Fin efficiency of annular fins made of two materials

The efficiency of two-material fins is presented. The analytical solution i s compared to the expression obtained by Gardner for one-material fins. We conclude that Gardner's expression can be used for a two-material fin, by c hanging only the value of one parameter. The efficiency of a galvanized fin may be considerably increased by the coating. The ratio of the efficiency of the coated fun to the efficiency of the basic fin may increase by a fact or of two for thin fins having a large fin tip radius to base radius ratio. (C) 1999 Elsevier Science Ltd. All rights reserved.