Experimental Investigation and Optimization of Flow

This paper presents a systematic experimental investigation into the optimisation of internal pipe flow parameters for pressure drop, Darcy friction factor, and convective heat transfer coefficient using the Taguchi L9 orthogonal array design and Analysis of Variance (ANOVA). Three pipe materials — mild steel, copper, and PVC — were tested at three levels of flow velocity (0.5, 1.0, 1.5 m/s), pipe diameter (25, 40, 50 mm), and fluid temperature (30, 45, 60 °C) using water as the working fluid. Response variables measured include pressure drop (ΔP), Darcy-Weisbach friction factor (f), and convective heat transfer coefficient (h). Signal-to-Noise (S/N) ratio analysis identified the optimal parameter combination for minimum pressure drop as flow velocity 0.5 m/s, pipe diameter 50 mm, fluid temperature 30 °C, and copper pipe material. ANOVA revealed pipe diameter as the most significant factor with 46.2 percent contribution to pressure drop, followed by flow velocity (34.8 percent) and pipe material (11.6 percent). Empirical Nusselt number correlations derived from experimental data agree within 6.4 percent of the Dittus-Boelter equation predictions. Copper pipe at 60 °C fluid temperature achieved the highest heat transfer coefficient of 3,842 W/m²K, outperforming mild steel and PVC by 18.3 percent and 41.7 percent respectively. Confirmation experiments validated predicted optimal values with errors below 4.1 percent.