复合分子泵牵引级螺旋槽深对压缩比的影响

建立了描述复合分子泵牵引级抽气性能的理论模型.依据该理论模型,在牵引级不同螺旋升角、转子-定子间隙、转子转速、被抽气体流动状态条件下,对牵引级螺旋槽深与压缩比的关系进行了研究.结果表明:压缩比随螺旋槽深的减小,先增加后减小,存在最优螺旋槽深,使牵引级的压缩比达到最大;螺旋升角对最优螺旋槽深影响较小;最优螺旋槽深随转子-定子间隙减小而减小,随转子转速的增加而增加;当被抽气体为黏滞流时,最优槽深值更小.

Effect of Spiral Groove Depth of Compound Molecular Pump’s Drag Stage on Compression Ratio

A theoretical model for describing the pumping performance of compound molecular pump’s drag stage was established. According to the theoretical model， the relationship between the depth of drag stage’s spiral groove and compression ratio was studied under different spiral angles， rotor-stator clearances， rotor speeds and gas flows. The results showed that compression ratio firstly increases and then decreases with the decrease of spiral groove’s depth. There exists the optimal groove depth， which result in the maximum compression ratio of drag stage. The spiral angles have little effect on the optimal groove depth which decreases with the decrease of the rotor-stator clearances， and increases with the increase of the rotor speed. The optimal groove depth is smaller when the gas flow is viscous.