Mechanical properties of ferrofluid applications: Centering effect and capacity of a seal

This paper presents three-dimensional study of a ferrofluid seal, its centering effect and its static capacity. Thus, a method based on a potential energy criterion has been put forward to study the seal shape. But such a use of ferrofluid seals is interesting only if the magnetic field created by the permanent magnets saturates totally the ferrofluid. Two cylindrical structures consisting of two and three outer ring permanent magnets with an inner non-magnetic cylinder are considered. The calculation of the magnetic pressure of the ferrofluid seal is analytically established.