Electro-osmosis refers to the fluid flow that occurs when an electric field is applied to the electrical double layer, an intrinsic property of a fluid-solid pair. This phenomenon has proven to have significant practical importance for microfluidic applications. FLOW-3D enables the modeling of combined pressure- and electro-osmotic-driven flows, with or without a free surface, in one- or two-fluid configurations.
By creating a series of deep slots in a microchannel, and then applying a potential across the channel, fluid flow can be controlled in a MEMS-scale pump. By adjusting the applied potential, the flow rate can be controlled. The video below demonstrates the application of electro-osmosis for use with micro-pumps.
As illustrated in the animation above, FLOW-3D represents well the streamlines at any point in time for a complex and evolving flow field. The streamlines and particles in this animation show the inefficiencies in this pump design by capturing recirculation zones. These zones reduce efficiency when not all flow is driven forward effectively.
In the animation above, a non-uniform potential is created on the walls of a microchannel to induce a helical flow inside the channel. FLOW-3D clearly shows the mixing effect as the fluid stretches and folds, indicated by marker particles.