权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Transient Heat Transfer in a Tube during Pressure Reduction from Supercritical to Subcritical Pressure

从超临界压力降至亚临界压力期间管内的瞬态传热

基本信息

批准号：
16560188
负责人：
MORI Hideo
金额：
$ 2.43万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16560188/
关键词：
Transient heat transfer Pressure reduction Supercritical pressure Critical heat flux condition In-tube flow SCPR

项目摘要

For the development of a supercritical pressure water cooled power reactor, experiments were carried out to clarify the characteristics of the transient heat transfer in a tube during rapid pressure reduction from supercritical to subcritical pressure, using HCFC22 as the test fluid, and transient heat transfer characteristics were clarified comparing with data under steady state conditions. The test section was a circular tube of 4.4 mm I.D. The pressure was in the range of a supercritical pressure 5.5 MPa (a reduced pressure of 1.1) down below to a subcritical pressure 4.0 MPa (a reduced pressure of 0.8), and the mass velocity was 400 and 700 kg/(m^2s).Following results were obtained.1.Under steady state conditions, a reduction in the heat transfer due to the occurrence of critical heat flux condition of film boiling was found in the region of pressure slightly below the critical pressure of 5.0 MPa, even when the heat flux was such a low value at which no heat transfer deterioration was observed at a supercritical pressure of 5.5 MPa. The heat transfer reduction was found at lower pressure with increasing heat flux.2.In the transient conditions of reducing pressure, the same reduction of heat transfer due to the occurrence of film boiling was also recognized in the pressure region slightly below the critical pressure, even when no heat transfer deterioration was observed at the initial supercritical pressure condition. The heat transfer reduction and resulting tube wall temperature rise, however, were noticed to continue down to the pressure region much lower than the critical pressure. During the pressure reduction, the maximum tube wall temperature in the film boiling was kept almost constant independently of pressure reduction rate. Furthermore, the maximum temperature became higher with an increase of heat flux.

针对超临界压力水冷动力堆的研制，以HCFC 22为工质，对超临界压力至亚临界压力快速降压过程中管内瞬态传热特性进行了实验研究，并与稳态工况下的数据进行了比较。试验段为内径4.4 mm的圆管。压力在超临界压力5.5MPa的范围内（减压1.1）降至亚临界压力4.0 MPa以下（减压0.8），质量流速为400和700 kg/（m^2s）。在压力略低于临界压力5.0MPa的区域中发现由于膜沸腾的临界热通量条件的出现而导致的热传递的减少，即使当热通量是在5.5MPa的超临界压力下没有观察到传热恶化的如此低的值时也是如此。2.在减压的瞬态条件下，即使在初始超临界压力条件下没有观察到传热恶化，但在略低于临界压力的压力区域也会出现由于膜沸腾而导致的传热降低。然而，注意到传热减少和由此产生的管壁温度升高继续下降到远低于临界压力的压力区域。在减压过程中，膜沸腾的最高管壁温度几乎保持不变，与减压速率无关。此外，最高温度随着热流密度的增加而升高。