Rapid Mixing in an Overlapping Crisscross Micromixer

We have developed a novel PDMS-based microfluidic mixer that incorporates an overlapping crisscross entrance with patterned microchannels and that acts as a high-performance micromixer. Such an entrance design generates significant flow tumbling and promotes axial advection between mixing fluids. A systematic numerical analysis reveals the overall mixing trends and the bulk flow structure. The downstream mixing performance is greatly enhanced as a result of the design of the entrance, at which there is vertical advection between mixing fluids, and four split flow zones generated by a staggered floor structure. After flowing through 12 pattern grooves, the mixing indexes of this device range between 0.16 and 0.51. The variation of aspect ratio of the microchannels controls the turning ratio of diverting flow rate versus straightforward flow rate and might be extensible for implementation in a disposable device. The effects of dimensionless control parameters and experimental investigation will be further discussed in the final draft.