Simultaneous effects of MWCNT and SiO2 on the rheological behavior of cooling oil and sensitivity analysis

Abstract

Many scholars are attracted to nano-lubricants due to their unique properties. In the present study, the rheological behavior of a new generation of lubricants has been investigated. SiO2 nanoparticles with an average diameter of 20–30 nm along with MWCNT with an internal diameter of 3–5 nm and the external diameter of 5–15 nm has been dispersed in 10W40 engine oil as base-lubricant and MWCNTs-SiO2 (20%–80%)/10W40 hybrid nano-lubricant has been produced. Nano-lubricant behavior agrees with the Herschel-Bulkley model and is of Bingham pseudo-plastic type below 55°C. Also, in the temperature of 55°C, nano-lubricant behavior has changed to Bingham dilatant. The viscosity is increased by 32% in the proposed nano-lubricant compared to base lubricant (Dynamics Viscosity Enhancement). Finally, a new correlation with a precision index of R-squared >0.9800, Adj. R-squared >0.9800, and the maximum margin of deviation of 2.72% has been presented, increasing the applicability of this nano-lubricant. Eventually, the sensitivity analysis of nano-lubricant has been conducted, studying the comparative effect of volume fraction and temperature on viscosity.