TY - JOUR
T1 - Impact of blockage ratio on thermal performance of delta-winglet vortex generators
AU - Yaningsih, Indri
AU - Wijayanta, Agung Tri
AU - Miyazaki, Takahiko
AU - Koyama, Shigeru
N1 - Funding Information:
Acknowledgments: The first author wishes to thank the Ministry of Research, Technology, and Higher Education (RISTEKDIKTI) and the Ministry of Finance, Indonesia Endowment Fund for Education (LPDP) of the Republic of Indonesia, for their support of this study within the framework of BUDI-LN. The authors wish to thank their former colleague, Adi Eka Pranata, for his assistance during the experiments.
Publisher Copyright:
© 2018 by the authors.
PY - 2018/1/26
Y1 - 2018/1/26
N2 - The impact of double-sided delta-winglet tape (DWTs) inserts on convective heat transfer and friction behaviors in a tube was experimentally investigated. Three DWTs with ratios of winglet-height (b) to inner tube diameter (di) called blockage ratio (Rb) of 0.28, 0.35 and 0.42 were tested and their performance was compared to that of a longitudinal strip and plain tube under similar test flow conditions. Experiments were conducted over a wide range of flow rates, 3.35 × 10-5-8.33 × 10-5 m3/s, which correspond to 5500 ≥ Reynolds number (Re) ≥ 14,500 in the 14.3 mm i.d. tube. The results revealed that using DWTs dramatically increased the Nusselt number (Nu) by as much as 364.3% and the friction factor (f) by 15.5 times compared with those of a plain tube. Thermal performance (η) increased with a corresponding increase in Rb. The highest thermal performance (η) obtained was 1.4. Showing a notable improvement on the thermal performance of the system, DWTs are proposed as a favorable insert device.
AB - The impact of double-sided delta-winglet tape (DWTs) inserts on convective heat transfer and friction behaviors in a tube was experimentally investigated. Three DWTs with ratios of winglet-height (b) to inner tube diameter (di) called blockage ratio (Rb) of 0.28, 0.35 and 0.42 were tested and their performance was compared to that of a longitudinal strip and plain tube under similar test flow conditions. Experiments were conducted over a wide range of flow rates, 3.35 × 10-5-8.33 × 10-5 m3/s, which correspond to 5500 ≥ Reynolds number (Re) ≥ 14,500 in the 14.3 mm i.d. tube. The results revealed that using DWTs dramatically increased the Nusselt number (Nu) by as much as 364.3% and the friction factor (f) by 15.5 times compared with those of a plain tube. Thermal performance (η) increased with a corresponding increase in Rb. The highest thermal performance (η) obtained was 1.4. Showing a notable improvement on the thermal performance of the system, DWTs are proposed as a favorable insert device.
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U2 - 10.3390/app8020181
DO - 10.3390/app8020181
M3 - Article
AN - SCOPUS:85041227759
SN - 2076-3417
VL - 8
JO - Applied Sciences (Switzerland)
JF - Applied Sciences (Switzerland)
IS - 2
M1 - 181
ER -