Abstract
The problem of unsteady natural convection in a square region filled with a fluid-saturated porous medium having non-uniform internal heating and heated laterally is considered. The heated wall surface temperature varies sinusoidally with the time about fixed mean temperature. The opposite cold wall is maintained at a constant temperature. The top and bottom horizontal walls are kept adiabatic. The flow field is modelled with the Darcy model and is solved numerically using a finite difference method. The transient solutions obtained are all periodic in time. The effect of Rayleigh number, internal heating parameters, heating amplitude and oscillating frequency on the flow and temperature field as well as the total heat generated within the convective region are presented. It was found that strong internal heating can generate significant maximum fluid temperatures above the heated wall. The location of the maximum fluid temperature moves with time according to the periodically changing heated wall temperature. The augmentation of the space-averaged temperature in the cavity strongly depends on the heating amplitude and rather insensitive to the oscillating frequency.
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Abbreviations
- A, a:
-
Amplitude, dimensionless amplitude
- f :
-
Dimensionless oscillating frequency
- g :
-
Gravitational acceleration
- G :
-
Measure of the internal heat generation
- ℓ :
-
Width of the cavity
- K :
-
Permeability of the porous medium
- p :
-
Local heating exponent
- Q :
-
Space-averaged temperature
- Ra :
-
Rayleigh number
- t′, t:
-
Time, dimensionless time
- t p :
-
Dimensionless period
- \({\ddot{t}}\) :
-
Denoting a summation of time steady state and initial periods
- T :
-
Fluid temperature
- u, v:
-
Velocity components in the x- and y-directions
- x′, y′ & x, y:
-
Space coordinates & dimensionless space coordinates
- α m :
-
Effective thermal diffusivity
- β :
-
Thermal expansion coefficient
- γ :
-
Internal heating parameter
- ψ′, ψ:
-
Stream function, dimensionless stream function
- θ :
-
Dimensionless temperature
- μ :
-
Dynamic viscosity
- ν :
-
Kinematic viscosity
- ω :
-
Oscillating frequency
- av:
-
Average
- c :
-
Cold
- h :
-
Hot
- max:
-
Maximum
- ss:
-
Basic steady state
- –:
-
denoting a quantity average over time
References
Al-Taey K.A.: Natural convection in a laterally and volumetrically heated square enclosure with time-periodic boundary conditions. Int. J. Heat Technol. 27, 77–85 (2009)
Antohe, B.V., Lage, J.L.: Natural convection in an enclosure under time periodic heating: an experimental study. ASME, Heat Transfer Division, (Publication) HTD 324 (1996)
Bejan A.: On the boundary layer regime in a vertical enclosure filled with a porous medium. Lett. Heat Mass Transf. 6, 93–102 (1979)
Brooks K., Glasser D.: A simplified model of spontaneous combustion in coal stockpiles. Fuel 65, 1035–1041 (1986)
Brooks K., Balakotaiah V., Luss D.: Effect of natural convection on spontaneous combustion of coal stockpiles. A.I.Ch.E. J. 34, 353–365 (1988)
El Ayachi R., Raji A., Hasnaoui M., Bahlaoui A.: Combined effect of radiation and natural convection in a square cavity differentially heated with a periodic temperature. Numer. Heat Transf. Part A 53, 1339–1356 (2008)
Gray B.F., Sexton M.J., Halliburton B., Macaskill C.: Wetting-induced ignition in cellulosic materials. Fire Saf. J. 37, 465–479 (2002)
Gross, R.J., Bear, M.R., Hickox, C.E.: The application of flux-corrected transport (FCT) to high Rayleigh number natural convection in a porous medium. In: Proceedings of the Eighth International Heat Transfer Conference, San Francisco, CA (1986)
Haajizadeh M., Ozguc A.F., Tien C.L.: Natural convection in a vertical porous enclosure with internal heat generation. Int. J. Heat Mass Transf. 27, 1893–1902 (1984)
