Summary
Coupled heat and mass transfer in mixed convection about a wedge embedded in saturated porous media has been analyzed by nonsimilar solutions for the case of variable heat flux (VHF) and variable mass flux (VMF). The entire regime of the mixed convection is included, as the mixed convection parameter χ* varies from 0 (pure free convection) to 1 (pure forced convection). The transformed nonlinear system of equations is solved by using an implicit finite difference method. The dimensionless temperature profiles, the dimensionless concentration profiles, the local Nusselt number and the local Sherwood number are presented. The decay of the dimensionless temperature profiles and the dimensionless concentration profiles has been observed in all cases. The local Nusselt number and the local Sherwood number increase for the increase in buoyancy ratioN *, wall heat/mass flux exponents and for the decrease in wedge angle parameter λ. The variations of the local Nusselt number and the local Sherwood number with the increase of χ* have the phenomenon of minimum. For a positive (negative)N *, increasing the Lewis number decreases (increases) the local Nusselt number. On the other hand, the local Sherwood number enhances as the Lewis number increases. Moreover, it is observed that the Lewis number has a more pronounced effect on the local Sherwood number than it has on the local Nusselt number.
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Abbreviations
- a :
-
constant
- B :
-
constant
- b :
-
constant
- C * :
-
dimensionless concentration
- c :
-
concentration
- D :
-
mass diffusivity
- f * :
-
dimensionless stream function
- g :
-
gravitational acceleration
- h :
-
local heat transfer coefficient
- K :
-
permeability of the porous medium
- k :
-
thermal conductivity
- Le:
-
Lewis number
- m :
-
local mass flux
- N * :
-
buoyancy ratio
- Nu x :
-
local Nusselt number
- Pe x :
-
local Péclét number
- q :
-
local heat flux
- Ra x * :
-
modified local Rayleigh number
- s :
-
exponent of wall heat/mass flux
- Sh x :
-
local Sherwood number
- T :
-
temperature
- U ∞ :
-
velocity of the potential flow outside the boundary layer
- u :
-
Darcy velocity in thex-direction
- v :
-
Darcy velocity in they-direction
- x :
-
streamwise coordinate
- y :
-
transverse coordinate
- α:
-
thermal diffusivity
- β c :
-
coefficient of concentration expansion
- β T :
-
coefficient of thermal expansion
- η* :
-
pseudosimilarity variable
- θ* :
-
dimensionless temperature
- λ:
-
wedge angle parameter
- ν:
-
kinematic viscosity of convective fluid
- χ* :
-
mixed convection parameter
- ψ:
-
stream function
- Ω:
-
half angle of the wedge
- ω:
-
condition at the wall
- ∞:
-
condition at infinity
References
Cheng, P.: Combined free and forced convection flow about inclined surfaces in porous media. Int. J. Heat Mass Transfer20, 807–814 (1977).
Joshi, Y., Gebhart, B.: Mixed convection in porous media adjacent to a vertical uniform heat flux. Int. J. Heat Mass Transfer28, 1783–1786 (1985).
Lai, F. C., Kulacki, F. A.: The influence of lateral mass flux on mixed convection over inclined surfaces in saturated porous media. J. Heat Transfer112, 515–518 (1990).
Jang, J. Y., Ni, J. R.: Mixed convection adjacent to inclined flat surfaces embedded in a porous medium. Wärme-Stoffübertrag.27, 103–108 (1992).
Hsieh, J. C., Chen, T. S., Armaly, B. F.: Nonsimilarity solutions for mixed convection from vertical surfaces in porous media: variable surface temperature or heat flux. Int. J. Heat Mass Transfer36, 1485–1493 (1993).
Vargas, J. V. C., Laursen, T. A., Bejan, A.: Nonsimilar solutions for mixed convection on a wedge embedded in a porous medium. Int. J. Heat Fluid Flow16, 211–216 (1995).
Hsieh, J. C., Chen, T. S., Armaly, B. F.: Mixed convection along a non-isothermal vertical plate embedded in a porous medium: the entire regime. Int. J. Heat Mass Transfer36, 1819–1825 (1993).
Hooper, W. B., Chen, T. S., Armaly, B. F.: Mixed convection from a vertical plate in porous media with surface injection or suction. Numer. Heat Transfer Part A25, 317–329 (1994).
Kumari, M., Gorla, R. S. R.: Combined convection along a non-isothermal wedge in a porous medium. Heat Mass Transfer32, 393–398 (1997).
Lai, F. C.: Coupled heat and mass transfer by mixed convection from a vertical plate in a saturated porous medium. Int. Comm. Heat Mass Transfer18, 93–106 (1991).
Yih, K. A.: The effect of transpiration on coupled heat and mass transfer in mixed convection over a vertical plate embedded in a saturated porous medium. Int. Comm. Heat Mass Transfer24, 265–275 (1997).
Yih, K. A.: Uniform transpiration effect on coupled heat and mass transfer in mixed convection about inclined surfaces in porous media: the entire regime. Acta Mech.132, 229–240 (1999).
Yih, K. A.: coupled heat and mass transfer in mixed convection over a vertical flat plate embedded in saturated porous media: PST/PSC or PHF/PMF. Heat mass Transfer34, 55–61 (1998).
Cebeci, T., Bradshaw, P.: Physical and computational aspects of convective heat transfer. New York: Springer 1984.
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Yih, K.A. Coupled heat and mass transfer in mixed convection over a VHF/VMF wedge in porous media: The entire regime. Acta Mechanica 137, 1–12 (1999). https://doi.org/10.1007/BF01313140
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DOI: https://doi.org/10.1007/BF01313140