thermo-hydraulic performance of tube type heat exchanger with semi-circular cut twisted tape insert: a numerical exploration

The present study aimed to investigate the effects of the semi-circular cut twisted tape insert in tube type heat exchangers. the study selected twist ratios of 4.5, 5.5, and 6.5mm, and cut diameters of 5mm, 8mm, and 11mm. the reynolds number ranged from 4000-16000. the study quantitatively demonstrated the impacts of cut diameter and twist ratio in terms of nusselt number, friction factor, and thermal performance factor. the aforementioned output parameters were employed as metrics to assess the efficacy of the twisted tape insert. the obtained results reveal that smaller twist generates extra swirl which intensifies heat transfer. also, as the diameter of the cut increases nusselt number increases. in a quantitative analysis, it was observed that when re=4000, the plain twisted tapes with y=4.5, 5.5, and 6.5 exhibited maximum thermal performance factors of 1.36, 1.32, and 1.21, respectively. on the other hand, for the modified twisted tapes (having a cut diameter of 11mm), the values were higher, measuring 1.84, 1.77, and 1.68 for the same respective ‘y’ values.