Second-Law Analysis of Buoyancy-Driven Flow inside a Rectangular Porous Enclosure with Three Adiabatic Walls
In the present paper, a second-law analysis is undertaken to study buoyancy-driven flow inside a rectangular porous enclosure with three adiabatic walls. To this aim, the conservation equations for mass, momentum, and energy are solved numerically using a control-volume based computational procedure. Thereafter, the generation of entropy is calculated in terms of heat transfer irreversibility and fluid friction irreversibility. All walls of the enclosure are thermally insulated except the bottom wall which is partially heated and cooled with a sinusoidal temperature profile. Results for a base case are presented in terms of streamlines, isothermal lines, iso-entropy generation lines, and iso-Bejan lines. Thereafter, effect of aspect ratio of the enclosure on the development of flow and thermal fields as well as entropy generation characteristics is examined. Finally, variations of average Nusselt number, global entropy generation rate, and global Bejan number are analyzed over a wide range of Darcy-modified Rayleigh number (), aspect ratio parameter (), and amplitude of the sinusoidal temperature function ().
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