Particle Structure Evolution in Micro Flow of Electrorheological Suspensions in Nonuniform Electric Fields

A modified version of the distributed Lagrange multiplier method (DLM) [11] is used to study the dynamics of particle scale structure in electrorheological (ER) liquids subjected to spatially non-uniform electric field (also see [7, 18]). The time duration in which the particles are collected, near the electric field magnitude minimums or maximums, depends on a parameter defined by the ratio of the dielectrophoretic and viscous forces. Another parameter defined by the ratio of the electrostatic particle-particle interaction and dielectrophoretic forces also influences the time duration in which the particles are collected, as when this parameter is greater than one the particles to organize in chains which decreases their speed. The numerical results agree qualitatively with experiments which show that when the electrostatic particle-particle forces dominate the particles form chains that collect near the electrode edges.