Electro-osmosis - Microfluidic CFD Applications
Electro-osmosis refers to the fluid flow that occurswhen an electric field is applied to the electrical double layer (EDL), 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. Two examples are given below.
for use with micro-pumps
A non-uniform potential is created on the walls of a microchannel to induce a helical flow inside the channel. In the schematic (left), strips indicate where the potential is imposed. In the results from FLOW-3D, the mixing effect is seen, as the fluid stretches and folds (as indicated by marker particles).
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 image to the left demonstrates the application of electro-osmosis for use with micro-pumps.