Negative Magneto-Rheological Effect of a Dispersion Composed of Spindle-Like Hematite Particles

Control of the orientational characteristics of disk-like hematite particles by a simple shear flow

“…A suspension composed of hematite particles exhibit characteristic magneto-rheological properties completely different form those of ordinary ferromagnetic particles (Ozaki et al, 1988;Ozaki and Matijević, 1985;Varanda et al, 2001). That is, this suspension exhibits negative magneto-rheological effects in a certain situation of an applied magnetic field, which has already been verified by an experimental study using a cone-plate-type rheometer (Satoh and Ozaki, 2006;Satoh and Sakuda, 2007;Satoh, 2013;Sakuda et al, 2012). From this background, we understand that it is important to conduct a systematic series of studies in order to investigate the behaviors of non-spherical magnetic particles, which may be lead to new Satoh, Mechanical Engineering Letters, Vol.2 (2016) [DOI: 10.1299/mel.…”

Brownian dynamics simulation of a dispersion composed of disk-like hematite particles regarding aggregation phenomena

“…This negative magneto-rheological effect was theoretically predicted from the theory based on the orientational distribution function in a simple shear flow [23][24][25]. Quite recently, by performing an experiment using a cone-plate type rheometer, we have succeeded in experimentally verifying that the negative magneto-rheological effect arises in an actual situation [26]. Our research group has been investigating an effective technique for control of the characteristic aggregate structures and negative magneto-rheological effect.…”

Brownian dynamics simulation of a dispersion composed of disk-like hematite particles regarding the orientational distribution and the magneto-rheological properties

“…Moreover, the theoretical analysis based on the orientational distribution function had shown that a needle-like hematite particle suspension can exhibit a negative viscosity effect in certain situations [37,39,45]: the negative viscosity effect occurs when the viscosity component due to the magnetic properties of the particles becomes negative, but it is noted that the net viscosity of the fluid remains positive. From an experimental study using a cone-plate type rheometer, the predicted negative viscosity effect has been observed to arise in a sample suspension of hematite particles [46]. We therefore have been attempting the development of effective control techniques in regard to the characteristic aggregate structures and the negative magnetorheological effect.…”