Abstract
This work is focused on the numerical modeling of steady, laminar, heat and mass transfer by MHD mixed convection from a semi-infinite, isothermal, vertical and permeable surface immersed in a uniform porous medium in the presence of thermal radiation and Dufour and Soret effects. A mixed convection parameter for the entire range of free-forced-mixed convection is employed and the governing equations are transformed into non-similar equations. These equations are solved numerically by an efficient, implicit, iterative, finite-difference scheme. The obtained results are checked against previously published work on special cases of the problem and are found to be in excellent agreement. A parametric study illustrating the influence of the thermal radiation coefficient, magnetic field, porous medium inertia parameter, concentration to thermal buoyancy ratio, and the Dufour and Soret numbers on the fluid velocity, temperature and concentration as well as the local Nusselt and the Sherwood numbers is conducted. The obtained results are shown graphically and the physical aspects of the problem are discussed.
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Abbreviations
- B 0 :
-
magnetic field strength
- C :
-
dimensionless concentration, C = (c−c ∞)/(c w−c ∞)
- c :
-
concentration at any point in the flow field
- c s :
-
concentration susceptibility
- c w :
-
concentration at the wall
- c ∞ :
-
concentration at the free stream
- D :
-
mass diffusivity
- D f :
-
Dufour number, D f = Dk T (c w − c ∞)/[α e c s c p (T w − T ∞)]
- F :
-
inertia coefficient of the porous medium
- f :
-
dimensionless stream function, f = ψ /[ α e (Pe 1/2 x + Ra 1/2 x ) ]
- g :
-
gravitational acceleration
- h :
-
local convective heat transfer coefficient
- h m :
-
local mass transfer coefficient
- K :
-
permeability of the porous medium
- k e :
-
porous medium effective thermal conductivity
- k T :
-
thermal–diffusion ratio
- k*:
-
mean absorption coefficient
- L :
-
characteristic length
- Le :
-
Lewis number, Le = αe/D
- M :
-
square of the Hartmann number, M = (σ B 0 K)/(ɛ μ)
- N :
-
buoyancy ratio, N = β c (c w−c ∞)/[β T (T w−T ∞)]
- Nu x :
-
local Nusselt number, Nu x = hx/k e
- p :
-
Fluid pressure
- Pe x :
-
local Peclet number, Pe x = V ∞ x/αe
- Pe L :
-
Peclet number at x = L
- q r :
-
radiative heat flux
- Ra x :
-
local Rayleigh number, Ra x = x/αe[ρ g β T |T w−T ∞|K/μ]
- Ra L :
-
Rayleigh number at x = L
- S r :
-
Soret number, S r = Dk T (T w − T ∞)/[α e T m (c w − c ∞)]
- Sh x :
-
local Sherwood number, Sh x = h m x/D
- T :
-
temperature at any point
- T m :
-
mean fluid temperature
- T w :
-
wall temperature
- T ∞ :
-
free stream temperature
- u :
-
tangential or x-component of velocity
- v :
-
normal or y-component of velocity
- v 0 :
-
wall mass transfer coefficient
- V ∞ :
-
free stream velocity
- x :
-
distance along the plate
- y :
-
distance normal to the plate
- ε:
-
porosity of porous medium
- Γ:
-
dimensionless porous medium inertia coefficient, Γ = 2FK(Pe 1/2 L + Ra 1/2 L )/(μ L)
- αe :
-
effective thermal diffusivity of the porous medium
- β c :
-
concentration expansion coefficient
- β T :
-
thermal expansion coefficient
- η:
-
coordinate transformation in terms of x and y, η = y(Pe 1/2 x + Ra 1/2 x )/x
- χ:
-
mixed convection parameter, \(\chi = [1 + ({Ra_{x} } \mathord{\left/ {\vphantom {{Ra_{x} } {Pe_{x} }}} \right. \kern-\nulldelimiterspace} {Pe_{x} })^{{1 \mathord{\left/ {\vphantom {1 2}} \right. \kern-\nulldelimiterspace} 2}} ]^{{ - 1}} \)χ = [1 + (Ra x /Pe x )1/2]−1
- ψ:
-
stream function
- θ:
-
dimensionless temperature, θ = (T−T ∞)/(T w−T ∞)
- ρ:
-
fluid density
- σ:
-
fluid electrical conductivity
- σ* :
-
Stefan–Boltzmann constant
- ξ:
-
transformed suction or injection parameter, ξ = v 0 x (Pe 1/2 x + Ra 1/2 x )− 1 /αe
References
Vafai K, Tien CL (1981) Boundary and inertia effects on flow and heat transfer in porous media. Int J Heat Mass Transf 24:195–203
Cheng P, Minkowycz WJ (1977) Free convection about a vertical flat plate embedded in a porous medium with application to heat transfer from a dike. J Geophys Res 82:2040–2044
