FLUIDELELASTIC INSTABILITY, VORTEX-INDUCED VIBRATION AND SYMMETRY BREAKING IN HELICAL ARRAYS OF CYLINDERS SUBJECTED TO CROSS-FLOW

横流圆柱螺旋阵列中的流体弹性不稳定性、涡激振动和对称性破缺

• 批准号: RGPIN-2020-06955
• 负责人: mureithi, njuki
• 金额: $ 2.33万
• 依托单位: École Polytechnique de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754482
• 关键词: FLUIDELELASTIC; INSTABILITY; VORTEX; INDUCED; VIBRATION

The proposed research program investigates the problem of fluid-structure interaction in large systems consisting of multiple components interconnected with high spatial symmetry. The physical system under consideration is an array of helical tubes subject to external flow parallel to the helix axis. Helical geometry tube arrays are ideal for compact heat-exchanger design. Compared to straight or U-bend tube heat exchangers, helical tube heat exchangers have a much larger heat transfer surface per unit volume of space occupied by the heat exchanger. The recent technological developments and focus on small-scale energy generation systems (e.g. small modular nuclear reactors, thermal solar power systems) is driving renewed interest in fluid-structure interaction in helical geometry heat exchangers. In addition to industrial applications, the highly complex flows in helical tube arrays presents some challenging fundamental research problems in the area fluid-structure interaction. The strong auto-coupling of the helical tubes can lead to enhanced instability due to strong fluid-structure correlation along the helix. Strong vortex-induced vibration due to vortex shedding synchronization along the helix is also expected to be an important problem. The primary objective of the proposed research is to investigate the fluid-structure interaction dynamics of helical geometry structures subjected to flow parallel to the helix axis. The primary flow-excitation phenomena expected are vortex-induced vibration and fluidelastic instability. While these phenomena are fairly well understood for arrays of straight tubes the helical tube geometry changes the FSI problem in a non-trivial manner. The proposed research program will address several related fluid-structure interaction (FSI) problems. The first is the problem of fluidelastic instability in helical tube array geometries. Experimental testing and theoretical model development will be done.  The second  FSI problem relates to vorticity shedding and Vorticity Induced Vibrations (VIV). This problem will be addressed using computational fluid dynamics  (CFD) and experimental methods. Experimental flow visualization using PIV techniques will also be performed in the helical tube array.  The research program aims to address the fundamental mechanisms underlying flow-induced vibrations in helical geometry tube arrays. These arrays are the key component of highly compact helical geometry heat exchangers and steam generators. The proposed research program is expected to contribute to the development of new methods for the stability analysis of these industrial components.

拟议的研究计划研究由多个高度空间对称性互连的组件组成的大型系统中的流体-结构相互作用问题。所考虑的物理系统是受到平行于螺旋轴的外部流动的螺旋管阵列。与直管或 U 形弯管换热器相比，螺旋管换热器每单位体积的换热器占用的传热面积更大，是理想的选择。小型能源发电系统（例如小型模块化核反应堆、太阳能热发电系统）正在重新激发人们对螺旋几何热交换器中的流固相互作用的兴趣。除了工业应用之外，螺旋管阵列中的高度复杂的流动也带来了一些挑战。流体-结构相互作用领域的基础研究问题，由于沿螺旋线的强流体-结构相关性，螺旋管的强自耦合会导致不稳定性增强。沿螺旋线的同步预计也将是一个重要问题，该研究的主要目标是研究平行于螺旋轴流动的螺旋几何结构的流体-结构相互作用动力学。虽然对于直管阵列来说，这些现象已经被很好地理解，但螺旋管的几何形状以一种不平凡的方式改变了 FSI 问题，所提出的研究计划将解决一些相关的流体-结构相互作用。 (FSI) 问题。第一个是螺旋管阵列几何形状的流体弹性不稳定性问题。第二个 FSI 问题涉及涡量脱落和涡量引起的振动 (VIV)。使用计算流体动力学 (CFD) 和实验方法，使用 PIV 技术进行实验流动可视化。该研究项目旨在解决潜在的基本机制。螺旋几何管阵列中的流动引起的振动。这些阵列是高度紧凑的螺旋几何热交换器和蒸汽发生器的关键部件，预计将有助于开发这些工业部件的稳定性分析新方法。