Design a novel mixing structure consisting of several oppositely distributed expansion and contraction sections

which can generate Dean flow and expansion vortex.Based on this

the micromixer structure can realize high-efficiency mixing.The mechanism of forming Dean flow and expansion vortex are described first

then 3D numerical simulation is carried out to verify liquid flow mixing process by COMSOL

analyze effect of different flow rates on strong or weak of the multivortex and mixing degree.Finally

the micromixer is fabricated.Two different dyes are used for mixing experiment.Both the simulation and experimental results show that the mixer can obtain high efficient and fast mixing at the low rate of 0.01 μL/s as well as high input flow rate of 7 μL/s

the highest mixing efficiency is up to 98.6 % at the flow rate of input 5 μL/s.