The effect of temperature and solid concentration on dynamic viscosity of MWCNT/MgO (20-80)-SAE50 hybrid nano-lubricant and proposing a new correlation: An experimental study

The main objective of the present paper is to investigate the dynamic viscosity of MWCNT/MgO (20-80)-SAE50 hybrid nano-lubricant. The experiments carried out in solid concentrations ranging from 0.25% to 2% and temperatures ranging from 25 °C to 50 °C. The results revealed that the nano-lubricant shows Newtonian behavior in all the studied temperatures and solid concentrations. Furthermore, the experimental results showed that the dynamic viscosity decreased as the temperature increased. It is also revealed that increasing the solid concentration leads to increasing the dynamic viscosity of the nano-lubricant in all the temperatures. The maximum increase in dynamic viscosity took place at the solid concentration of 2% and temperature of 40 °C by 65% while the minimum increase was at the solid concentration of 0.25% and temperature of 25 °C by 14.4%. Finally, applying curve fitting method on the experimental data, a new model to predict the dynamic viscosity of the studied nano-lubricant in terms of temperature and solid concentration has been proposed.