爪式真空泵全光滑直爪的设计与工作过程模拟

Design of Completely Smooth Straight Claw Rotors and Working Process Simulations for Claw Vacuum Pumps

爪式转子型线是提高真空泵工作性能的关键因素;针对现有的直爪转子存在尖点或不光滑连接点的问题,本文通过研究共轭曲线的啮合理论,提出了一种新型能够实现正确啮合的全光滑直爪转子,推导了其型线方程。利用三维数值模拟研究了直爪爪式真空泵的工作过程,得到了其内部流场,比较了新型全光滑直爪转子与现有直爪转子的不同。研究结果表明:所提出的转子在工作中不存在余隙容积中气体的过压缩过程,因而在工作性能和内部流动方面都优于现有的爪式转子。

The claw rotor profile is one of the key factors for improving pump performance.With the aim of sowing the problem that the conventional straight claw rotor profiles contain cusps or unsmooth connection points,the meshing theory of the conjugate curve is studied,and then a novel completely smooth profile of the straight claw rotor which can mesh correctly is proposed in this paper.Profile equations are derived,too.The working process of the claw vacuum pump with straight claw rotors is investigated by means of three dimensional numerical simulation.The internal flow fields are obtained.The proposed rotor is compared with the conventional rotor.Results indicate that the over-compression process of gases in the carryover does not occur in the working process for the proposed rotor.Therefore,the proposed rotor is superior to the conventional rotor in terms of working performance and internal flows.