小型大气细粒子谱仪关键部件研制

发布时间：2018-02-14 15:47

本文关键词： 大气细粒子谱电晕放电电迁移率平板差分电迁移分析仪法拉第杯敏感电极　出处：《中国科学技术大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着中国经济的不断发展,能源、汽车消费日益增多,环境问题变得尤其突出,特别是以大气颗粒物污染为代表的大气环境污染已经严重影响人民生产生活。世界卫生组织公布的全球空气污染互动式地图表明中国颗粒物污染状况非常严重,环保部公布的2015年环境报告也同样显示着国内有近八成的城市空气质量不达标。与传统的PM10、PM2.5相比,低于500nm的小粒径颗粒物对于人体的造成的损害更大,更不容易去除。而传统的空气动力学粒径检测法和激光散射强度检测法都是基于光学方法,对于300nm以下的超细颗粒物难以准确检测。而基于颗粒物的电迁移检测原理,没有光学和激光部件,不需要维持特定的检测环境,且在理论上不存在检测下限,同时结构尺寸更易于小型化。相比于传统的圆筒型差分电迁移分析仪,平板型差分电迁移分析仪具有更高的空间利用率,同时具有更低的制作成本,配合法拉第杯静电计的微弱电流检测更适用于分布式的联网监测和移动便携式使用,因此逐渐成为国际上研究大气细颗粒监测的主流方法。本文主要围绕着基于电迁移的微电流检测粒径原理的小型大气细粒子谱仪的研制展开,本文的主要研究内容有以下四部分组成。1.对小型大气细粒子谱仪的颗粒物荷电部分——气溶胶荷电器的研究设计。根据电晕放电理论结合扩散荷电技术,设计了一个小型单极性荷电系统。其中该系统有两部分组成,电晕放电部分为基于电晕放电理论研制的气溶胶荷电器,另一部分为高压恒流源。气溶胶荷电器采用针尖-圆弧放电结构,高压恒流源为气溶胶荷电器提供一个保持稳定的电晕放电电流的高压。对荷电系统进行了正极性和负极性电晕荷电效果的比较,并完成了不同粒径大小的颗粒物荷电效率的标定。对比了不同电晕电流下的内外荷电效率,获取到该系统最优的外荷电效率和内荷电效率。2.对小型大气细粒子谱仪的颗粒物分级部分——差分电迁移分析仪设计和研究。根据带电粒子的电迁移理论,结合平板型差分电迁移分析仪的检测理论,研制了一版小型平板型差分电迁移分析仪,理论计算了不同粒径下的偏转电压。结合实验现有实验条件,设计出颗粒物粒径偏转电压标定方案,测试并标定了设计的平板型差分电迁移分析仪的各颗粒物粒径的偏转电压。3.对小型大气细粒子谱仪的检测部分——法拉第杯的设计和改进。主要从法拉第杯的检测原理,机械结构设计入手。设计出一种结构简单,体积较小,可用于小型大气细粒子谱仪的法拉第杯。通过对法拉第杯的离子检测模型进行分析和建模,表明提高法拉第杯中敏感电极碰撞表面积可有效提高法拉第杯的离子检测效率。4.根据设计的三个主要的部件,初步搭建了小型大气细粒子谱仪的样机,完成各个部件的控制。对颗粒物的数浓度进行初步的反演,获取实验室内大气细粒子的粒径分布谱图。
[Abstract]:With the continuous development of economy, Chinese energy, automobile consumption is increasing, environmental issues become particularly prominent, especially air pollution by particulate air pollution as the representative has a serious impact on people's production and life. The global air pollution WHO announced the interactive map shows that the status of China particulate pollution is very serious, the Ministry of Environmental Protection announced in 2015 the environmental report also revealed that domestic city has nearly 80% air quality non-compliance. Compared with the traditional PM10, PM2.5, 500nm lower than the smaller particle size is greater for the damage caused by the human body, more difficult to remove. While the traditional aerodynamic diameter detection method and laser scattering intensity are based on optical method for ultrafine particles, 300nm accurately detecting the particles. And electromigration detection based on the principle of no optical and laser components, not The need to maintain a specific environmental detection, and the detection limit does not exist in theory, and the structure size is easier for miniaturization of cylinder type. Compared to the traditional differential migration analyzer, flat type differential migration analyzer has higher space utilization, and lower production costs, with the weak current detection of the Faraday cup the electrometer is more suitable for distributed network monitoring and mobile portable use, it has gradually become the mainstream of international monitoring of atmospheric fine particles. This paper mainly focuses on the development of electric transfer micro current detection principle of small particle size of atmospheric fine particle spectrometer based on expansion, the main contents of this paper are the following four particles part.1. of the small atmospheric fine particle spectrometer charged part -- Study on the design of aerosol electric charges. According to the theory of corona discharge combined with diffusion charging technology. Design a small unipolar charge system. The system is composed of two parts, part of the corona discharge aerosol developed corona discharge theory of electric charges based on the other part for high voltage constant current source. The aerosol charge electric appliance tip arc discharge structure, high voltage constant current source provides a stable corona voltage the discharge current for aerosol charge electric appliance of charged system. Compared the positive and negative corona discharge effect, and completed the calibration of different particle size of the charging efficiency. Comparing the different inside and outside the corona current under the charge transfer efficiency, access to the design and study of particle analyzer the classification system optimal external charge efficiency and charge efficiency of.2. for small atmospheric fine particle spectrometer part. According to the difference of charged particle migration theory, differential mobility analyzer with flat type electric The detection theory, developed a small flat version of differential migration analyzer, theoretical calculation of the deflection voltage of different grain sizes. Combined with the existing experiment, design a particle size deflection voltage calibration scheme, testing and calibration of the flat design of poor design and improvement of electric migration deflection voltage.3. shift analyzer the particle size of small atmospheric fine particle spectrometer detection part of the Faraday cup. Mainly from the detection principle of the Faraday cup, starting with the design of mechanical structure. To design a simple structure, small size, can be used for small type atmospheric fine particle spectrometer of the Faraday cup. Analysis and modeling by ion the detection model of the Faraday cup, Faraday cup that raise sensitive electrode collision surface area can effectively improve the detection efficiency of the Faraday cup ion.4. according to the three main parts of the design, preliminary set A prototype of small atmospheric fine particle spectrometer was built to control all components. A preliminary inversion of particle number concentration was carried out to obtain the particle size distribution spectrum of fine particles in the laboratory.

【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X851

【参考文献】