Abstract
There has been a long-standing need for a piezoviscous parameter αfilm that, together with the ambient viscosity μ0, will completely quantify the Newtonian rheology so that the film thickness for liquids that do not shear-thin in the inlet may be calculated as h =h(μ0, αfilm,...), regardless of the details of the pressure-viscosity response. It seems that Blok's reciprocal asymptotic isoviscous pressure has certain advantages over the conventional pressure-viscosity coefficient, which is poorly suited for this purpose. The first detailed review of piezoviscous models for low pressures is provided. A simulation code that is apparently stable for all realistic pressure-viscosity response was utilized with diverse piezoviscous models and model liquids to develop a satisfactory definition of αfilm that reads αfilm=[1-exp(-3)]/[∫03/α * μ(0)dp/μ(p)]; 1/α*= ∫0∞μ(0)dp/μ(p). In the case of μ=μ0 exp(αp), αfilm = α and formulas are provided for other models.
Original language | English (US) |
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Pages (from-to) | 624-631 |
Number of pages | 8 |
Journal | Journal of Tribology |
Volume | 128 |
Issue number | 3 |
DOIs | |
State | Published - Jul 1 2006 |
Keywords
- Elastohydrodynamics
- Film thickness
- Newtonian
- Piezoviscous
- Pressure-viscosity coefficient
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering
- Surfaces and Interfaces
- Surfaces, Coatings and Films