基于分合式混合单元的微混合器设计与研究

摘要

In order to realize quick and uniform mixing of micro scale, a splitting and recombination (SAR) mixing unit based on principle of fluid splitting and recombination was designed. Its branch angle θ was optimized by fluent and θ =70° was chosen as the optimized structure parameter. The SAR-micromixer and compound-SAR-micromixer(CSAR-micromixer) were fabricated by a standard photolithographic technique which is much easier than the fabrication of some 3D micromixer. SAR-micromixer, CSAR-micromixer and slant block micromixer ( SBM ) were tested under Re = 0.052 ～ 20, using the mixture of glycerol and water with volumetric ratio 5: 95 (0. 000 97 Pa · s). The test results show that, mixing length of SBM is larger than 20 mm when Re ≥ 1.23, in contrast, maximum mixing of SAR-micromixer is only 7.6 mm and CSAR-micromixer which is the most efficient is about 5.4 mm. SAR-micromixer and CSAR-micromixer can be easily realized and integrated to microfluidic systems.%为实现微尺度下流体的快速均匀混合,基于对流体的分割、合并实现流体间接触面积指数式增长的原理,提出了一种分合式(SAR)混合单元,通过仿真对其支路夹角进行了优化,并最终确定支路夹角θ=70°.利用成熟的标准SU-8光刻及PDMS制作工艺,制作了分合式与组合分合式两种微混合器.采用甘油-水按体积比5:95(0.000 97 Pa·s)混合而成的溶液对两种微混合器和斜阻块式微混合器进行了实验(Re=0.052～20).实验结果表明,斜阻块式微混合器在Re≥1.23时,混合长度超过20 mm,而分合式微混合器最大混合长度约7.6 mm,组合分合式微混合器的混合性能最好,其最大混合长度约为5.4 mm.设计的分合式和组合分合式微混合器制作方便,易与微流体系统集成.