Optimization of heat transfer and pressure drop in a tube with loose-fit perforated twisted tapes by Taguchi method and grey relational analysis

Abstract

This work introduces the determination of the optimum values of the design parameters in a tube with loose-fit perforated twisted tapes. The effects of the design parameters such as twist ratio (y/D), width ratio (W/D), hole diameter ratio (d/D) and Reynolds number (Re) on heat transfer (i.e. Nusselt number) and pressure drop (i.e. friction factor) were analyzed by Taguchi method (TM) and grey relational analysis (GRA). The Nusselt number and friction factor were taken into account as performance parameters. Taguchi Method is based on analysis of variances and implements the orthogonal arrays for experimental design. L16 orthogonal array was selected as experimental plan. Firstly, each performance parameter was optimized, independently. Then, all the performance parameters were optimized together by TM and GRA. According to the experimental plan results, the most important factor for both Nusselt number and friction factor is Reynolds number, while the least significant factors are twist ratio (y/D) and width ratio (W/D).