Optimal tip clearance in the laminar forced convection heat transfer of a finned plate in a square duct

A joint experimental and numerical investigation of laminar forced convection heat transfer of a finned plate in a square duct is reported. The heat transfer rates were measured for fixed fin heights, fin thicknesses, and base-plate geometries, with systematically varied fin spacing, tip clearance, Prandtl number and Reynolds number. The optimal tip clearances were identified, which maximized the total heat transfer. The total heat transfer rate at the optimal tip clearance was maximum 33% higher than that at the largest tip clearance. It decreased as the Prandtl number increased and as the Reynolds number increased. The dependence of the heat transfer rate on the tip clearance weakened as the fin spacing increased.