为研究管壳式熔盐空气换热器U型管弯管段受空气冲击诱导振动响应特性,依托中国科学院战略性先导科技专项——钍基熔盐堆核能系统(Thorium Molten Salt Reactor,TMSR)综合仿真实验平台,采用单管双向流固耦合方法进行仿真。计算加速度值与实验值较为吻合,误差范围为-12%~15%,证明了单管双向流固耦合方法分析换热管流致振动问题的可行性。数值模拟还表明:流致振动具有在初始0.06 s时间内空气流动和传热管位移趋于稳定和外扩-回弹的周期性变化等特征,最终将在一微小区间内做"8"字往复运动。
This paper concentrates on investigating the mechanical stability of a Beam Position Monitor (BMP)support prototype of the Shanghai Synchrotron Radiation Facility(SSRF)project.Both finite element analysis and vibration measurements have been performed.Inconsistent results between the simulations and experiments motivate us to study three connections between the support and the ground:ground bolt(used in the initial design),part grout and full grout(proposed in the later research).After changing the connection, the first eigenfrequency is increased from 20.2Hz to 50.2Hz,and the ratio of the integrated RMS displacement (4—50Hz)is decreased from 4.36 to 1.23 in the lateral direction.The mechanical stability is improved greatly.
钍基熔盐堆(Thorium Molten Salt Reactor,TMSR)控制棒通道套管是典型的承受外压的高温薄壁长圆柱壳,蠕变-屈曲失稳是其主要失效模式。本文旨在利用数值模拟方法研究控制棒通道套管高温下的蠕变屈曲失稳行为。首先基于UNS N10003合金的高温蠕变试验数据获得了该材料的Norton蠕变模型及材料参数;然后利用有限元分析软件ABAQUS进行了TMSR控制棒通道套管的特征值屈曲分析与蠕变屈曲分析,并对屈曲失稳的关键因素进行了敏感性分析,获得了蠕变屈曲寿命的经验公式。分析结果表明,温度、压力、结构尺寸均会对套管的蠕变屈曲寿命产生显著影响。本文的研究结果对TMSR控制棒通道套管以及复杂结构与载荷条件下的高温结构的稳定性设计提供了工程指导依据,也为其他高温薄壁结构的蠕变屈曲寿命预测提供了依据。
