On the theory of magnetoviscous effect in magnetorheological suspensions

Andrey Zubarev (1) , L. Iskakova (1) , Modesto Lopez-Lopez (2) , Pavel Kuzhir (3) , Georges Bossis (4)

1 Department of Mathematical Physics
2 Departamento de Fisica Aplicada [Granada]
3 LPMC - Laboratoire de physique de la matière condensée
4 LPMC - Laboratoire de physique de la matière condensée

A theoretical model of magnetoviscous effect in a suspension of non-Brownian linearly magnetizable particles is suggested. A simple shear flow in the presence of an external magnetic field aligned with the velocity gradient is considered. Under the action of the applied field, the particles are supposed to form dense highly elongated drop-like aggregates. Two different scenarios of the aggregates' destruction under shearing forces are considered, namely a "bulk" destruction of aggregates into pieces, and an "erosive" destruction connected to the rupture of individual particles from the aggregate surface. Both models are based on a balance of forces acting either on the whole aggregate or on individual particles. The two approaches lead to qualitatively different Mason number (Ma) behaviors of the magnetic suspensions: the suspension viscosity scales as either Ma^-2/3 for the bulk destruction of aggregates or Ma^-4/5 for the erosive destruction. In any case, we do not recover Bingham behavior (M^a-1) often predicted by chain models of the magneto- or electrorheology. Our theoretical results are discussed in view of comparison with existing theories and experimental results in the wide range of Mason numbers.

Domaines: Mécanique des fluides [physics.class-ph]; Mécanique des fluides [physics.class-ph]

Andrey Zubarev, L. Iskakova, Modesto Lopez-Lopez, Pavel Kuzhir, Georges Bossis. On the theory of magnetoviscous effect in magnetorheological suspensions. Journal of Rheology, 2014, 58, pp.1673. ⟨10.1122/1.4889902⟩. ⟨hal-01073526⟩