Numerical Investigation of Heat Transfer Enhancement in Circular Channel with Variation in Angle of Delta-Winglet Vortex Generator

Vortex generators have been used to enhance heat transfer in numerous industries. Vortex generators improve flow mixing by destroying the thermal boundary layer, which improves heat transfer. This study aimed to improve heat transfer in circular channels by installing delta-winglet vortex generators. Accordingly, delta-winglet vortex generators with different angles – 90°, 105°, 120°, 135°, and 150° – were installed in an in-line arrangement. The k–ω turbulent SST model was applied to Reynolds numbers ranging from 4,000 to 12,000, varied at an interval of 2,000. The results indicated that a delta-winglet vortex generator with an angle of 90° increased heat transfer by 4.05% compared to that with an angle of 150°, while the flow resistance also increased by 7.18%. The delta-winglet vortex generator with an angle of 90° achieved the highest thermal enhancement factor of 2.55, whereas that with an angle of 150° provided the lowest cost–benefit ratio of 0.61.