Effects of thermal boundary conditions, surface radiation and aspect ratio on thermal performance in “T” shallow cavity

¹ Laboratoire de Mécanique, Matériaux et Energétique (L2ME), Faculté de Technologie, Université A. Mira de Bejaia, 06000 Bejaia, Algérie
² Laboratoire de Physique Théorique (LPT), Faculté des sciences, Université A. Mira de Bejaia, 06000 Bejaia, Algérie
³ Laboratoire Energétique, Mécanique et Ingénieurie (LEMI), Université B. Bouguerra de Boumerdes, 35000 Boumerdes, Algérie

^a Corresponding author: bachir.meziani@univ-bejaia.dz

Received: 11 March 2014
Accepted: 20 May 2014

Abstract

The main objective of this article is to study the effect of 2D coupled mode free convection with surface radiation on the fluid flow behavior in an air filled partitioned and shallow cavity subjected to isothermal or insulated boundary conditions. The dimensionless governing equations under Boussinesq approximation are coupled with a radiative model through the boundaries conditions and solved by the finite volume method. The numerical results are discussed in terms of streamlines, isotherms, convective and radiative Nusselt numbers along the cover plate for various aspect ratios (a, b and c), emissivities and Rayleigh number. These results highlighted the condition of the enclosure performance and revealed among other that isothermal boundaries induce better convective heat exchange compared to adiabatic cases. Also, it is noticed that varying aspect ratio (a) causes strong influence on both Nusselt numbers compared to the aspect ratios (b) and (c). The increase of (ϵ_o) raises Nu_conv and decreases Nu_rad slightly. Whereas, an increase of (ϵ_C) leads to minor changes in Nu_rad when (b) or (c) vary, this effect becomes appreciable with increasing (a).