A comparative study of the airside performance of winglet vortex generator and wavy fin-and-tube heat exchangers

This study presents airside performance of the delta winglet vortex generator (VG) vs. a wavy fin surface in both dry and wet conditions. The fin pitch of the test samples is 1.7 mm and the number of tube rows is 2 and 4, respectively. For the airside performance tested in dry condition, the heat transfer coefficient for the wavy fin surface is only 6% higher than that of the winglet VG at N = 2, but the pressure drop is about 15% higher. Conversely, the heat transfer coefficients for the winglet surface are higher than those of the wavy fin surface by approximately 5% with comparable pressure drop at N = 4. For the airside performance tested in wet conditionne heat transfer performance of the winglet VG is superior to that of the wavy fin surface for both N = 2 and N = 4. Furthermore, the pressure drop for winglet VG is considerably lower (15-40%). It is likely that this phenomenon is due to better condensate drainage caused by the swirled motion of the VG surface.