Magnetorheological Fluid-Based Seal

Abstract

The present experimental work has been done to study the characteristics of the simplest one-step magnetofluid seal (MFS) of the rotary shaft in which the MR fluid (MRF) serves as a sealing medium. The experiments show that the characteristics of the MRF-based seal differ very much from those of the ferrofluid (FF)-based one. In the static regime (stationary shaft), all other things being equal, the MRF holds an approximately three-fold pressure drop. The distinguishing feature of the functioning of such a seal is revealed and lies both in sharply elevating the pressure drop in the dynamic regime (rotary shaft) as against the static one and in having a maximum on the dependence of the pressure drop on the shaft rotation speed. In this regime, the MRF efficiency grows almost by the order of magnitude. However, the seal under study has an increased friction torque due to the growth of the shear stress of the MRF volume subject to shearing in the magnetic field.