Forced convection and entropy generation from elliptic tubes with longitudinal fins

An experimental investigation has been conducted to clarify heat transfer characteristics and entropy generation for individual elliptic tubes with longitudinal fins. The investigated geometrical parameters included the placement of the fins at the front of the tube, at the rear of the tube and at the front and rear of the tube. The experiments have been carried out on the different cases of electrically heated elliptic tubes which are separately installed in a square tunnel. The surface temperature at different cases of elliptic tubes, have been measured. The testing fluid was air and the Reynolds number ranged from about 4.75 x 10(3) to 3.96 x 10(4). The analysis of the entropy generation is based on the principle of minimizing the rate of total entropy generation that includes the generation of entropy due to heat transfer and friction forces are presented. The results indicate that the fin position on the elliptic tube has an effect on the results of heat transfer coefficient, friction factor and irreversibility ratio. The correlations of average Nusselt number, friction factor and irreversibility ratio with Re are presented. (C) 2009 Elsevier Ltd. All rights reserved.