Experimentally Investigate The Heat Transfer Performance Of Annular Fins

Performance of annular fins of different shapes subject to locally variable heat transfer coefficient is investigated experimentally in this paper. The performance of the fin expressed in terms of fin efficiency, effectiveness and thermal resistance as a function of the ambient temperature and fin geometry parameters has been presented in the literature in the form of curves known as the fin-efficiency curves for different types of fins without use the diamond shape, but in the present work, we study this shape with others. However, for cases in which the heat transfer from the fin is dominated by natural convection, the analysis of fin performance based on locally variable heat transfer coefficient would be of primer importance. The local heat transfer coefficient as a function of the local base temperature has been obtained using the available equations of natural convection for copper pipe. Results have been obtained and presented in a series of fin-efficiency curves for annular fins of circular, diamond and elliptical, at constant heat flow area for a wide range of temperatures from 100 to 220 oC . The dimensionless parameter Biot no. on the locally variable environmental condition is examined for heat transfer rate. The deviation between the overall fin efficiency calculated of elliptical fin shape based on constant heat transfer area is greater than other shapes used reported in the our work, and that presently calculated based on variable heat transfer coefficient, has been estimated and presented for all fin shapes. In this paper the effectiveness and fin shape tube efficiency for diamond , circular and elliptical annular fins were analyzed for different environmental conditions. Experimental results observes that the performance of heat transfer rate to elliptical fin is better than diamond and circular fin for day and night condition with the high range of temperatures used.