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基于双螺杆真空泵气体输运的特点,将泵腔内级间的泄漏通道简化为不同类型的真空管路,采用相邻级间的平均压强确定不同压强下级间泄漏气体的流态,计算得到级间泄漏的质量流量。根据质量守恒定律,建立了双螺杆真空泵气体输运过程的数学模型。以渐开线型端面的等螺距螺杆真空泵为研究对象,计算分析了泵从大气压到极限真空的整个抽气过程。对不同入口压强下的级间泄漏量与抽速进行了研究,研究表明:不同的泄漏通道对级间泄漏的影响有所不同。在排气端,齿顶圆与泵腔内壁之间的泄漏通道对级间泄漏的影响较大;在吸气端,两转子齿顶齿根面之间、斜齿面之间以及凹齿面之间这三种泄漏通道对级间泄漏的影响较大。
Based on the characteristics of gas transport in twin-screw vacuum pump, the leakage channels between the stages in the pump chamber are simplified to different types of vacuum lines. The average pressure between adjacent stages is used to determine the flow pattern of the leakage gas between the lower and the lower pressure levels. Leaking mass flow. According to the law of conservation of mass, a mathematical model of the gas transport process of twin screw vacuum pump was established. Taking the involute type constant pressure screw vacuum pump as the research object, the whole pumping process of the pump from the atmospheric pressure to the ultimate vacuum was calculated and analyzed. The interstage leakage rate and pumping speed under different inlet pressures are studied. The results show that different leakage channels have different effects on interstage leakage. At the exhaust end, the leakage channel between the addendum circle and the inner wall of the pump chamber has a greater influence on the interstage leakage. At the suction end, the root surfaces of the top and bottom teeth of the rotor, the helical tooth surfaces and the concave tooth surfaces The three leakage channels between the level of leakage greater impact.