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Research and Development on Shapes of Non-Vibrational Thermocouple in the Pipe System of Industrial Plants

工业厂房管道系统非振动热电偶形状的研究与开发

基本信息

批准号：
14350091
负责人：
OKAJIMA Atsushi
金额：
$ 8.77万
依托单位：
Kanazawa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14350091/
关键词：
Flow-induced vibration In-line oscillation Bluff body Circular cylinder Reduced mass damping parameter Aspect ratio Taperd circular cylinder Turbulent flow 減衰質量比ボイド率

项目摘要

Flow-induced oscillation of circular and rectangular cylinders were studied by free-oscillation tests in a water tunnel and a wind tunnel and also by numerical simulations. Flow-induced oscillation of bluff bodies occurs in industrial plants such as nuclear power plants, petroleum/chemical plants and offshore platforms. Usually, a thermocouple and a sensor probe are inserted in the pipe system. If the working fluid is a liquid, such cantilever-shaped structures with extremely small mass ratios may be easily induced by the flow to oscillate. We carried out multiple experimental and numerical studies where cylinders were elastically supported at both ends and where the cylinder was cantilevered. The main conclusions to obtained from these experiments and numerical simulations are as follows.(1)The response characteristics of cylinders with aspect ratios of 5 and 10 show single excitation region in the range of reduced velocity Vr from 1.0 to 4.0, in contrast to the cylinders with aspect … More ratios of 14 and 21. Most notably, the aspect ratio affects the depth of valley between the first and second excitation regions and the amplitudes of the second excitation regions.(2)It was found that cylinders with taper ratios of 2.5% to 10% had two excitation regions, while cylinders with taper ratios less than 1% had one excitation region. The taper ratio, therefore, affects the amplitude of the second excitation region. The reference diameter of the tapered cylinder was defined by the diameter at 1/3 length from tip in consideration of the results of oscillation characteristics of tested cylinders. The cylinder with any taper ratio did not oscillated at Vr<1.0. The amplitude of the cylinder with any taper ratio was suppressed at less mass-damping parameter Cn than 2.5, which is the suppression criteria for in-line oscillation of 2-dimensional cylinder.(3)The publication "Guideline for Evaluation of Flow-Induced Vibration of a Cylindrical Structure in a Pipe" by the Japan Society of Mechanical Engineers, Standard JSME S012-1998 is certified to include the case of a cantilever-shaped cylinder with a finite span length. Less

通过水洞和风洞中的自由振荡试验以及数值模拟，研究了圆形和矩形圆柱体的流致振荡。流致钝体振荡发生在核电站、石油/化工厂和海上平台等工厂中。通常，热电偶和传感器探头插入管道系统中。如果工作流体是液体，这种质量比极小的悬臂结构很容易被流动引起振荡。我们进行了多项实验和数值研究，其中圆柱体两端均弹性支撑，并且圆柱体悬臂式。从这些实验和数值模拟中得到的主要结论如下：(1)与长宽比为14和21的圆柱体相比，长径比为5和10的圆柱体的响应特性在折合速度Vr从1.0到4.0的范围内显示出单一激励区域。最值得注意的是，长宽比影响第一和第二激励区域之间的谷深和 (2)发现锥度比为2.5%~10%的圆柱体有两个激励区域,而锥度比小于1%的圆柱体有一个激励区域。因此，锥度比影响第二激励区域的幅度。考虑到测试圆柱体的振动特性结果，圆锥圆柱体的参考直径定义为距顶端 1/3 长度处的直径。任意锥度比的圆柱体在Vr<1.0时均不发生振荡。在质量阻尼参数 Cn 小于 2.5 时，任何锥度比的圆柱体的振幅均受到抑制，这是二维圆柱体直线振动的抑制标准。(3)日本机械工程师学会出版的“管道中圆柱结构流致振动评估指南”，标准 JSME S012-1998 经认证，包括具有有限跨度长度的悬臂形圆柱体的情况。较少的