Experimental Investigation of Turbulent Heat Transfer by Counter and Co-Swirling Flow in a Flat Tube Fitted with Twin Twisted Tapes

The use of inserts has gained extensive attention due to their role in improving the efficiency of thermal systems. In this study, an experimental investigation was conducted to explore the effect of twin counter and co-twisted tapes on heat transfer rate (Nu), friction factor (f) and thermal enhanc...

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Main Authors:	M. Kh., Abdolbaqi, Azmi, W. H., R., Mamat, N. M. Zuki, N. M., G., Najafi
Format:	Article
Language:	English
Published:	Elsevier 2016
Subjects:	TJ Mechanical engineering and machinery
Online Access:	http://umpir.ump.edu.my/id/eprint/8253/ http://umpir.ump.edu.my/id/eprint/8253/ http://umpir.ump.edu.my/id/eprint/8253/ http://umpir.ump.edu.my/id/eprint/8253/1/Experimental%20Investigation%20of%20Turbulent%20Heat%20Transfer%20by%20Counter%20and%20Co-Swirling%20Flow%20In%20A%20Flat%20Tube%20Fitted%20With%20Twin%20Twisted%20Tapes.pdf

id	ump-8253
recordtype	eprints
spelling	ump-82532018-01-30T02:41:02Z http://umpir.ump.edu.my/id/eprint/8253/ Experimental Investigation of Turbulent Heat Transfer by Counter and Co-Swirling Flow in a Flat Tube Fitted with Twin Twisted Tapes M. Kh., Abdolbaqi Azmi, W. H. R., Mamat N. M. Zuki, N. M. G., Najafi TJ Mechanical engineering and machinery The use of inserts has gained extensive attention due to their role in improving the efficiency of thermal systems. In this study, an experimental investigation was conducted to explore the effect of twin counter and co-twisted tapes on heat transfer rate (Nu), friction factor (f) and thermal enhancement index (η). The twin counter twisted tapes (CTT) and twin co-twisted tapes (CoTT) were used as swirl flow generators in a test section. The tests were conducted using the CTT and CoTT with three different twist ratios (H/D) = 5, 10 and 15) for Reynolds numbers range between 7200 and 32,400 under uniform heat flux conditions. The results show that Nusselt number (Nu), friction factor (f) and thermal enhancement index (η) increase with decreasing twist ratio (H/D) and the CTT is more efficient than the CoTT for heat transfer enhancement. Within the scope of this study, heat transfer rates in the flat tube fitted with the CTT are around 22.5% and 61% higher than those with the CoTT and plain flat tube, respectively. The maximum thermal enhancement index (η) obtained at the constant flow rate by the CTT with H/D = 5, 10 and 15, are 1.58, 1.44 and 1.15 respectively, while those obtained using the CoTT with the same range of H/D are 1.43, 1.19 and 1.04, respectively. Furthermore, the empirical correlations of the heat transfer (Nu), friction factor (f) and thermal enhancement index (η) are also reported. Elsevier 2016 Article PeerReviewed application/pdf en http://umpir.ump.edu.my/id/eprint/8253/1/Experimental%20Investigation%20of%20Turbulent%20Heat%20Transfer%20by%20Counter%20and%20Co-Swirling%20Flow%20In%20A%20Flat%20Tube%20Fitted%20With%20Twin%20Twisted%20Tapes.pdf M. Kh., Abdolbaqi and Azmi, W. H. and R., Mamat and N. M. Zuki, N. M. and G., Najafi (2016) Experimental Investigation of Turbulent Heat Transfer by Counter and Co-Swirling Flow in a Flat Tube Fitted with Twin Twisted Tapes. International Communications in Heat and Mass Transfer, 75. pp. 295-302. ISSN 0735-1933 http://dx.doi.org/10.1016/j.icheatmasstransfer.2016.04.021 DOI: 10.1016/j.icheatmasstransfer.2016.04.021
repository_type	Digital Repository
institution_category	Local University
