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

Abstract

Computational studies on entropy generation during laminar mixed convection in porous square enclosures have been carried out based on Darcy-Brinkman-Forchheimer model using the penalty finite element method. Finite element simulations are performed for the isothermally hot bottom wall, adiabatic top wall, and isothermally cold side walls (case 1) or linearly heated side walls (case 2) or linearly heated left wall with isothermally cold right wall (case 3) for a wide range of modified Darcy numbers (10 À5 Da m 10 À2 ), Grashof numbers (Gr ¼ 10 3 À 10 5 ), and modified Prandtl numbers (Pr m ¼ 0.026 and 7.2). Further, the effects of Da m on the total entropy generation (S total ), average Bejan number (Be av ), and average Nusselt number ðNu b Þ are discussed. It is found that Re ¼ 100 is preferred over Re ¼ 1 based on larger heat transfer rate with minimum entropy generation for Pr m ¼ 0.026 and 7.2, 10 À5 Da m 10 À2 at Gr ¼ 10 5 for all the cases.

Determining the structure of a laminar detachable current in an open cavity

“…Of applied character, in solving the conjugated problems of hydrodynamics and thermal exchange, is the series of papers that employ a joint solution to the equations of motion and energy [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. If one examines, in the problem on a medium's motion in a cavity, the joint effect of the fields of speed, pressure, and temperature, a given problem then could be applied when the heat exchange is intensified.…”

“…The influence of the plate size and its orientation relative to the vector of gravity force on the convective heat exchange and the flow structure inside a cavity has been studied and highlighted. Work [18] numerically studies a laminar mixed convection in the cavity at different configurations of heating of its walls.…”

Prandtl Number Effects on the Entropy Generation During the Transient Mixed Convection in a Square Cavity Heated from Below

“…Secondly, as to the mixed convection, Roy et al [23][24][25] investigated the effect of the Prandtl on entropy generation during the mixed convection in a square cavity where the bottom wall is isothermally hot, sidewalls are cold, and the top wall is adiabatic. Simulations were carried out for Prandtl number Pr = 0.026 and 7.2, the Reynolds number Re varied between 10 and 100, and Grashof number Gr varied between 10 3 and 10 5 .…”

“…Simulations were carried out for Prandtl number Pr = 0.026 and 7.2, the Reynolds number Re varied between 10 and 100, and Grashof number Gr varied between 10 3 and 10 5 . In Roy et al [23] the effect of moving horizontal or vertical wall(s) was considered, in Roy et al [24], the cavity was filled with porous media and the effect of thermal boundary condition was highlighted and in Roy et al [25] the effect of various thermal boundary conditions is studied. More recently, Roy et al [26] dealt with the same problem as those described above but in porous triangular cavities.…”

Numerical study of laminar mixed convection flow in a lid-driven square cavity filled with porous media

“…Also, Roy et al (2015a) studied the influence of entropy generation with mixed convection in porous square enclosures. The Darcy-Brinkman-Forchheimer model has been established.…”