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A STUDY ON FLUIDELASTIC VIBRATIONS OF TUBE ARRAYS SUBJECTED TO CROSSFROW IN HEAT EXCHANGERS

换热器横流管阵列流弹性振动研究

基本信息

批准号：
07455101
负责人：
HAYAMA Shinji
金额：
$ 3.9万
依托单位：
UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07455101/
关键词：
VIBRATION OF TUBE ARRAY FLUIDELASTIC VIBRATION CRITICAL VELOCITY HYDRAULIC COEFFICIENTS

项目摘要

A vast number of papers have been published on the fluid-elastic vibrations of heat exchanger tube arrys subjected to crossflow, in almost all of which the hydrodymanic coefficients necessary to evaluate critical flow velocities are obtained experimentally. In this study it is aimed at obtaining the hydro-dynamic coefficients analytically by using the leakage-flow theory developed by the author. The results obtained are as follows.1.The measurements of pressure distribution in the streamwise direction in the three-row tube array show that the total pressure drop occurs at the first row. This fact means that the firsst row acts like a row of nozzles in impulse turbines. The minimum pressure occurs at the minimum gap and then the flow separates from the tube walls at about 5-10 degree after the minimum gap. The second row receives velocity energy and the pressure rises just before the minimum gap and then drops again after the minimum gap.2.Fluid forces acting on a tube in one-row tubes when it vibrates in the row direction are calculated by using the leakage-flow theory and compared with the experimental results obtained by Tanaka. Fairly well agreement is obtained, which confirms the validity of applying the leakage-flow theory for gap flow between tubes.3.Stability analysis shows that at gap velocity instability is caused by fluid negative damping, and that at high gap velocity whirling mode instability occurs. The latter is caused by velocity-squared fluid-stiffness, where the critical velocities are proportional to the root of mass damping parameters.4.Resonant pressure pulsations in the stremwise direction occur with high sound level in the duct containing tube array in a certain range of flow rate.

关于换热器管阵在横流作用下的流体弹性振动问题已经发表了大量的论文，几乎所有的论文都是通过实验获得了计算临界流速所需的流体动力系数。本文的研究目的是利用作者提出的泄漏流动理论解析求得水动力系数。得到的结果如下：1。对三排管阵流向压力分布的测量表明，总压降发生在第一排。这一事实意味着，第一行的作用就像脉冲涡轮中的一排喷嘴。最小压力出现在最小间隙处，然后在最小间隙后约5-10度处流体与管壁分离。第二排接收速度能量，压力在最小间隙前上升，在最小间隙后又下降。利用泄漏流理论计算了单排管内管内沿排方向振动时作用在管内的流体力，并与Tanaka的实验结果进行了比较。得到了较好的一致性，证实了泄漏流理论应用于管间间隙流动的有效性。稳定性分析表明，在间隙速度下失稳是由流体负阻尼引起的，在高间隙速度下发生旋转模态失稳。后者是由速度平方流体刚度引起的，其中临界速度与质量阻尼参数的根成正比。在一定的流量范围内，含管管道阵列在高声级情况下会发生流向共振压力脉动。