Heat transfer augmentation of internal flow using twisted tape insert in turbulent flow

Abstract

Heat transfer augmentation of turbulent single-phase flow in a concentric tube heat exchanger with short-length twisted tape inserts was numerically examined herein. The twisted tape length ratios were 0.25, 0.5, 0.75, and 1.0. The twisted tape was comprised of an aluminum strip with a constant thickness, a pitch, and a width of 0.7, 35, and 12.6 mm, respectively. This study was conducted for heat exchangers with/without twisted tape inserts. The Reynolds numbers ranging from 4,500 to 18,500 were applied. The analyses showed an improvement in heat transfer and friction factor in each of the tube systems, and the results were used to determine the system that delivered the best performance. The correlations of Gnielinski and Petukhov were also used for validating the predicted Nusselt number and friction factor for the plain tube. The results indicated that heat transfer augmentation was elevated as the tape-length ratio increased. The respective highest average Nusselt number and friction factor obtained in this study were 0.51 and 2.84 times greater than that of the plain tube.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Acknowledgments

The authors wish to thank their former colleague, Mr. Aprivianto Tri Wijanarko, for his kind assistance during the data collection. The first author also wishes to acknowledge the Education and Culture Attaché, the Embassy of the Republic of Indonesia in London, for the opportunity to have a research visit to the United Kingdom during the revision of the article.

Additional information

Funding

We are grateful to Universitas Sebelas Maret for funding this study. The financial assistance partially provided by Tokyo Institute of Technology is gratefully acknowledged.

Notes on contributors

Agung Tri Wijayanta

Agung Tri Wijayanta is an Associate Professor at the Mechanical Engineering, Sebelas Maret University, Surakarta, Indonesia. Presently, he is the Head of Doctoral Program in Mechanical Engineering, Graduate School of Engineering and also a leader of Research Group of Sustainable Thermofluids. He received the B.Eng. in Mechanical Engineering from Gadjah Mada University, Yogyakarta, Indonesia in 1996. He obtained his M.Eng and Ph.D. from Kyushu University, Japan in 2004 and 2007, respectively. He continued his Postdoctoral position at Kyushu University and finished in 2014. His research interests include energy and thermal engineering both numerical and experimental methods.

Mirmanto

Mirmanto received the Bachelor Degree in Mechanical Engineering from Gadjah Mada University Indonesia in 1996 and his Master Degree in Mechanical Engineering from Gadjah Mada University, Indonesia in 2000, respectively. His Ph.D. was achieved at the Mechanical Engineering Department, School of Engineering and Design, Brunel University, the United Kingdom in 2013. He is a lecturer at the Mechanical Engineering Department of Mataram University, Indonesia. His research interests are in the area of fluid and heat transfer, flow in microchannels, renewable energy, and energy recovery.

Muhammad Aziz

Muhammad Aziz received B.Eng., M.Eng., and D.Eng. degrees from Kyushu University, Japan, in 2004, 2006 and 2008, respectively. He previously worked for Seiko-Epson Corp., Japan, until 2009 and finished his postdoctoral position at The University of Tokyo in 2011. He moved then to Tokyo Institute of Technology, Japan, as assistant professor until received the current position as an associate professor at the same university in 2015. He has authored more than 100 peer-reviewed journals and book chapters, especially in energy systems, energy and exergy analysis, energy management systems, and heat transfer.