scholarly journals CFD Analysis of Enhancement of Turbulent Flow Heat Transfer in a Horizontal Circular Tube with Twisted Tape Inserts

Author(s):  
Chitti Babu Gaddem
2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
R. J. Yadav ◽  
A. S. Padalkar

CFD investigation was carried out to study the heat transfer enhancement characteristics of air flow inside a circular tube with a partially decaying and partly swirl flow. Four combinations of tube with twisted-tape inserts, the half-length upstream twisted-tape condition (HLUTT), the half-length downstream twisted-tape condition (HLDTT), the full-length twisted tape (FLTT), and the plain tube (PT) with three different twist parameters (, 0.27, and 0.38) have been investigated. 3D numerical simulation was performed for an analysis of heat transfer enhancement and fluid flow for turbulent regime. The results of CFD investigations of heat transfer and friction characteristics are presented for the FLTT, HLUTT, and the HLDTT in comparison with the PT case.


2011 ◽  
Vol 133 (4) ◽  
Author(s):  
J. U. Ahamed ◽  
M. A. Wazed ◽  
S. Ahmed ◽  
Y. Nukman ◽  
T. M. Y. S. Tuan Ya ◽  
...  

An experimental investigation has been carried out for turbulent flow in a tube with perforated twisted tape inserts. The mild steel twisted tape inserts with circular holes of different diameters (i.e., perforation) are used in the flow field. An intensive laboratory study is conducted for heat transfer and pressure drop characteristics in the tubes for turbulent flow with various airflow rates. Heat transfer and pressure drop data are engendered for a wide range Reynolds number (1.3×104–5.2×104). Tube wall temperature, pressure drop, air velocity, and its temperature are measured both for plain tube and for tube with perforated twisted tape inserts. Heat transfer coefficients, Nusselt number, pumping power, and heat transfer effectiveness are calculated for both cases. Experimental results showed that perforated twisted inserts of different geometry in a circular tube enhanced the heat transfer rate with an increase in friction factor and pumping power for turbulent flow. The pumping power, heat transfer coefficient, and effectiveness in the tube with the twisted tape inserts are found to increase up to 1.8, 5.5, and 4.0 times of those for the plain tube for same Reynolds number, respectively. Finally, a correlation is developed for prediction of the heat transfer rate for turbulent flow through a circular tube with perforated twisted tape inserts.


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