AC-driven electrothermal flow is used to enhance the chaotic mixing through vortex flow in micro-fluidic systems by nearly an order of magnitude. Diffusion of heat and momentum can be increased because of the electrothermal force acting on the fluid through the applied AC electric field. Numerical simulation of vortex-assisted mixing in circular microchannel flow is investigated by solving a set of governing partial differential equations with computational fluid dynamics (CFD) software