Simulation and optimization of chaotic micromixer using lattice Boltzmann method

To improve the mixing performance of the chaotic mixer for a microchannel, the staggered herringbone mixer (SHM) with patterns of herringbone grooves on the floor of the channel is studied using lattice Boltzmann method (LBM), which is a relatively new numerical method based on particle mesoscopic kinetic equations. Firstly, the mixing process in a SHM is simulated. The streamtraces in the velocity field of the flow and detailed particle mixing images are gotten. These images agree well with the previous experiment. Then two geometrical parameters of the SHM, the width fraction of the channel occupied by the wide arms of the herringbones and the number of the grooves per half cycle are investigated. With the computed standard deviations of the particle concentration distributions in the cross sections of the mixing flows, it is found that the width fraction about 0.60 in a SHM is optimal and the SHM with five or six grooves per half cycle has better performance than others in the simulations. It is demonstrated that the LBM provides an efficient tool for micromixer design optimization.