The dielectric spectrum and the electrorheological effect in suspensions of varying conductivity -: Part 2.: Modeling of the electrorheological effect

In this part, attention is given to the electrorheological effect of suspensions of polarizable particles in three different liquids of varying conductivity. The electrorheological properties of the suspensions are analyzed with a kinetic model that describes the flow-induced modification of the structures formed by the particles under de electric fields. Under quiescent conditions, the model describes the variation of viscosity of the suspension with the electric field and particle concentration, as well as the change in the yield stress with electric field. The effect of non-linear conductivity is introduced in the model to account for the trend towards saturation observed in the viscosity at high electric fields and particle concentration. Furthermore, the contribution of non-linear conduction in the model allows the prediction of the yield stress at high electric fields. The model further describes the variation of viscosity with shear rate under a given electric field, and time-dependent phenomena arising from the dynamics of the breakage-reformation process of the structures. (c) 2007 Elsevier B.V. All rights reserved.