A dynamic concentration model for lubrication with oil-in-water emulsions

Wilson, W. R. D.; Sakaguchi, Y.; Schmid, Steven R.

doi:10.1016/0043-1648(93)90471-w

Cited by 72 publications

(24 citation statements)

References 9 publications

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“…Some authors have tried to explain the high speed behaviour using the dynamic concentration theory [13,15]. This theory was firstly introduced by Wilson et al [16,17] and applied in subsequent work [18,19]. The basic assumption of the dynamic concentration model is that the oil is preferentially entrained into the inlet zone due to its relatively high viscosity and piezoviscous effects.…”

Section: Introductionmentioning

confidence: 99%

The effect of emulsifier concentration on the lubricating properties of oil-in-water emulsions

et al. 2006

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Although the use of oil-in-water (O/W) emulsions as metalworking fluids is widespread, the mechanisms of emulsion lubrication are not yet well understood. Several theories have been proposed but there is not a clear agreement about the effect of different operating conditions and emulsion properties on the lubricating performance of O/W emulsions. In the present study, the film forming ability of O/W emulsions as a function of emulsifier concentration is studied. The emulsifier content exerts a strong influence on all the emulsion properties, such as stability, droplet size distribution, surface and interfacial tension, wetting ability, etc., as well as on the lubricating behaviour, so it has been used to ascertain the relationship between all the properties involved. Three different emulsifiers-anionic, nonionic and cationic-were used at different concentrations in the design of lubricant O/W emulsions. Experimental results show that the work of adhesion of oil droplets on the metal surface is a valuable parameter to predict the ability of emulsions to form thick films in elastohydrodynamic (EHD) contacts. The influence of pH value of O/W emulsions on their lubricating behaviour is also verified. The overall conclusion is that the interactions between metal and oil droplets rule the mechanism of lubrication and that this interaction is primarily controlled by emulsifier concentration.

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Section: Introductionmentioning

confidence: 99%

The effect of emulsifier concentration on the lubricating properties of oil-in-water emulsions

et al. 2006

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“…The dynamic concentration theory is based on the idea that, once the roll bite traps the oil droplets of the emulsion, the concentration of the oil increases while excluding water in the roll bite. This theory has been widely reported by Kimura et al, 1) Wilson et al 2) and Azushima et al 3) since the 1980s. On the other hand, the plate-out theory is based on the idea that the oil phase in the emulsion is only formed on the strip surface.…”

Section: Introductionmentioning

confidence: 62%

Influence of Plate-out Oil Film on Lubrication Characteristics in Cold Rolling

Fujita¹,

Kimura²

2012

ISIJ International

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Oil-in-water (O/W) emulsions are widely used in tandem cold rolling mills as coolants in order to reduce frictional forces and prevent heat scratches. Although the lubricating properties of O/W emulsions are determined by various factors, two particularly important ones are the amount of plate-out oil on the strip surface and the dynamic concentration mechanics of the emulsion at the inlet of roll bite, which has been a subject of much interest since the 1970s.As many studies have focused only on a single phenomenon, it is important to simulate the interaction of the two phenomena as it occurs in actual cold rolling.In this paper, first, a new method of evaluating the relationship between plate-out oil and lubrication characteristics is proposed, which enables control of plate-out oil before rolling.It was found that rolling force decreased when a plate-out oil film was formed before rolling, but the reduction of rolling force was saturated when the amount of plate-out oil exceeded a certain level. The influence of roughness, the roll coolant, and other factors were also examined using the proposed method. In particular, in tandem cold rolling, it is necessary to consider the influence of plate-out oil carried over by the preceding stand on the lubrication characteristics of the following stand.The results of this research suggest that it is possible to clarify the mechanism of emulsion lubrication using the proposed method.

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“…As there is little pressure increase and the pressureviscosity coefficient of water is low, it can be shown [6] that the oil concentration in the concentration region between x a and the start of the concentration process (see figure 1) follows From x a the hydrodynamic pressure starts to develop and the authors [8] have applied a concentration model based on the extended Reynolds equation of Yan and Kuroda [7]. (1) Inlet zone X a ‡ X ‡ X 1 .…”

Section: Theorymentioning

confidence: 99%

“…Prior to the inlet zone, oil droplets are captured in the conjunction. The effectiveness of the droplet capture process is represented by a capture coefficient, C [6], which defines the film thickness at the starting of the concentration process (h s ) i.e.…”

Section: Theorymentioning

confidence: 99%

“…As most industrial rolling applications operate at much higher speed than this second critical speed, it seems that emulsion lubrication mechanism at the critical speed regime and beyond can be described as a combined capture and concentrate process, for which some concentration theories have been put forward [6,7]. The dynamic concentration model [6] describes emulsion concentration in the gap between the surfaces once droplets are captured in the conjunction. However, as the droplet capture process is not yet fully understood, a proportional constant known as capture coefficient, which ranges from 0.33 to 1, is used.…”

Section: Introductionmentioning

confidence: 99%

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