共轭转子的顶径对泵容积效率最大化的影响分析

Impact of Top-Radius of Conjugate Rotor on Volume Efficiency Optimization of Roots Pump

为阐述共轭转子的形状尺寸对泵容积效率的影响机理与规律。以最普遍的3叶圆弧转子为例,由"圆柱-平面"等效的缝隙泄漏与当量曲率半径的负相关性,取当量曲率半径为缝隙泄漏的替代研究对象,分析转子尺寸之形状系数、节径对容积利用率、三大内泄漏率的定量、定性影响效果。结果表明:形状系数越大,容积利用率越大,节径的影响可忽略;形状系数越大,共轭泄漏越小,径向泄漏缓慢增加;节径越大,三大内泄漏越小。得出转子的顶径越大,泵的容积效率越高的重要结论,研究内容为最终建立转子泵的内泄漏率或容积效率的计算模型,提供理论依据。

The influence of the shape-factor and pitch-circle radius of the conjugate rotor,as exemplified in a typical 3-lob circular arc rotor-pump,on the volume utilization rate and radial/axial/conjugate internal leakage rates was empirically approximated,mathematically formulated with the equivalent cylindrical-planar surfaces gap model and theoretically analyzed.The leakage rates can be derived by calculating the equivalent curvature radius of the gap instead.The calculated results show that the shape-factor and pitch-circle radius have a major impact.For example,as the shape-factor increases,the volume utilization rate rapidly and radial leakage rate slowly increase,and the conjugate leakage rate decreases,accompanied by a fast decreasing impact of the pitch-circle radius;as the pitch-circle radius increases,the radial/axial/conjugate leakage rates decrease.We suggest that the volume utilization efficiency may be optimized by maximizing the top radius of conjugate rotor.