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A Study on Flow in a Rod Bundle Influenced Strongly by Buoyant Force

受浮力影响较大的杆束流动研究

基本信息

批准号：
01580229
负责人：
NAKAJIMA Tsuyoshi
金额：
$ 0.64万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01580229/
关键词：
Rod bundles Turbulent heat flux between subchannels Thermal plume LDV Laser induced fluorescence 04Simultaneous measurement of velocity and temperature 温度速度同時測定レ-ザ-流速計レ-ザ励起蛍光法

项目摘要

The experimental study of the thermal plumes in a rod bundle has been performed to measure the turbulent heat flux between subchannels and to provide information on the thermal plume behavior at the gap. An Ar-ion laser was used to measure velocity and temperature simultaneously without disturbing the flow field. A fiber LDV was made and inserted into a glass pipe with a Nichrome film heater on its outer surface, through which the laser beam was introduce into the fluid. The velocity information was obtained from the light scattered from SiC scattering particles and the temperature was estimated from the change of fluorescence of Rhodamine B solution. The turbulent heat flux at the gap center was measured under the conditions of Re=50-400 and Gr_<DELTAT>=300-1300 for various power skews. The experimental results show that the turbulent heat flux obtained experimentally was for smaller than the predicted values. Therefore, for application to the sodium cooled reactors it was expected that the turbulent heat flux might be negligibly small. The turbulent heat flux increased with Re and Gr_<DELTAT>. Negative turbulent heat flux, that is, counterflux heat transfer was observed. The change of temperature and velocity with time showed that the phase difference between velocity and temperature brought the counterflux. The phase difference is considered to be a reason for smaller turbulent heat flux than the predicted values. The simultaneous measurement system for velocity and temperature used in the present study operated quite well and is expected to display its ability not only in rod bundles but also in general thermal fluid study.

对棒束中的热羽流进行了实验研究，测量了子通道之间的湍流热流，并提供了差距处热羽流行为的信息。采用氩离子激光器在不干扰流场的情况下同时测量速度和温度。制作光纤LDV，将光纤LDV插入外表面带有镍铬合金薄膜加热器的玻璃管中，通过加热器将激光束引入流体中。利用SiC散射粒子的散射光获得了速度信息，利用罗丹明B溶液荧光的变化估计了温度。在Re=50-400和Gr =300-1300的条件下，测量了不同功率偏斜下差距中心的湍流热流密度<DELTAT>。实验结果表明，实验获得的湍流热流密度小于预测值。因此，对于钠冷反应堆的应用，预计湍流热通量可能小到可以忽略不计。湍流热通量随Re和Gr_2的增大而增大<DELTAT>。观察到负湍流热通量，即逆流传热。温度和速度随时间的变化表明，速度与温度的相位差产生了逆流。相位差被认为是湍流热通量小于预测值的原因。本研究中使用的速度和温度的同时测量系统运行良好，预计将显示其能力，不仅在棒束，而且在一般的热流体研究。