MECHANICAL PROPERTIES OF A FERROFLUID SEAL: THREE-DIMENSIONAL ANALYTICAL STUDY BASED ON THE COULOMBIAN MODEL

International audienceThis 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 three-dimensional 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, 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 1T. The magnetic field we use in order to align the magnetic particles is very intense, greater than $400$~kAm$^{-1}$. Consequently, the magnetic particles are assumed to be saturated and the magnetic field they create can be omitted