直动式溢流阀的分岔分析与实验

为了改善广泛应用的直动式溢流阀的颤振行为,考虑油液压缩性、管道弹性和阀芯碰撞阀座时的能量损失,建立了溢流阀无量纲形式的数学模型。以4种不同的弹簧预压缩量,作出了相位和向量场分布图,得到了系统的稳定平衡状态。应用非光滑动态系统理论和计算软件MATLAB,画出了单参数和双参数分岔图,发现系统存在Hopf分岔、极限环鞍结点分岔、广义Hopf分岔和尖点分岔等分岔现象。搭建了测试平台,得到了阀芯位移分岔图和频谱瀑布图,对数学模型进行了实验验证。结果表明,小流量时为混沌或周期碰撞震荡,增大流量可改善阀芯颤振行为,为周期非碰撞震荡或稳定平衡状态。此研究工作为直动式溢流阀的失稳机理和颤振行为提供了理论依据。

Bifurcation Analysis and Experimental Study of Direct-Acting Relief Valve

To improve the operation characteristics of a direct-acting relief valve with chatter, a non-dimensional mathematical model is derived considering fluid compressibility, tubes elasticity and energy loss during the collision between the valve poppet and its seat. First, the stable equilibrium states of the system are learned from the phase and vector field diagrams drawn under four different pre-stress value of the spring. Then, one-parameter and two-parameter bifurcation diagrams, which are based on the theory of non-smooth dynamical systems drawn by MATLAB, reveal Hopf bifurcation, saddle-node bifurcation of cycles, generalized Hopf bifurcation and cusp bifurcation in the system. Finally, the spool displacement bifurcation diagram and spectra waterfall diagram are measured on the test platform for the verification of the mathematical model of the relief valve. The results show that the chaos or period impacting-scillation at low flow rate could turn into period non-pacting- scillation or stable equilibrium by increasing the flow rate. Thus, the operation characteristics of a direct-acting relief valve with chatter are improved.