防振条约束失效对蒸汽发生器传热管面内流弹失稳的影响研究

根据防振条布置以及面内支承连续失效个数，将防振条面内约束失效分析划分为多种工况，分析了不同工况下面内约束失效对传热管面内模态的影响，采用各位置阻尼在振型函数上进行加权平均的方法计算了各阶模态的阻尼比，进而研究了防振条面内不同约束对传热管面内流弹失稳的影响。分析结果表明，随着面内支承连续失效位置的增多，弯管段面内首阶模态频率不断降低，出现在弯管段的振型越加明显；弯管段面内首阶模态不一定是最大流弹失稳比值出现的模态，最大流弹失稳比值出现模态的振型几乎都出现在弯管段；随着面内支承连续失效位置的增多，面内流弹失稳比值不断增大，当连续3个及以上防振条面内约束失效时，将出现流弹失稳现象。

Effect of Constraint Failure of Anti-vibration Bar on In-plane Flow-elastic Instability of Steam Generator Heat Transfer Tube

According to the arrangement of the anti-vibration bars (AVBs) and the number of continuous failure of in-plane supports, the in-plane constraint failure analysis of AVBs was classified into several cases. The effects of in-plane constraint failures on the in-plane modes of steam generator heat transfer tubes under different cases were analyzed. The mode damping ratio was calculated by performing a weighted average method based on the mode shape function, and then the effects of different constraints by AVBs on flow-elastic instability of steam generator heat transfer tubes were studied. The analysis results show that with the increase of the continuous failure position of the in-plane support, the first-order modal frequency in the elbow section area decreases continuously, and the more vibration modes appear in the elbow section. The first-order mode in the elbow section is not necessarily the mode in which the maximum flow-elastic instability ratio occurs. The vibration mode with the maximum flow-elastic instability ratio appears almost in the elbow section. With the increase of the continuous failure position of the in-plane support, the flow-elastic instability ratio increases continuously. When three or more in-plane constraints fail continuously, the flow-elastic instability will occur.