Magnetocaloric Fluids - Magnetocaloric Energy Conversion: From Theory to Applications - page 180

(continued)
Title A new generation of magneto-rheological fl uid dampers

(Gordanlnejad et al. [ 79 ])
dependent yield stress. In the case when the yield stress is to high
(pre-yield region), MRPG behaves as a viscoelastic solid, and
therefore, the shear below the yield stress was given by the complex
material modulus and the shear strain, which was also eld
dependent. The dynamic yield stress increased signi cantly with an
increase in magnetic flux density. Authors applied the Ginder ' s
model (Eqs. 5.26 - 5.28 ) for the yield stress

Viscosity Apparent viscosity was derived by the ratio between shear stress and

shear rate, and decreased with increasing shear rate, which show the
shear-thinning behaviour and it appears due to the presence of
micron-sized particles. At higher shear rates the apparent viscosity
decreases and then reaches a constant value

Title Magnetorheology of submicron diameter iron microwires dispersed

in silicone oil (Bell et al. [ 80 ])

Materials used for
investigation

Magnetorheological uid containing iron microwires with 260 nm

diameter and two distinct length distributions of 5.4

fl

± 5.2 μ m and

7.6 m suspended in silicone oil (0.45 Pa s). The micro-wire-

based suspensions compared to spherical suspensions lead to higher
yield stresses at low magnetic elds. The sedimentation effect can be
also substantially reduced compared to conventional MR

± 5.1 μ

uids.
However, maximum volume fraction of microwires was much less
than the desired 30

fl

40 vol% achievable with spherical particles.
Authors conclude that suspensions comprised of microwires are
more useful in applications where sedimentation would be extremely
detrimental and low yield stresses are suf cient

-

Constitutive model Authors applied the Bingham model (Eq. 5.14). For microwire-based

suspensions, the trend in the yield stress data was found to be
proportional to the square root of the applied eld

Title Viscosity behaviour of magnetic suspensions in fl uid-assisted

nishing (Cheng et al. [ 81 ])

Materials used for
investigation

Magnetic suspensions of micrometre-sized carbonyl iron (CI)
particles with and without abrasive cerium oxide (CeO 2 ) particles are
studied for their ensuing polishing effectiveness. Volumetric com-
ponent ratios of the magnetorheological fluid in the study were
33.84 % CI particles, 57.34 % silicone oil, 2.82 % stabilizing agent,
and 6 % CeO 2 as abrasive particle

Constitutive model Authors applied the Bingham model (Eq. 5.14)

Viscosity The relation between the magnetic intensity H and the viscosity ʿ f

the fl uid was taken from Shulman et al. [ 82 ]

Title Synthesis and magnetorheology of suspensions of submicron-sized

cobalt particles with tunable particle size (Lopez et al. [ 83 ])

Synthesized cobalt powders with diameters in the range 50 nm - 1 μ m
were used for the preparation of MR suspensions (solid concentra-
tion 5 vol%). These suspensions were prepared by dispersing
(continued)

Materials used for
investigation