This study presents the determination of the optimum values of the design parameters in a tube with equilateral triangular cross-sectioned coiled wire inserts. The effects of the design parameters such as the ratio of the distance between the coiled wire and test tube wall to tube diameter (s/D), pitch ratio (P/D), ratio of the side length of equilateral triangle to tube diameter (a/D) and Reynolds number (Re) on heat transfer and pressure drop were investigated by using Taguchi method. The Nusselt number and friction factor were considered as performance parameters. An L-9(3(4)) orthogonal array was chosen as experimental plan. The goal of this study is to reach maximum heat transfer (i.e. Nusselt number) and minimum pressure drop (i.e. friction factor). First of all, each goal was optimized, separately. Then, all the goals were optimized together, considering the priority of the goals. Contribution ratios for each parameter on the heat transfer and pressure drop were determined. Consequently, the optimum results were found to be s/D = 0.0357, P/D = 1, a/D = 0.0714 and Re = 19800. (C) 2011 Elsevier Ltd. All rights reserved.
This study presents the determination of the optimum values of the design parameters in a tube with
equilateral triangular cross-sectioned coiled wire inserts. The effects of the design parameters such as the
ratio of the distance between the coiled wire and test tube wall to tube diameter (s/D), pitch ratio (P/D),
ratio of the side length of equilateral triangle to tube diameter (a/D) and Reynolds number (Re) on heat
transfer and pressure drop were investigated by using Taguchi method. The Nusselt number and friction
factor were considered as performance parameters. An L9(34) orthogonal array was chosen as experimental
plan. The goal of this study is to reach maximum heat transfer (i.e. Nusselt number) and
minimum pressure drop (i.e. friction factor). First of all, each goal was optimized, separately. Then, all the
goals were optimized together, considering the priority of the goals. Contribution ratios for each
parameter on the heat transfer and pressure drop were determined. Consequently, the optimum results
were found to be s/D ¼ 0.0357, P/D ¼ 1, a/D ¼ 0.0714 and Re ¼ 19800.