Heat and mass transfer from annular fins of different cross sectional area. Part II. Optimal dimensions of fins

The optimal dimensions of annular fins of constant and variable cross sectional area when subjected to both heat and mass transfer were investigated by a numerical scheme. A non-linear model representing both heat and mass transfer mechanisms was solved using finite difference over-relaxation scheme. Numerical solutions are obtained for the dimensionless heat transfer rate for completely wet conditions as a function of important dimensionless parameters (u,v,w)(u,v,w) for annular fins. The results are presented in a graphical form as well as regression equations for rectangular, triangular, convex and concave parabolic annular fins. It is shown that these dimensionless parameters represent modified version of fin parameter(moL)(moL), non-dimensional fin material volume and fin base ratio (outer radius of tube to thickness of fin at its conjunction with tube). Keeping the two dimensionless parameters constant (u,v)(u,v) and considering ww as the only independent variable, the maximum heat dissipated from the fin is obtained.

► Optimal dimensions of annular fins of different configurations are presented. ► Numerical results are introduced for totally wet conditions. ► Results are discussed both in a graphical form as well as regression equations. ► Constant thickness fin take maximum amount of material for a specified heat rate.