热流逸效应的抽真空特性分析  

Effect of Thermal Transpiration on Vacuum Pumping Characteristics:A Theoretical Study

作　　者：王博韬 卢苇[1] 徐昆[1] 王祥 Wang Botao Lu Wei Xu Kun Wang Xiang(School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004)

机构地区：[1]广西大学化学化工学院,南宁530004

出　　处：《真空科学与技术学报》2017年第9期866-872,共7页Chinese Journal of Vacuum Science and Technology

基　　金：广西自然科学基金资助项目(2016GXNSFAA380232);国家自然科学基金资助项目(51366001);广西研究生教育创新计划资助项目(YCSW2017035)

摘　　要：热流逸效应可输送气体并产生压力差,可利用其抽真空。本文建立了描述热流逸效应及其抽真空泵送特性的数学模型,以空气为例探讨了气体流态(努森数)、微通道特征尺寸和径长比以及温差等参数对压力比、净质量流量、抽速和无量纲抽气时间的影响。结果表明,压力比、净质量流量、抽速和无量纲抽气时间均随温差的增大而增大,但过大的温差对提高流量不明显且使抽真空达到稳态过程变得相对缓慢,应根据实际条件确定适宜温差。净质量流量和抽速随努森数增大而减小,且在过渡流区域还受径长比的影响;压力比和无量纲抽气时间在过渡流区域随努森数增大而增大,但在自由分子流区域与努森数无关;故应根据实际需求权衡净质量流量与压力比以确定适宜的热流逸发生条件、并控制气体流态来调整抽气特性。Thermal transpiration in vacuum pumping of micro-channels was mathematically modeled and theoretically analyzed. The impact of the pumping conditions including the air flow regime（ Knudsen number）,microchannel＇s aspect-ratio and temperature-difference,on the pumping characteristics,such as the pressure-ratio,net mass-flow rate,pumping speed and non-dimensional pumping time was investigated. The results show that the temperature-difference and Knudsen number significantly affect the pumping behavior. For example,as the temperature difference increases,the pressure ratio,net mass-flow rate,pumping speed and non-dimensional pumping time change in a rapid increase slow level-off mode; in the transition flow regime,as Knudsen number increases,the net mass-flow and pumping speed decrease,depending on the aspect-ratio; the pressure ratio and non-dimensional pumping time increase,being irrelevant to Knudsen number in the free molecular flow regime. We suggest that the calculated results be of some basic and technological interest in design of micro-machined Knudsen pump.

关 键 词：微通道 净质量流量 压力比 温差 真空抽气特性 

分 类 号：O356[理学—流体力学]