Numerical study on heat transfer enhancement of circular tube bank fin heat exchanger with interrupted annular groove fin

• Conjugate heat transfer performance of an IHAG fin-tube heat exchanger was studied.
• IHAG fin has dual efficacy of fluid flow guiding and detached eddy inhibition.
• IHAG fin could not efficiently enhance heat transfer at lower Reynolds numbers.
• IHAG fin has an excellent performance at higher Reynolds numbers.
• The studied locations of IHAG have fairly limited effects on average characteristics.

A variation in fin surface geometry is an effective approach to improve streamline pattern when fluid flows through the channel form by circular tube bank fins. The structure of interrupted half annular groove (IHAG) fin is different from commonly used fin patterns. In this paper, a conjugate heat transfer numerical method is employed to investigate the average heat transfer and fluid flow characteristics of the staggered circular tube bank fin heat exchanger with IHAG fin. The reference fin is the plain fin with a corresponding configuration. The annular groove's radial and circumferential locations are the main parameters to investigate. The results reveal that (1) The interrupted annular groove has dual efficacy of fluid flow guiding and detached eddy inhibition to reduce the size of wake region; (2) At lower Reynolds numbers, the interrupted annular groove fin surface could not efficiently enhance heat transfer under identical pumping power criteria, and the excellent performance of the interrupted annular groove fin can be achieved at higher Reynolds numbers. There is an average 35% increase in the friction factor, while for Reynolds number ranged from 600 to 2500, the average Nusselt number is increased by 10%–40%, and the corresponding thermal performance factor ranges from 7% to 27%; (3) The studied annular groove's radial and circumferential locations have a fairly limited effect on the average heat transfer and fluid flow characteristics.