Optimization design of slotted fins based on exergy destruction minimization coupled with optimization algorithm

Abstract

In this paper, the influence of the slot parameters of the slotted fins on the flow and heat transfer performance and the exergy destruction are studied by numerical simulation, and the optimal parameters corresponding to the best overall performance and the minimum exergy destruction are obtained by the method of CFD coupled with optimization algorithm, respectively. In current work, the slot length and width are taken as parameters (slot length 1.2–2.1 mm, slot width 0.1–1.0 mm), 100 different cases are studied under the same boundary conditions, and the results are analyzed and optimized by the neural network and genetic algorithm. The overall performance is taken as the evaluation of the heat transfer performance and the power consumption, while exergy destruction caused by heat transfer and fluid flow are taken as the estimate of the loss of available energy and mechanical work. The results show that the overall performance is best when the slot length and width are 1.38 mm and 0.27 mm respectively, and the overall performance is 13.1% higher than that of flat fin. While the exergy destruction caused by heat transfer and fluid flow are minimized synergistically when the slot length and width are 1.37 mm and 0.12 mm, and the irreversible loss caused by heat transfer is reduced by 19.13%, at the cost of an increase of 40.6% in the irreversible loss caused by fluid flow. The difference between the parameters corresponding to best overall performance and exergy destruction minimization means the irreversible loss of heat transfer and fluid flow process is not minimum when the overall performance is best, and indicates the exergy destruction minimization can be a principle to evaluate the heat transfer and flow process. The result in this paper is of great significant to the energy utilization and the improvement of the thermal quality in waste heat recovery.