Characterization of Magnetorheological Suspension for Seal

Abstract

Magnetorheological suspension (MRS) dispersing spherical several gm of iron particles in the low vapor pressure of dimethylpolysiloxane has been prepared. Yield stress has been proportional to square of magnetic field intensity and increases as containing larger volume fraction of iron particles and using solvent that is more viscous. The plastic viscosity increased linearly as a function of volume fraction of iron particles. The burst pressure of MRF seal is related on the dispersed iron particle size. The burst pressure is related on the magnetization curve in the MRS dispersing less than several gm of iron particles. On the other hand, the surface tension of solvent influences on the burst pressure in the MRS dispersing more than several gm of iron particles. Also the burst pressure is affected on the seal gap. In the large gap, the burst pressure in stationary condition adds the pressure by the yield stress of MRS. However, in the small gap the burst pressure of rotating condition is almost the same as that of stationary condition because the arranged iron particles cannot be reconstructed in a small gap. The larger viscosity of solvent and volume of iron in MRS increases the burst pressure.

Smart sealing for magnetorheological fluid actuators

“…A closer look at the structure of the MRF sealing reveals the reason for the leakage. The dynamic pressure of a MRF sealing consists of two components, as investigated in Fujita et al (1999). On one hand, the dynamic pressure is based on the magnetically induced yield stress of the particle chains.…”

Physical characteristics of magnetorheological suspensions and their applications

“…The distance d between the magnetic poles and rotary shaft was fixed from 0.06 mm to 0.5 mm and from 1 mm to 1.7 mm, respectively. Fujitu et al [131] reported that the yield stress of MR suspension was proportional to the square of the magnetic field intensity and increased linearly with increasing volume fraction of iron particles and through the use of a more viscous solvent. In addition, the burst pressure of the MR suspension seal was reported to be related to the dispersed iron particle size.…”

“…The magnitude of M s was determined by Fujitu et al [131] after achieving a magneto-fluidic composite. This includes iron microparticles and nanoparticles dispersed in a solvent (dimethyl polysiloxane).…”

The Recent Advances in Magnetorheological Fluids-Based Applications

“…The study showed that critical pressure is proportionally related to the square of the applied magnetic field strength. Fujita et al [57] showed that the burst pressure of the seal is a function of size and the volume fraction of MRFs.…”