Synthesis of MWCNT@Ag and application of it for investigation of the nanofluids viscosity variation based on the 2-level factorial design

ABSTRACT The viscosity of nanofluids is affected by several factors such as temperature and weight fraction. In this study, we investigate for the first time the effect of them on the viscosity of nanofluids containing MWCNTs-Ag, with different amount of Ag nanoparticles (MWAg-1 and MWAg-2) using 2-level factorial design. The results of FTIR and XRD analysis confirm the presence of synthesized Ag nanoparticles on the surface of MWCNTs. TEM results reveal that Ag nanoparticles can successfully introduce on the surface of oxidized MWCNTs. The results of the analysis of variance (ANOVA) confirm that both models are significant for viscosity prediction of nanofluids. Meanwhile, the results reveal that the temperature (40 and 70) and weight fraction (0.125 and 0.5) have a significant effect on the viscosity of MWAg-1 nanofluids. In addition, the results confirmed that the importance of temperature is more than the concentration of MWAg-1. The contribution percent of temperature and weight fraction reveals that the contribution of weight fraction (44.08) is higher than that of temperature (37.71°C) at the proposed model. However, in the MWAg-2 nanofluids, only the temperature has a significant effect on the viscosity. The F-values of model in MWAg-1and MWAg-2 nanofluids are 20.21 and 15.70, respectively.