Experimental and numerical analyses of thermal-hydraulic characteristics of aluminium flying-wing fins

Abstract

• In general, the flying-wing fin performs better than the wavy fin at the same Re . • The field synergy of the flying-wing fin is much better than that of the wavy fin. • There exist the butterfly-shaped low velocity zones perpendicular to the streamwise direction. • The heat transfer coefficient on the obtuse-angled side of the fin is larger. • Both fin length and fin thickness have little effect on the performance of the fin. The secondary heat transfer surface of the shovel-cut finned tube, called the flying-wing fin, eliminates the thermal contact resistance. In the present study, the thermal-hydraulic characteristics of the flying-wing fin at Reynolds number range of 1500–3000 were studied, including overall quantitative analysis and three-dimensional thermophysical field analysis. It was found that the ratio of Nu · η 0 / f 1/3 of the flying-wing fin (Case A1) is about 8.6% larger than that of the wavy fin (Case B3). The fundamental reason is that the flying-wing fin has a smaller average field synergy angle than the wavy fin. There is a butterfly-shaped low-velocity zone at the root of the wave trough of the monitoring section on the acute-angled side of the flow channel. In addition, along the fin height direction, the influence range of this low-velocity zone on the flow field is less than around 1.34 mm. Similarly, there are butterfly-shaped zones for the temperature and field synergy angle distributions. The average value of the convective heat transfer coefficient on the left side of the flying-wing fin is greater than that on the right side. In general, the promising flying-wing fins show better thermal-hydraulic performances than the wavy fins with similar geometric parameters, which deserve further promotion and engineering application.