The influence of ferromagnetic fluids on performance of hydrodynamic bearings
| Autor: | Jaroslav Zapoměl, Petr Ferfecki |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
Ferrofluid
Bearing (mechanical) Materials science Materials Science (miscellaneous) Fluid bearing Mechanics Industrial and Manufacturing Engineering Magnetic flux Reynolds equation law.invention Physics::Fluid Dynamics law Magnetorheological fluid Shear stress Business and International Management Lubricant |
| Zdroj: | Vibroengineering PROCEDIA. 27:133-138 |
| ISSN: | 2538-8479 2345-0533 |
| DOI: | 10.21595/vp.2019.20950 |
| Popis: | The rotors are often mounted in hydrodynamic bearings. To achieve their optimum performance in a wide range of operating speeds, their stiffness and damping parameters must be adaptable to the current angular velocity. This is offered by application of smart fluids sensitive to a magnetic field. The detailed analysis shows that application of ferromagnetic fluids is possible only for small sliding bearings. For bearings, the operation of which requires to generate high pressure, this concept fails. This arrived at the idea to use the ferrofluids-based magnetorheological fluids as a lubricant. This paper deals with the development of a basic concept of such a bearing and with the principle considerations on the magnetic flux generation and its propagation in the bearing housing and the lubricating layer. The developed mathematical model of the bearing was applied for investigation of the influence of changes of the lubricant properties by means of a magnetic field on the vibration attenuation of a rigid rotor excited by unbalance. The pressure distribution in the bearing gap is governed by the Reynolds equation adapted to non-Newtonian lubricant, the yielding shear stress of which depends of magnetic induction. The magnetic flux propagation in the bearing housing is described by the Hopkinson law. The results of the simulations show that the increase of the yielding shear stress of the lubricant by action of a magnetic field rises the bearing load capacity and does not destabilize the rotor vibration. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|