NUMERICAL STUDY OF THE CONJUGATE HEAT TRANSFER IN A HORIZONTAL PIPE HEATED BY JOULEAN EFFECT

Abstract

The three dimensional mixed convection heat transfer in a electrically heated horizontal pipe conjugated to a thermal conduction through the entire solid thickness is investigated by taking into account the thermal dependence of the physical properties of the fluid and the outer heat losses. The model equations of continuity, momentum and energy are numerically solved by the finite volume method. The pipe thickness, the Prandtl and the Reynolds numbers are fixed while the Grashof number is varied from 104to107. The results obtained show that the dynamic and thermal fields for mixed convection are qualitatively and quantitatively different from those of forced convection, and the local Nusselt number at the interface solid-fluid is not uniform: it has considerable axial and azimuthally variations. The effect of physical variables of the fluid depending on temperature is significant, which justifies its inclusion. The heat transfer is quantified by the local and average Nusselt numbers. We found that the average Nusselt number of solid-fluid interface of the duct increases with the increase of Grashof number. We have equally found out that the heat transfer is improved thanks to the consideration of the thermo dependence of the physical properties. We have tried modelling the average Nusselt number as a function of Richardson number. With the parameters used, the heat transfer is quantified by the correlation: 0.156 Nu 12 .753 Ri A .

Keywords

Dates

  • Submission Date2010-11-20
  • Revision Date2010-12-28
  • Acceptance Date2011-08-09

DOI Reference

10.2298/TSCI101120080T

References

  1. Orfi, J. And Galanis, N., Bifurcation in Steady Laminar Mixed Convection Flow in Uniformly Heated Inclined Tubes, International Journal of Numerical Methods for Heat and Fluid Flow, 9 (1999), 5, pp. 543-567
  2. Kokugan, T., Kinoshita, T., Natural Convection Flow Rate in a Heated Vertical Tube, Journal of Chemical Engineering of Japanese, 8, (1975), 6, pp. 445-450
  3. Fukusako, S., Takahashi, M., Free Convection Heat Transfer of Air-Water Layers in a Horizontal Cooled Circular Tube, International Journal of Heat and Mass Transfer, 34 (1991), 3, pp. 693-702
  4. Ouzzane, M. and Galanis, N., Effets de la Conduction Pariétale et de la Répartition du Flux Thermique sur la Convection Mixte près de l'Entrée d'une Conduite Inclinée, International Journal of Thermal Sciences, 38, (1999), pp. 622-633
  5. Mohammed, H. A. and Salman Y. K., Laminar Air Flow Free Convective Heat Transfer Inside a Vertical Circular Pipe With Different Inlet Configurations, Thermal Science,11,(2007), pp. 43-63
  6. Mohammed, H. A. and Salman Y. K., Numerical Study of Combined Convection Heat Transfer For Thermally Developing Upward Flow In A Vertical Cylinder, Thermal Science,12,(2008), 2, pp. 89-102
  7. J. C. Curnia, Sasmito A., and Mujumdar A. S., Laminar For In-Plane Spiral Coils Of Noncircular Cross Sections Ducts: A Computational Fluid Dynamics Study, Thermal Science, (2011), doi:10.2298/TSCI100627014K
  8. Abid, C., Papini, F., Ropke, A. and Veyret, D., Etude de la Convection Mixte dans un Conduit Cylindrique. Approche Analytique/Numérique et Détermination Expérimentale de la Température de Paroi par Thermographie Infrarouge, International Journal of Heat and Mass Transfer, 37, (1999), pp. 91-101.
  9. T. Boufendi and M. Afrid, Three-dimensional Conjugate Conduction-Mixed Convection With Variable Fluid Properties in a Heated Horizontal Pipe, Revue des Energies Renouvelables, 8, (2005), pp.1- 18
  10. T. Boufendi, Contribution à l'Etude Théorique des Transferts Thermiques dans un Conduit Cylindrique Horizontal Soumis à un Phénomène de Convection Mixte, Doctorate'State thesis (Ph. D.), University of Mentouri, Constantine, Algeria, 2005
  11. Churchill, S.W., Chu, H.S., Correlating Equation for Laminar and Turbulent Free Convection from a Horizontal Cylinder, International Journal of Heat and Mass Transfer, 18, (1975) pp. 1049-1053
  12. Patankar, S.V., Numerical Heat Transfer and Fluid Flow, McGraw-Hill, New-York, 1980
Volume 16, Issue 1, Pages53 -67