双喷嘴挡板伺服阀工作过程的数值模拟

摘要

为从理论上研究双喷嘴挡板伺服阀的工作性能，需对其建立较为精确的数学模型。针对电液伺服阀工作过程固有的机电液耦合特性，选择可统一处理多能域复杂系统的键合图法作为建模工具。根据衔铁、挡板组件和阀芯的运动规律，考虑喷嘴射流液动力等非线性因素，采用集中参数构建了系统的键合图模型，并推导出描述伺服阀工作过程内部能量供给、传递、转化和消耗的状态方程。结合某型伺服阀的相关参数，采用四阶 Runge-Kutta 法进行数值求解。数值模拟结果表明：伺服阀输入阶跃电流后，预测的负载流量阶跃响应的变化趋势能与试验结果较好吻合，并且模型能预测伺服阀系统内部状态变量的动态特性，为伺服阀结构参数优化研究和动态性能分析提供了理论依据。%To investigate the working performance of a twin-flapper-nozzle servo valve in theory,its accurate mathematical model needs to be established.According to electromechanical coupled characteristics of a servo valve,the bond graph method was taken as the modeling tool with advantages for dealing with multi-energy domain complex systems. According to the geometric relationship among the armature,baffle components and the main valve,the bond graph model of the servo valve was constructed based on its working mechanism,the nozzle jet fluid power and other nonlinear factors, and the system state-equations describing the energy input,transfer,translation and dissipation of the servo valve were deduced.Numerical simulation based on the four order Runge-Kutta method was performed with relavant parameters of a certain type of servo valve.The results showed that the trend of the load flow rate step response agrees well with that of the experimental results,the dynamic characteristics of the system internal state variables can be predicted with the model,so this modeling method provides a theoretical basis for the optimal design and dynamic analysis of servo valves.