Shape and Orientation Effect on Natural Convection Around a Heated Vertical Cone, Which Loses Heat from All Its Surfaces

Abstract

In this study, we present the idea of natural convection heat transfer from vertical cones with active base (i.e. all the surfaces are contributing in heat transfer process) for laminar flow in the range of Rayleigh number from 103 to 106. We did numerical simulations for different r/l ranging from 0.9 to 0.1 and orientation (tip upward and tip downward) keeping the total heat transfer area same for all the cases. From the numerical results, it can be concluded that average Nusselt number of downward tip cone is more compared to upward tip cone at same Rayleigh number for low r/l and for high r/l both give almost the same Nu when suspended in the air. When the cone is placed on the ground, downward tip cone is always more effective in natural convection than the upward tip cone. Average Nu and heat flux increase at particular Ra with decrease in r/l. A detailed study of the parameters like r/l, Rayleigh number on average Nu, heat flux, heat transfer ratio, flow field, and temperature plume can be found in this work. Finally simple and very accurate correlations for predicting average Nu are developed for all the studied cases of cone with varying r/l and Ra which will be very useful in designing heat transfer equipment.