Assessment of Thermal Performance of the Functionally Graded Materials in Annular Fins

Heat transfer enhancement in the annular fins with uniform profile is investigated in the present study. Conventional fin materials are replaced with the functionally graded materials in order to increase the rate of heat transfer and corresponding fin efficiency. Here, the fin material properties, such as conductivity, are assumed to be graded along the annular fin radius, R, as a linear function. The governing equation of the annular fin is computed with an approximate analytical method using the mean value theorem. It is revealed that the in-homogeneity index, beta, of the fin material plays an important role on the thermal characteristics of the annular fins. Alternatively, heat dissipation between the fin surface and surrounding fluid in the annular fins increases with increasing the inhomogeneity indices, beta. Finally, it is stated that application of the functionally graded material in the annular fins enhances the fin efficiency in comparison to the annular fins with homogeneous material. It is hoped that the results obtained from this study arouse interest among thermal designers and heat exchanger industries.