Optimization of Parameters for Heat Transfer and Pressure Drop in a Tube with Twisted Tape Inserts by Using Taguchi Method

This study focuses on the determination of the optimum values of the design parameters for heat transfer and pressure drop in a tube equipped with twisted tape using Taguchi method. Design parameters affecting the heat transfer rate and pressure loss were chosen as clearance ratio (c/D = 0.0178, 0.0357, 0.0535 and 0.0714), twist ratio (y/D = 2, 2.5, 3 and 3.5), and Reynolds number (Re = 5,200, 9,600, 14,000 and 18,400). Thus, Nusselt number in terms of heat transfer and pressure drop (Delta P) basis of flow friction were considered as performance parameters. L-16(4(3)), where 16, 4, 3 indicates the number of experiments, levels and parameters, orthogonal array was selected as experimental plan. Signal to noise ratios and contribution ratios of each parameter were calculated. The purpose of this study is to obtain the highest Nusselt number and the lowest pressure drop by reducing the number of experiments, and so to provide less experimental cost and time. Consequently, the heat transfer augments with the decrease of twist ratio, clearance ratio, but the increase of Reynolds number. In addition, pressure drop decreases with the increase of twist ratio, clearance ratio, and the decrease of Reynolds number. Optimum values were found as c/D = 0.0178, y/D = 2 and Re = 18,400 for Nusselt number and c/D = 0.0714, y/D = 3.5 and Re = 5200 for pressure drop.