Heat transfer efficiency enhancement using zigzag louvered fin

Abstract

The present study numerically examines the impact of zigzag fin surface pattern structures in a micro-channel heat exchanger on heat transfer efficiency using a commercial computational fluid dynamics program. The three newly designed louvered fin structures that comprise four triangular zigzag patterns, alternately spaced structures on both fin sides, a flat or zigzag fin structure on either side, and nine triangular zigzag patterns on both fin sides are compared with the reference flat fin. The air inlet velocity and temperature are 5 m/s and 30 °C, respectively, whereas the pressure at the outlet is atmospheric pressure. The wall temperature remains constant at 10 °C. The heat transfer performance is evaluated using the JF factor value, which reflects a performance comparison with the reference. The results show that the zigzag pattern changes the airflow direction, and the time air is trapped inside a fin domain increases. Air also tends to flow toward the zigzag pattern center, increasing the velocity and the heat transfer. The nine triangular zigzag fin pattern structures with the largest heat transfer area provide the best performance with the biggest JF factor increase of 3.24%. This result is obtained despite the comparison of the biggest friction factor values of the three new fin structures, suggesting that the impact of the JF factor far outweighed that of the friction factor.

Additional information

Funding

This work was supported by the Faculty of Engineering, Kasetsart University, Bangkok, Thailand under Grant number 60/12/ME/M.ENG.