Thermal-hydraulic characteristic of a novel wavy fin-and-circle tube heat exchanger with concave curved vortex generators

Abstract

This paper proposes a novel configuration of two pairs of concave curved vortex generators located beside each tube in a wavy fin-and-circle tube heat exchanger. The effect of the concave curved vortex generator pairs with different transverse locations and attack angles on the thermal-hydraulic characteristics of the heat exchanger is numerically reported. The studied range of attack angle is 20° - 50° for five different transverse locations of vortex generators. The results show that the combination of concave curved vortex generators and wavy fins can significantly improve the heat transfer performance of the wavy fin-and-tube heat exchanger. Nu of the proposed fin configuration is enhanced by 30.6%, and the maximum thermal performance factor is increased by 24.0% compared with the wavy fin-and-tube heat exchanger without vortex generators. The multi-objective optimization and a neural network are adopted to optimize the vortex generator arrangements for the best heat transfer capacity. At the optimal Pareto front, the optimal heat transfer capacity is increased by 35.73% under the same pumping power. Correlations of Nu, f, JF and the optimal Qv and Pv are presented as a function of Re, transverse location, and attack angle of the vortex generator.