Relationship Between Dimension and Steady Time in Electroosmotic Microchannel Flows

Numerical simulation of transient state based on finite element method is presented aiming at the straight parallel-plate hydrophilic and hydrophobic microchannel. The influence of dimensions of microchannel to velocity in spatial and time is analyzed. The results of numerical simulation show that the transient characteristic of microflow is similar, which develops from the “saddle-like” at the beginning to the “plug-like” at the steady state, while the magnitude of steady time of microflow is proportional to the square of the dimension of microchannel according with viscous flow theory, and the scale is microsecond. The results provide the guidelines for the application of electroosmotic driven in the hydrophilic and hydrophobic microfluidic chips and the precision control of microfluid.