三叶渐开线罗茨风机转子数值分析与优化

Numerical Analysis and Optimization for Three-Lobe Involute Roots Blower

为了获得三叶渐开线罗茨风机基圆半径变化对风机性能的影响关系,首先从几何原理角度,分析了渐开线基圆变化对风机转子啮合渐开线的影响,给出了符合啮合条件的渐开线基圆半径变化范围,及不同基圆半径对转子面积利用率系数的影响情况。在此基础上利用数值分析方法,对同种叶型不同基圆半径时的风机转子流场进行数值计算,运用动网格技术分析了风机内部的压力场、涡的强度变化和进气口质量流量变化情况。模拟结果表明:同种叶型渐开线基圆半径增加,能够削弱涡的强度和速度,增加进气口质量流量,提高风机效率,因此风机生产企业设计时应选择较大的渐开线基圆半径。

In order to obtain the relationship between the changes of base circle radius on three-lobe Roots blower and the blower performance, first the influence of blower rotor involutes from the changes of base circle radius is analyzed from the perspective of geometric principles, and the available range of involute base circle radius is given as well as its influence of area utilization factor. Then based on the numerical analysis method, the blower internal pressure field, the vortex intensity variation and the inlet mass flow rate changes under the same rotor type and different base circle radius are calculated by the dynamic mesh technique. Simulation results show that: the increase of the same kind of rotor type involute base circle radius can weaken the vortex strength and speed, increase inlet mass flow, and improve efficiency of the Roots blower. The blower manufacturer should therefore choose a larger involute base circle radius.