Entropy Generation During Natural Convection in a Porous Cavity: Effect of Thermal Boundary Conditions

Abstract

Entropy generation plays a significant role in the overall efficiency of a given system, and a judicious choice of optimal boundary conditions can be made based on a knowledge of entropy generation. Five different boundary conditions are considered and their effect of the permeability of the porous medium, heat transfer regime (conduction and convection) on entropy generation due to heat transfer, and fluid friction irreversibilities are investigated in detail for molten metals (Pr ¼ 0.026) and aqueous solutions (Pr ¼ 10), with Darcy numbers (Da) between 10 À5 -10 À3 and at a representative high Rayleigh number, Ra ¼ 5 Â 10 5 . It is observed that the entropy generation rates are reduced in sinusoidal heating (case 2) when compared to that for uniform heating (case 1), with a penalty on thermal mixing. Finally, the analysis of total entropy generation due to variation in Da and thermal mixing and temperature uniformity indicates that, there exists an intermediate Da for optimal values of entropy generation, thermal mixing, and temperature uniformity.

Analysis of Entropy Generation During Mixed Convection in Porous Square Cavities: Effect of Thermal Boundary Conditions

“…A fair number of studies on entropy generation during natural convection process in closed cavities filled with fluid and porous medium were carried out in last few years [20][21][22][23][24][25][26][27][28][29][30][31]. Mahapatra et al [20] studied entropy generation analysis in a square enclosure filled with air in presence of adiabatic and isothermal blocks.…”

“…A detailed analysis on entropy generation due to buoyancy driven flow in discretely heated porous square cavities was done by Kaluri and Basak [27]. Further, Basak et al [28] performed entropy generation analysis in porous square cavities with various thermal boundary conditions. Anandalakshmi and Basak [29] showed the effect of inclination angle on entropy generation in a porous rhombic cavity and compared the results with square cavity.…”

Inherent irreversibility analysis in a buoyancy induced magnetohydrodynamic couple stress fluid

“…In their report, they stated that entropy generation increases with an increase in magnetic parameter. Other studies on the analysis of entropy generation in various fluid flows can be found in [1,5,6,8,13,20,28].…”

Entropy Generation and Natural Convection of CuO-Water Nanofluid in C-Shaped Cavity under Magnetic Field

“…Analyses of the second law of thermodynamics are also focused on saturated porous cavities, as in Baytas [8], Al-Hadhrami et al [9], Mahmud and Fraser [10], Hooman and Ejlali [11], Zahmatkesh [12], Varol et al [13], and Basak et al [14].…”