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Fluid Dynamic Aspect in the Heat Removal near the Spacer of the Fuel Rods of a Nuclear Reactor

核反应堆燃料棒间隔件附近散热中的流体动力学方面

基本信息

批准号：
61550131
负责人：
FUKANO Tohru
金额：
$ 1.22万
依托单位：
Kyushu 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：
1986
资助国家：
日本
起止时间：
1986 至 1987
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61550131/
关键词：
Two-phase flow Film flow Spacer Obstacle Fuel rod 原子炉

项目摘要

In this research project (1) flow mechanism of a thin liquid film flowing concurrently with a high speed gas flow, (2) mechanism of a large disturbance wave generation, and (3) the interaction between a flat-plate type flow obstruction with a cylindrical projection and a thin liquid film, are investigated. The results are summarized as follows; (1) Although the film Reynold's number was 150 at the most in this research, the film flow is laminar only in the very narrow region close to the duct wall due to the momentum exchange between a gas flow and surface waves. Then the temperature boundary layer becomes extremely thin and the liquid film is easy to break by the accerelated evaporation. (2) The disturbance wave, which plays an important role in the formation of a liquid film, is generated when the velocity of the particles exceed that of thd wave at the interface. The boundary of the existence of the disturbace wave depends strongly on the pipe orientation in the low gas velocity region. (3) The projection attached to the flat plate has a strong effect on the liquid film breakdown, while the flat plate without a projection is effective to keep a thin liquid film near the obstacle. In the case with the projection three types of the film breakdown are observed, i.e (a) the upstrem-side film breakdown due to a horse shoe vortex just in front of the projection, (b) the downstream-side film breakdown extending far downstream of the obstacle and (c) the downstream-side film breakdown limited within the gap of the obstacle. These three types of the film breakdown will be a main factor to restrict the maximum heat removal of the nuclear reactor.

本课题主要研究：(1)细液膜与高速气流同时流动的流动机理；(2)大扰动波的产生机理；(3)圆柱形投影平板型流阻与细液膜的相互作用。结果总结如下：(1)虽然本研究中膜雷诺数最多为150，但由于气流与表面波之间的动量交换，膜流仅在靠近管壁的非常狭窄的区域为层流。此时温度边界层变得极薄，液膜容易因加速蒸发而破裂。(2)当颗粒在界面处的速度超过d波的速度时，就会产生扰动波，它对液膜的形成起着重要的作用。在低气速区，扰动波存在的边界很大程度上取决于管道的方向。(3)附着在平板上的凸出物对液膜击穿有较强的作用，而没有凸出物的平板则能有效地在障碍物附近保持较薄的液膜。在有投影的情况下，观察到三种类型的膜击穿，即(a)由于投影前方的马蹄形涡流导致的上游侧膜击穿，(b)下游侧膜击穿延伸到障碍物的下游，(c)下游侧膜击穿限制在障碍物的间隙内。这三种类型的膜击穿将是制约核反应堆最大排热的主要因素。