【作者】 杜兵；

【导师】 唐委校；

【作者基本信息】 山东大学 ， 化工过程机械， 2008， 硕士

【摘要】 管道在工业领域中应用十分广泛,而管内流体与管道间的流固耦合作用引起的管道系统振动,会大大降低系统运行可靠性,恶化工作环境,影响仪器仪表的精度,甚至使管道爆裂。在电厂、石油及化工行业中,很多管道在运行过程中会产生较大的位移,必需使用恒力支吊结构支承。恒力支承可以提供一种不随支承方向的位移发生变化的恒定支承力,可以避免管道系统产生危险的弯曲应力及位移。恒力支承对输流管道系统的动态特性也有影响。因此,研究输流管道系统中恒力支承及流固耦合作用对输流管道动态特性的影响,准确分析系统的动力学特性、对于管道系统的优化设计、提高系统运行可靠性具有十分重要的理论意义和工程价值。本文对恒力支承下的输流管道系统进行了动态特性分析,具体工作包括以下几个方面:1.考虑流固耦合作用及恒力支承影响,以流体运动的连续方程、动量方程和管道的振动方程为基础,建立带恒力支承输流管道的动力学模型,推导了输流管道轴向及横向振动的运动微分方程。2.基于输流管道轴向及横向振动的微分方程,考虑流体与管道之间的泊松耦合,推导出输流直管的轴向及横向振动的传递矩阵;同时采用中线不可伸长理论的离散模型,将弯管离散为一组首尾相连成一定角度排列的短直管单元,通过力的平衡方程和连续性方程,构建了弯管振动的传递矩阵。3.采用传递矩阵法对带恒力支承的输流直管和弯管进行了模态分析,并与典型的RPV系统算例及采用ANSYS有限元数值计算结果进行了比较分析,验证了所建动力学模型和传递矩阵的正确性。分析结果表明,流固耦合作用对系统模态频率的影响较大,对系统模态振型的影响较小;使用恒力支承的输流管道的动态特性与固支、简支的输流管道的动态特性有明显不同,使用恒力支承的输流管道的各阶固有频率均较小,且在恒力支承的情况下,流固耦合作用对管道系统的动态特性影响更大。更多还原

【Abstract】 Piping system has already been widely used in many fields of industry, and play an important role. However, the vibrations of piping systems that caused by fluid structure interaction (FSI) between fluid and the pipe wall, deteriorates the performance of the system, worsens the reliability of operation, affects the precision of the instruments, and even blows out the pipe. In the field of Petroleum and chemical industry, large displacements would appear in many pipes during running. In this condition, the constant hanger is necessary to be used. Constant hanger can produce an constant force that wouldn’t change with the displacement along the support direction, which can avoid the appearance of dangerous bending stress and displacement in the piping system. Dynamic characteristics of piping system can also be influenced by the Constant hanger. Therefore, research on the influence of constant hanger and the FSI to the dynamic characteristics of piping system has an important value both in theory and engineering for understanding the dynamics characteristics and upgrading the running reliability of the piping system.In this thesis we studied dynamic analysis for the liquid-filled pipe under constant hanger. The research work involves several aspects as follows:Considering the influence of FSI and constant hanger, dynamic model of liquid-filled pipe with constant hanger was established and linear differential equations of axial and transverse vibrations was developed on the basis of continuity equation, momentum equation and vibration equation of pipe.Based on the axial and transverse vibration differential equations for the fluid-conveying straight pipe and L-shaped pipe, considering Poisson coupling between the liquid and the pipe, the transfer matrixes of the axial and transverse movements for the fluid-conveying straight pipe were developed. According to the inextensible axes discrete model, the bended pipe is viewed as a series of end to end short straight pipe elements jointed together. Then based on the force balance equations and continuity equations, the transfer matrix of the L-shaped pipe vibration was established. The modal analysis was done to the fluid-conveying straight pipe and L-shaped pipe supported by constant hanger with transfer matrixes method, and the numerical results were compared with those from RPV and from ANSYS, which proved the validity of our dynamic model and transfer matrixes. It turned out that the coupling effect of the liquid and solid had a great influence on the model frequency, and it had a little influence on the model vibration; The dynamic identity of fluid-conveying pipe supported by constant hanger was different from this with supported edges of clamped edges, and the natural frequency of fluid-conveying pipe supported by constant hanger was small, and the coupling effect of the liquid and solid had a greater influence on the pipe system instead.更多还原