NUMERICAL INVESTIGATION OF BOUNDARY SURFACE EFFECTS ON NATURAL CONVECTION IN A HORIZONTAL POROUS CAVITY BY USING NON-DARCIAN FLOW

RafaeMahmood, Omar; Atiya Mohamed, Ibrahim

	NUMERICAL INVESTIGATION OF BOUNDARY SURFACE EFFECTS ON NATURAL CONVECTION IN A HORIZONTAL POROUS CAVITY BY USING NON-DARCIAN FLOW
AL-TAQANI
Article 1, Volume 26, Issue 5, 2013, Pages 0-0
Authors
Omar RafaeMahmood; Ibrahim Atiya Mohamed
Abstract
In this paper, Non–Darcian steady flow two-dimensional natural convective heat transfer in an rectangular and square porous cavities with two parallel walls kept at constant different temperatures, while the other two parallel walls were well insulated, had been studied numerically. The governing equations had been solved using finite difference method with Gauss-Seidel iteration. Results have been obtained for a modified Rayleigh number of the range of (100 – 1000), enclosure aspect ratio of (0.5 – 3.0), and Darcy number( 6 4 ) 10 10− − − . The results showed (Multicellular Flow) when the aspect ratio less than one and disappeared this flow when the aspect ratio A ≥1. The rate of heat transfer was increase when the (aspect ratio and modified Rayleigh number) increased and Darcy number decreased, except when the boundary layer flow was encountered, also for any constants modified Rayleigh number and Darcy number the maximum Nusselt number was obtained at one aspect ratio . As certain value Darcy number, any increase in the aspect ratio will lead to appearance of boundary layer flow at low modified Rayleigh number. The increase in Darcy number enhances the boundary layer thickness. The effect of Darcy number became more significant at (Da=10-4), also the effect of the Darcy number decreases when increase the aspect ratio. The Nusselt number was found a strong function of modified Rayleigh numberand aspect ratio.
Keywords
non; Darcian flow; Porous medium; Natural convective heat transfer; Brinkman viscous term; modified Rayleigh number

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