Effects pressure on natural convection from an incline isothermal cylinder in an inert environment

Abstract

Experimental investigation of natural convection heat transfer from. a -heated cylinder at different pressure and inclinations to ambient air and argon was carried out. The test cylinder was maintained at a constant temperature of 91S c. The measurements covered the fluid pressure ranging from 5 to 1700 mm of Hg absolute. The inclinations of the axis of the cylinder with vertical were 0', 30', 45', 60' and 90'. The range of Rayleigh number covered was 103~aL$1.5X1 07 The investigations show that heat transfer coefficient vary logarithmically with pressure. The plots of Nusselt number a+winst pressure and against Rayleigh number are both linear on a log-log plot. From the experimental results, correlations are developed in terms of Nusselt number, Rayleigh number, and inclination of the cylinder. The reliability of these correlations are all , within :tl 0% of the experimental data.