The rheological behavior of MWCNTs-ZnO/Water-Ethylene glycol hybrid non-Newtonian nanofluid by using of an experimental investigation

In the current study, an experimental study was carried out on the rheological properties of hybrid non -Newtonian nanofluid (MWCNTs-ZnO/Water-Ethylene glycol (80:20 vol.%)) to develop a new model. The viscosities of nanofluid were evaluated in the temperature range of 25-50 C with volume fractions of yo = 0.075%, 0.15%, 0.3%, 0.6%, 0.9%, and 1.2%. We find that the effect of changes is more obvious when the yo is increased. So the property of non Newtonian nanofluid is more likely to appear. In addition to a temperature of 25 C, the viscosity increase from a yo = 0% to 1.2% is higher than 90%, which is very significant. Also, in the maximum yo, at T= 50 C, 40 C and 30 C, the viscosity reduction is 21%, 17%, and 8%, respectively, relative to the reference temperature (25 C). The above results can be of great help to engineers in designing thermal systems to increase heat transfer and considering pumping power. (C) 2020 The Author(s). Published by Elsevier B.V.