Minkowycz WJ, Cheng, P, Moalem F (1985) The effect of surface mass transfer on buoyancy-induced Darcian flow adjacent to a horizontal heated surface. Int Commun Heat Mass Transf 12:55–65
Ranganathan P, Viskanta R (1984) Mixed convection boundary layer flow along a vertical surface in a porous medium. Numer Heat Transf 7:305–317
Nakayama A, Koyama HA (1987) General similarity transformation for free, forced and mixed convection in Darcy and non-Darcy porous media. J Heat Transfer 109:1041–1045
Hsieh JC, Chen TS, Armaly BF (1993) Non-similarity solutions for mixed convection from vertical surfaces in a porous medium. Int J Heat Mass Transf 36:1485–1493
Lai FC (1991) Coupled heat and mass transfer by mixed convection from a vertical plate in a saturated porous medium. Int Commun Heat Mass Transf 18:93–106
Raptis A, Massias C, Tzivanidis G (1982) Hydromagnetic free convection flow through a porous medium between two parallel plates. Phys Lett 90A:288–289
Aldoss TK, Al-Nimr MA, Jarrah MA, Al-Sha’er BJ (1995) Magnetohydrodynamic mixed convection from a vertical plate embedded in a porous medium. Numer Heat Transf 28A:635–645
Cheng P (1977) The influence of lateral mass flux on free convection boundary layers in a saturated porous medium. Int J Heat Mass Transf 20:201–206
Lai FC, Kulacki FA (1990) The influence of surface mass flux on mixed convection over horizontal plates in saturated porous media. Int J Heat Mass Transf 33:576–579
Lai FC, Kulacki FA (1990) The influence of lateral mass flux on mixed convection over inclined surfaces in saturated porous media. J Heat Transf 112:515–518
Hooper WB, Chen TS, Armaly BF (1993) Mixed convection from a vertical plate in porous media with surface injection or suction. Numer Heat Transf 25:317–329
Postelnicu A (2004) Influence of a magnetic field on heat and mass transfer by natural convection from vertical surfaces in porous media considering Soret and Dufour effects. Int J Heat Mass Transf 47:1467–1472
Eckert ERG, Drake RM (1972) Analysis of heat and mass transfer. McGraw Hill, New York
Baron JR (1963) Thermal diffusion effects in mass transfer. Int J Heat Mass Transf 6:1025–1033
Sparrow EM, Minkowycz WJ, Eckert ERG (1964) Diffusion-thermo effects in stagnation-point flow of air with injection of gases of various molecular weights into the boundary layer. AIAA J 2:652–659
Sparrow EM, Minkowycz WJ, Eckert ERG (1964) Transpiration induced buoyancy and thermal diffusion–diffusion thermo in a helium–air free convection boundary layer. J Heat Mass Transf 64:508–513
Dursunkaya Z, Worek ZW (1992) Diffusion thermo and thermal diffusion effects in transient and steady natural convection from a vertical surface. Int J Heat Mass Transf 35:2060–2065
Benano-Melly LB, Caltagirone J-P, Faissat B, Montel F, Costeseque P (2001) Modeling Soret coefficient measurement experiments in porous media considering thermal and solutal convection. Int J Heat Mass Transf 44:1285–1297
Anghel M, Takhar HS, Pop I (2000) Dufour and Soret effects on free convection boundary-layer over a vertical surface embedded in a porous medium. Studia Universitatis Babes-Bolyai, Mathematica XLV:11–21
El-Arabawy H (2003) Effect of suction/injection on the flow of a micropolar fluid past a continuously moving plate in the presence of radiation. Int J Heat Mass Transf 46:1471–1477
Blottner FG (1970) Finite-difference methods of solution of the boundary-layer equations. AIAA J 8:193–205
Cheng P, Ali CL, Verma AK (1981) An experimental study of non-Darcian effects in free convection in a saturated porous medium. Lett Heat Mass Transf 8:261–265
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Chamkha, A.J., Ben-Nakhi, A. MHD mixed convection–radiation interaction along a permeable surface immersed in a porous medium in the presence of Soret and Dufour’s Effects. Heat Mass Transfer 44, 845–856 (2008). https://doi.org/10.1007/s00231-007-0296-x
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DOI: https://doi.org/10.1007/s00231-007-0296-x