Experimental Investigation on Natural Convection Heat Transfer from Inclined Square Ducts

Abstract

Natural convection heat transfer from inclined square ducts is studied experimentally. Experiments have been conducted in still air with duct oriented at an angle of 45O. In the present study two ducts having different area ratio are considered and uniform heat flux conditions are maintained. Variable heat inputs are applied to the centrally located resistance heating element in order to understand convection phenomenon in laminar and transition regions. Experimental data have been reduced in terms of Nusselt and modified Rayleigh numbers, Local values are evaluated by considering axial distance and average values by using square side length. Correlations were proposed in terms of local and modified Nusselt and modified Rayleigh numbers. Comparison of Experimental results with those reported in the literature pertaining to vertical cylinders is observed to be in close conformity.