Investigation on Convective Heat Transfer from Transverse Plate Finned Surfaces

Abstract

In order to improve the heat transfer performance of the gas side surfaces in ordinary heat exchangers and gas cooled reactors, many types of extended surfaces are used. In these surfaces, heat transfer for transverse fins normal to the flow direction is extremely affected by the behavior of vortex flow aroused in fin spaces. However, there are no available information on the relation between the heat transfer performance and the behavior of the vortex flow in fin spaces. In this paper, to increase the heat transfer rate from transverse finned surfaces, rear corners of fin surfaces are chamfered. The heat transfer rate is measured, and the behavior of the vortex flow is analysed by a hot-wire anemometer in a wind tunnel and a visualization technique using polystyrene particles in a water tunnel. The exchange rate of fluid between the main flow and the vortex flow in fin spaces is measured. It is made clear that the surfaces with chamfered fins increase the heat transfer rate owing to the increases of speeds, turbulence intensities and the exchange rate of the fluid in fin spaces.