黏度对凸轮转子泵效率影响的数值分析

Numerical investigation of viscosity impact on rotary lobe pump performance

为了研究输送介质黏度对凸轮转子泵效率的影响,运用三维造型软件建立三叶凸轮转子泵的参数化模型,采用尺寸函数对转子泵模型进行网格划分,并对转子附近区域进行网格加密.采用RNG k-ε湍流模型、动网格技术对转子泵进行数值模拟,得到不同输送介质所对应的转子泵效率,并探讨介质黏度对转子泵的效率影响.结果表明,当进出口压差从0.1 MPa增至0.6MPa时,不同黏度介质所对应的容积效率均呈下降趋势,但黏度较大(>250 cP)的流体介质对压差的敏感性较小.当压差不变,转速从200 r/min增至600 r/min时,低黏度流体介质(<100 cP)的容积效率得到明显提高,而高黏度流体介质变化幅度不大.不同黏度的流体达到最高效率时所对应的工况不同,黏度较大的流体介质达到最高效率时转速较低.

In order to study the effect of the transmission medium viscosity on lobe pump efficiency, the 3D modeling software was used to build parametric models of the lobe pump. The size function was applied to mesh the lobe pump model and the grid near the rotors was refined. On the computational fluid dynamics software platform, the numerical simulation of lobe pump was performed with RNG k -ε turbulence mode and dynamic mesh technique. By comparing the lobe pump efficiencies with different transmission media, the impact of medium viscosity on the lobe pump efficiency was revealed. The results show that when the pressure differential is increased from 0.1 MPa to 0.6 MPa, the volumetric efficiency corresponding to each viscosity of the medium is decreased, but the medium with larger viscosity （ 〉250 cP） is less sensitive to pressure differential. When pressure differential is constant and rotation speed is increased from 200 r/min to 600 r/min, volumetric efficiency of low-viscosity fluid medium （ 〈 100 cP） has been significantly improved, and the high-viscosity fluid medium changes only slightly. Along with the increase of medium viscosity, the rotation speed for the maximum efficiency of lobe pump decreases. This paper has reference value for a reasonable selection of lobe pump in dif- ferent operational conditions and improvement of lobe Dump efficiency.