A Further Investigation on the Shear Thinning Rheology Model Based on the Time of Recovery and a Simulation of the Rheological Behavior of Squalane

The authors of this paper have proposed recently a new rheological model based on the recovery time of the rod-ball deformation. The new model had a relatively simple form, however, could predict the friction coefficient curves of the high viscosity lubricant PAO 650 quite accurately. In this study, the application of this model was extended to predict the rheological features of a low viscosity lubricant, that is, squalane. Using the formula of this model to the point contact thermal elastohydrodynamic lubrication, full numerical solutions of squalane were obtained to determine the rheological parameters from the comparison between the numerical and experimental data of the friction coefficients. Results indicate that the solved pressure, film thickness and temperature were reasonable as expected, and the curves of the friction coefficients obtained theoretically and experimentally were in good agreement. The new rheological model, therefore, was demonstrated to be accurate enough for both high viscosity and low viscosity oils, that is, the correctness and applicability of the model based on the time of recovery were validated. In addition, there was an approximately horizontal segment in the curves of the shear stress obtained from the new model for squalane, which explained theoretically, to some extent, the limiting shear stress phenomenon reported in the experimental results of the rheological study in the literature.