In this study, the effects of incorporatingMWCNTs nanoparticles on paraffin liquid-based viscosity behaviorwere
examined. Viscosity of the prepared samples ofMWCNTs-liquid paraffin is measured within the temperature of
5–65 °C at volume fractions of 0.005, 0.01, 0.05, 0.1, 0.5, 1 and 5%. Experiment results showed that nanofluid of
MWCNTs-liquid paraffin should be characterized as a fluid with non-Newtonian behavior (shear-thinning).
The behavior of the consistency index is such that it tends to decrease with increasing temperature and decreasing
volume fraction. Itwas observed thatwith increasing volume fraction or temperature, fluid behavior deviates
more fromNewtonian behavior (decreasing power-lawindex). Temperature and volumefraction are two important
and effective parameters on nanofluid viscosity. Increasing the temperature strengthens the effect of the volume
fraction on the viscosity, but increasing the volume fraction weakens the effect of temperature on the
viscosity. Due to the increase in volume fraction, the maximum intensification in viscosity was calculated to be
12.66%. Finally, two correlations were derived to calculate the consistency index and power-law index,
respectively.