Natural convection heat transfer from a horizontal cylinder in liquid sodium - Part 2: generalized correlation for laminar natural convection heat transfer

Rigorous numerical solution of natural convection heat transfer, from a hor izontal cylinder with uniform surface heat flux or with uniform. surface te mperature, to liquid sodium was derived by solving the fundamental equation s for laminar natural convection heat transfer without the boundary layer a pproximation. It was made clear that the local and average Nusselt numbers experimentally obtained and reported in part 1 of this paper were described well by the numerical solutions for uniform surface heat fluxes, but that those for uniform surface temperatures could not describe the angular distr ibution of the local Nusselt numbers and about 10% underpredicted the avera ge Nusselt numbers. Generalized correlation for natural convection heat tra nsfer from a horizontal cylinder with a uniform surface heat flux in liquid metals was presented based on the rigorous theoretical values for a wide r ange of Rayleigh numbers. It was confirmed that the correlation can describ e the authors' and other workers' experimental data on horizontal cylinders in various kinds of liquid metals for a wide range of Rayleigh numbers. An other correlation for a horizontal cylinder with a uniform surface temperat ure in liquid metals, which may be applicable for special cases such as nat ural convection heat transfer in a sodium-to-sodium heat exchanger etc. was also presented based on the rigorous theoretical values for a wide range o f Rayleigh numbers. These correlations can also describe the rigorous numer ical solutions for non-metallic liquids and gases for the Prandtl numbers u p to 10. (C) 1999 Elsevier Science S.A. All rights reserved.