Experimental Study of Rheological Behavior of MgO-MWCNT/5W-50 Hybrid Nanofluid: Proposing a New Three-variable Correlation

In the present study, the rheological behavior of hybrid nanofluid (MgO(65%) – MWCNT(35%)/5w50) has been studied. the viscosity of mentioned nanofluid was measured at 5oC- 55oC and 0% – 1% volume fraction range. then the effect of these two parameters on viscosity was studied. Also, the effect of shear rate changes (665.5 s-1 - 11997 s-1 ) on viscosity changes was studied. Fitting power law curves on experimental data and achieve R2's with very close to unity was considered as a sign of non-Newtonian behavior of present nanofluid. In order to forecast viscosity quantities as functions of solid volume fraction, temperature, and shear rate, a novel three variable correlation has been proposed (with R2=0.999). Viscosity reduction of nanofluid in comparison with the base oil in solid volume fractions of 0.05%, 0.1%, and 0.25% is another remarkable result of the present study.