基于微流控技术的微细气泡生成特性及其试验研究

发布时间：2018-07-01 21:09

本文选题：微细气泡 + 生成特性　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：微细气泡是指粒径为百微米级以下的气泡,具有比表面积大、存在时间长、传质效率高等特点,在化工、环境、医学及医药工程等诸多领域有着极为重要的潜在应用价值。作为一种先进的微细气泡制备方法,微流控技术能够集成利用微细流道、流动聚焦、电雾化等手段,生成粒径较小、尺度均匀且可控的微细气泡,这是常规的微细气泡制备方法所无法媲美的。本课题以在水溶液介质中注入微细气泡为应用背景,以微流控装置中的微细气泡生成演变特性为主线开展研究。开展流动聚焦环境中的微细气泡生成理论模型研究。通过建立合理假设,简化微细气泡在其生成过程中的力学条件,建立流动聚焦环境中单个微细气泡的球体及非球体理论预测模型。建立基于MATLAB/Simulink的微细气泡生成理论模型的仿真模型,预测微细气泡的脱离体积、生成时间及其生成演变过程,为集成化微细气泡生成装置的研制及集成方法的探究奠定理论基础。基于拉伸成锥的石英毛细管,研制机械装配型微流控芯片,并利用高速显微系统、微量注射装置及MATLAB图像处理工具,搭建微流控芯片中的微细气泡生成特性试验及测量系统。通过开展微细气泡生成试验,探究气体压强和液体流量对微细气泡脱离体积、生成频率、体积演变、中心位移及其运动速度的影响,验证流动聚焦环境中的微细气泡力学特性分析结果。开展低频振动条件下的微细气泡生成特性试验研究。基于压电陶瓷的逆压电效应,研制低频微型振动试验平台。利用柔性铰链的杠杆式位移放大原理,研制位移放大机构,实现对压电陶瓷叠堆输出位移幅值的放大。利用高速摄像系统和所编制的图像处理程序,搭建振动条件下的微细气泡生成特性试验及测量系统,并通过开展系列试验,探究压电陶瓷叠堆的正弦信号频率和电压幅值对微细气泡平均粒径和生成频率的影响。基于上述微流控芯片中的流动聚焦原理,利用3D打印工艺和石英毛细透明管,研制新型微流控装置。搭建了高速显微观测系统,开展新型微流控装置中的微细气泡生成特性试验,探究其微细气泡生成能力的同时,获得气泡脱离体积和生成时间随输入参数的变化规律。以生成大量粒径较小且均匀可控的微细气泡为目标,以基于不同流道形式的各种集成化方法为手段,探究微流控装置的规模化集成方法,完成集成式微流控装置的原理样机研制。
[Abstract]:Micro bubble is a bubble with a diameter of less than 100 microns. It has the characteristics of large specific surface area, long existence time and high mass transfer efficiency. It has very important potential application value in many fields, such as chemical industry, environment, medicine and medical engineering. As an advanced method for the preparation of micro bubbles, microfluidic technology can integrate micro flow channels, flow focusing, electroatomization and other means to generate small size, uniform and controllable size of micro bubbles. This is not comparable to conventional microbubble preparation methods. In this paper, the micro bubble injection in aqueous solution is used as the application background, and the evolution characteristics of micro bubble formation in the micro fluidic device are taken as the main line of study. The theoretical model of micro bubble formation in flow focusing environment was studied. By establishing reasonable assumptions and simplifying the mechanical conditions of micro bubble formation, a theoretical prediction model of sphere and non-sphere of a single micro bubble in a flow focusing environment is established. A simulation model based on MATLAB / Simulink is established to predict the separation volume, generation time and evolution process of micro bubble, which lays a theoretical foundation for the development of integrated micro bubble generation device and the exploration of integration method. A mechanically assembled microfluidic chip was developed based on stretching tapered quartz capillary. The test and measurement system of micro bubble formation characteristics in microfluidic chip was built by using high speed micro system, micro injection device and MATLAB image processing tool. The effects of gas pressure and liquid flow on the separation volume, formation frequency, volume evolution, center displacement and velocity of movement of micro bubble were investigated by means of micro bubble formation test. The results of mechanical analysis of micro bubbles in flow focusing environment were verified. An experimental study on the formation characteristics of micro bubbles under low frequency vibration was carried out. Based on the inverse piezoelectric effect of piezoelectric ceramics, a low frequency micro vibration test platform was developed. Based on the lever displacement amplification principle of flexure hinge, a displacement amplification mechanism is developed to amplify the output displacement amplitude of piezoelectric ceramic stack. By using the high speed camera system and the image processing program, the test and measurement system for the formation characteristics of micro bubbles under vibration conditions was built, and a series of tests were carried out. The effects of sinusoidal signal frequency and voltage amplitude of piezoelectric ceramic stack on the average particle size and generation frequency of micro bubbles were investigated. Based on the flow focusing principle of the microfluidic chip mentioned above, a new type of microfluidic device was developed by using 3D printing technology and quartz capillary transparent tube. A high speed microscopic observation system was set up to test the formation characteristics of micro bubbles in a new type of micro fluidic device. At the same time, the variation law of bubble separation volume and generation time with input parameters was obtained as well as the ability of micro bubble formation. In order to generate a large number of micro bubbles with small particle size and uniform and controllable size, and taking various integration methods based on different flow channels as the means, this paper explores the large-scale integration method of microfluidic devices. The principle prototype of integrated microfluidic device is developed.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN492

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