Correlations and optimization of a heat exchanger with offset fins by genetic algorithm combining orthogonal design

In this paper, the study is focused on a double flow plate-fin heat exchanger (PFHE) which heat transfer element is staggered offset fin, and heat transfer model and the energy equations for the structure have been established, seven geometric parameters such as the fin height, fin length and fin wrinkling angle are taken as the decision variables for optimization. A genetic algorithm (GA) combined with orthogonal design is used to search for the optimal overall structure and the correlations about the fin heat transfer factor j and the friction factor f. The maximum total heat transfer rate and the minimum total pressure drop are taken as objective functions in the GA, respectively. Performance of the optimized structure is evaluated and correspondingly the heat transfer and hydrodynamic characteristics of the full-size PFHE are calculated by using a porous media approach. Numerical results show that the total heat transfer rate of the optimized structure is improved about 6.2% comparing with the original design, the total pressure drop decreases by about 40% and the volume can reduce about 2.7%. (C) 2016 Elsevier Ltd. All rights reserved.