Thermal Characterization of Turbulent Flow in a Tube With Discrete  Coiled Wire Insert

Ahmed Hasan Salih, Ibtisam

	Thermal Characterization of Turbulent Flow in a Tube With Discrete Coiled Wire Insert
Journal of Engineering and Sustainable Development
Article 1, Volume 18, Issue 6, 2014, Pages 126-143
Author
Ibtisam Ahmed Hasan Salih
Abstract
The present study aims to investigate the effect of adding discrete coiled wire to enhance the heat transfer in heat exchanger. The coiled wire used in experiments were made from steel circular cross section wire with (b = 4 mm) diameter. The outer coil wire's diameter was (B=36.5 mm) and length after been winding is (l = 100 mm), the discrete distribution of coil wires, by different spacing (S) between them with (S/l = 0.22 ,0.57 &1.2) ,which require to distribute 10, 8 & 6 coiled wires along test section respectively, were considered in the experimental study . The experiments have been carried at constant heat flux rate and different flow rates of air that started from (Re=6000) and increased gradually to reach the following Re. (7500, 9000, 10500, 12000 and 13500). The results show that the use of the S/l=0.57 results in the augmentation of pressure loss around 33.2% higher than that of the S/l=0. In addition, it can be found that for using coiled wire turbulator with spacing ratios(0, 0.22, 0.57,& 1.2 ), the improvement of average heat transfer rate is, respectively, about 112%, 119.3%, 141.3%&132% higher than those the plain tube while the friction factor is 300%,392% ,432%, and 322% times of the plain tube.
Keywords
Heat exchanger enhancement; Discrete coiled wire; turbulent flow; Pressure drop

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