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Computational Thermal Sciences: An International Journal
ESCI SJR: 0.249 SNIP: 0.434 CiteScore™: 0.7

ISSN Imprimir: 1940-2503
ISSN En Línea: 1940-2554

Computational Thermal Sciences: An International Journal

DOI: 10.1615/ComputThermalScien.2016011763
pages 163-176

NATURAL CONVECTION IN TALL AND SHALLOW POROUS RECTANGULAR ENCLOSURES HEATED FROM BELOW

Zineddine Alloui
Département du socle commun des Sciences et Technique, Faculté de Technologie, Université El-Hadj-Lakhdar Batna, 05000 Batna, Algeria
Patrick Vasseur
Ecole Polytechnique, Université de Montréal, C.P. 6079, Succ. "Centre ville", Montréal, Québec H3C 3A7, Canada

SINOPSIS

The Darcy model with the Boussinesq approximation is used to study both analytically and numerically natural convection in a porous medium saturated by a Newtonian fluid. The geometry considered is a rectangular cavity heated from below and cooled from above by a constant heat flux while the sidewalls are maintained adiabatic. The governing parameters for the problem are the thermal Darcy-Rayleigh number R and the aspect ratio of the cavity A. In the limit of extremely confined geometries the parallel flow approximation is used to predict the flow behavior in the case of a tall vertical layer (A >> 1) or shallow horizontal one (A << 1). For a tall cavity, the existence of multicellular flow patterns, consisting of m vertical cells, is predicted by the present analytical model. Also, for a shallow cavity, it is demonstrated that the flow pattern can be either unicellular or multicellular. This is confirmed by the numerical results obtained by solving the full governing equations.