A complete numerical model for electrokinetic flow and species transport in microchannels

A theoretical model is developed to investigate electrokinetic driven fluid flow and species transport. A typical cross-channel geometry is chosen with applications of species on-chip injection-separation analysis. The electrical potential, fluid flow and species concentration fields are presented in detail. These governing equations are non-dimensionalized uniquely to identify the controlling factors in microchannel performance. For the unsteady species transport equation, two different non-dimensionalization methods are compared. A preferred way to non-dimensionalize time in the concentration transport equation provides superior insight and understanding. Using a non-uniform staggered grid, a finite control volume method and line-by-line iterative procedure are implemented for the simulations. The Semi Implicit Method for Pressure Linked Equations (SIMPLE) algorithm is employed to solve the discrete equations. Grid independence and convergence studies are performed.