中间约束输流管道流固耦合振动的数值模拟

Numerical Simulation on Fluid-solid Coupling Vibration of Fluid-conveying Pipes with Intermediate Constraint

基于流体层流假设,研究细长输流圆管在弹簧约束条件下的动力学特性.根据虚功原理建立输流管道系统的控制方程,应用有限差分法离散求解域,采用两端简支的边界条件导出了系统广义复特征方程,随后研究了管道固有频率与流体粘性及弹簧刚度的关系.数值求解了流体临界速度,分析了弹簧刚度对临界速度的影响.结果表明:流体平均速度增大则固有频率降低;流体平均速度相同的条件下,粘性的存在使得固有频率降低;弹簧对系统固有频率和临界速度的影响与弹簧刚度和弹簧的布置位置相关.

Based on the assumption of fluid laminar flow,this paper studies the dynamic characteristics of slender tubes with flow transport under spring constraints.Based on the principle of virtual work,the governing equation of fluid-conveying pipe system is established.The solution domain is discretized by the finite difference method,and the generalized complex characteristic equation of the system is derived by using the simply supported boundary conditions at both ends.Then the relationship between the natural frequencies of the pipe system and the fluid viscosity and the spring stiffness is studied.The critical velocity of fluid is solved numerically and the influence of spring stiffness on the critical velocity is analyzed.The results show that the natural frequency decreases as the average velocity of fluid increases.When the average velocity of fluid is the same,the viscosity reduces the natural frequency.The influence of the spring on the natural frequency and critical velocity of the system is related to the spring stiffness and the spring arrangement position.