Abstract:

As an important part of microfluidic equipment, the micro mixer is widely used in the biochemical field. Because the fluid flow in the micro channel is laminar and the mixing is poor, the mixing becomes the main factor affecting the efficiency for rapid reaction. In this paper, three kinds of micro mixer structures that affect the mixing efficiency were numerically simulated. By changing the three structural parameters of the micro mixer, namely, the channel width to height ratio, the maximum width at the divergence, and the dislocation height at the collision, the mixing performance under laminar flow was simulated. The results showed that the height of dislocation at the fluid collision had the most obvious influence on the mixing performance. The structure of the micro mixer (MST) with the best simulation results was further optimized to obtain a new micro mixer (MTT). The MTT was compared with MST and ordinary T-type micro mixer (MT). The mixing index at the outlet of MTT micro mixer reached 81%, while that of ordinary T-type micro mixer was only 5.3% under the same conditions. Through simulation and analysis of the mixing process, the structure of the dislocation collision type micro mixer was effectively improved, which was conducive to improving the fluid mixing efficiency and the reaction speed.

Key words: mixing performance, micro mixer, dislocation collision, laminar flow, numerical simulation

摘要：

微混合器作为微流控设备的重要组成部分，广泛应用于生化领域，由于在微通道下流体流动为层流，混合较差，对于快速反应，混合是影响效率的主要因素。本文对影响混合效率的3种微混合器结构进行了数值模拟，通过变化微混合器的通道宽高比、发散处最大宽度、碰撞处错位高度3个结构参数，模拟研究其在层流下的混合性能。结果表明，流体碰撞处错位高度对混合性能影响最明显。对模拟结果最佳的微混合器（MST）进一步优化其结构得到新的微混合器（MTT），将MTT与MST及普通T型微混合器（MT）进行比较。MTT微混合器出口处的混合指数达到81%，而普通T型微混合器在相同的条件下只有5.3%。通过模拟分析混合过程，有效改善了错位碰撞型微混合器的结构，有利于提高流体混合效率，提高反应速度。

关键词: 混合性能, 微混合器, 错位碰撞, 层流, 数值模拟