Heat Transfer Coefficient for a Long Horizontal Fin Cooled by Natural Convection and Radiation

Abstract

The objective of this fundamental study is to determine the average or representative heat transfer coefficient for fins cooled by natural convection and radiation using both experimental data and numerical prediction. The physical situation considered is a horizontal fin with a cylindrical cross-section. One end of the fin is maintained at a constant elevated temperature, and the fin is sufficiently long so that heat loss from the tip is negligible. Heat is transferred by conduction along the fin and dissipated from the surface via natural convection and radiation. A general finite difference formulation, that accounts for natural convection with a published correlation and for radiative heat transfer with a simple model, is used to predict the temperature and rate of heat transfer along the fin. This predicted temperature distribution is then used to calculate the average or representative heat transfer coefficient. To verify the numerical predictions, temperature measurements are fit to an exponential model using a least squares approach and an average heat transfer coefficient is obtained. Agreement between the numerical and experimental results is very good.