Asymptotic and Numerical Solution for Electrokinetic Flow Around a Spherical Particle

Roman Zeyde, M.Sc. Thesis Seminar
Wednesday, 7.11.2012, 12:30
Taub 601
Prof. Irad Yavneh

A numerical framework for the simulation of electrokinetic migration of particles in an electrolyte solution due to the application of an external electric field is presented. The electrokinetic transport process is described by a system of nonlinear partial differential equations (PDE). A thin boundary layer forms around the particle due to strong electrostatic forces. The resulting scale disparity of the boundary layer is used to derive nonlinear effective boundary conditions for the numerical solver using the specific chemical properties of the particle. The nonlinear system is discretized and an iterative Newton solver is constructed automatically from the discrete equations and boundary conditions. An asymptotic analytical solution is derived for the validation of the solver. Numerical results are obtained for an ion-exchanger and for a surface charged inert particle. The numerical results are compared to the asymptotic solutions, and good correspondence is achieved.

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