Open Access

ARTICLE

Numerical Study of Double Diffusive Convection in presence of Radiating Gas in a Square Cavity

by F. Moufekkir¹, M.A. Moussaoui¹, A. Mezrhab¹, H. Naji³, M. Bouzidi⁵

1 Laboratoire de Mécanique & Energétique, Faculté des sciences, Département de physique, 60000 Oujda, Maroc.
2 Correspondence author: amezrhab@yahoo.fr.
3 Laboratoire Génie Civi & géo-Environnement (LGCgE- EA 4515), UArtois/FSA Béthune, F62400 Béthune, France.
4 Université Lille Nord de France, F-59000 Lille/Université d’Artois/FSA, F-62400 Béthune, France.
5 Institut Pascal UBP/CNRS/IFMA, IUT d’Allier, B.P. 2235, Avenue Aristide Briand, 03101 Montluçon cedex.

Fluid Dynamics & Materials Processing 2012, 8(2), 129-154. https://doi.org/10.3970/fdmp.2012.008.129

Abstract

The problem related to coupled double diffusive convection in a square enclosure filled with a gray gas in the presence of volumetric radiation is examined numerically. The horizontal walls are assumed to be insulated and impermeable. Different temperatures and species concentrations are imposed at vertical walls. In particular, we propose a 2-D numerical approach based on a hybrid scheme combining a multiple-relaxation-time lattice Boltzmann model (MRT-LBM) and a standard finite difference method (FDM). The radiative term in the energy equation is treated using the discrete ordinates method (DOM) with a S8 quadrature. The influence of various parameters (such as the Rayleigh number, the buoyancy number, the optical thickness and Lewis number) on fluid flow, heat and mass transfer is evaluated. Results show that for the case of cooperating flows, the isotherms and isoconcentrations are inclined in the core cavity and the flow is relatively stable whereas multicellular recirculations appear in the opposing-flows case. Generally when the mass effect is dominant, the flow is slowed and the influence of radiation is considerable on the thermal field and negligible on the dynamic and concentration fields. However, when thermal effects are dominant, the volumetric radiation accelerates the flow and significantly alters the structure of velocity, concentration and temperature fields.

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