Simulation Of Fluid Flow And Mixing In Microchannels By Using The Lattice-Boltzmann Method

In this study, we performed 2-D and 3-D numerical simulations using the lattice Boltzmann method (LBM) to investigate the electrokinetic effect on the fluid flow and mixing in rectangular microchannels. Firstly, we applied LBM to several simple fluid problems and analyzed the numerical stability and accuracy depending on the implementation method of boundary conditions. Then, we designed two new electro-osmoticaly driven microchannel mixers with different electrode distributions. We simulated the fluid flows and mixing behaviors, and evaluated the mixing performance in the microchannels. In two designs, the zeta-potential was employed as the main factor representing the electrokinetic effect; one used the periodically distributed rectangular electrodes on lateral walls of the microchannel with time-periodic application of the electric potential on the electrodes; in another model, with periodic array of trapezoidal electrodes with a constant electric charge on them were attached on the bottom walls. Through the numerical simulation, we demonstrated that it was simple and effective to use LBM in the analysis of the performance of micromixers. With the parametric studies for both designs, it was shown that there existed an optimum parameter value leading to a good mixing performance.