Molecular dynamics simulations and experimental investigation of viscosity of CuO-oil nanolubricant at different temperatures and volume fractions of nanoparticles.

Nanolubricant viscosity plays a crucial role in various industries due to its impact on pressure drop, pumping power, and heat transfer. The purpose of this research is to measure the viscosity of a (base oil) CH-CuO nano-lubricant experimentally using a viscometer and determine its viscosity using the equilibrium molecular dynamics (MD) simulation. In addition, the impacts of nano CuO particle volume fraction and temperature on the viscosity were investigated within different concentrations of nano CuO particles (0%, 0.25%, 0.5%, and 0.75%) and variable temperatures (300 K, 313 K, 323 K, and 373 K). The simulation results agreed with experimental results and depicted that the viscosity of base oil and nano lubricant of CuO-base oil decreased with increasing temperature. Additionally, increasing the concentration of nanoparticles increased the viscosity of the nano lubricant, but the effect of increasing the concentration of nanoparticles at high temperatures was not significant. For instance, the viscosity of the base oil increased by 1.2% and 1.5% after adding 0.5% and 0.75% copper oxide nanoparticles at 373 K. Based on our research; no study has been done to calculate the viscosity of nanolubricant (CH (base oil) - CuO) and its influencing factors by molecular dynamics simulation and compare its results with experimental methods. The research findings have practical implications for using nano lubricants in various industries, such as the internal combustion engine industry or other industries that use lubricants, and it is a critical parameter in heat transfer.