The New Jersey Institute of Technology's
Electronic Theses & Dissertations Project

Title:	Direct simulation of electrorheological suspensions subjected to pressure driven flow and spatially non-uniform electric field
Author:	John Kadaksham, Arun Thankamony
View Online:	njit-etd2003-048 (xiii, 81 pages ~ 8.6 MB pdf)
Department:	Department of Mechanical Engineering
Degree:	Master of Science
Program:	Mechanical Engineering
Document Type:	Thesis
Advisory Committee:	Singh, Pushpendra (Committee chair) Aubry, N. (Committee member) Rosato, Anthony D. (Committee member)
Date:	2003-05
Keywords:	Electrorheological suspensions Electric fields
Availability:	Unrestricted
Abstract:	A numerical method based on the distributed Lagrange Multiplier method is developed for direct simulation of electrorheological (ER) suspensions subjected to pressure driven flows and spatially non-uniform electric fields. The flow inside particle boundaries is constrained to be rigid body motion by the distributed Lagrange multiplier method and the point-dipole approximation is used to model the electrostatic forces acting on the polarized particles. Simulations show that the particles move to the regions of high electric field when the value of β, the Clausius-Mossotti factor is positive and they move to the regions of low electric field when the value of β is negative. Also, dielectrophoretic force can be used for separating particles with different β values. Using the simulation method the evolution of the microstructure under the influence of electrostatic forces (particle-particle interaction force and dielectrophoretic force) and hydrodynamic forces is analyzed. The different microstructures formed are explained on the basis of non-dimensional parameters that determine the relative strength of the various forces. Simulations show that even when the particle-particle interaction force, dielectrophoretic force and hydrodynamic force coexists, the parameters can be judiciously manipulated so that either the yield stress and viscosity of the ER fluid increases or the particles get collected in the regions of low or high electric fields.