Journal of Applied Physics · 1991 · 184 citations · 13 references
Natural SciencesPhysicsElectrochemistryElectromagnetismFluid MechanicsDielectric ResponseDielectricsElectric FieldsElectrical ConductivityIntermolecular ForcesDielectric ConstantDielectric StrengthElectric Field DistributionElectrorheological FluidsElectrostatic InteractionsLaplace EquationLaplace's EquationParticle-particle Interactions
The study develops a model for particle‑particle interactions in chains of spherical particles in electrorheological fluids, expanding the potential to satisfy Laplace’s equation. Using this model, the authors calculate the electric‑field distribution and force‑distance relationship between particles as functions of the dielectric contrast Kp/Kf and interparticle spacing. The calculations show electric‑field concentrations about an order of magnitude higher near contacts, yielding forces roughly ten times stronger than the classical point‑dipole approximation and aligning with experimental measurements, while also revealing subtle carrier‑fluid effects that explain the non‑Ohmic behavior of ER fluids.
A model for the particle-particle interaction in a chain of spherical particles in an electrorheological (ER) fluid is developed based on an expansion of the potential which satisfies the Laplace equation. The electric-field distribution and force-distance relationship between particles are calculated as a function of Kp/Kf (the dielectric constant of the sphere relative to that of the medium) and particle-particle spacing using this model. The calculations predict electric-field concentrations of about an order of magnitude near particle contacts. This gives a force between particles that is approximately an order of magnitude higher than predicted by the classical point-dipole approximation, and is in reasonable agreement with that measured experimentally. Subtle effects of the carrier fluid on the interaction force and an explanation for the non-Ohmic behavior of ER fluids are deduced in terms of its dielectric constant and dielectric strength.
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