Optimum Convection Through Parabolic Fins in Annulus of Double Pipe

摘要

Optimum configurations of the parabolic finned annulus have been investigated for maximum convection by employing a genetic algorithm. The objective of the work is to enhance the heat transfer rate and minimize the pressure loss in the flow direction for optimum use of thermal energy and savings of cost. Flow is considered to be steady, laminar, incompressible, and fully developed, subjected to the constant heat flux boundary condition imposed at the finned inner pipe, made up of highly conductive material. Acomparison of the present optimum configurations has been carried out with those based on the Nusselt number as an objective function. The results indicate that the present objective function gives, in many cases, cost- and weight-efficient optimum configurations with considerable reduction in pressure loss and provides optimum use of thermal energy along with handsome savings of cost. A comparison of the present optimum configurations of parabolic fins has also been carried out with those of trapezoidal and triangular fins. The results indicate that no single shape is best in all the situations and for all the criteria. The performance evaluation and comparison led to some very interesting findings regarding the configurations of the finned annulus and the choice of the objective function. The local results show that the fin tip plays a vital role for promoting the higher heat transfer rate.