Abstract This paper presents an analysis of flow in the shell side of a 24-degree cut helical coil steam generator (HCSG) with large eddy simulation (LES). In the study, the open source, high-order spectral element CFD code Nek5000 was employed for numerical simulation. LES was performed at a Reynolds number of 9000 based on the inlet velocity and tube diameter. Spectral analysis was carried out along the tube bundle to investigate vortex shedding and to reveal shedding frequencies in HCSGs. Wavelet analysis was carried out to determine the time-frequency information of the fluctuating velocities in the domain. Flow was decomposed into modes with proper orthogonal decomposition, which revealed coherent structures in the flow and evolution of coherent structures in time. For the validation of Nek5000 in complex geometries, results from the numerical simulation were compared with experiments conducted at Texas A&M University. Overall, the LES results showed good agreement with experimental data.

中文翻译：

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大涡模拟螺旋盘管蒸汽发生器实验中流动的频谱和模态分析

摘要 本文通过大涡模拟 (LES) 对 24 度切割螺旋盘管蒸汽发生器 (HCSG) 的壳侧流动进行了分析。在研究中，采用开源的高阶光谱元 CFD 代码 Nek5000 进行数值模拟。基于入口速度和管径，LES 以 9000 的雷诺数进行。沿管束进行光谱分析以研究涡旋脱落并揭示 HCSG 中的脱落频率。进行小波分析以确定域中波动速度的时频信息。流被适当的正交分解分解为模式，揭示了流中的连贯结构和连贯结构的时间演化。为了在复杂几何形状中验证 Nek5000，数值模拟的结果与德克萨斯 A&M 大学进行的实验进行了比较。总体而言，LES 结果与实验数据显示出良好的一致性。