Starvation Phenomena in E.H.L. Point Contacts: Influence of Inlet Flow Distribution.

Chevalier, Florian; Lubrecht, Antonius; Cann, P. M.; Colin, François; Dalmaz, G.

doi:10.1016/s0167-8922(08)70785-5

Cited by 29 publications

(28 citation statements)

References 7 publications

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“…2 (lower profile) is very different to the fully flooded case as the minimum is in the centre of the contact, while the thickness at the sides is close to the fully flooded level [10]. The passage of the ball pushes most of the oil to the side of the track and thus the distorted film shape reflects the oil distribution in the inlet region [10,11].…”

Section: Starved Fluid Film Ehlmentioning

confidence: 96%

Thin-film grease lubrication

Cann

1999

Proceedings of the Institution of Mechanical Engineers, Part J:

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One of the most important examples of the thin-film regime is in the grease lubrication of rolling element bearings. Grease lubrication is not usually considered in this context and yet there is considerable evidence that many bearings operate under starved conditions where the film thickness drops to a fraction of the fully flooded value. Thus it is the mechanisms of lubricant supply and film formation in the starved regime that are important in ensuring the successful operation of a bearing. The aim of this paper, therefore, was to explore grease lubrication from a thin-film perspective and to examine the many factors that could influence starved film formation. Much of the current understanding in this area is derived from studies of starved fluid film lubrication and this provides a convenient starting point for the discussion. Grease lubrication is considered as a replenishment problem and recent experimental work is presented illustrating some of the aspects discussed in the text. The effect of grease properties, bearing operation and design on film formation is examined. Grease lubrication in the thin-film regime is a complex problem. It includes aspects of non-Newtonian rheology, surface chemistry, capillary flow and starved elastohydrodynamic lubrication (EHL). All of these aspects need to be resolved in any future model that will be capable of explaining and predicting grease lubricating behaviour in bearings.

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Section: Starved Fluid Film Ehlmentioning

confidence: 96%

Thin-film grease lubrication

Cann

1999

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…Theoretical models for point contact-starved lubrication were investigated by Ranger et al [4] and Hamrock and Dowson [5], they used small inlet region boundaries to simulate the effect of the reduced pressure generation compared with a fully flooded contact. Based on the study of Elrod [6] and Chevalier et al [7,8] presented a steady-state solution for circular EHL contact with the multilevel method that facilitated the simulation of starvation/cavitation problems as a free boundary problem. And later, Damiens et al [9] studied the starved elliptical EHL contact.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of the Oil-Supply Condition in Isothermal Elastohydrodynamic Lubrication of Finite Line Contacts

Liu

Yang

2010

Tribol Lett

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In order to investigate the effect of oil-supply condition on the lubrication performance of machine components, such as gears and roll bearings, a full numerical solution of the isothermal finite line contact elastohydrodynamic lubrication (EHL) problem under different oil-supply conditions was obtained. The supplied oil quantity was given with the thicknesses of layers of oil films on both solid surfaces, and an equivalent thickness of such supplied oil films was introduced. An algorithm similar to that proposed by Elrod in 1981 was developed to determine the pressure starting position automatically. The pressure field was solved with a multi-grid solver which enables the difficulty of the huge mesh differences in two directions be overcome easily. The surface deformation produced by pressure was calculated with a multilevel multi-integration method. Based on the Newtonian lubricant assumption, comparisons of solutions between the starved and fully flooded contacts have been made. Results show that the pressure starting position and the central and minimum film thicknesses vary with different oil-supply thicknesses. In addition, the influence of the thickness of the oil-supply layer, the end profile radius, the entrainment velocity, and the maximum Hertzian pressure on the starved fluid film thickness has been investigated. In conclusion, the optimum quantity of the supplied oil is very important for the discussed problem.

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“…4. Nevertheless, it can be inferred from the results of the whole oil pool that oil starvation occurred according to the distance from the inlet region to the Hertzian contact region [20]. It may, however, be noted that oil starvation stems from a lubricant redistribution away from the contact track, originating from the ball passages.…”

Section: Oil Starvationmentioning

confidence: 99%

Experimental Investigation of Lubrication Failure of Polyalphaolefin Oil Film at High Slide/Roll Ratios

et al. 2011

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Lubrication failure of polyalphaolefin (PAO) oil film at high slide/roll ratios of more than 1.9 has been experimentally investigated based on a ball-on-disc configuration. The central film thickness and the oil pool shape in the contact were determined by optical interferometry and fluorescence microscopy, respectively, and the traction coefficient and surface profiles of the tribopairs were measured using a tension-compression sensor and light surface profilometer, respectively. The results demonstrate that the central film in the contact was in the elastohydrodynamic lubrication regime at the initial stage under high slide/roll ratios. Variation in the traction coefficient and the presence of wear scars on the disc surface shows that the sliding speed played an important role in lubrication failure. We propose that a thermal effect explains the obtained results at high slide/roll ratios. The fluorescence technique combined with optical interferometry was also used to gain more understanding of lubrication properties under mixed slide/roll conditions.

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Starvation Phenomena in E.H.L. Point Contacts: Influence of Inlet Flow Distribution.

Cited by 29 publications

References 7 publications

Thin-film grease lubrication

Thin-film grease lubrication

Numerical Analysis of the Oil-Supply Condition in Isothermal Elastohydrodynamic Lubrication of Finite Line Contacts

Experimental Investigation of Lubrication Failure of Polyalphaolefin Oil Film at High Slide/Roll Ratios

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