干式罗茨真空泵吸气级内流动的瞬态模拟

Transient Numerical Simulation of Gas Flow in Suction Stage of Dry Roots-Type Vacuum Pump

基于动网格方法建立了干式真空泵罗茨型吸气级的三维瞬态数值计算模型。模拟结果与抽速曲线对比,入口压力为1000 Pa时误差为11.5%,100 Pa时误差为34.2%,表明计算流体力学(CFD)方法不适用于入口压力较低及极限真空时真空泵内的流动研究,但在入口压力较高时具有较好的数值精度。由于干式真空泵的主要设计问题多集中于入口压力较高,负荷较大的运行工况,应用CFD方法研究干式真空泵的流动特性具有实用价值。文中计算了真空泵的性能参数,分析了泵腔内的流动现象和流场的主要特征。

The transient gas flow in the suction stage of the dry roots-type vacuum pump was tentatively modeled,carefully approximated,and numerically simulated with the software package ANSYS-CFX,based on computational fluid dynamics（CFD）.The simulated results were then compared with the realistic pumping speed curve.The fact that at an inlet pressure of 1000 Pa,the error was 11.5%,and at 100 Pa,the error was 34.2% indicates that the CFD scheme works fairly well for the flow study in the range of high inlet pressure,but fails in the range of low inlet pressure,especially at the ultimate low pressure.Since the design considerations of the vacuum pump center on the realistic conditions： high inlet pressure,heavy load and large gas flow,the simulated results may be of some basic and technological interest.