高真空干泵螺旋级抽气性能的数值计算模型

Numerical Simulation of Screw-Stage Pumping Behavior of High Vacuum Dry Pump

微型化和一体化是干式真空泵发展的重要趋势,高真空干泵是具有代表性的一种新型干泵。本文对高真空干泵的重要部件之一的单螺旋转子进行了数值研究,通过对几何模型重要参数的分析,结合了直接模拟蒙特卡罗的程序思想,对单螺旋转子工作过程进行仿真。模拟得到了单螺旋转子几何参数对抽气效率的影响机制,得到影响高真空干泵性能的参数调节机制,为高真空干泵的设计提供了理论依据和指导。

The pumping characteristics in screw stage of the high vacuum dry pump（ HVDP） with the newlyoptimized single screw rotor,whose outer / inner spirals are on the cylindrical / conical surfaces,respectively,was mathematically modeled,theoretically analyzed in molecular aerodynamics,numerically simulated in direct simulation Monte Carlo（ DSMC） method,and experimentally tested. The impact of the rotor＇s geometry,including the height,speed and opening angle of the rotor,on the pumping coefficient was investigated. The simulated results show that the rotor＇s geometry significantly affects the pumping coefficient. To be specific,as the rotor height increases,the pumping coefficient changes in a rapid increase-decrease mode; the coefficient increases with an increase of the opening angle till 80°,and then slowly decreases; but the coefficient increases with an increase of the rotor speed.The simulated and measured results are in good agreement with a discrepancy below 6. 75% in an inlet pressure range of 10^-4Pa - 10^-1Pa.