Air side heat transfer enhancement using radiantly arranged winglets in fin-and-tube heat exchanger

The enhancement of airside heat transfer in fin-and-tube heat exchanger is crucial for reducing the pumping power, saving materials and so on. In this paper, the authors propose to arrange the winglets radiantly around the tubes on the fin to enhance the airside heat transfer in fin-and-tube heat exchanger. The airside flow and heat transfer characteristic are numerically investigated. The position and the geometric dimensions of the vortex generators are also optimized. The simulation results show that the Colburn j-factor and the friction factor f both increase with VG number. The fin structure has the best comprehensive performance when its VGs are uniformly arranged both in the upwind and backwind regions of the tubes, and at the same time make the enhanced zones the widest in the tube radial direction. With the increase of the VG length, the comprehensive performance factor JF gets lower. The comprehensive performance of the proposed fin with five rows of tubes are demonstrated to be better than a reference fin used in industry with the same fin thickness, tube diameter, fin pitch and tube pitch.