In this video, we simulate an electrokinetic valve. Using the Transport of Diluted Species, Creeping Flow, and Electric Currents interfaces, this video shows the complete analysis of a typical microfluidic valve design. This example is divided into two parts: the focusing stage (shown here) and the injection stage (shown in a follow-up video). During the focusing stage, an ionic sample solution and buffer solution are forced into two microchannels at a constant rate. Once a steady-state profile is reached, the device turns off the pressure-driven flow, completing the focusing stage. At this point, there is a focused concentration profile at the junction of the two microchannels called "the focusing zone". In the follow-up video, which shows the injection stage, electric currents are applied along the microchannels, driving ions from the focusing zone into the injection channel of the electrokinetic valve.
Watch the second video, Modeling the Injection Stage of an Electrokinetic Valve