ABSTRACT
In this paper, we analyze numerically the effects of the inclination angle on natural convection heat transfer and entropy generation characteristics in a two-dimensional square enclosure saturated with a porous medium. There is a significant alteration in Nusselt number with the orientation of the enclosure at higher values of Rayleigh number. It reveals that the variation of entropy generation rate with the inclination angle is significant for higher values of Darcy number. The dominant source of irreversibility is due to heat transfer at low values of Darcy number, whereas entropy generation due to fluid flow dominates over that due to heat transfer for larger values of Darcy number.
Nomenclature
Be | = | Bejan number |
Da | = | Darcy number |
g | = | gravitational acceleration, ms−2 |
k | = | thermal conductivity, Wm−2K−1 |
K | = | permeability of the medium |
L | = | length of the enclosure, m |
Nu | = | Nusselt number |
Pr | = | Prandtl number |
Ra | = | Rayleigh number |
S | = | entropy generation rate |
T | = | dimensionless temperature |
T0 | = | bulk temperature (Th + Tc)/2 |
u, v | = | dimensionless velocity components |
x, y | = | dimensionless Cartesian coordinates |
ρ | = | density, kgm−3 |
α | = | thermal diffusivity, m2s−1 |
β | = | volumetric expansion coefficient, K−1 |
ν | = | kinematic viscosity, m2s−1 |
ϕ | = | angle of inclination of the enclosure |
ξ | = | irreversibility distribution ratio |
Subscripts | = | |
avg | = | average |
c | = | cold |
h | = | hot |
T | = | total |
θ | = | heat transfer |
μ | = | fluid friction |
Superscripts | = | |
* | = | dimensional quantity |
Nomenclature
Be | = | Bejan number |
Da | = | Darcy number |
g | = | gravitational acceleration, ms−2 |
k | = | thermal conductivity, Wm−2K−1 |
K | = | permeability of the medium |
L | = | length of the enclosure, m |
Nu | = | Nusselt number |
Pr | = | Prandtl number |
Ra | = | Rayleigh number |
S | = | entropy generation rate |
T | = | dimensionless temperature |
T0 | = | bulk temperature (Th + Tc)/2 |
u, v | = | dimensionless velocity components |
x, y | = | dimensionless Cartesian coordinates |
ρ | = | density, kgm−3 |
α | = | thermal diffusivity, m2s−1 |
β | = | volumetric expansion coefficient, K−1 |
ν | = | kinematic viscosity, m2s−1 |
ϕ | = | angle of inclination of the enclosure |
ξ | = | irreversibility distribution ratio |
Subscripts | = | |
avg | = | average |
c | = | cold |
h | = | hot |
T | = | total |
θ | = | heat transfer |
μ | = | fluid friction |
Superscripts | = | |
* | = | dimensional quantity |