Accurate Measurements of Pressure-Viscosity Behavior in Lubricants

Bair, Scott; Qureshi, Farrukh

doi:10.1080/10402000208982564

Cited by 65 publications

(47 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…(7) are determined by enforcing the continuity of both g and dg/dp at p = p a and p = p b . The good agreement between the measurements, which are performed using a high-pressure viscometer [43], and the predictions of Eq. (7) is observed in Fig.…”

Section: Resultsmentioning

confidence: 98%

Determination of the accelerated RCF operating condition of the sun-planet contact of a tractor final drive using a computational method

Wagner

2016

Meccanica

View full text Add to dashboard Cite

This study proposes a computational approach to determine the operating condition, under which the rolling contact fatigue (RCF) crack nucleation of the sun-planet mesh of a tractor final drive is accelerated. Although the experimental RCF time period can be reduced by increasing the rotational velocity, the resultant increase in the film thickness promotes the lubrication condition and thus lengthens the fatigue life. To counteract this fatigue performance variation, it is proposed to increase the lubricant temperature at the same time. In the process, the lubricant viscosity decreases and offsets lubrication film thickness increase introduced by the rotational velocity increase. A physics-based gear contact fatigue model that includes the descriptions of the mixed elastohydrodynamic lubrication, the multiaxial stresses and the multi-axial fatigue is used to quantify the impacts of the lubricant temperature and the rotational velocity on the crack formation, allowing the fine tune of the temperature and velocity parameters.

show abstract

Section: Resultsmentioning

confidence: 98%

Determination of the accelerated RCF operating condition of the sun-planet contact of a tractor final drive using a computational method

Wagner

2016

Meccanica

View full text Add to dashboard Cite

show abstract

“…These definitions and calculations assume that Blok's integral will converge for the liquid, a fact not in evidence. These measured values are substantially lower than pressure-viscosity coefficients usually measured for common hydrocarbon oils that are usually in the range of 15-25 Gpa −1 at room temperature [23,37,38]. The pressure-viscosity coefficients of [Choline] [Proline] are also compared to some other ionic liquids [39][40][41][42][43][44][45], summarized in [46] and shown in Table 4 .…”

Section: Resultsmentioning

confidence: 99%

“…The measurements were conducted at the Center for High-Pressure Rheology at Georgia Institute of Technology following the procedure described in [23]. Because of the low shear stress used in these stress-controlled measurements, the viscosities may be considered to be the limiting-low-shear viscosities.…”

Section: Limiting Low Shear Measurements and Pressure-viscosity Calcumentioning

confidence: 99%

Elastohydrodynamic Performance of a Bio-Based, Non-Corrosive Ionic Liquid

Björling

Bair

et al. 2017

Applied Sciences

Self Cite

View full text Add to dashboard Cite

Abstract:To improve performance of machine components, lubrication is one of the most important factors. Especially for use in extreme environments, researchers look for other solutions rather than common lubricant base stocks like mineral oils or vegetable oils. One such example is ionic liquids. Ionic liquids have been defined as molten salts with melting points below 100 • C that are entirely ionic in nature, comprising both cationic and anionic species. The industrial use of ionic liquids is mostly as solvents, electrolytes, extractants and catalysts. In tribological applications, ionic liquids are mainly studied in boundary lubrication and in pure sliding contacts. In this work, the elastohydrodynamic performance of a bio-based, non-corrosive, [choline][L-proline] ionic liquid is evaluated in terms of pressure-viscosity response, film forming capability and friction. The results show a pressure-viscosity coefficient of below 8 GPa −1 at 25 • C, among the lowest reported for any ionic liquid. The ionic liquid generated up to 70% lower friction than a reference paraffin oil with a calculated difference in film thickness of 11%. It was also shown that this ionic liquid is very hygroscopic, which is believed to explain part of the low friction results, but also has to be considered in practical applications since the water content will influence the properties and thus the performance of the lubricant.

show abstract

“…The LVDT (Schaevitz XSA-253) surrounds the entire assembly. 1 The sinker used in this study is of the "cup" style explained in [23], with an outside diameter of 6.17 mm, and is guided by four pads, 1 mm 2 , arranged in a cruciform pattern about each end. The removable cartridge incorporates an o-ring sealed piston for volume compensation.…”

Section: Instrument Descriptionmentioning

confidence: 99%

“…The viscometer employed in this study is of the guided falling-cylinder type and has been described in [23,24]. The position of the magnetic sinker (AISI O1 tool steel) is continuously detected by a linear variable differential transformer (LVDT).…”

Section: Instrument Descriptionmentioning

confidence: 99%

High-Pressure Viscosity Measurements of 1,1,1,2-Tetrafluoroethane

Laesecke

Bair

2011

Int J Thermophys

Self Cite

View full text Add to dashboard Cite

Viscosity measurements have been carried out with a falling-cylinder instrument in the compressed liquid and supercritical regions of the hydrofluorocarbon 1,1,1,2-tetrafluoroethane (R134a). A highly pure sample was used. The measurement region at temperatures from 293.15 K to 438.15 K with pressures from 10 MPa to 400 MPa extends the existing data range substantially. With estimated uncertainties of 3.5 % for viscosity, the greater of 1 MPa or 0.5 % for pressure, and 0.4 K for temperature, the new results can be used to reconcile inconsistencies between literature data sets. They also provide a test of the extrapolation capability of existing viscosity correlations for this fluid and enable the development of a more accurate and wider ranging formulation.

show abstract

Accurate Measurements of Pressure-Viscosity Behavior in Lubricants

Cited by 65 publications

References 14 publications

Determination of the accelerated RCF operating condition of the sun-planet contact of a tractor final drive using a computational method

Determination of the accelerated RCF operating condition of the sun-planet contact of a tractor final drive using a computational method

Elastohydrodynamic Performance of a Bio-Based, Non-Corrosive Ionic Liquid

High-Pressure Viscosity Measurements of 1,1,1,2-Tetrafluoroethane

Contact Info

Product

Resources

About