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: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=741511
• 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.

拟议的研究计划调查的问题，在大型系统的流体结构相互作用的多个组件相互连接的高度空间对称性。所考虑的物理系统是一组螺旋管，其承受平行于螺旋轴的外部流动。 螺旋几何管阵列是紧凑型换热器设计的理想选择。与直管或U形弯管热交换器相比，螺旋管热交换器具有由热交换器占据的每单位体积空间的大得多的传热表面。最近的技术发展和对小规模能量产生系统（例如，小型模块化核反应堆、热太阳能发电系统）的关注正在推动对螺旋几何形状热交换器中的流体-结构相互作用的新兴趣。 除了工业应用之外，螺旋管阵列中高度复杂的流动还在流体与结构相互作用领域提出了一些具有挑战性的基础研究问题。螺旋管的强自耦合可由于沿着螺旋的强流体-结构相关性而导致增强的不稳定性。强烈的涡激振动由于涡脱落同步沿着螺旋线也预计是一个重要的问题。 本文的主要目的是研究平行于螺旋轴线流动的螺旋几何结构的流固耦合动力学。预计的主要流动激励现象是涡激振动和流体弹性不稳定性。虽然这些现象是相当好地理解为阵列的直管的螺旋管的几何形状改变了流固耦合问题在一个非平凡的方式。 拟议的研究计划将解决几个相关的流固耦合（FSI）问题。首先是螺旋管阵列几何形状的流体弹性不稳定性问题。第二个流固耦合问题涉及涡量脱落和涡激振动（VIV）。这个问题将使用计算流体动力学（CFD）和实验方法来解决。实验流场显示使用PIV技术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的流致振动的基本机制。这些阵列是高度紧凑的螺旋几何形状的热交换器和蒸汽发生器的关键组成部分。拟议的研究计划预计将有助于这些工业部件的稳定性分析的新方法的发展。