Natural convection heat transfer from horizontal cylinders to air, water and silicone oils for rayleigh numbers between 3 × 102 and 2 × 107

Abstract

This paper presents the results of an experimental investigation of heat transfer by natural convection from horizontal cylinders to air, water and three silicone oils. The experimental range of the Rayleigh number was from 2.5 × 102 to 1.8 × 107 and the Prandtl number varied from 0.7 to 3090. On the basis of the experimental data gathered here, three correlation equations have been determined. These equations have the same algebraic form and differ only in the method used in each to evaluate fluid properties as a function of temperature. The influence of viscous dissipation is discussed. © 1977.