Prediction of Lubricant Viscosity from Nonequilibrium Molecular Dynamics Simulation

Nonequilibrium molecular dynamics simulation (NEMD) was used to compute the viscosity of a pure polyol ester, −1 to 1010pentaerythritol tetrahexanoate (PEC6), for a broad range of strain rate (107 s s−1), temperature (258 K to 373 K), and pressure (0.1 MPa to 1 GPa). The Newtonian viscosity was obtained by fitting the viscosities at different strain rates to the Eyring model. The predicted Newtonian viscosities agree well with the experimental data with respect to temperature and pressure. The molecular dynamics simulation is pure prediction because it requires only the chemical structure as the input. Therefore, molecular dynamics can be especially useful in simulating those hypothetical molecules and those experimentally inaccessible conditions, which can reduce the cost and time of experimentation and facilitate the development of high-performance lubricants