Rheological Characteristics for Thin Film Elastohydrodynamic Lubrication

Abstract

This paper uses three lubrication models to explore the differential phenomenon in the status of thin film lubrication (TFL). According to the viscous adsorption theory, the modified Reynolds equation for thin film elastohydrodynamic lubrication (TFEHL) is derived. In this theory, the film thickness between lubricated surfaces is simplified as three fixed layers across the film, and the viscosity and density of the lubricant vary with pressure in each layer. Under certain conditions, such as a rough or concentrated contact of a nominally flat surface, films may be of nanometer scale. The thin film elastohydrodynamic lubrication (EHL) analysis is performed on a surface forces (SF) model which includes van der waals and solvation forces. The results show that the proposed TFEHL model can reasonably calculate the film thickness and the average relative viscosity under thin film EHL. The adsorption layer thickness and the viscosity influence significantly the lubrication characteristics of the contact conjunction. The differences in pressure distribution and film shape between surface forces model and classical EHL model were obvious, especially in the Hertzian contact area. The solvation force has the greatest influence on pressure distribution.

Solid phase extraction—Non-aqueous capillary electrophoresis for determination of metformin, phenformin and glyburide in human plasma

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Effects of adsorption layers and elastic deformation on thin-film lubrication of circular contacts with non-Newtonian lubricants

“…A typical problem with W = 3.64 Â 10 À8 , U = 1.87 Â 10 À12 , G = 2417 and S = 0.0 is solved and discussed. Using the finite difference method (FDM) and the Gauss-Seidel iteration method, the solver developed by Chu et al (2005) is extended to obtain the film shape and pressure distribution of the circular contact. Most cases presented in this paper use a domain extending from x in = À4.0b to x out = 1.4b and -1.8b y 1.8b.…”

“…Power-law fluid models (Dien and Elrod, 1983;Buckholz, 1985;Bhattacharjee and Das, 1996;Lin et al, 2006) are widely used owing to the wide coverage in the analysis of lubricants and its mathematical simplicity. Chu et al (2005) presented a modified Reynolds equation for power-law fluid that is derived from the viscous adsorption theory for thin-film elastohydrodynamic lubrication (TFEHL) of line contacts with different flow indices for adsorption layers and middle layer, but TFEHL of circular contacts have not been discussed. Exploring the rheological properties of different flow indexes in adsorption layers and middle layer is necessary.…”

Characteristics of laterally vibrating resonant microcantilevers in viscous liquid media

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