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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=718574
• 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高空间对称性互连的多个组件组成的大型系统中的流固相互作用问题。所考虑的物理系统是一系列螺旋管，受到平行于螺旋轴的外部流动。 螺旋几何管阵列是紧凑型热交换器设计的理想选择。与直管或U形弯管换热器相比，螺旋管换热器在换热器所占据的单位体积空间内具有更大的传热表面。最近的技术发展和对小型能源发电系统（例如小型模块化核反应堆、太阳能热发电系统）的关注正在推动人们对螺旋几何热交换器中的流固相互作用重新产生兴趣。 除了工业应用之外，螺旋管阵列中高度复杂的流动在流固耦合领域提出了一些具有挑战性的基础研究问题。由于沿螺旋线的强流固相关性，螺旋管的强自耦合会导致不稳定性增强。由于沿螺旋线的涡旋脱落同步而引起的强烈涡旋振动预计也将成为一个重要问题。 本研究的主要目的是研究平行于螺旋轴流动的螺旋几何结构的流固相互作用动力学。预期的主要流动激励现象是涡流引起的振动和流体弹性不稳定性。虽然这些现象对于直管阵列来说是相当容易理解的，但螺旋管的几何形状以一种不平凡的方式改变了 FSI 问题。 拟议的研究计划将解决几个相关的流固耦合（FSI）问题。第一个是螺旋管阵列几何形状中的流体弹性不稳定性问题。将进行实验测试和理论模型开发。 第二个 FSI 问题涉及涡度脱落和涡度诱发振动 (VIV)。该问题将通过计算流体动力学 (CFD) 和实验方法来解决。使用 PIV 技术的实验流可视化也将在螺旋管阵列中进行。 该研究计划旨在解决螺旋几何管阵列中流动引起的振动的基本机制。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组件。拟议的研究计划预计将有助于开发这些工业部件稳定性分析的新方法。