An immersed boundary-lattice Boltzmann method to simulate chaotic micromixers with baffles

In this paper, a new immersed boundary-lattice Boltzmann method (IB-LBM) including velocity and mass flux correction is developed. In the framework of IB-LBM, Dirichlet condition (no-slip) is imposed by using velocity correction and the concentration correction is used for Neumann (mass flux) condition. Velocity correction is transformed into a forcing term and added to the momentum equation, and a mass source/sink is introduced to convection-diffusion equation representing concentration correction. Eliminating sophisticated mesh generation processes, simplicity and effectiveness while preserving numerical accuracy, are the major advantages of the presented method. The proposed method is well validated through its application to simulate chaotic micromixers with obstructions. Micromixers with three different shaped baffles were used to investigate the effect of baffles and the merit of the new IB-LBM. The mixing performance is evaluated by the mixing efficiency and the performance index. The results indicate that regardless of the baffle shape, the mixing efficiency is enhanced by using baffles. Furthermore, as the distance between baffles decreases, the performance is more enhanced.