摘要
为充分利用平凸共轭的轮廓质量和克服低容积利用系数的不足,提高了一种顶直的、高形的平凸工作轮廓。先后从高形构造、顶直工作轮廓、高形避让轮廓、最大形状系数等四方面,逐步展开容积利用系数所涉及公式的推导。结果表明:直谷转子的形状系数为2叶、3叶、4叶的1.293、1.134、1.0761;容积利用系数为0.3748、0.1873、0.0973,仅限于2叶使用。顶直转子的形状系数为1.333、1.310、1.277;容积利用系数为0.4233、0.4013、0.3722,容积利用系数增效为12.94%、114.3%、282.5%。高形转子(τ=2°)的形状系数分别为1.413、1.396、1.370;容积利用系数为0.4865、0.4732、0.4549,容积利用系数再增效14.39%、17.92%、22.22%。高形转子的叶数敏感度低,利于多叶应用以提高脉动质量;高形角对高形系数具有负线形相关;重心明显偏向根部,利于提高转子系统的动不平衡性能。高形圆弧、平-凸共轭轮廓降低了径向和共轭泄漏;转子形状系数采用最大值,提高了容积利用系数,二者共同实现了泵的轻量化。为转子泵的进一步研究提供了基础理论。
A novel rotor with higher shape-factor was proposed to decrease the gross weight and to increase the volume utilization coefficient of Roots vacuum pump with flat-convex rotor profile.The volume utilization coefficient and shape-factor of the straight-valley rotor,straight-top rotor and novel rotor with higher-shape factor were analytically derived and calculated,respectively.For example,the shape-factor(the volume utilization coefficient)of the new rotor,at an angle of 2°and with 2,3 and 4 lobes,were 1.413,1.396 and 1.370(0.4865,0.4732 and 0.4549 and with the increase of 14.39%,17.92%and 22.22%),respectively.The advantages of the proposed rotor with higher shape-factor include greater volume utilization coefficient,lighter weight,smaller radial/conjugate leakages,lower center of gravity,higher dynamic stability,less noises and weaker vibration.We suggest that the calculated results be of basic and technological interest in design optimization of lightweight Roots vacuum pumps.
作者
刘萍
Liu Ping(School of Mechanical and Electrical Engineering,Suqian College,Suqian 223800,china)
出处
《真空科学与技术学报》
EI
CAS
CSCD
北大核心
2020年第5期400-404,共5页
Chinese Journal of Vacuum Science and Technology
基金
江苏高校“青蓝工程”资助(2017852)
宿迁市科技项目(Z2018229,K201924)。
关键词
泵
高形转子
最大形状系数
容积利用系数
工作轮廓
避让轮廓
Pumps
High-shape rotor
Maximum shape factor
Volume utilization coefficient
Working profile
Avoidance profile
