Experimental Study on Heat Transfer and Friction Factor of Nanodiamond-Nickel (ND-Ni) Nanocomposite Nanofluids Flow in a Tube with Twisted Tape Inserts

The heat transfer and friction factor analysis of nanodiamond-nickel (ND-Ni) nanofluids flow in a tube with full length twisted tape inserts were studied experimentally. The heat transfer and friction factor experiments were conducted at different volume concentrations (0.1% and 0.3%), different Reynolds number (3000 to 22000), and different twist ratios of twisted tape inserts (H/D = 5,10 and 15). The Nusselt number is enhanced up to 24.66% and 35.43% at 0.1% and 0.3% volume concentrations of ND-Ni nanofluids at a Reynolds number of 22000 compared to water data. The Nusselt number is further enhanced up to 53.63% and 73.15% at 0.1% and 0.3% volume concentration of ND-Ni nanofluids flow in a tube with twisted tape inserts of H/D = 5 at a Reynolds number of 22000 compared to water data. The friction factor penalty of 1.086-times and 1.10-times, for 0.1% and 0.3% nanofluid at a Reynolds number of 22000 compared with water. The further friction factor penalty of 1.18-times and 1.23-times at 0.3% nanofluid flow in a tube with twisted tape inserts of H/D = 5, as compared to water data. Based on the experimental data, Nusselt number and friction factor correlations were proposed.