Dynamic Viscosity of Some Lubricants in Terms of Local Nano-Void Fraction

Abstract

In  the  current  study,  the  dynamic  viscosity  has  been  established  by  the  preceding  viscosity correlation equation in terms of thermo-occupancy function, Y_h=Y_h(h,T),  for  three types  of  chemically different pure substances between  283.15–398.15 K  and  up to 100 MPa. The thermo-occupancy function, Y_h=Y_h(h,T), comprises temperature T and hole (nano-void) fraction h=h(P,T) estimated by the Simha–Somcynsky equation of state through the published density data. The density fitting results were found by this report  to  be  from  0.026  to  0.051%.  The  predictive  dynamic viscosity  of  dialkyl  carbonates,  ethylene  glycol  dimethyl  ethers, and  di(2-ethylhexyl) sebacate was obtained with an overall uncertainty of 0.29%, 0.40%, and 0.38%, respectively. The effects of the optimized volumetric and rheological parameters on the compounds' molecular structure and architecture were investigated.  The increase in fraction h with  an  increasing temperature  suggests  a decrease in the rate of change in dynamic viscosity (viscoholibility) of the samples over a computed hole fraction range.