for Double Diffusive Convection Flow of a Gas Mixture in a Chamfered Corners Square Enclosure F
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RESEARCH ARTICLE-CHEMICAL ENGINEERING
Irreversibility Analysis for Double Diffusive Convection Flow of a Gas Mixture in a Chamfered Corners Square Enclosure Filled with a Porous Medium Mounir Bouabid1 · Naoufal Ghoudi1 · Rahma Bouabda1 · Mourad Magherbi2 Received: 25 October 2019 / Accepted: 30 April 2020 © King Fahd University of Petroleum & Minerals 2020
Abstract An analysis of thermodynamic irreversible principle (TPI), through determination of entropy generation rate, during doublediffusive convection in an octagonal shape, filled with saturated fluid in a porous enclosure, is numerically investigated in this work, by studying the influence of thermodiffusion effect on entropy generation variations. According to the fluid flow evolution under consideration, the influence of mass flux due to temperature gradient is incorporated into the governing equations of the problem, which are solved numerically, using the COMSOL software. Appropriated thermal and solutal Dirichlet boundary conditions are used under the Boussinesq approximation. For the porous medium, the Darcy–Brinkman model is assumed in coupling with energy and mass transfer balance equations. The flow model is described in terms of mass flux due to temperature gradient, buoyancy ratio, thermal Rayleigh number and porosity of the medium. Results of the variations of heat transfer and entropy generation in the studied enclosure are graphically illustrated and are basically discussed, through various physical aspects of the problem. The numerical computations are presented for various values of thermal Rayleigh number (RaT), thermal diffusion parameter (Kt), Darcy number (Da), buoyancy ratio (N) and porosity of the medium (ε). In addition, the total entropy generation due to thermal, species and mixed diffusion gradients; Darcy–Brinkman dissipation; and fluid friction are studied and discussed. It is found that the entropy generation increases strongly when passing from the cooperative case of buoyancy forces to the opposite case. A similar behaviour is obtained with increasing the thermal diffusion ratio, at a constant buoyancy ratio. Also, an accentuated increase in entropy generation is observed when the Darcy number exceeds the value 1 0−6. Moreover, the results show that the augmentation of the thermodiffusion effect induces an increase in total entropy generation, at fixed value of the porosity. Keywords Mixed convection · Porous medium · Square cavity with chamfer · Entropy generation · Numerical simulation · Thermodiffusion * Mounir Bouabid [email protected] Naoufal Ghoudi [email protected] Rahma Bouabda [email protected] Mourad Magherbi [email protected] 1
Applied Thermodynamics Research Unit, Chemical Engineering Process Department, Engineers National School of Gabes, Gabes University, Omar Ibn El Khattab Street, 6029 Gabès, Tunisia
Industrial Chemistry and Chemical Engineering Process Department, High Institute of Applied Sciences and Technology, Gabes University, Omar Ibn El Khattab Street, 6072 Gabès, Tunisia
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