a Simulation of the Turbulence Response of Heat Exchanger Tubes in Lattice-Bar Supports
a Simulation of the Turbulence Response of Heat Exchanger Tubes in Lattice-Bar Supports
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DOI：
10.1006/jfls.2002.0468
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发表时间：
2002-12
影响因子：
3.6
通讯作者：
Marwan Hassan;D. Weaver;M. Dokainish
中科院分区：
文献类型：
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作者：
Marwan Hassan;D. Weaver;M. Dokainish
在核电站和化工厂的热交换器运行中，由于过度的流动诱导振动而导致的管道故障是一个主要问题。在可能的激励机制中，磁感应力具有持续的影响，因此是决定热交换器长期可靠性的重要因素。当管/支架发生碰撞时产生的冲击力在确定管磨损方面起着至关重要的作用。为了解决这个问题，管/支持相互作用模型在内部有限元程序中实现，并对三个已发表的例子进行验证。利用虚拟力和模态叠加法求解了格构式支座中松套管的非线性运动方程。时域模拟的非线性响应的管，以确定各种管和支持系统的振动特性的参数的影响。特别注意的是增加间隙的影响，在格子杆支撑管的响应。分析了管道响应、冲击力和接触比，并以无量纲形式表示。开发的无量纲参数被证明是有效的崩溃的数据有关不同的流速在单一的曲线。这些是有用的，在确定几个关键变量的作用，改变管动态。此外，这些参数还可以用于缩放结果，以考虑几何和材料特性的差异。
Tube failures due to excessive flow-induced vibrations are a major concern with regards to the operation of heat exchangers in nuclear power and chemical process plants. Among the possible excitation mechanisms, turbulence-induced forces have a persistent effect and thus are an important factor in determining the long-term reliability of heat exchangers. Impact forces which occur when tube/support collisions take place play a vital role in determining tube wear. To address this issue, a tube/support interaction model was implemented in an in-house finite element program and validated against three published examples. Pseudo-forces in conjunction with modal superposition were utilized in solving the nonlinear equations of motion of loose tubes in lattice-bar supports. Time-domain simulations of the nonlinear response of the tube are presented to determine the effect of various tube and support parameters on the vibratory characteristics of the systems. Special attention was paid to the effect of increased clearance on the response of tubes in lattice-bar supports. The tube response, impact force and contact ratio were analysed and represented in dimensionless form. The dimensionless parameters developed proved effective in collapsing the data pertaining to different flow velocities over single curves. These are useful in identifying the roles of several key variables in altering tube dynamics. Moreover, these parameters may also be used to scale the results to account for differences in geometrical and material properties.