Abstract

A micro analyzer based on the concept of “Lab on a Chip” has a higher performance due to the relation between useful area over volume. The integration of multiple processes in a single microdevice makes possible the reduction of both, the amount of the necessary samples and the analysis time, making it be the next generation of the analyzer for the life-science. A better and efficient way of controlling the flow in a microchannel-based analyzer is by applying an electric field to induce the fluid motion and enhance or suppressing the mixing process when is necessary. The induced electrokinetic instabilities behavior is characterized by the dimensionless electric Rayleigh number and a geometrical aspect ratio. In this research, we stated that then flow instability by electrokinetic occurs when the Rayleigh number is surpassed the critical value and, that it is possible to reduce significantly the critical Rayleigh number by using a microchannel with symmetric wave shape, that triggers and enhances the flow mixing process. In this work, we experimentally and numerically study induced electrokinetic instabilities in a cross-shaped microchannel with wavy walls for the mixing process when a critical Rayleigh number is surpassed. A computational simulation study was carried out using the finite element computational program, which allows us the characterization of flow instability according to real fluid parameters such as the electrical conductivity, dynamic viscosity and zeta potential, which was validated experimentally. From the results, it is observed that the mixing process is favored with the induced and sustained electrokinetics instabilities obtaining a better flow mixing enhancement that the one of a state flow.