Heat transfer characteristics in micro-fin tube equipped with double twisted tapes： Effect of twisted tape and micro-fin tube arrangements

• Published in: Journal of hydrodynamics. Series B Vol. 25; no. 2; pp. 205 - 214
• Main Authors: Eiamsa-Ard, S., Wongcharee, K.
• Format: Journal Article
• Language: English
• Published: Singapore Elsevier Ltd 01.04.2013; Springer Singapore; Department of Mechanical Engineering, Faculty of Engineering, Mahanakorn University of Technology, Bangkok10530, Thailand%Department of Chemical Engineering, Faculty of Engineering, Mahanakorn University of Technology, Bangkok10530, Thailand
• Subjects: co-swirl; counter-swirl; Devices; double twisted-tapes (DTs); Engineering; Engineering Fluid Dynamics; Fluid dynamics; Fluid flow; friction; Friction factor; Heat transfer; heat transfer enhancement; Hydrology/Water Resources; micro-fin tube (MF); Numerical and Computational Physics; Simulation; Tubes; Turbulence; Turbulent flow; 传热特性; 实验性; 微肋管; 性能系数; 扭带; 系数和; 紊流流动; 配备; co-swirl; double twisted-tapes (DTs); counter-swirl; heat transfer enhancement; micro-fin tube (MF)
• ISSN: 1001-6058; 1878-0342
• DOI: 10.1016/S1001-6058(13)60355-8

An experimental study was carried out to investigate the influence of double twisted-tape inserts （DTs） in micro-fin tubes （MFs） on heat transfer, friction factor and thermal performance factor characteristics of the compound devices in the following configurations： （1） twisted tapes acted in the same direction （for co-swirl） while MF and twisted tapes acted in the same （parallel） direction （MF-CoDTs：P）, （2） twisted tapes acted in the same direction （for co-swirl） while micro-fin tube and twisted tapes acted in opposite directions （MF-CoDTs：O） and （3） twisted tapes acted in opposite directions for counter swirl （MF-CDTs）. The MF alone and the MF equipped with a single twisted tape in parallel/opposite arrangement were also considered for comparison. The experiments were conducted for the flows with the Reynolds numbers between 5 650 and 17 000, under uniform heat flux condition. The experimental results indicate that MF-CDTs induce stronger swirl/turbulence flow, resulting in higher heat transfer rate, friction factor and thermal performance factor than other combined devices. The thermal performance factors associated with the use of MF-CDTs were found to be higher than those associated with the uses of MF-CoDTs：P, MF-CoDTs：O and MF alone up to 9.3%, 6.5% and 56.4%, respectively. The empirical correlations developed using the present experimental data for the Nusselt number, friction factor and thermal performance factor are also reported.