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Development of a Monitoring Device of Wall Deposition and Evaluation of Deposition Behavior for Gaseous and Cluster Contaminants in Air

壁沉积监测装置的研制及空气中气态和团簇污染物沉积行为的评价

基本信息

批准号：
12650755
负责人：
SHIMADA Manabu
金额：
$ 2.24万
依托单位：
HIROSHIMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

(1) A piezo sensor was constructed by combining a quartz crystal oscillator and a high-frequency generator to develop a high-sensitivity mass monitor for indicating the amount of deposited contaminants. Performance evaluation of the monitor was made by using test contaminant gas. The time resolution of the measurements of deposited amount was improved drastically by increasing the standard frequency of the crystal oscillator.(2) The time resolution of the present monitor was found to be several tens of seconds, which verified the availability of the monitor as a real-time monitoring device. The change of deposition rate with environmental factors was clarified. The dependence of deposition rate on the material of walls was also clarified by coating the crystal oscillator with different materials.(3) Performance evaluation using a clean room under operation was made. The present monitor could measure the deposited amount with sufficiently high time-resolution even when deposition and desorption take place successively. A real-time estimation of the sources of contaminant gas was also found possible by performing simultaneous measurements using multiple sensors. A monitoring of air downstream of a chemical filter was made to prove that the monitor could detect the breakthrough of the filter promptly.(4) The size distribution of clusters generated from airborne ions was clarified by constructing a measurement system. The deposition rate of water clusters onto a wall was obtained as well as the deposition behavior of clustered gases onto fine particles.(5) Models to describe the transport and deposition of contaminant gas considering both adsorption and desorption were presented for the case in which more than one species of contaminant gas coexisted. By comparing the calculated results with the experimental data on deposition, the models were verified well and the factors influencing on the deposition of contaminant gas could be organized.

(1)压电传感器是由一个石英晶体振荡器和一个高频发生器相结合，开发一个高灵敏度的质量监测器，用于指示沉积的污染物的量。利用测试污染气体对监测仪进行了性能评价。通过提高晶体振荡器的标准频率，大大提高了沉积量测量的时间分辨率。(2)该监测仪的时间分辨率为几十秒，验证了该监测仪作为实时监测设备的可用性。阐明了沉积速率随环境因素的变化规律。通过在晶体振荡器上涂敷不同的材料，也阐明了沉积速率对壁材料的依赖关系。(3)使用运行中的洁净室进行性能评价。本监测器可以测量沉积量具有足够高的时间分辨率，即使当沉积和解吸连续发生。污染气体的来源的实时估计也被发现可能通过使用多个传感器进行同时测量。对化学过滤器下游的空气进行了监测，证明该监测仪可以及时检测过滤器的穿透。(4)通过构建测量系统，阐明了由空气离子产生的团簇的尺寸分布。得到了水分子团簇在壁面上的沉积速率以及团簇气体在细颗粒上的沉积行为。(5)针对多组分污染气体共存的情况，建立了同时考虑吸附和解吸的污染气体输运和沉积模型。通过计算结果与实验数据的对比，验证了模型的正确性，并对影响污染气体沉积的因素进行了整理。