Experimental and numerical study of thermal-hydraulic performance in a heat exchanger tube with circular ring’s angular cutting inserts

ABSTRACT

This paper experimentally and numerically studied the effects of inserting circular rings with four angular indexes and three diameter ratios at Re = 5000–24000 using air as the working fluid in a pipe. Researchers have proposed obstacles with various geometries to improve thermal performance in heat exchangers. However, research has not fully addressed the application of circular ring obstacles with different angle indexes and obstacle structure optimization. The results indicated, the Nusselt number increased by inserting a circular ring with an angular index of (360, 270, 180, and 90) by 3.9, 3.15, 2.92, and 2.74 times compared to a smooth tube, respectively. Likewise, the thermal performance coefficient for ring obstacles improves by 1.32, 1.39, 1.55, 1.8 times, respectively. Also, by increasing the ring diameter ratio, the Nusselt number increases, the friction coefficient decreases, and the thermal performance coefficient increases. Thus, it is be concluded that the better thermal performance of a circular ring’s cut sections as a passive component makes it a good choice for heat transfer and industrial applications. Besides, the results indicate that thermal efficiency in the case of using a ring with less angular index is higher, making it an appropriate choice economically.

KEYWORDS:

• Thermal performance
• circular ring
• angle ratio
• heat exchanger

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Disclosure statement

The authors declare that they have no conflict of interest..