Shape optimization of water-to-water plate-fin heat exchanger using computational fluid dynamics and genetic algorithm

In the design calculation of a plate-fin heat exchanger, the convective heat transfer coefficients of the plate and fin are often simplified to the same value. Further, in the calculation of the convective heat transfer coefficient, the Colburn heat transfer factor and Fanning friction factor are generally obtained using empirical equations. In this work, to obtain more precise results, the convective heat transfer coefficients of the plate and fin are defined as independent parameters. The Colburn factor and Fanning factor are obtained according to the results of computational fluid dynamics. The fin height, fin pitch, fin thickness, and fin length are considered as four design parameters. A modified number of entropy production units (Ns) is adopted. Ns due to friction (NsΔP), Ns due to heat transfer (NsΔT), and NsTotal are considered as three objective functions. The optimal structural parameters of a water-to-water plate-fin heat exchanger applied to an air-conditioning system are obtained using genetic algorithm by single objective optimization and multi-objective optimization.