ABSTRACT
The aim of the present investigation is to analyze the effect of the motion of horizontal walls on the entropy generation and heat transfer rates in an entrapped triangular porous cavity during mixed convection. Two different thermal boundary conditions are considered as follows: (i) hot inclined walls and cold horizontal walls and (ii) cold inclined walls and hot horizontal walls. Overall, Re = 100 may be recommended at Prm = 0.026, 7.2, Gr = 105, and Dam = 10−4 to 10−2 within the upper and lower cavities for cases 1 and 2.
Nomenclature
Be | = | Bejan number |
Dam | = | modified Darcy number |
g | = | acceleration due to gravity, m/s2 |
Gr | = | Grashof number |
K | = | medium permeability |
L | = | base of the triangular cavity, m |
= | average Nusselt number | |
P | = | dimensionless pressure |
Pem | = | modified Peclet number |
Prm | = | modified Prandtl number |
Re | = | Reynolds number |
Ri | = | Richardson number |
Sθ, Sψ | = | dimensionless entropy generation due to heat transfer and fluid friction |
T | = | temperature of the fluid, K |
Tc, Th | = | temperature of cold wall and hot wall, K |
u, v | = | x and y components of velocity, m/s |
U, V | = | x and y components of dimensionless velocity |
x, y | = | distances along x and y coordinates, m |
X, Y | = | dimensionless distances along x and y coordinates |
Greek Symbols | = | |
α | = | thermal diffusivity, m2/s |
β | = | volume expansion coefficient, K−1 |
γ | = | penalty parameter |
θ | = | dimensionless temperature |
ν | = | kinematic viscosity, m2/s |
ρ | = | density, kg/m3 |
Φ | = | basis function |
ψ | = | dimensionless streamfunction |
µ | = | dynamic viscosity, kg/m/s |
Ω | = | two-dimensional domain |
ϵ | = | porosity of the medium |
Subscripts | = | |
av | = | spatial average |
b, t, l, r | = | bottom, top, left, and right walls |
eff, f | = | effective and fluid properties |
i, k | = | global and local node numbers |
total | = | total |
Superscript | = | |
e | = | element |
Nomenclature
Be | = | Bejan number |
Dam | = | modified Darcy number |
g | = | acceleration due to gravity, m/s2 |
Gr | = | Grashof number |
K | = | medium permeability |
L | = | base of the triangular cavity, m |
= | average Nusselt number | |
P | = | dimensionless pressure |
Pem | = | modified Peclet number |
Prm | = | modified Prandtl number |
Re | = | Reynolds number |
Ri | = | Richardson number |
Sθ, Sψ | = | dimensionless entropy generation due to heat transfer and fluid friction |
T | = | temperature of the fluid, K |
Tc, Th | = | temperature of cold wall and hot wall, K |
u, v | = | x and y components of velocity, m/s |
U, V | = | x and y components of dimensionless velocity |
x, y | = | distances along x and y coordinates, m |
X, Y | = | dimensionless distances along x and y coordinates |
Greek Symbols | = | |
α | = | thermal diffusivity, m2/s |
β | = | volume expansion coefficient, K−1 |
γ | = | penalty parameter |
θ | = | dimensionless temperature |
ν | = | kinematic viscosity, m2/s |
ρ | = | density, kg/m3 |
Φ | = | basis function |
ψ | = | dimensionless streamfunction |
µ | = | dynamic viscosity, kg/m/s |
Ω | = | two-dimensional domain |
ϵ | = | porosity of the medium |
Subscripts | = | |
av | = | spatial average |
b, t, l, r | = | bottom, top, left, and right walls |
eff, f | = | effective and fluid properties |
i, k | = | global and local node numbers |
total | = | total |
Superscript | = | |
e | = | element |