Detail publikace

An Experimental Validation of the Recently Discovered Scale Effect in Generalized Newtonian EHL

KŘUPKA, I. HARTL, M. BAIR, S. KUMAR, P. KHONSARI, M.M.

Anglický název

An Experimental Validation of the Recently Discovered Scale Effect in Generalized Newtonian EHL

Typ

Článek recenzovaný mimo WoS a Scopus

Jazyk

en

Originální abstrakt

New quantitative numerical simulations of the elastohydrodynamic lubrication (EHL) film forming ability of generalized Newtonian liquids have elucidated a previously unrecognized property of EHL films. The dependency of the film thickness on the scale of the contact is greater when the viscosity is shear dependent within the inlet. Measurements of film thickness were performed in a ball on disc experiment using balls ranging from 5.5 to 35 mm in diameter. Three liquids were investigated with varying shear dependence in the range of stress important to film forming. The experimental results confirm the previous analytical findings. Numerical simulations using the measured viscosities show that the increased scale sensitivity is substantially the result of shear-thinning. However, the smallest scales produced films thinner than even the shear-dependent prediction, possibly indicating molecular degradation. It is quite likely that some machine components, which were designed using the effective viscous properties derived from a larger scale film thickness measurement, are operating with substantially lower film thickness than the designer had intended.

Klíčová slova anglicky

Elastohydrodynamic; Film thickness; EHL; Rheology

Vydáno

2008-12-03

Nakladatel

Springer

ISSN

1023-8883

Časopis

Tribology letter

Ročník

33

Číslo

X

Strany od–do

1–9

Počet stran

9

BIBTEX


@article{BUT48047,
  author="Ivan {Křupka} and Martin {Hartl}",
  title="An Experimental Validation of the Recently Discovered Scale Effect in Generalized Newtonian EHL",
  journal="Tribology letter",
  year="2008",
  volume="33",
  number="X",
  pages="1--9",
  issn="1023-8883"
}