Impact of Blockage Ratio on Thermal Performance of Delta-Winglet Vortex Generators
AbstractThe 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. View Full-Text
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Yaningsih, I.; Wijayanta, A.T.; Miyazaki, T.; Koyama, S. Impact of Blockage Ratio on Thermal Performance of Delta-Winglet Vortex Generators. Appl. Sci. 2018, 8, 181.
Yaningsih I, Wijayanta AT, Miyazaki T, Koyama S. Impact of Blockage Ratio on Thermal Performance of Delta-Winglet Vortex Generators. Applied Sciences. 2018; 8(2):181.Chicago/Turabian Style
Yaningsih, Indri; Wijayanta, Agung T.; Miyazaki, Takahiko; Koyama, Shigeru. 2018. "Impact of Blockage Ratio on Thermal Performance of Delta-Winglet Vortex Generators." Appl. Sci. 8, no. 2: 181.
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