Experimental Study of Rheological Behavior of MWCNT-Al2O3/SAE50 Hybrid Nanofluid to Provide the Best Nano-lubrication Conditions

In this study, MWCNT-Al2O3 hybrid nanoparticles with a composition ratio of 50:50 in SAE50 base oil are used. This paper aims to describe the rheological behavior of hybrid nanofluid based on temperature, shear rate ($$\dot{\gamma })$$ γ ˙ ) and volume fraction of nanoparticles ($$\varphi$$ φ ) to present an experimental correlation model. Flowmetric methods confirm the non-Newtonian behavior of the hybrid nanofluid. The highest increase and decrease in viscosity ($${\mu }_{\rm nf}$$ μ nf ) in the studied conditions are measured as 24% and − 17%, respectively. To predict the experimental data, the five-point-three-variable model is used in the response surface methodology with a coefficient of determination of 0.9979. Margin deviation (MOD) of the data is determined to be within the permissible limit of − 4.66% < MOD < 5.25%. Sensitivity analysis shows that with a 10% increase in $$\varphi$$ φ at $$\varphi =$$ φ = 1%, the highest increase in $${\mu }_{\rm nf}$$ μ nf of 34.92% is obtained.