Simple passive micromixer using recombinant multiple flow streams

A passive microfluidic mixer with high performance is designed and fabricated in this work. Diamond-shaped obstacles were chosen to split the flow into several streams, which are then guided back together after the obstacle. To keep pressure drop low, the channel cross-sectional area was maintained equal to the input cross-sectional area, and this was held constant throughout the device. The proposed design was modeled using computational fluid dynamics (CFD) software. The effects of channel width, channel length, location of obstructions, and Reynolds Number (Re) were investigated. The simulated results were verified experimentally. Simulation data showed that the designed micromixer achieved 90% mixing at a channel length of 4.35 mm with pressure drop of 584 Pa at Re = 1, while experimental data for Re = 0.1 showed 90% mixing at 7 mm. The mixer functions well especially at the low Re (Re = 0.1).