A novel design of passive split and recombination micromixer with trapezoidal zigzag channels

In this paper, we proposed a novel passive micromixer to provide effective mixing performance even at very low Reynolds number (Re). The micromixer consists of trapezoidal channels that facilitate the mixing between top-fluid and bottom-fluid. In addition, the zigzag arrangement of trapezoidal channels creates transversal flows, thus enhancing the mixing in transversal direction. The micromixer also creates high distortion of fluid streams based on chaotic advection, producing very high mixing efficiency. We conducted numerical study to evaluate mixing performance of our micromixer using COMSOL Multiphysics based on Finite Element Method. The simulation results indicated that the micromixer has a high mixing efficiency over 81% for an entire range of Reynolds number from 0.1 to 80. A mixing efficiency over 90% was achieved when Re ≤ 0.9 and Re ≥ 20. When operating with Re = 20, our micromixer achieved a mixing efficiency that are 4.07 and 5.58 times higher than those of 3-split rhombic micromixer and T-shaped micromixer. Furthermore, our micromixer has a small footprint, which is advantageous to integrate into various microfluidic systems.