Heat Transfer Enhancement in Turbulent Tube Flow Through Delta-winglet Tapes
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Abstract
This article presents the influence of Delta-Winglet Tapes (DWT) placed in a uniform heat-fluxed tube on thermal and flow resistance characteristics. In the current experiment, the DWTs with inclination angle (β) of 45º are inserted into the tube with three winglet blockage ratios (b/D = 0.1, 0.15 and 0.2) and three relative winglet-pitches (P/D = 1, 2 and 3). Air as the test fluid flows through the tube for Reynolds number of about 4,200–25,800. The experimental results reveal that the DWT can considerably enhance the heat transfer rate up to 4.06 times above the smooth tube whereas the friction factor is up to 31.63 times. The increase in b/D leads to higher heat transfer and friction loss while the increment in P/D provides the reversing trend. The thermal enhancement factor of the DWT is in the range of 1.16–1.51 where its maximum regarded as the optimum point is at b/D = 0.15 and P/D = 1. Nusselt number (Nu) and friction factor (f ) correlations for the DWT are also determined.
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References
[2] P. Eiamsa-ard, N. Piriyarungroj, C. Thianpong, and S. Eiamsa-ard, “A case study on thermal performance assessment of a heat exchanger tube equipped with regularly-spaced twisted tapes as swirl generators,” Case Studies in Thermal Engineering, vol. 3, pp. 86–102, 2014.
[3] E. F. Akyürek, K. Gelis, B. Sahin, and E. Manay, “Experimental analysis for heat transfer of nanofluid with wire coil turbulators in a concentric tube heat exchanger,” Results in Physics, vol. 9, pp. 376–389, 2018.
[4] K. Nanan, C. Thianpong, M. Pimsarn, V. Chuwattanakul, and S. Eiamsa-ard, “Flow and thermal mechanisms in a heat exchanger tube inserted with twisted cross-baffle turbulators,” Applied Thermal Engineering, vol. 114, pp. 130–147, 2017.
[5] S. Skullong, P. Promvonge, C. Thianpong, and N. Jayranaiwachira, “Thermal behaviors in a round tube equipped with quadruple perforateddelta-winglet pairs,” Applied Thermal Engineering, vol. 115, pp. 229–243, 2017.
[6] M. M. K. Bhuiya, M. S. U. Chowdhury, M. Saha, and M. T. Islam, “Heat transfer and friction factor characteristics in turbulent flow through a tube fitted with perforated twisted tape inserts,” International Communications in Heat and Mass Transfer, vol. 46, pp. 49–57, 2013.
[7] M. M. K. Bhuiya, A. S. M. Sayem, M. Islam, M. S. U. Chowdhury, and M. Shahabuddin, “Performance assessment in a heat exchanger tube fitted with double counter twisted tape inserts,” International Communications in Heat and Mass Transfer, vol. 50, pp. 25–33, 2014.
[8] A. Saysroy and S. Eiamsa-ard, “Periodically fully-developed heat and fluid flow behaviors in a turbulent tube flow with square-cut twisted tape inserts,” Applied Thermal Engineering, vol. 112, pp. 895–910, 2017.
[9] S. Skullong, P. Promvonge, N. Jayranaiwachira, and C. Thianpong, “Experimental and numerical heat transfer investigation in a tubular heat exchanger with delta-wing tape inserts,” Chemical Engineering and Processing, vol. 109, pp. 164–177, 2016.
[10] F. P. Incropera, P. D. Dewitt, T. L. Bergman, and A. S. Lavine, “Foundations of Heat Transfer,” 6th ed., John-Wiley & Sons Inc., 2012.
[11] A. Kumar, R. P. Saini, and J.S. Saini, “Development of correlations for Nusselt number and friction factor for solar air heater with roughened duct having multi vshaped with gap rib as artificial roughness,” Renewable Energy, vol. 58, pp. 151–163, 2013.
[12] T. Alam, R. P. Saini, and J. S. Saini, “Effect of circularity of perforation holes in Vshaped blockages on heat transfer and friction characteristics of rectangular solar air heater duct,” Energy Conversion and Management, vol. 86, pp. 952–963, 2014.