【作者】 刘素芬；

【导师】 杨华勇； 傅新；

【作者基本信息】 浙江大学 ， 机械电子工程， 2005， 博士

【摘要】 现代分析仪器的一个发展趋势就是设备的微型化、集成化与便携化。微流控芯片则主要以分析化学和分析生物化学为基础，以MEMS加工技术为依托，以微管道网络为结构特征，连接具有流体致动、控制以及检测等功能的元器件，是当前微全分析系统发展的重点。微混合器是一种重要的微流控器件，不但要实现不同试剂或试样分子级混合的功能，还应兼具结构简洁易加工，以及易于集成于微流控系统中，操作条件易于控制，设备体积小，内在安全性能好等特点。 本论文针对微尺度混合的特点，提出了一种以玻璃湿法刻蚀加工技术为基础，基于混沌对流混合机理的三维静态微混合器——SOR微混合器。通过在微管道内设置周期交替排列的导流块，轴向的压力梯度可产生横向的速度分量，诱发混沌对流。在流场数值仿真的基础上分析了SOR微混合器内速度场的分布规律。利用计算可视化和实验可视化技术相结合的研究方法，确定了最佳的结构参数，并分析了雷诺数对混合效果的影响。同时采用与相同横截面和长度的微直管道相比较的方法，来度量SOR微混合器的压力损失大小。以微混合器中三维速度场作为动力系统，采用拉格朗日跟踪法研究了SOR微混合器的混沌混合特征。研究结果表明：微管道内周期交替排列的导流块，完全可以诱发混沌现象来实现微尺度条件下的层流混合。SOR微混合器的结构简单，加工工艺与MEMS技术兼容，而且加工材料不限制于玻璃，为微流控系统中被动混合提供了一种新的选择。 论文的主要内容如下： 第一章，综述了微流控系统的背景以及相关知识，重点阐述了微流控系统典型器件——微混合器的分类及微尺度混合方法、加工技术以及主要研究进展，在此基础上提出论文的主要内容。 第二章，简述了微尺度流动特征以及微流体混合的物理本质，并对流体混沌混合过程中相关的基本概念进行了阐述。结合本课题研究的特点，提出了研究微流体混沌混合的方法。 第三章，针对微尺度条件下，低雷诺数层流混合的特点，提出了一种以玻璃湿法刻蚀加工技术为基础，基于混沌对流混合机理的三维静态微混合器——SOR微混合器，论述了微混合器的结构设计原理。详细阐述了微混合器的几何结构特点以及加工过程。 第四章，利用流场数值仿真技术直接对SOR微混合器进行数值模拟，求解两种物质混合时的对流—扩散模型。通过对微混合器内的流场进行数值模拟，可以得到微混合器内流场的速度矢量分布、任意空间位置上某种流体介质所占的质量百分比、压力分布等，分析了不同流动条件对混合效果的影响，得到了最佳的几何结构参数。 第五章，利用实验可视化技术对SOR微混合器的混合性能进行了综合分析，比更多还原

【Abstract】 The leading development trend of modern analytical instrument is miniaturization, integration and portability. Microfluidic chip is primarily based on analytical chemistry, analytical biochemistry, and supported by the manufacturing technology of MEMS. MicroChannel net is the structure characteristic of microfluidic chip, which connects functional elements of actuate, control and detection. Microfluidic chip is the developing focus of micro total analysis system. A micromixer is an important part of microfluidic system, whose function is to realize effective mixing. The micromixer should possess compact structure to be easy fabricated and integrated into microfluidic system. The micromixer should also take up as little space as possible. The output flow rate and concentration should both be adjustable so the output is exactly what is desired. Finally, the micromixer should demonstrate good inherent security.A novel three-dimensional static micromixer, called SOR micromixer, is put forward which was designed according to the characteristic of mixing liquids on the microscale. The device was fabricated on glass substrates using wet-etching technique. Under a steady axial pressure gradient, staggered oriented ridges arranged periodically in microchannel can generate transverse and three-dimensional flow. Chaotic advection is induced in the microchannel, which stretches and folds material interface and passively enhances fluid mixing. The computational fluid dynamics method (CFD) was used to analyze distribution rule of velocity field in the SOR micromixer. Through computation and experiment visualization methods, the optimal structure parameters have been found and the impact of Reynolds number on mixing performance was analyzed. The value of pressure drop of the micromixer was evaluate through the method which computing the ratio of pressure drop between the micromixer and the straight microchannel with the same cross section and length as the micromixer. Finally, the three-dimensional velocity field in the micromixer was regarded as nonlinear dynamic system, and the characteristic of chaotic mixing in the micromixer was studied with Lagrangian tracer tracking techniques. According to the study, staggered oriented ridges arranged periodically in microchannel surely induce chaos phenomena to achieve mixing in microscale. The micromixer possesses compact structure, and its fabrication process is compatible with the technology of MEMS. At the same time, the substrate material is not limit to glass. So a new choice of good passive mixing method was provided.In chapter 1, the background of the microfluidic system and the relevant knowledge of MEMS were reviewed. The different types of micromixer, designing mechanisms,更多还原