Self-Excited Vibration of a Flexible Shell Caused by Fluid Discharge

流体放电引起的柔性壳体自激振动

基本信息

批准号：
02650173
负责人：
KANEKO Shigehiko
金额：
$ 1.34万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02650173/
关键词：
Flow Induced Vibration Self-Excited Vibration Nuclear Reactor Component Fast Breeder Reactor Overflow Weir Shell Vibration Sloshing Time Delay

项目摘要

A new type of self-excited osillation due to the fluid discharge was observed during test operations of the Super Phenix LMFBR in France. Two types of instability modes were observed : one is the sloshing mode the meaning of which is the oscillation of a weir associated with both feeding and restitution collectors ; the other is hydroelastic mode the meaning of which is the osillation of a weir associated with fluid shell modes. In this investigation, the excitation mechanism of both modes is discussed both theoretically and experimentally. In the experiments, rectangular and annular tank were designed and manufactured to investigate the effect of fall hight and supply flow rate on the instability. Both sloshing and hydroelastic modes were observed in a rectangular tank. On the other band, only asloshing mode instability was observed in an annular tank. To establish the theory which can explain the mechanism of this instability, theoretical model was proposed. In this theory, basic equations are composed of the momentum equation of the downstream tank sloshing and conservation of supply flow rate. To formulate the fluid force colliding with free surface, momentum theory was employed. Finally, we succeeded in deriving the simplified governing equation of this instability. Theoretical results show the following ; (l)the frequency of this unstable oscillation is almost equal to the first natural frequency of the downstream tank sloshing, (2)unstable vibration can occur at the range of certain fall height, (3)the range of which becomes narrow with increasing supply flow rate. These theoretical results agree well with experimental results and the validity of the theory was confirmed.

在法国超级Phinix LMFBR的测试操作期间，观察到了一种新型的自振荡渗透性。观察到两种类型的不稳定性模式：一种是荡妇模式，其含义是与喂养和恢复原状相关的堰的振荡；另一种是水力弹性模式，其含义是与流体壳模式相关的堰的渗透。在这项研究中，在理论上和实验上都讨论了两种模式的激发机制。在实验中，设计和制造了矩形和环形储罐，以研究秋天的高高和供应流速对不稳定性的影响。在矩形储罐中观察到晃动和水理模式。在另一个频段上，仅在环形储罐中观察到令人垂涎的模式不稳定性。为了建立可以解释这种不稳定性机制的理论，提出了理论模型。在这个理论中，基本方程是由下游坦克倾斜和供应流量保存的动量方程组成的。为了制定与自由表面碰撞的流体力，采用了动量理论。最后，我们成功地得出了这种不稳定的简化管理方程。理论结果显示了以下内容；（l）这种不稳定振荡的频率几乎等于下游坦克宽度的第一个固有频率，（2）在某些秋季高度的范围内，不稳定的振动可能发生，（3）随着供应流量的增加，其范围变得狭窄。这些理论结果与实验结果非常吻合，并确认了理论的有效性。