institution	Universiti Malaysia Pahang
building	UMP Institutional Repository
collection	Online Access
language	English
topic	TJ Mechanical engineering and machinery
spellingShingle	TJ Mechanical engineering and machinery M. Kh., Abdolbaqi Azmi, W. H. R., Mamat N. M. Zuki, N. M. G., Najafi Experimental Investigation of Turbulent Heat Transfer by Counter and Co-Swirling Flow in a Flat Tube Fitted with Twin Twisted Tapes
description	The use of inserts has gained extensive attention due to their role in improving the efficiency of thermal systems. In this study, an experimental investigation was conducted to explore the effect of twin counter and co-twisted tapes on heat transfer rate (Nu), friction factor (f) and thermal enhancement index (η). The twin counter twisted tapes (CTT) and twin co-twisted tapes (CoTT) were used as swirl flow generators in a test section. The tests were conducted using the CTT and CoTT with three different twist ratios (H/D) = 5, 10 and 15) for Reynolds numbers range between 7200 and 32,400 under uniform heat flux conditions. The results show that Nusselt number (Nu), friction factor (f) and thermal enhancement index (η) increase with decreasing twist ratio (H/D) and the CTT is more efficient than the CoTT for heat transfer enhancement. Within the scope of this study, heat transfer rates in the flat tube fitted with the CTT are around 22.5% and 61% higher than those with the CoTT and plain flat tube, respectively. The maximum thermal enhancement index (η) obtained at the constant flow rate by the CTT with H/D = 5, 10 and 15, are 1.58, 1.44 and 1.15 respectively, while those obtained using the CoTT with the same range of H/D are 1.43, 1.19 and 1.04, respectively. Furthermore, the empirical correlations of the heat transfer (Nu), friction factor (f) and thermal enhancement index (η) are also reported.
format	Article
author	M. Kh., Abdolbaqi Azmi, W. H. R., Mamat N. M. Zuki, N. M. G., Najafi
author_facet	M. Kh., Abdolbaqi Azmi, W. H. R., Mamat N. M. Zuki, N. M. G., Najafi
author_sort	M. Kh., Abdolbaqi
title	Experimental Investigation of Turbulent Heat Transfer by Counter and Co-Swirling Flow in a Flat Tube Fitted with Twin Twisted Tapes
title_short	Experimental Investigation of Turbulent Heat Transfer by Counter and Co-Swirling Flow in a Flat Tube Fitted with Twin Twisted Tapes
title_full	Experimental Investigation of Turbulent Heat Transfer by Counter and Co-Swirling Flow in a Flat Tube Fitted with Twin Twisted Tapes
title_fullStr	Experimental Investigation of Turbulent Heat Transfer by Counter and Co-Swirling Flow in a Flat Tube Fitted with Twin Twisted Tapes
title_full_unstemmed	Experimental Investigation of Turbulent Heat Transfer by Counter and Co-Swirling Flow in a Flat Tube Fitted with Twin Twisted Tapes
title_sort	experimental investigation of turbulent heat transfer by counter and co-swirling flow in a flat tube fitted with twin twisted tapes
publisher	Elsevier
publishDate	2016
url	http://umpir.ump.edu.my/id/eprint/8253/ http://umpir.ump.edu.my/id/eprint/8253/ http://umpir.ump.edu.my/id/eprint/8253/ http://umpir.ump.edu.my/id/eprint/8253/1/Experimental%20Investigation%20of%20Turbulent%20Heat%20Transfer%20by%20Counter%20and%20Co-Swirling%20Flow%20In%20A%20Flat%20Tube%20Fitted%20With%20Twin%20Twisted%20Tapes.pdf
first_indexed	2023-09-18T22:05:37Z
last_indexed	2023-09-18T22:05:37Z
_version_	1777414688092454912

Experimental Investigation of Turbulent Heat Transfer by Counter and Co-Swirling Flow in a Flat Tube Fitted with Twin Twisted Tapes

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