A comparative study of the rheological behavior of nano-oils containing different percentages of nanoparticles in the base oil and determining the most optimal nano-lubricant

The investigation of the properties of two hybrid nano-lubricants MWCNT (30%)/ZnO(70%)-SAE40 and MWCNT(50%)/ZnO(50%)-SAE40 in different conditions by experimental and modeling methods and introducing a better nano-lubricant are done in this study. Experiments are performed in the temperature range of 25-50°C, volume fraction of 0.0625-1% and shear rate of 666.5-9331s-1 and the viscometer of Brookfield CAP 2000+ is used the results showed that both nano-lubricants have non-Newtonian and pseudo-plastic behavior. The highest increase of viscosity is occurred for nano lubricant of MWCNT-ZnO (50%-50%)/SAE40 by 28%, and the highest drop is occurred for nanolubricant MWCNT-ZnO (30%-70%)/SAE40 by 3% and therefore MWCNTZnO (30%-70%)/SAE40 nanolubricant has better performance. The results of the correlation provided by rsm method are in good agreement with the experimental data and R2 = 0. 9998 is obtained. The value of -0.95% <MOD < 1.10% is obtained and indicates a low modeling error. The sensitivity of nano-oil also increased with increasing the volume fraction.