Environmental Engineering Reference
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Fig. 6.26 An example of applying the MHD principle for the contact thermal diode mechanism
6.4.4 Magnetorheology and Electrorheology
Despite the fact that magnetorheology deals with magnetic
fl
uids as well, one
should distinguish between ferro
uids. The latter are
pended any more by Brownian motion. Also, the volume fraction of solid magnetic
particles in the carrier
fl
uids and magnetorheological
fl
uid (mineral or silicone oils, kerosene, water and water
solutions, etc.) can be substantially higher (e.g. 20
-
50 %) than is the case for
ferro
fl
fl
uids. Magnetorheologic
fl
uids can be successfully applied in dampers, brakes,
valves, clutches, etc. [
120
124
]. They are becoming an indispensable part of the
future automotive industry [
120
], aerospace industry, medicine, etc. [
125
]. A spe-
cial research direction is also focused on magnetisable gels (ferrogels) and polymers
[
126
-
128
], which can be designed with nano- or micro-sized particles.
Magnethorheologic (MR)
-
uids exhibit a substantial change in their rheological
properties in an alternating magnetic
fl
eld, the
micron-sized magnetic particles tend to form chain-like structures in the direction of
the magnetic
eld. Under an applied magnetic
eld
(along the channel). The magnetorheologic suspensions behave as non-Newtonian
fl
eld (Fig.
6.27
). This drastically in
fl
uences the axial velocity
uids in the absence of a magnetic
eld. Such
fl
uids are mostly dependent on the
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