多级热流逸式真空泵流量与压力特性分析  

Analysis of Flow Rate and Pressure Characteristics for Multistage Thermal Transpiration Based Vacuum Pump

作　　者：覃日帅 蒙仕达 王博韬 卢苇 QIN Rishuai;MENG Shida;WANG Botao;LU Wei(School of Mechanical Engineering,Guangxi University,Nanning 530004,China;Analysis and Evaluation Department,Sichuan Lijiu Law Firm,Chengdu 618200,China)

机构地区：[1]广西大学机械工程学院,南宁530004 [2]四川力久律师事务所分析评议部,成都618200

出　　处：《真空科学与技术学报》2022年第11期815-821,共7页Chinese Journal of Vacuum Science and Technology

基　　金：国家自然科学基金项目(52066002);广西自然科学基金项目(2019GXNSFAA185024)。

摘　　要：为满足流量和压力要求,热流逸式真空泵通常采用多级串联结构。本文依据稀薄气体动力学建立了多级热流逸式真空泵运行特性数学模型,探讨了温差、努森数、串联级数对流量和压力的影响。研究表明,在满足真空度要求的前提下,为获得较大流量并减少串联级数,应合理增大多级热流逸式真空泵各级的温差;并尽可能采用特征尺寸大的连接通道,以使其内气体处于连续流区域;但微通道的特征尺寸须视情况而定,以确保其内气体处于高努森数的过渡流区域。从大气端指向真空端,多级热流逸式真空泵内的压力大致呈指数规律降低;越接近大气端的级,其内压力变化越显著;就每一级而言,压力在连接通道内略微升高,而在微通道内大幅降低。Thermal transpiration based vacuum pump is often designed as a multistage type in series in order to meet the needs of flow rate and pressure. In this paper, a mathematical model of working characteristics was established for multistage thermal transpiration based vacuum pump according to rarefied gas dynamics. Then the effects of temperature difference, Knudsen number and stage numbers on flow rate and pressure were discussed. Some findings are as follows in consideration of the requirement of a vacuum degree. The temperature difference in each stage of a multistage thermal transpiration based vacuum pump should reasonably be increased to obtain a relatively high flow rate and to decrease the number of stages in series. The connecting channels with large characteristic dimensions as far as possible, make the inside gas flow in a continuous flow regime. However, the characteristic dimensions of microchannels should be determined according to operating conditions to ensure the inside gas flow in the high-Knudsen-number transition flow regime. From the atmospheric end to the vacuum end, the pressure in multistage thermal transpiration based vacuum pump decreases exponentially. The closer the stage is to the atmosphere end, the more significant the change of internal pressure is. In each stage, the pressure increases slightly in the connecting channels while decreases significantly in the microchannels.

关 键 词：热流逸效应 多级串联 稀薄气体流动 流量特性 压力特性 

分 类 号：TB752[一般工业技术—真空技术] O356[理学—流体力学]