Abstract
The flow and heat transfer from a heated semi-infinite horizontal circular cylinder which is moving with a constant speed into a porous medium is considered. It is assumed that the Grashof and Reynolds numbers are large so that the governing equations are the three dimensional boundary-layer equations. A numerical procedure for solving these equations is described and the asymptotic solutions which are valid both near and distant from the leading edge of the cylinder are presented. The range of validity of these asymptotic solutions is discussed and the results are compared in detail with the full numerical solution. The problem is of practical importance, for example in the drilling of pipes into a geothermal reservoir.
Zusammenfassung
Es wird die Strömung und der Wärmeübergang an einem beheizten, halbunendlichen horizontalen Kreiszylinder betrachtet, der mit konstanter Geschwindigkeit sich in ein poröses Medium bewegt. Dabei wird angenommen, daß die Grashof- und Reynolds-Zahlen groß sind, so daß die Bestimmungsgleichungen von den dreidimensionalen Grenzschichtgleichungen gebildet werden. Es wird ein numerisches Verfahren zur Lösung dieser Gleichungen beschrieben und eine asymptotische Lösung präsentiert, die sowohl in der Nähe als auch in großem Abstand von dem vorderen Ende des Zylinders gültig ist. Der Gültigkeitsbereich dieser asymptotischen Lösungen wird diskutiert und die Ergebnisse werden im Detail mit vollständigen numerischen Lösungen verglichen. Das Problem ist z.B. beim Eindringen von Rohrleitungen in geothermische Reservoire von praktischer Wichtigkeit.
Similar content being viewed by others
Abbreviations
- a :
-
radius of cylinder
- Gr :
-
Grashof number (=gχ(Tw-T∞a/ν2)
- g :
-
acceleration due to gravity
- χ :
-
permeability in the porous medium
- Nu :
-
local Nusselt number
- \(\overline {Nu} \) :
-
total heat flux from cylinder
- q w :
-
heat flux from cylinder
- r :
-
radial co ordinate
- Ra :
-
Rayleigh number (=g β χ(Tw - Tt8) a/α ν)
- Re :
-
Reynolds number (=U t8 a/ν)
- T :
-
temperature
- u, v, w :
-
speeds inx, ϕ, r directions
- x :
-
axial co ordinate
- α:
-
equivalent thermal diffusivity
- β :
-
thermal expansion coefficient
- ɛ :
-
ratioGr/Re
- η :
-
similarity variable
- θ :
-
dimensionless temperature (=(T- T)/(T w- T∞)
- ν :
-
kinematic viscosity
- ϕ :
-
azimuthal co ordinate
- w :
-
cylinder surface
- ∞:
-
free stream
References
Cheng, P.: Heat transfer in geothermal systems. Adv. Heat Transfer 14 (1978) 1–105
Cheng, P.: Natural convection in a porous medium: External flows. In: Kakac, S.; Aung, W.; Viskanta, R. (eds.): Proceedings of the advanced study institute on natural convection - fundamentals and applications. Washington. D.C.: Hemisphere 1985
Bejan, A.: Convection heat transfer. New York: Wiley 1984
Merkin, J. H.: Free convection boundary layers on axisymmetric and two dimensional bodies of arbitrary shape in a saturated porous medium. Int. J. Heat Mass Transfer 22 (1979) 1461–1462
Ingham, D. B.; Merkin, J. H.; Pop, I.: Flow past a suddenly cooled vertical flat surface in a saturated porous medium. Int. J. Heat Mass Transfer 25 (1982) 1916–1919
Ingham, D. B.; Merkin, J. H.; Pop, I.: Flow past a suddenly cooled horizontal flat surface in a saturated porous medium. Acta Mech. 56 (1985) 205–217
Pop, I.; Cheng, P.: The growth of a thermal layer in a porous medium adjacent to a suddenly heated semi-infinite horizontal surface. Int. J. Heat Mass Transfer 26 (1983) 1574–1576
Cheng, P.; Pop, I.: Transient free convection about a vertical flat plate embedded in a porous medium. Int. J. Eng. Sci. 22 (1984) 253–264
Wooding, R. A.: Convection in a saturated porous medium at large Rayleigh or Peclet number. J. Fluid Mech. 15 (1963) 527–544
Ackroyd, J. A. D.: On the laminar compressible boundary layer with starting origin on a moving flat wall. Proc. Cambridge Philos. Soc. 63 (1967) 871–888
Banks, W. H. H.: Similarity solutions of the boundary-layer equations for a stretching wall. J. Mécan. Théor. Appl. 2 (1983) 372–392
Singh, K. R.; Cowling, T. G.: Thermal convection in magneto-hydrodynamics, Part 1: Boundary layer flow up a hot vertical plate. Quart. J. Mech. Appl. Math. 16 (1963) 1–15
Blythe, P. A.; Daniels, P. G.; Simpkins, D. G.: Thermally driven cavity flows in porous media, Part 1: The vertical boundary layer structure near the corners. Proc. Roy. Soc. London Ser. A 380 (1982) 119–136
Yao, L. S.; Catton, I.; McDonough, J. M.: Bouyancy-driven asymmetric water boundary layer along a heated cylinder. J. Fluid Mech. 98 (1980) 417–433
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Ingham, D.B., Pop, I. Free-forced convection from a heated longitudinal horizontal cylinder embedded in a porous medium. Warme- und Stoffubertragung 20, 283–289 (1986). https://doi.org/10.1007/BF01002419
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF01002419