Abstract:

Concentric circular tube bundles are widely used in the nuclear industry, with transitional arrangements being the most representative configuration among them. Studying the vortex shedding characteristics of transitional tube bundles can provide valuable insights for the design, manufacturing, and maintenance of this type of heat exchanger. This study aimed to explore in depth the vortex shedding characteristics of concentrically arranged transitional tube bundles under different pitch-to-diameter ratios (1.25, 1.5, 1.75, and 2.0). By employing numerical simulations combined with monitoring of flow velocity and lift coefficient, vortex shedding data were obtained and Fourier transformed to determine the vortex shedding frequency. The results indicated that in the transitional arrangement, tube bundles with pitch-to-diameter ratios between 1.25 and 2.0 were significantly influenced by adjacent tubes, making it difficult to produce clear vortex shedding phenomena and resulting in lower vortex shedding frequencies. The pitch-to-diameter ratio was one of the main factors affecting vortex shedding. As this ratio increased, the vortex shedding phenomena became more pronounced. The findings provided practical guidance for optimizing the design of concentric circular transitional tube bundle structures and reducing vortex-induced vibrations.

Key words: concentric circularly arranged tube bundles, vortex shedding, transverse flow induced vibrations, computational fluid dynamics, fluid induced vibration, numerical simulation

摘要：

同心圆排布管束在核工业中应用广泛，过渡排布是同心圆排布管束中最具有代表性的排布方式，对过渡排布管束的旋涡脱落特性研究可以为该类型换热器的设计制造及维护提供参考。本文旨在深入探讨同心圆过渡排布管束在不同节径比（1.25、1.5、1.75和2.0）下的旋涡脱落特性。通过数值模拟结合对流速与升力系数的监测，获取旋涡脱落数据并进行傅里叶变换以获取旋涡脱落频率。结果表明，在过渡排布方式中，1.25~2.0节径比下管束的旋涡脱落受临近管影响较大，难以产生明显的旋涡脱落现象，旋涡脱落频率较低。节径比是旋涡脱落的主要因素之一，随着节径比增加，旋涡脱落现象显著增强，本文研究结果为同心圆过渡排布管束结构的设计优化和降低旋涡脱落振动提供实践指导。

关键词: 同心圆排布管束, 旋涡脱落, 横向流诱导振动, 计算流体力学, 流致振动, 数值模拟