This video shows the second stage of an electrokinetic valve simulation, modeling the injection stage. The video demonstrates how to model a complete analysis of a typical microfluidic valve design using the Transport of Diluted Species, Creeping Flow, and Electric Currents interfaces available in COMSOL Multiphysics. The modeling example is divided into two parts: the focusing stage (shown in a previous video) and the injection stage (shown in this video). At this point, the system has reached a steady state profile, where a focused concentration profile has formed at the the focusing zone of the microchannels. Moving into the injection stage, electric currents are applied along the channels, driving ions from the focusing zone into the injection channel. There are two modes within the injection stage, differing only by the electric fields. The Cut Line 3D feature is used to plot the concentration of the ionic sample along the injection channel at the different time steps. The sample concentration is shown both in a 3D animation and by a pair of line graphs comparing the two different modes of the injection stage.
Watch the first video, Modeling the Focusing Stage of an Electrokinetic Valve
For more information about this model, check out the model documentation: comsol.com/electrokinetic-valve