Sealing mechanism investigation of convergent ferrofluid seals with staggered pole teeth.

To reveal the pressure transfer and the failure mechanism of the convergent ferrofluid seal (CFFS) with staggered pole teeth (SPT), an experiment observation apparatus has been designed to direct monitoring of morphological transformations in the ferrofluid film. The pressure transfer and failure processes of CFFS-SPT during the pressurization process was investigated experimentally. The effects of eccentricity distance of axial pole teeth and magnetic isolation materials on pressure resistance of the seal were investigated. The results indicate that the pressure transfer in the radial chamber of CFFS-SPT is faster than that in the axial chamber. When seal fails, CFFS-SPT experiences micro-leakage and complete leakage stages. Moreover, the change in eccentricity distance of axial pole teeth does not affect the sealing mechanism. • A CFFS-SPT capable of observing changes in the surface shape of the FF film was designed. • There are two forms of CFFS-SPT failure, micro-leakage and complete leakage. • The pressure in radial chamber increases almost simultaneously, while the pressure in axial chamber increases incrementally. • The seal pressure resistance increases as the eccentricity distance of axial pole teeth increases. • This study provides important guidance for the development of FFS with high sealing performance. [ABSTRACT FROM AUTHOR]