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Thermal characteristics in a heat exchanger tube fitted with zigzag-winglet perforated-tapes |
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| รหัสดีโอไอ | |
| Creator | S. Suwannapan, S. Skullong and P. Promvonge |
| Title | Thermal characteristics in a heat exchanger tube fitted with zigzag-winglet perforated-tapes |
| Publisher | Thai Society of Mechanical Engineers |
| Publication Year | 2558 |
| Journal Title | Journal of Research and Applications in Mechanical Engineering |
| Journal Vol. | 3 |
| Journal No. | 1 |
| Page no. | 29-36 |
| Keyword | Thermal performance, zigzag-winglet, perforated-tape, Nusselt number, Reynolds number |
| ISSN | 2229-2152 |
| Abstract | The paper presents an experimental investigation on enhanced heat transfer and pressure loss characteristics using zigzag-winglet perforated-tape inserts (ZW-PT) in a round tube having a uniform heat-fluxed wall for the turbulent air flow, Reynolds number (Re) from 4200 to 26,000. In the present work, the ZW-PT having the winglet attack angle of 45? were inserted into the test tube at two different winglet pitch ratios (P/D=PR=1 and 1.5) and four winglet-width or blockage ratios (b/D=BR=0.1, 0.15, 0.2 and 0.25). The experimental results of the heat transfer and pressure loss due to friction for propelling air through the tube are presented in terms of Nusselt number (Nu) and friction factor (f), respectively, reveal that the Nu and f increase with the increment of BR and Re but with the decreasing PR. The Nu for the inserted tube is in a range of 3.15.1 times above that for the plain tube while the f is around 12.553.6 times. In addition, the use of the ZW-PT with PR=1.0 leads to better thermal enhancement factor (TEF) than that with PR=1.5 around 35%. |
