摘要
热流逸真空泵利用其内部微通道结构产生的热流逸效应来工作,故其本身也存在流导。本文建立了几种典型截面形状长微通道和短微通道的流导计算模型,进而分析了流导随努森数、温差及微通道特征尺寸变化的规律。结果表明,微通道在过渡流区域的流导比在自由分子流区域的大2~4个数量级;短微通道的流导性能优异长微通道的;绝大多数情况下,截面形状的对称性越强则其流导性能越好;在自由分子流区域,截面形状对流导的影响不大,但在过渡流区域,不同截面形状的流导差异显著。可见,应尽可能将热流逸真空泵设计在过渡流区域工作,且应优先采用截面形状对称性强的短微通道结构,但需要综合考虑努森数、温差和微通道特征尺寸之间的相互协同与制约。
The conductance of micro-channels,in thermal transpiration vacuum pump,was mathematically modeled and theoretically analyzed.The influence of the four key variables,including the free molecular and transitional flow regions,Knudsen-number,temperature-difference and feature-size(length and cross-sectional symmetry)of micro-channels,on the conductance was investigated.The results show that the four-variables all have a major impact.For example,as Knudsen-number increases,the conductance decreases;as the temperature difference increases,the conductance increases;and short micro-channels have larger conductance than the long ones.In transitional flow region,the conductance is 102~4 times larger than those in free molecular flow region,and significantly depends on the cross-section symmetry.We suggest that the conductance optimization may require transitional flow region,short micro-channels with highly symmetric cross-section,and compromised Knudsen-number/temperature-difference.
作者
卢苇
邢鹏浩
王博韬
Lu Wei;Xing Penghao;Wang Botao(School of Mechanical Engineering,GuangXi University,Nanning 530004,China;Sichuan Center for Patent Examination and Cooperation of the Patent Office of the State Intellectual Property Office,.Chengdu 610213,China)
出处
《真空科学与技术学报》
EI
CAS
CSCD
北大核心
2020年第5期478-484,共7页
Chinese Journal of Vacuum Science and Technology
基金
广西自然科学基金资助(2019GXNSFAA185024,2016GXNSFAA380232)
国家自然科学基金资助(51366001)。
关键词
流导
热流逸效应
微通道
截面形状
Conductance
Thermal transpiration effect
Microchannel
Cross section geometry
