An investigation of the airside performance of fin-andtube heat exchangers with delta-winglet

In this paper, 3-D numerical simulations are carried out to study the fluid flow and heat transfer of fin-and-tube heat exchangers with delta-winglet vortex generators. The numerical results show that for both the inline tube arrangement and the staggered tube arrangement, the delta-winglet vortex generators can significantly enhance the heat transfer performance of fin-and-tube heat exchangers with relatively low penalty of pressure drop for the Reynolds number range under consideration. The enhanced configurations are more effective for lower Reynolds numbers than for higher Reynolds numbers. The numerical results are also analyzed from the view point of field synergy principle which says that the reduction of the intersection between velocity and temperature gradient is the basic mechanism for heat transfer augmentation.