螺旋管式蒸汽发生器管束振动响应机制研究

Study on Vibration Response Mechanism of Tube Bundle for Helical Coil Steam Generator

  • 摘要: 螺旋管管束在流体冲击作用下发生振动,长期发生此现象,会导致螺旋管因微动磨损而逐渐失效,而短时间内出现过度振动,则会造成螺旋管失效破坏。因此,揭示螺旋管管束振动响应机制是非常重要的。本文建立了螺旋管管束流动激振模型,通过比较实验结果与仿真结果以验证数值方法的鲁棒性。基于螺旋管振动时域数据,利用小波分析方法研究了管的相对位置与管束结构参数对螺旋管振动响应的影响。结果表明,沿流体流动方向上,螺旋管越靠后,面外方向的振动响应越剧烈。相邻管层节径比越小,振幅越大,波动越剧烈。同层管间节径比与螺旋角对两方向上的振幅影响不明显。研究结果为螺旋管管束的湍流抖振与流体弹性不稳定性分析奠定了理论基础。

     

    Abstract: The helical tube bundle vibrates under the action of fluid impact. If this phenomenon occurs for a long time, the helical tube will gradually fail due to fretting wear, while excessive vibration in a short time will cause damage. Therefore, it is important to reveal the vibration response mechanism of helical tube bundles. In this paper, a flow excitation model with regard to the tube bundle was established, and the robustness of the numerical method was verified by comparing the experimental results with the simulation results. The core component of the shock vibration test system is a simplified three-layer helical tube bundle. The inlet is located below the shell and in the middle of the two supporting parts, that is, the middle and lower part of the span. The outlet is located at the top, opposite the entrance. The winding direction of the tube changes alternately, from inside to outside are left, right and left. The structural parameters of the pitch diameter ratio between adjacent tube layer (a=1.5), the pitch diameter ratio in the same layer (b=2.6) and the helix angle (α=15°) are used for the experimental bundle. The helical tube is stuck in the groove of the support, and then a support is constrained in the outer layer of the helical tube, and the two supports are matched with each other to fix the winding tube. The sensor is attached to the middle position of the test tube to monitor the vibration response of the helical tube in the in-plane and out-of-plane directions respectively. The wire of the sensor is fixed along the wall of the tube and extended to the supporting positions at both ends respectively. The wire is led out of the inside of the housing by using preset perforated bolts. Based on the time-domain data of the helical tube vibration, the influence of the relative position of the tube and the structural parameters of the tube bundle on the tube vibration response was studied by wavelet analysis method. The results show that along the fluid flow direction, the more backward the helical tube is, the more intense the vibration response in the out-of-plane direction is. The smaller the pitch diameter ratio between adjacent tube layers, the larger the amplitude and the more violent the fluctuation. The effects of pitch diameter ratio in the same layer and helix angle on the amplitude in both directions are not obvious. The research results provide a theoretical basis for the analysis of turbulent buffeting and fluid elastic instability for the helical tube bundles.

     

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