Fluid flow and heat transfer of natural convection induced around a row of heated horizontal cylinders placed in inclined plane

Abstract

The natural convective flow and heat transfer of air induced around an inclined row of heated horizontal cylinders have been investigated experimentally. The experiments were carried out with the ten-cylinders row placed in the plane of inclination angles θ=0°, 30°, 45°, 60°, 75° and 90° from horizontal. The cylinders in the row were heated with constant heat flux and their diameter d and gap G were varied as d=8.4, 14.4mm and G=3.6 to 20.6mm. The Nusselt numbers Nu_d from the cylinders in the row were measured. They showed maxima and minima for the horizontal and vertical rows, while intermediate Nusselt numbers were obtained for the inclined rows. Those Nusselt numbers were next converted to the gap-based Nusselt numbers Nu_G, and, then, rearranged with the non-dimensional parameter Ra_G^*(G/d). The result showed that the Nusselt numbers Nu_G are predicted well with the parameter Ra_G^*(G/d) for the whole rows of inclination angle from horizontal to vertical.