Four analytic methods are used to analyze a rectangular profile annular fin. For this annular fin with constant fin base temperature and non-insulated tip, the fin base thickness and fin height as well as fin length are variable. The relative error of heat loss between the 2-D general analytic method and 2-D new analytic approach, as well as the relative error between the 2-D general analytic method and 1-D general analytic method are investigated as a function of the fin height, fin length, and convection characteristic number. The relative error of heat loss between the 1-D general analytic method and 1-D approximate analytic method is presented as a function of the fin length and the convection characteristic number. One of the results shows that the error of heat loss from the 2-D new analytic approach relative to heat loss from the 2-D general analytic method decreases as the fin length and/or the convection characteristic number decrease, while the error of heat loss decreases as the fin height increases.

analytic methods, convection characteristic number, relative error of heat loss, fin base thickness, fin radius.