Effect of EHL Contact Conditions on the Behavior of Traction Fluids

Webster, M. N.; Lee, Gordon H.; Chang, L.

doi:10.1080/10402000600815016

Cited by 9 publications

(10 citation statements)

References 8 publications

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“…These observations suggest that the cross-film shear localization is an active mechanism of the dramatic reduction of the EHL traction and may be linked to the experimental observations in Willermet, et al (3) and Webster, et al (4). Data in Webster, et al (4) show that the dramatic reduction is often accompanied by significant fluctuations in the traction curve as the data are collected in the experiments. This fluctuation suggests that the reduction is likely to result from some unstable effects, which are often the characteristics of non-uniform, local phenomena.…”

mentioning

confidence: 50%

“…Table 1 lists the input parameters common to the problems studied. These parameters are similar to those used in the experiments of Webster, et al (4). Figure 1 shows the viscosity and pressure-viscosity coefficient as functions of the temperature for the highest viscosity lubricant (polybutene C) used in Webster, et al (4).…”

Section: Mathematical Modelmentioning

confidence: 87%

“…The above assertion of hydrodynamics has gained support from Webster, et al (4) who studied the traction behavior of polybutenes and other high-viscosity lubricants. They attempted to correlate their experimental data to the regime of lubrication.…”

Section: Introductionmentioning

confidence: 88%

“…These parameters are similar to those used in the experiments of Webster, et al (4). Figure 1 shows the viscosity and pressure-viscosity coefficient as functions of the temperature for the highest viscosity lubricant (polybutene C) used in Webster, et al (4). The viscosity is determined by a capillary viscometer and the pressure-viscosity coefficient by back-calculation from optical EHL film thickness measurements using the equation by Hamrock and Dowson (11).…”

Section: Mathematical Modelmentioning

confidence: 97%

“…The energy equation, Eq. [4], used in the model includes the heating associated with the compression of the lubricant. This heat generation may become important in near rolling contacts in which the heat generated by surface sliding is relatively small.…”

Section: Mathematical Modelmentioning

confidence: 99%

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On the Mechanisms of the Reduction in EHL Traction at Low Temperature

Chang

Webster

et al. 2006

Tribology Transactions

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Various experiments have revealed a dramatic traction reduction in elastohydrodynamic lubrication (EHL) contacts under subambient temperatures or with fluids of high viscosity and high pressure-viscosity coefficients. This paper conducts a systematic theoretical analysis to identify and analyze the mechanisms of this reduction. A thermal EHL model is used for the analysis that is capable of capturing many possible effects, including a thermally induced cross-film shear localization within the EHL film. The analysis is carried out for a wide range of ambient viscosity and pressure-viscosity coefficients. The results and analysis suggest that the thermal effects are responsible for the dramatic reduction of the EHL traction. Two thermal effects become particularly pronounced with high viscosity and high pressure-viscosity coefficients. One is the lubricant re-circulation induced inlet shear that generates and accumulates heat in a prolonged inlet region and significantly increases the film temperature in the region of high pressure. The other is the thermally induced cross-film shear localization that generates high temperature in a small central layer of the EHL film.

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mentioning

confidence: 50%

Section: Mathematical Modelmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 88%

Section: Mathematical Modelmentioning

confidence: 97%

Section: Mathematical Modelmentioning

confidence: 99%

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On the Mechanisms of the Reduction in EHL Traction at Low Temperature

Chang

Webster

et al. 2006

Tribology Transactions

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Effects of thermally induced inhomogeneous shear and surface thermal boundary conditions on the shear stress in sliding elastohydrodynamic contacts

Chang

2009

Lubrication Science

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Numerous research work has shown that signifi cant thermally induced cross-fi lm inhomogeneous shear or thermal shear localisation may be developed in sliding elastohydrodynamic lubrication (EHL) contacts with pronounced consequences. This paper uses the theoretical framework established in previous research to further analyse the effects of the shear localisation on the lubricant shear stress and thus the EHL traction. Results obtained suggest that the shear localisation signifi cantly accelerates the thermally induced reduction of the shear stress in sliding EHL contacts. The study also shows dramatic reduction of the shear stress in EHL contacts with one-insolated surface, which is signifi cantly attributed to the more intensifi ed thermal shear localisation near the insolated surface. The practical signifi cance of the dramatic shear stress reduction is discussed.

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Effect of Film Thickness on Slip and Traction Performances in Elastohydrodynamic Lubrication by a Molecular Dynamics Simulation

Shi

Wang

et al. 2021

Tribol Lett

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Effect of EHL Contact Conditions on the Behavior of Traction Fluids

Cited by 9 publications

References 8 publications

On the Mechanisms of the Reduction in EHL Traction at Low Temperature

On the Mechanisms of the Reduction in EHL Traction at Low Temperature

Effects of thermally induced inhomogeneous shear and surface thermal boundary conditions on the shear stress in sliding elastohydrodynamic contacts

Effect of Film Thickness on Slip and Traction Performances in Elastohydrodynamic Lubrication by a Molecular Dynamics Simulation

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