Publication Date:
2012-11-03
Description:
Numerical simulations were performed to study the fluid flow and heat transfer in a tube with staggered twisted tapes with central holes. In the range of Reynolds numbers between 6000 and 28 000, the modified twisted tapes increased the Nusselt number by 76.2 ∼ 149.7 % and the friction factor by 380.2 ∼ 443.8 % compared to the smooth tube. Compared to the typical twisted tapes, the modified twisted tapes produced an acceleration flow through the triangle regions leading to the enhancement of heat transfer, and the holes in the modified tapes reduced the severe pressure loss. It was found that the modified twisted tapes decreased the friction factor by 8.0 ∼ 16.1 % and enhanced the heat transfer by 34.1 ∼ 46.8 % in comparison with the typical tapes. These results indicated that the performance ratio values of the tube with modified twisted tapes were higher than 1.0 in the range of Reynolds numbers studied. The computed performance ratios of the tube with modified twisted tapes were much higher than those of the tube with typical twisted tapes. This means that the integrated performance of the tube with staggered twisted tapes with central holes is superior to that of the tube with typical twisted tapes. A new type of tube with staggered twisted tapes with central holes is presented. Heat transfer and pressure performance of the new tube with the modified twisted tapes are investigated numerically. The criterion of the thermal-hydraulic performance is used to evaluate the heat transfer and pressure drop performance of the tube with staggered twisted tapes with central holes.
Print ISSN:
0930-7516
Electronic ISSN:
1521-4125
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
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