Ingham D.B., Pop I.: Transport Phenomena in Porous Media. Elsevier Science, Oxford (1998)
Ingham D.B., Bejan A., Mamut E., Pop I.: Emerging Technologies and Techniques in Porous Media. Kluwer, Dordrecht (2004)
Ingham D.B., Pop. I.: Transport Phenomena in Porous Media III. Elsevier Science, Oxford (2005)
Joshi M.V., Gaitonde U.N., Mitra S.K.: Analytical study of natural convection in a cavity with volumetric heat generation. J. Heat Transf. 128, 176–182 (2006)
Kazmierczak M., Chinoda Z.: Buoyancy-driven flow in an enclosure with time periodic boundary conditions. Int. J. Heat Mass Transf. 35, 1507–1518 (1992)
Kim G.B., Hyun J.M., Kwak H.S.: Enclosed buoyant convection with internal heat generation under oscillating sidewall temperature. J. Heat Transf. 124, 577–580 (2002)
Lage J.L., Bejan A.: The resonance of natural convection in an enclosure heated periodically from the side. Int. J. Heat Mass Transf. 36, 2027–2038 (1993)
Manole, D.M., Lage, J.L.: Numerical benchmark results for natural convection in a porous medium cavity. In: Heat and Mass Transfer in Porous Media. ASME Conference, HTD-vol. 216, pp. 55–60 (1992)
Mealey L.R., Merkin J.H.: Steady finite Rayleigh number convective flows in a porous medium with internal heat generation. Int. J. Therm. Sci. 48, 1068–1080 (2009)
Nield D.A., Bejan A.: Convection in Porous Media, 3rd edn. Springer, New York (2006)
Nithyadevi, N., Kandaswamy, P., Sivasankaran, S.: Natural convection in a square cavity with partially active vertical walls: time-periodic boundary condition. Math. Prob. Eng. 23425, 1–16 (2006)
Pop I., Ingham D.B.: Convective Heat Transfer: Mathematical and Computational Modelling of Viscous Fluids and Porous Media. Pergamon, Oxford (2001)
Rao Y.F., Wang B.X.: Natural convection in vertical porous enclosures with internal heat generation. Int. J. Heat Mass Transf. 34, 247–252 (1991)
Saeid N.H., Pop I.: Transient free convection in a square cavity filled with a porous medium. Int. J. Heat Mass Transf. 47, 1917–1924 (2004)
Saeid N.H., Mohamad A.A.: Periodic free convection from a vertical plate in a saturated porous medium, non-equilibrium model. Int. J. Heat Mass Transf. 48, 3855–3863 (2005)
Sexton M.J., Macaskill C., Gray B.F.: Self-heating and drying in two-dimensional bagasse piles. Combust. Theory Model. 5, 517–536 (2001)
Sisson R.A., Swift A., Wake G.C., Gray B.F.: The self-heating of damp cellulosic materials: I. High thermal conductivity and diffusivity. IMA J. Appl. Math. 49, 273–291 (1992)
Vafai, K. (eds): Handbook of Porous Media, 2nd edn. Taylor and Francis, New York (2005)
Walker K.L., Homsy G.M.: Convection in porous cavity. J. Fluid Mech. 87, 449–474 (1978)
Wang G., Zeng M., Huang Z., Wang Q.: Numerical study of natural convection heat transfer in a porous cavity under time-periodic boundary conditions. Jisuan Wuli (Chin. J. Comput. Phys.) 24, 282–286 (2007)
Wang G., Wang Q., Zeng M., Ozoe H.: Natural convection heat transfer in an inclined porous cavity under time-periodic boundary conditions with positive/negative inclined angles. J. Porous Media 11, 541–555 (2008)
Wang G., Wang Q., Zeng M., Ozoe H.: Numerical study of natural convection heat transfer in an inclined porous cavity with time-periodic boundary conditions. Transp. Porous Media 74, 293–309 (2008)
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Saleh, H., Hashim, I. & Saeid, N. Effect of Time Periodic Boundary Conditions on Convective Flows in a Porous Square Enclosure with Non-Uniform Internal Heating. Transp Porous Med 85, 885–903 (2010). https://doi.org/10.1007/s11242-010-9597-5
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DOI: https://doi.org/10.1007/s11242-010-9597-5