INVESTIGATION OF NONLINEAR ELECTRO KINETIC an‎d RHEOLOGICAL BEHAVIORS OF TYPICAL NON-NEWTONIAN BIO FLUIDS THROUGH ANNULAR MICRO CHANNELS

Electro osmosis is the predominant mechanism for flow generation in lab-on-chip devices. Since most bio fluids encountered in these devices reveal non-Newtonian behavior, a special understanding of the fundamental physics of the relevant transport phenomena seems vital for an accurate design of such miniaturized devices. In this study, a numerical analysis is presented to explore transport characteristics of typical non-Newtonian bio fluids through annular micro channels under combined action of pressure and electro kinetic forces. The flow is considered steady and hydrodynamic ally fully developed. A finite difference method is used to solve the Poisson-Boltzmann and Cauchy momentum equations, while the classical boundary condition of no velocity-slip for the flow field is applied. The Poisson-Boltzmann equation is solved in the exact form without using the Debye-Huckel approximation. After numerically solving the governing equations, role of the key parameters in hydrodynamic behavior of the flow is analyzed and discussed.