Study of MWCNT (40 %) – CuO (60 %)/10W40 hybrid nanofluid for improving laboratory oil performance by laboratory method and statistical response surface methodology

In this study, the rheological behavior of a specific type of hybrid nanofluid (HNF) in the temperature range of 5–55 °C and different laboratory conditions is investigated. The results of laboratory studies and flow and power-law curves indicate the non-Newtonian behavior of HNFs. Improving the viscosity behavior of HNFs (compared to 10W40 base oil) at certain temperatures and solid volume fractions (SVFs) is one of the unique and valuable results of this research. According to the obtained results, the maximum decrease in viscosity (−15.20 %) observed at T = 35 °C and SVF = 0.05 % and the maximum increase in viscosity (+21.9 %) is observed at T = 25 °C and SVF = 1 %. On the other hand, to be more accurate, and with the aim of saving time and reduce economic costs, experimental data predicted using response surface methodology (RSM). So A new nonlinear relationship in terms of temperature, SVF and shear rate (SR) with a coefficient of determination of R2 = 0.9997 presented. The results indicate the high accuracy of the proposed model and the conformity of the model with the experimental results.