# Thermal characteristics in a heat exchanger tube fitted with zigzag‐winglet perforated‐tapes

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## 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 ZWPT 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 drop in terms of the respective 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 3.1-5.1 times above that for the plain tube while the f is around 12.5-53.6 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 3-5%.

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## Article Details

*Journal of Research and Applications in Mechanical Engineering*,

*3*(1), 29–36. Retrieved from https://ph01.tci-thaijo.org/index.php/jrame/article/view/141535

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

## References

[2] Promvonge, P. Thermal performance in circular tube fitted with coiled square wires, Energy Convers. Manage., Vol. 49, 2008, pp. 980-987.

[3] Eiamsa-ard, S., Thianpong, C. and Promvonge, P., Experimental investigation of heat transfer and flow friction in a circular tube fitted with regularly spaced twisted tape elements, Int. Commun. Heat Mass Transfer, Vol. 33(10), 2006, pp. 1225-1233.

[4] Promvonge, P., Skullong, S., Kwankaomeng, S. and Thiangpong, C. Heat transfer in square duct fitted diagonally with angle-finned tape–Part 1: Experimental study, Int. Commun. Heat Mass Transfer, Vol. 39, 2012, pp. 617-624.

[5] Promvonge, P., Skullong, S., Kwankaomeng, S. and Thiangpong, C. Heat transfer in square duct fitted diagonally with angle-finned tape–Part 2: Numerical study, Int. Commun. Heat Mass Transfer, Vol. 39, 2012, pp. 625-633.

[6] Tandiroglu, A. Effect of flow geometry parameters on transient heat transfer for turbulent flow in a circular tube with baffle inserts, Int. J. Heat Mass Transfer, Vol. 49, 2006, pp. 1559-1567.

[7] Eiamsa-ard, S., Wongcharee, K., Eiamsa-ard, P. and Thianpong, C. Heat transfer enhancement in a tube using delta-winglet twisted tape inserts, Appl. Therm. Eng., Vol. 30, 2010, pp. 310-318.

[8] Ozceyhan, V. Conjugate heat transfer and thermal stress analysis of wire coil inserted tubes that are heated externally with uniform heat flux, Energy Convers. Manag., Vol. 46(9-10), 2005, pp. 1543-1559.

[9] Chokphoemphun, S., Pimsarn, M., Thianpong, C. and Promvonge, P. Heat transfer augmentation in a circular tube with winglet vortex generators, Chin. J. Chem. Eng. Vol. 23, 2015, pp. 605-614.

[10] Eiamsa-ard, S., Thianpong, C. and Promvonge, P. Experimental investigation of heat transfer and flow friction in a circular tube fitted with regularly spaced twisted tape elements, Int. Commun. Heat Mass Transfer, Vol. 33(10), 2006, pp. 1225-1233.

[11] Promvonge, P. Thermal augmentation in circular tube with twisted tape and wire coil turbulators, Energy Convers. Manage., Vol. 49(11), 2008, 2949-2955.

[12] Krishna, S.R., Pathipaka, G. and Sivashanmugam, P. Heat transfer and pressure drop studies in a circular tube fitted with straight full twist, Exp. Therm. Fluid Sci., Vol. 33(3), 2009, pp. 431-438.

[13] Eiamsa-ard, S., Thianpong, C., Eiamsa-ard, P. and Promvonge, P. Convective heat transfer in a circular tube with short-length twisted tape insert, Int. Commun. Heat Mass Transfer, Vol. 36(3), 2009, pp. 365-371.

[14] Chiu, Y.W. and Jang, J.Y. 3D numerical and experimental analysis for thermal–hydraulic characteristics of air flow inside a circular tube with different tube inserts, Appl. Therm. Eng., Vol. 29(2-3), 2009, 250-258.

[15] Promvonge, P., Tamna, S., Pimsarn, M. and Thianpong, C. Thermal characterization in a circular tube fitted with inclined horseshoe baffles, Appl. Therm. Eng., Vol. 75, 2015, pp. 1147-1155.

[16] Eiamsa-ard, S., Wongcharee, K. and Sripattanapipat, S. 3-D Numerical simulation of swirling flow and convective heat transfer in a circular tube induced by means of loose-fit twisted tapes, Int. Commun. Heat Mass Transfer, Vol. 36(9), 2009. pp. 947-955.

[17] Incropera, F.P., Witt, P.D., Bergman, T.L. and Lavine, A.S. Fundamentals of heat and mass transfer, John-Wiley & Sons, 2006.