主动液压激波作用下管道振动控制的运动分析与试验研究

为研究在主动液压激波作用下管道振动的动力学特性,建立流体的数学模型,设计出变频液压管网激振测试系统,用特征线法编程对激波作用下的有压脉动内流进行数值模拟。采用有限元法把管道简化为梁模型,建立考虑流固耦合的充液管道在激波作用下的振动方程,在保证特征线各断面与有限元节点重合的前提下,采用Newmark法编程将特征线法求得的流体各断面横向压力载荷施加到管道有限元的单元节点上,求得各断面处的动力响应。仿真结果表明,管道在轴向弹性支撑条件下,在激波作用下管道各断面压力和流速为简谐波,但两者呈反相关系。其横向各断面运动为简谐振动,振幅随系统压力的升高而升高,发现管道横向各断面振动波明显滞后于各断面对应的压力波,而轴向振动则由于弹簧与液体轴向力的耦合作用而出现较高的振动频率。数值模拟结果与试验结果基本比较吻合,揭示出流体动力学参数与管道振动之间的耦合关系,为激波作用下管道的二维振动特性及可控性研究提供了一些理论依据。

Kinematic Analysis and Experimental Research of Pipe Vibration Control Based on Active Hydraulic Excitation Force

To study dynamic characteristics of pipe vibration under hydraulic excitation force generated actively,at first mathematical model of pulsating fluid is established and a computer code based on the method of characteristics(MOC) is developed to simulate it.Then the vibration equation is derived considering the fluid-structure interaction,after which the pipe is simplified as beam model and analyzed by finite element method(FEM),where the nodes of the fluid adopted by MOC are coincided with that of the pipe by FEM.Using Newmark method,the dynamic response at every cross section of the pipe is worked out.Besides,an experimental system that axial direction of the pipe with elastic supports is designed to verify it.The numerical simulations show that a simple harmonic motion arises at every cross section of the pipe,but where excitation force is inverse trends with flow velocity.The lateral vibration amplitude of every node along the pipe increases as the rising system pressure,but the lateral vibration amplitude lags behind the excitation force obviously.Meanwhile,axial vibration frequency of the pipe is far higher than that of the excitation force due to the axial spring.Measured data is basically consistent with the numerical simulations.Some coupling relationships between fluid dynamic parameters and pipe vibration are revealed.So,this work is expected to provide some theoretical basis for two dimensional vibration characteristics of pipe and some exploratory study on its controllability.