Numerical study of bistable flow phenomena in square tube bundles based on Large Eddy Simulation

IF 2.3 3区工程技术 Q1 NUCLEAR SCIENCE & TECHNOLOGY

Annals of Nuclear Energy Pub Date : 2025-09-11 DOI:10.1016/j.anucene.2025.111868

Junshuai Sun , Rulei Sun , Pengrui Qiao , Sichao Tan , Ruifeng Tian

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引用次数: 0

Abstract

The nuclear energy industry is growing in the pursuit of high efficiency and safe operation. Consequently, the performance demand of key equipment, such as steam generators, is increasing. The existence of the bistable flow phenomenon in the tube bundles can result in a dynamic change in the fluid forces acting on the tubes. This, in turn, can have a non-negligible influence on the flow-induced vibration behaviour of the tube bundles. To explore the mechanism of the bistable flow phenomenon on the fluid forces and provide reliable technical support for the analysis of flow-induced vibration of tube bundles, this paper has numerically studied the bistable flow phenomenon in a square tube bundle with P/D = 1.40 (P, tube pitch, D, tube diameter) by using Large Eddy Simulation (LES). The three-dimensional turbulence effect in the tube bundles can be effectively simulated when the tube spreading length is larger than πD/4. The two quasi-steady flow modes in the bistable flow phenomenon were captured and distinguished, and exhibited random switching characteristics, indicating a chaotic phenomenon. By analysing the flow characteristics of the different modes in detail, it was found that there were significant differences in the velocity and pressure distributions in terms of values and trends. An in-depth study was carried out on the fluid forces acting on the tubes, particularly the lift force. The influence of three physical mechanisms on the lift force was revealed: the shear layer shedding of the tube itself, the intermittent interference of the shear layer of the upstream tube, and the inter-tube vortex interactions. The Strouhal numbers (Sr) corresponding to these three mechanisms are 0.205, 0.296, and 0.387, respectively. These values provide key parameters for quantitatively analysing the frequencies of the three mechanisms, and in turn, provide an important theoretical basis for the analysis of the flow-induced vibration and optimization design of the tube bundles.

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基于大涡模拟的方管束双稳态流动现象数值研究

核能工业在追求高效率和安全运行的过程中不断发展。因此，对蒸汽发生器等关键设备的性能要求越来越高。管束内双稳态流动现象的存在会导致作用在管束上的流体力发生动态变化。这反过来又会对管束的流激振动特性产生不可忽略的影响。为了探索双稳流动现象对流体力的影响机理，为管束流激振动分析提供可靠的技术支持，本文采用大涡模拟（LES）方法对P/D = 1.40 （P，管距，D，管径）的方形管束内的双稳流动现象进行了数值研究。当管束展开长度大于πD/4时，可以有效地模拟管束内的三维湍流效应。捕获并区分了双稳态流动现象中的两种准稳态流动模式，并表现出随机切换特性，表明存在混沌现象。通过对不同模态的流动特性进行详细分析，发现速度和压力分布在数值和趋势上存在显著差异。对作用在管道上的流体力，特别是升力进行了深入的研究。揭示了三种物理机制对升力的影响：管道本身剪切层脱落、上游管道剪切层的间歇性干涉和管道间涡相互作用。三种机制对应的Strouhal数Sr分别为0.205、0.296和0.387。这些数值为定量分析三种机构的频率提供了关键参数，进而为管束流激振动分析和优化设计提供了重要的理论依据。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Annals of Nuclear Energy 工程技术-核科学技术

CiteScore

4.30

自引率

21.10%

发文量

632

审稿时长

7.3 months

期刊介绍： Annals of Nuclear Energy provides an international medium for the communication of original research, ideas and developments in all areas of the field of nuclear energy science and technology. Its scope embraces nuclear fuel reserves, fuel cycles and cost, materials, processing, system and component technology (fission only), design and optimization, direct conversion of nuclear energy sources, environmental control, reactor physics, heat transfer and fluid dynamics, structural analysis, fuel management, future developments, nuclear fuel and safety, nuclear aerosol, neutron physics, computer technology (both software and hardware), risk assessment, radioactive waste disposal and reactor thermal hydraulics. Papers submitted to Annals need to demonstrate a clear link to nuclear power generation/nuclear engineering. Papers which deal with pure nuclear physics, pure health physics, imaging, or attenuation and shielding properties of concretes and various geological materials are not within the scope of the journal. Also, papers that deal with policy or economics are not within the scope of the journal.