基于POD方法的燃料棒模态特征及流致振动响应降阶模型研究  

A Reduced-Order Model of Mode Characteristics and Flow-Induced Vibration Response of Fuel Rod Based on POD Method

作　　者：闵光云 姜乃斌 Min Guangyun;Jiang Naibin(Sino-French Institute of Nuclear Engineering and Technology,Sun Yat-sen University,Zhuhai,Guangdong,519082,China)

机构地区：[1]中山大学中法核工程与技术学院,广东珠海519082

出　　处：《核动力工程》2024年第4期142-149,共8页Nuclear Power Engineering

基　　金：国家自然科学基金(11872060);广东省重点领域研发计划项目(2021B0101250002)。

摘　　要：本文搭建了一个快速预测燃料棒模态特征及流致振动响应的降阶模型(ROM)。首先,基于有限元分析软件ANSYS的批处理功能得到不同刚度下燃料棒的模态数据,将模态数据组装成快照矩阵。接着,基于商用数学软件MATLAB和半经验公式批量计算燃料棒的流致振动响应,将流致振动响应数据组装成快照矩阵。然后,采用本征正交分解(POD)方法将快照矩阵投影到低维空间,并根据特征值大小选出能量占比最高的POD模态。基于选出的POD模态将快照矩阵重构回物理空间,实现了模态和流致振动响应的快速计算。研究发现:对于1阶模态和流致振动响应的重构,刚度越小所需要的POD模态数量越多;对于相同刚度下不同阶模态的重构,模态阶次越高,所需要的POD模态数量越多。本文研究结果对于燃料棒模态特征和流致振动响应的快速计算具有一定的意义。A Reduced-Order Model(ROM)for swiftly predicting both the modes and flow-induced vibration response of fuel rods is introduced in this study.Firstly,modes for fuel rods with varying stiffness are obtained using ANSYS-Batch,and these modes are then compiled into a Snapshots matrix.Subsequently,leveraging MATLAB and semi-empirical formulas,the flow-induced vibration responses of fuel rods are batch-calculated,and the resulting data is assembled into another Snapshots matrix.The Proper Orthogonal Decomposition(POD)method is then applied to project the Snapshots matrix into a lower-dimensional space,with the POD modes having the highest energy contribution being selected based on the magnitude of eigenvalues.Finally,the Snapshots matrix is reconstructed back into physical space using the selected POD modes,enabling the rapid calculation of both mode and flow-induced vibration responses.Our study reveals that for reconstructing the first-order mode and flow-induced vibration responses,a smaller stiffness necessitates a greater number of POD modes.Furthermore,in the reconstruction of different-order modes with the same stiffness,higher-order modes require a greater number of POD modes.The findings of this study hold significance for the swift calculation of fuel rod mode characteristics and flow-induced vibration responses.

关 键 词：本征正交分解(POD)方法 燃料棒 降阶模型(ROM) 模态特征 流致振动响应 

分 类 号：TL352[核科学技术—核技术及应用]