Steady shear flow of magnetic fiber suspensions: theory and comparison with experiments

Gomez-Ramirez Ana (1) , Pavel Kuzhir (2) , Modesto Lopez-Lopez (1) , Georges Bossis (2) , Alain Meunier (2) , Durán Juan D.G. (1)

1 Departamento de Fisica Aplicada [Granada]
2 LPMC - Laboratoire de physique de la matière condensée

This paper is focused on the rheology of magnetic fiber suspensions in the presence of a magnetic field applied perpendicular to the flow. At low Mason numbers, Mn<0.1, the experimental flow curves show a steep initial section corresponding to the inclination and stretching of the gap-spanning aggregates formed upon magnetic field application. At higher Mason numbers, aggregates no longer stick to the walls and the flow curves reach a Bingham regime, with the dynamic yield stress growing with the magnetic field intensity. This yield stress appears to be about three times higher for the fiber suspensions than for the suspensions of spherical particles. Such difference, measured at relatively low magnetic field intensities, H0<30 kA/m, is explained in terms of the enhanced magnetic susceptibility of the aggregates composed of fibers compared to the aggregates composed of spherical particles. For weak magnetic fields, the forces of solid friction between fibers are expected to play a minor role on the stress level of the suspension. In order to confirm these findings, we propose a new theoretical model, taking into account hydrodynamic interactions. The flow curve and the yield stress predictions are in a good agreement with the experimental results for semi-diluted suspensions.

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

Gomez-Ramirez Ana, Pavel Kuzhir, Modesto Lopez-Lopez, Georges Bossis, Alain Meunier, et al.. Steady shear flow of magnetic fiber suspensions: theory and comparison with experiments. Journal of Rheology, 2011, 55, pp.43. ⟨10.1122/1.3523477⟩. ⟨hal-00558960⟩