Heat Transfer by Mixed Convection in the Opposing Thermally Developing Flow in a Vertical and Inclined Annulus
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Abstract
Combined convection heat transfer in an inclined (ψ=60o) and vertical (ψ=90o) annulus has been experimentally studied for opposing thermally developing and thermally fully developed laminar air flows with adiabatic inner tube and uniformly heated outer tube (r1/r2=0.41) for Reynolds number range from 450 to 1000 and heat flux is varied from 150 W/m2 to 780 W/m2. The hydrodynamically developed condition has been achieved by using entrance section annular pipe (calming section) having the same dimensions as test section (L/Dh≈40). The mixed convection regime has been bounded by the convenient selection of Re and heat flux ranges, so that the obtained Richardson number varied approximately from 0.05 to 0.97. The average heat transfer results have been correlated with an empirical correlation by dimensionless groups as logNum against logRa/Re and compared with available literature showed that the heat transfer process in the hydrodynamically fully developed region of duct is better than that in the developing region of this duct.
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References
Choudhury D. and Patankar S.V. “Combined Forced and Free Laminar Convection in the Entrance Region of an Inclined Isothermal Tube” J Heat Transfer, Vol.110, PP.901-909, November (1988). DOI: https://doi.org/10.1115/1.3250591
Grassi W. and Testi D. “Transitional Mixed Convection in the Entrance Region of a Horizontal Pipe” European Thermal Sciences Conference, the Netherlands, (2008).
Kotake S. and Hattori N” Combined Forced and Free Convection Heat Transfer for Fully Developed Laminar Flow in Horizontal Annuli” Int. J. heat mass transfer. Vol.28, No.11, PP.2113-2120, (1985). DOI: https://doi.org/10.1016/0017-9310(85)90105-X
Kaviany, M. “Laminar Combined Convection in a Horizontal Annulus Subject to Constant Heat Flux Inner Wall and Adiabatic Outer Wall” Transactions of the ASME, Vol.108, May (1986). DOI: https://doi.org/10.1115/1.3246935
Hanzawa T., Sako A., Endo H., Kagwa M. and Koto K., “Combined Free and Forced Laminar Convective Heat Transfer From Isothermally Heated Inner Tube in Vertical Concentric Annulus” J. Chemical Engineering of Japan, Vol.19,No.1,PP.78-81,(1986). DOI: https://doi.org/10.1252/jcej.19.78
Falah A. M. “Combined Free and Forced Convection in an Inclined Annulus” M.Sc. Thesis, University of Basra, College of Engineering, Mech. Dept., (1993).
Khalid A., Ihsaan Y. H., and Akeel A. M. “Experimental Investigation of Laminar Mixed Convection in an Inclined Annulus” Journal of Engineering, a scientific refereed journal published by College of Engineering University of Baghdad, No.1, Vol.12, PP.181-198, March (2006).
Ihsan Y. Hussain and Akeel A. Mohammed] “Laminar combined convection in the fully developed region of concentric inclined annulus with uniformly heated inner cylinder “, the 6th Engineering Conference, University of Baghdad, College of Engineering. Vol.3: Mechanical and Nuclear Engineering, PP.19-35, 5-7 April (2009).
Gada A. Sadiq “Developing Laminar Mixed Convection Heat Transfer Through Concentric Annuli with Adiabatic Inner Cylinder” M.SC. Thesis, University of Baghdad, College of Engineering, Mars (2009).
Incroper F. P. and Dewitt D.P. Fundamentals of Heat and Mass Transfer, Fifth ed., John Wiley and sons Inc. , (2003).
Shah R.K. and A. L. London “Laminar Flow Forced Convection in Duct” Advance in Heat Transfer, Academic Press, Newyork, (see chapter v, pages 98&99) (1978).
D.Bohne and E.Obemeier] “Combined Free and Forced Convection in a Vertical and Inclined Cylindrical Annulus” Universitat-Gesamthochschule Siege Bundesrepublik Deutschland. Bunsenges. PHYS. Chem., Vol.88, PP1401-1406, (1984).
W.M.Kays and M.E.Grawford “Combined Free and Forced Convection in a Vertical and Inclined Cylindrical Annulus” J Heat Transfer, Vol.100, PP.501-509, November (1986).