Free boundary of lubricant film in ferrofluid journal bearings

Kuzhir, Pavel

doi:10.1016/j.triboint.2007.07.006

Cited by 42 publications

(19 citation statements)

References 18 publications

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“…Then, its mechanical properties, such as its capacity or its stiffness can be studied. Further dynamic studies could also be carried out with a perturbation method from this rest position [37]. Figure 3 represents the magnetic pressure layer of the ferrofluid seal.…”

Section: Assumptionsmentioning

confidence: 99%

Mechanical Properties of a Ferrofluid Seal: Three-Dimensional Analytical Study Based on the Coulombian Model

Lemarquand

2009

PIER B

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Abstract-This paper presents a general method for studying the mechanical properties of a ferrofluid seal by using a three-dimensional analytical approach based on the coulombian model of a magnet. The fundamental Maxwell's equations lead us to define the concept of magnetic energy of the ferrofluid seal by using only the threedimensional equations of the magnetic field created by ring permanent magnets radially magnetized. Our study corresponds to the specific case when the ferrofluid is submitted to a very high magnetic field. Under these conditions, we assume that the mechanical properties of the ferrofluid depend only on the magnetic field created by the permanent magnets. Throughout this paper, the remanence polarization J of the magnets used is higher than 1 T. The magnetic field we use in order to align the magnetic particles is very intense, greater than 400 kA/m. Consequently, the magnetic particles are assumed to be saturated and the magnetic field they create can be omitted. In this paper, a cylindrical structure consisting of two outer ring permanent magnets radially magnetized and an inner nonmagnetic cylinder is considered. In addition, a ferrofluid seal is placed between them. The calculation of the magnetic pressure of the ferrofluid seal has been analytically established in three dimensions in order to determine its shape. Moreover, the geometrical evolution of the ferrofluid seal shape is presented when the inner non-magnetic cylinder crushes the ferrofluid seal. The radial stiffness of the ferrofluid seal is determined in three dimensions when the inner cylinder is decentered. Furthermore, a way of obtaining the ferrofluid seal static capacity is discussed.

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Section: Assumptionsmentioning

confidence: 99%

Mechanical Properties of a Ferrofluid Seal: Three-Dimensional Analytical Study Based on the Coulombian Model

Lemarquand

2009

PIER B

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“…This is completely opposite to the performance of the hydrodynamic journal bearing lubricated with ferrofluid that has received significant attention recently. 26–33…”

Section: Introductionmentioning

confidence: 99%

Load and stiffness of a planar ferrofluid pocket bearing

Lampaert

Spronck

Ostayen

2017

Proceedings of the Institution of Mechanical Engineers, Part J:

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A ferrofluid pocket bearings is a type of hydrostatic bearing that uses a ferrofluid seal to encapsulate a pocket of air to carry a load. Their properties, combining a high stiffness with low (viscous) friction and absence of stick-slip, make them interesting for applications that require fast and high precision positioning. Knowledge on the exact performance of these types of bearings is up to now not available. This article presents a method to model the load carrying capacity and normal stiffness characteristics of this type of bearings. Required for this is the geometry of the bearing, the shape of the magnetic field and the magnetization strength of the fluid. This method is experimentally validated and is shown to be correct for describing the load and stiffness characteristics of any fixed shape of ferrofluid pocket bearing.

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“…Yan [12,13] has found that the solid lubricant like polymer compound can improve the lubricating performance of MRF. Kuzhir [14] believed that the existence of large particles is more serious reasons for wear and tear. Even though the above research has made breakthrough progress to a certain extent, there is a very little attention given to finding the effect of solid lubricants with different hardness on the MRF friction performance.…”

Section: Introductionmentioning

confidence: 99%