Elastohydrodynamic lubrication properties and friction behaviors of several ester base stocks

He, Yiqian; Zolper, Thomas J.; Liu, Pinzhi; Zhao, Yuzhen; He, Xingyao; Shen, Xuejin; Sun, Hongwei; Duan, Qinghua; Wang, Qian

doi:10.1007/s40544-015-0090-6

Cited by 29 publications

(11 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Squalane (2,6,10,15,19,23-hexamethyltetracosane) is a linear C 24 alkane with six methyl branches that has commonly been employed as a model lubricant in both experiments and NEMD simulations. [38][39][40] Bis [2-ethylhexyl]decanedioate or diethylhexyl sebacate (DEHS) is an example of a synthetic ester oil 41 and its alkyl groups can be varied in order to modify its friction behaviour. 3…”

Section: Tribometer Experimentsmentioning

confidence: 99%

On the effect of confined fluid molecular structure on nonequilibrium phase behaviour and friction

Ewen

Gattinoni

Zhang

et al. 2017

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

A detailed understanding of the behaviour of confined fluids is critical to a range of industrial applications, for example to control friction in engineering components. In this study, a combination of tribological experiments and confined nonequilibrium molecular dynamics simulations has been used to investigate the effect of base fluid molecular structure on nonequilibrium phase behaviour and friction. An extensive parameter study, including several lubricant and traction fluid molecules subjected to pressures (0.5-2.0 GPa) and strain rates (10-10 s) typical of the elastohydrodynamic lubrication regime, reveals clear relationships between the friction and flow behaviour. Lubricants, which are flexible, broadly linear molecules, give low friction coefficients that increase with strain rate and pressure in both the experiments and the simulations. Conversely, traction fluids, which are based on inflexible cycloaliphatic groups, give high friction coefficients that only weakly depend on strain rate and pressure. The observed differences in friction behaviour can be rationalised through the stronger shear localisation which is observed for the traction fluids in the simulations. Higher pressures lead to more pronounced shear localisation, whilst increased strain rates lead to a widening of the sheared region. The methods utilised in this study have clarified the physical mechanisms of important confined fluid behaviour and show significant potential in both improving the prediction of elastohydrodynamic friction and developing new molecules to control it.

show abstract

Section: Tribometer Experimentsmentioning

confidence: 99%

On the effect of confined fluid molecular structure on nonequilibrium phase behaviour and friction

Ewen

Gattinoni

Zhang

et al. 2017

Phys. Chem. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…Although less viscous lubricants are considered more fuel economy, it also risks bringing about more asperity contacts, causing high friction and wear. The theoretical minimum lubricant lm thickness of the tribopairs has been evaluated via the widely used Hamrock-Dowson equation (as displayed in Appendix A1 [36,37]. Figure 5(c) illustrates the plots of the calculated theoretical minimum lubricant lm thickness.…”

Section: Resultsmentioning

confidence: 99%

Achieving Macroscale Liquid Superlubricity Using Lubricant Mixtures of Glycerol and Diols

Wang

Dong

2021

Preprint

View full text Add to dashboard Cite

Friction and wear are ubiquitous in moving mechanical systems, and achieving vanishing friction and wear could significantly improve energy efficiency and extend the service life of mechanical components. In this paper, various diols, viz. ethylene glycol (EG), 1,3-propanediol (13-PD), and 1,2-propdiol (12-PD), have been selected to be mixed with glycerol for superlubricity performance. The results show that the lubricant mixture of EG and glycerol (EG/glycerol) and the mixture of 13-PD and glycerol (13-PD/glycerol) are effective in providing superlow friction (COF < 0.01) for steel tribopairs under ambient atmosphere environment with little surface damage caused. However, 12-PD, which exhibits the same chemical formula as 13-PD except for the configuration of hydroxyl groups, is ineffective for superlubrication. Furthermore, compared with 13-PD, EG is more efficient in preparing superlubric lubricants. Experimental and molecular dynamics simulation results show that the superlow friction realized by the lubricant mixtures of glycerol and diols is related to their intermolecular hydrogen-bonding interaction and the adsorbed formation of adsorbed molecular layers. The intermolecular interaction could affect the rheological property of lubricant mixtures and the hydrodynamic lubricant film-forming capability at the interface, while the quality of the adsorbed molecular layers determines the passivating efficiency for asperity interactions between opposite surfaces. Due to the atomic structure difference, EG is the most desirable diol for this objective, followed by 13-PD, while 12-PD is ineffective. These findings could help enable the rational design of novel lubricants for superlubricating performance and push the development of liquid superlubricity for future engineering applications.

show abstract

“…Since the last century, Meng et al [10] and Cousseau et al [11] found that the colloidal dispersion system of lubricating grease will be destroyed at high temperature. Some scholars [12][13][14] believe that ageing is the decisive factor in grease failure, including oxidation deterioration, increase in acidity and viscosity, destruction of soap crystal structure, increase in oil separation, etc. The thermal-induced changes in the viscoelastic response of lubricating greases have been investigated by using different rheological techniques in a temperature range of 0-175 °C [15].…”

Section: Introductionmentioning

confidence: 99%

Effect of grease on bearing vibration performance caused by short-time high-temperature exposure

Xiong

et al. 2019

J Braz. Soc. Mech. Sci. Eng.

View full text Add to dashboard Cite

A short-time high-temperature environment is a common working condition in the use of bearings; it can occur as rapid heating before interference assembly of a bearing, or in a quick shutdown due to failure and heating of other parts of equipment. However, the current research mainly focuses on the influence of long-term high temperatures on bearing lubrication. In this paper, the 6204DDU ball bearing with lithium soap/mineral oil (paraffin base type) grease and fatty acid soap/mineral oil (refined white oil) grease (white grease) is investigated. The recovery performance of the two greases after a short-time high temperature is studied. It is found that a large number of fractures occur in the soap fibre of the white grease after 20 min exposure in 140 °C temperature environments, while lithium grease remains in a good working condition. The vibration velocity with white grease decreases during a temperature falls from 110 °C to the heated balanced temperature, while the vibration velocities with lithium grease is without significant fluctuations. Before and after heating, the vibration velocities in middle frequency band of rolling bearings with lithium grease and white grease increase with the increase in preload, but it is the opposite in the high frequency band except for white grease after heating condition. Infiltration with a small amount of water or oil can greatly affect the performance of white grease. Water can emulsify the white oil and accelerates the oxidation of white grease. The structure of the L-AN32 oil contaminant is different from that of white oil, resulting in uneven dispersion of saponified crystals and obvious flocculent agglomeration is presented.

show abstract

Elastohydrodynamic lubrication properties and friction behaviors of several ester base stocks

Cited by 29 publications

References 33 publications

On the effect of confined fluid molecular structure on nonequilibrium phase behaviour and friction

On the effect of confined fluid molecular structure on nonequilibrium phase behaviour and friction

Achieving Macroscale Liquid Superlubricity Using Lubricant Mixtures of Glycerol and Diols

Effect of grease on bearing vibration performance caused by short-time high-temperature exposure

Contact Info

Product

Resources

About