水基液三螺杆泵动态数值分析

Numerical Analysis of Water-based Liquid Three-screw Pump

为开发输送水基抗燃液压液的三螺杆泵,测量了水乙二醇难燃液压液黏温特性曲线,建立了三螺杆泵三维模型,进行了CFD数值分析和试验验证。CFD仿真计算时,为避免网格数量过多或出现负体积而无法保证实际啮合间隙问题,采用SCORG软件对泵内流道进行了共形结构网格的划分,并结合Pumplinx软件进行数据后处理。研究表明:采用动态数值模拟方法的仿真结果与实验结果吻合良好,并对32号液压油与水基液压液输送特性进行了对比分析,得出了主杆扭矩和泵泄漏量随液压介质温度变化关系图;水基液压液相较于滑油更容易产生气蚀,气蚀主要发生在泵进口腔,气蚀现象随着密封腔压力上升而渐减小,泵转速越高,空化气体体积分数越大;泵出口压力越小,空化气体体积分数也越大,随着出口压力的增加,转速对空化气体体积分数的作用越不明显;水基液三螺杆泵工作时更容易发生油膜破损,经流固耦合分析,油膜所承受最大应力为4. 369 9 MPa。

In order to develop a three-screw pump for water-based flame retardant hydraulic fluid,the viscosity-temperature characteristic curve of water-glycol flame retardant hydraulic fluid is measured,a three-dimensional( 3 D) model of three-screw pump is established,and Computational Fluid Dynamics( CFD) numerical analysis and experimental verification is carried out. In the CFD simulation calculation,in order to avoid the excessive mesh volume or negative volume,the actual meshing gap could not be guaranteed.The SCORG software was used to divide the common structure grid of the pump inner channel and combined with Pumplinx software for data post-processing. The research shows that the simulation results of the dynamic numerical simulation method are in good agreement with the experimental results,and the characteristics of the hydraulic fluid and water-based hydraulic fluid transfer are compared and analyzed. The relationship figure between the main rod torque and the pump leakage with varying temperature of the hydraulic medium is obtained. Water-based hydraulic liquid phase is more prone to cavitation than oil,cavitation mainly occurs in the pump inlet cavity,cavitation phenomenon gradually decreases as the seal chamber pressure rises,and the higher is the pump speed,the larger is the cavitation gas volume fraction. The smaller the pump outlet pressure is,the larger the cavitation gas volume fraction is. As the outlet pressure increases,the effect of the rotational speed on the cavitation gas volume fraction is less obvious. The water-based liquid threescrew pump is more prone to oil film damage during operation,and the maximum stress of the oil film is 4. 369 9 MPa through fluidsolid coupling analysis.