An experimental investigation on the effect of acid treatment of MWCNTs on the viscosity of water-based nanofluids and statistical analysis of viscosity in prepared nanofluids

The effect of temperatures (25, 40, 55, and 70 °C) and weight fraction of MWCNTs (0.125, 0.25, and 0.5 % wt) on the viscosity of nanofluids containing pristine and functionalized MWCNTs is investigated. For this purpose, all of the measurements were carried out in triplicate and were analyzed using the two-factor completely randomized design, and comparison of data means is carried out with Duncan’s multiple range tests. The level of statistical significance was determined at 95 %. The experimental and statistical results showed that the viscosity of the both nanofluids increased with respect to the weight fraction and the decreasing temperature. Statistical analysis of viscosity shows that temperature, weight fraction, and interaction effect have significant influence on the viscosity of nanofluids containing pristine and functionalized MWCNTs (α=0.05). Meanwhile, the results show that there is a significant difference at different levels of temperature on the viscosity of the both nanofluids.