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为了实现微量液体的快速均匀混合,设计了一种PDMS双层结构的新型微混合器。研究了混合器的制作方法以及几何尺寸和Re数对混合的影响。依据Fick第一定律介绍了主辅通道型微混合器的设计原理;采用有限元方法对不同几何尺寸及Re数下混合器中液体的速度流场及浓度场进行了数值模拟;数值分析显示,随着主辅通道出口宽度比的减小,通道长度的增加和雷诺数的减小,混合器的混合率增加。最后,依据仿真结果制作了主辅通道深度比为0.71,出口宽度比为1,通道长度为9mm的微混合器并进行了去离子水和红墨水的混合实验。实验结果表明:当Re<5时,设计的混合器能实现液体的快速混合,并且混合率随着Re的减小而增大,基本满足低Re数下微量液体快速均匀混合的要求。
In order to achieve rapid and uniform mixing of trace amounts of liquids, a new type of micromixer with double layer structure of PDMS was designed. The production method of the mixer and the influence of geometry and Re number on the mixing were studied. According to Fick’s first law, the design principles of the main and auxiliary channel micromixer are introduced. The finite element method is used to simulate the velocity and concentration fields of the liquid in the mixer with different geometric size and Reynolds number. Numerical analysis shows that, With the reduction of the width ratio at the outlet of the main and auxiliary channels, the increase of the length of the channel and the decrease of the Reynolds number, the mixing ratio of the mixer increases. Finally, based on the simulation results, the micromixer with main channel and auxiliary channel depth ratio of 0.71, outlet width ratio of 1 and channel length of 9mm was fabricated and mixed experiments of deionized water and red ink were carried out. The experimental results show that when Re <5, the designed mixer can realize the rapid mixing of liquid, and the mixing rate increases with the decrease of Re, which basically meets the requirement of rapid and uniform mixing of trace liquid with low Reynolds number.