Experimental investigation of long-term fretting wear of multi-span steam generator tubes with U-bend sections
Experimental investigation of long-term fretting wear of multi-span steam generator tubes with U-bend sections
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DOI：
10.1016/s0043-1648(98)00382-2
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发表时间：
1999-04-01
期刊：
影响因子：
5
通讯作者：
Magel, E
中科院分区：
文献类型：
--
作者：
Attia, MH;Magel, E
准确预测蒸汽发生器（SG）和热交换器（HX）管的微动磨损损伤增长速率是核电站安全、可靠和经济运行的需要。目前用于预测管的长期微动磨损行为的方法是基于将短期磨损数据库与管/支撑动态相互作用的非线性有限元冲击模拟相结合。本研究的主要目的是：（a）生成用于验证该方法的长期实验数据，（B）研究具有U形弯曲部分的多跨SG管的微动磨损是否是自限制的，以及（c）检查相邻管支撑之间的动态相互作用。建立了一套模拟全尺寸U形截面多跨SG管微动磨损行为的实验装置。在直管和U形弯管支架上安装了测量装置，用于测量管道的轨道运动和冲击力，在线计算了管道/支架界面处轴向和离面方向的能量耗散。结果分析表明，管/支撑间隙的增加导致磨损过程中能量耗散率（工作率）的非单调变化。这种行为，这表明，多跨管的微动磨损行为可能是自限制时，强制功能是不变的，是与计算机模拟预测。结果还表明，相邻支座之间存在较强的动力相互作用。还得出结论，比磨损率系数不是恒定的，并且取决于工作命运的大小。为了工作;速率范围内，磨损率系数在U形弯曲部分减少，并接近一个渐近值，随着工作速率的增加。结果还表明，最大磨损深度与平均磨损深度之比R-h = h（max）/h（av）随h（av）的增大而减小。(C)1999年由Elsevier Science S.A.出版All rights reserved.
Accurate prediction of the growth rate of fretting wear damage of steam generator (SG) and heat exchanger (HX) tubes is needed for safe, reliable and economical operation of the nuclear power plant. The methodology currently used to predict the long-term fretting wear behaviour of the tube is based on combining the short-term wear data base with non-linear finite element impact simulation of the tube/support dynamic interaction. The main objectives of this investigation are: (a) to generate long-term experimental data that will be used to verify this methodology, (b) to investigate whether the fretting wear of a multi-span SG tube with a U-bend section is self-limiting, and (c) to examine the dynamic interactions between adjacent tube supports. An experimental set-up has been developed to simulate the fretting wear behaviour of a full scale multi-span SG tube with U-bend section. Straight and U-bend tube supports were instrumented for in situ measurement of the tube orbital motion and impact forces, On-line calculation of the energy dissipated at the tube/support interface in the axial and out-of-plane directions was performed. Analysis of the results indicated that the increase in the tube/support clearance results in a non-monotonic change in the rate of energy dissipated in the wear process (work rate). This behaviour, which suggests that the fretting wear behaviour of a multi-span tube could be self-limiting when the forcing function is invariant, is in agreement with computer-simulation predictions. The results indicated also the strong dynamic interaction between adjacent supports. It has also been concluded that the specific wear rate coefficient is not constant, and depends on the magnitude of the work fate. For the work; rate range investigated, the wear rate coefficient at the U-bend section decreases and approaches an asymptotic value, as the work rate increases. Analysis of the results also showed that the ratio between the maximum and average wear depths, R-h = h(max)/h(av), decreases with the increase in h(av). (C) 1999 Published by Elsevier Science S.A. All rights reserved.