High-Speed Elastohydrodynamic Lubrication by a Dilute Oil-in-Water Emulsion
| Autor: | Leon Jacobs, Christophe Pelletier, Joslyn Hili, Andy Olver, Tom Reddyhoff |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Materials science
Mechanical Engineering medicine.medical_treatment 02 engineering and technology Surfaces and Interfaces Traction (orthopedics) 021001 nanoscience & nanotechnology Surfaces Coatings and Films Oil in water 020303 mechanical engineering & transports 0203 mechanical engineering Low speed Mechanics of Materials Phase composition Phase (matter) Emulsion Lubrication medicine Mechanical Engineering & Transports Composite material 0210 nano-technology Infrared microscopy 0913 Mechanical Engineering |
| Zdroj: | Tribology Transactions. 61:287-294 |
| ISSN: | 1547-397X 1040-2004 |
| DOI: | 10.1080/10402004.2017.1323146 |
| Popis: | When a concentrated contact is lubricated at low speed by an oil-in-water emulsion, a film of pure oil typically separates the surfaces (Stage 1). At higher speeds, starvation occurs (Stage 2) and the film is thinner than would be expected if lubricated by neat oil. However, at the very highest speeds, film thickness increases again (Stage 3), though little is known for certain about either the film composition or the mechanism of lubrication, despite some theoretical speculation. In this paper, we report the film thickness in a ball-on-flat contact, lubricated by an oil-in-water emulsion, at speeds of up to 20 m/s, measured using a new high-speed test rig. We also investigated the sliding traction and the phase composition of the film, using fluorescent and infrared microscopy techniques. Results show that, as the speed is increased, starvation is followed by a progressive change in film composition, from pure oil to mostly water. At the highest speeds, a film builds up that has a phase composition similar to the bulk emulsion. This tends to support the "micro-emulsion" view rather than the “dynamic concentration” theory. |
| Databáze: | OpenAIRE |
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