MULTICELLULAR FLOWS INDUCED BY NATURAL CONVECTION

IN A POROUS HORIZONTAL CYLINDRICAL ANNULUS

 

J. Belabid, A. Cheddadi*

« Systèmes Thermiques et Ecoulements Réels »,

Ecole Mohammadia d’Ingénieurs, Université Mohammed V-Agdal,

B.P. 765, Rabat, Maroc

* Corresponding author. E-mail:  cheddadi@emi.ac.ma

Received: 11 February 2013; revised version accepted: 13 October 2013

 

Abstract

     This work presents a numerical investigation of natural convection heat transfer within a two-dimensional horizontal annulus filled with a saturated porous medium. The governing equations (in the stream function and temperature formulation) were solved using the ADI (Alternating Direction Implicit) finite difference method. Multicellular flows develop for small values of the aspect ratio parameter R and high ones of the Rayleigh number Ra. Emphasis is put on the mesh effect on the determination of the bifurcation point between monocellular and bicellular flows for different values of the aspect ratio. The results are obtained for 1.1 £ R £ 2 and are very close to those obtained in the literature for R=2 and R=21/2 . We noticed that the bifurcation point decreases gradually when the mesh refinement is increased.

 

Keywords: Natural convection; Porous medium; Annular space; Multicellular flow; Bifurcation; Mesh effect.

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