Experimentally Study the Effects of Fins Height and Space Ratio (HS) to the Fin thermal performance by Natural Convections

摘要

Heat transfer enhancement devices are widely used in various industrial, transportation, or domestic applications such as thermal power plants, means of transport, heating and ah" conditioning systems, electronic equipments and space vehicles. In all these applications, improvements in the efficiency of heat exchangers can lead to substantial cost, space and materials savings. The research work summarized in this articles presents an experimental investigation on the effect of fin space (S) on the fin performance using rectangular plate type fins. The steady-state natural convection heat transfer from vertical rectangular fins extending perpendicularly from horizontal square base was investigated experimentally at high range of temperatures from 50 to 150 C°. The effects of fin space parameter, fin height-space (HNS) ratio and base-to-ambient temperature difference on the heat transfer performance of fin arrays were observed and the environmental condition were determined.. Five fin height-space ratios settings 1.31,1.43,1.67,1.85 and 2.27 with constant fin surface area were employed under free convection heat transfer conditions. The heat transfer area was kept the same. The performance of the fin expressed in terms of fin efficiency, effectiveness and thermal resistance as a function of the ambient temperature and fin space parameters has been study in this work. The dimensionless parameter Biot no. on the locally variable environmental condition is examined for different fin spaces and fin height-space (HS) ratio to the fin heat transfer rate. Also, the effect of environmental condition is study at the same (HNS) ratio. Experimental results show that the effect of Height-Space ratio (HNS) on fin performance is more significant.. The maximum increase in convection heat transfer coefficient value obtained is about 19 percent. The increase in heat transfer coefficient value is also manifested by a corresponding decrease in the fin base temperature. Also, it is concluded from the experimental results that the performance of heat transfer rate increase with increasing the height- space ratio (HNS) and decreasing the fin space in respect of heat transfer coefficient, thermal resistance ,overall efficiency and effectiveness,