Extrapolation of rheological properties for lubricant components with Stokes-Ginstein relationships
PA Gordon, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 44, 5828-5835 (2005).
In this paper we examine the scaling of transport properties obtained from molecular dynamics simulations on a number of model C-16 isoparaffin systems and interpreted in a Stokes-Einstein framework. The properties span a wide range of temperatures and pressures. The scaling behavior can be nonlinear and shows variation among different isomers. Nonetheless, for a given molecule, the scaling behavior of transport property data appears to be well-behaved, and we propose two approximate methods by which viscosity can be estimated from the self-diffusion coefficient and geometric characterization of the molecule in terms of an inertially equivalent prolate ellipsoid. Both methods rely on high- temperature simulations, which provide important scaling information about transport properties with reasonable computational effort. We compare the accuracy of the predictions of these approaches with several examples of lube-ranged model compounds.
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