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.

为了开发超临界压力水冷却功率反应器，进行了实验，以使用HCFC22作为测试流体来阐明管道快速减压从超临界到亚临界压力的快速压力降低，并在稳定状态条件下与数据进行比较。测试部分是I.D. 4.4 mm的圆管。压力在超临界压力的范围内5.5 MPa（降压1.1）下方至下降到亚临界压力4.0 MPa（降压为0.8），质量速度为400和700 kg/（M^2s）。取得较小的稳定状态，量的静电量较小。即使热通量如此低的值，在5.0 MPa的临界压力下，在5.5 MPa的超临界压力下未观察到热传递劣化。在较低的压力下发现热量减少，并增加热通量。2。在降压压力的瞬态条件下，在略低于临界压力的压力区域中，由于膜沸腾的发生而导致的传热相同，即使在初始超临界压力条件下也没有观察到临界压力。然而，注意到热量减少和导致的管壁温度升高，持续到远低于临界压力的压力区域。在减压期间，薄膜沸腾中的最大管壁温度几乎与减压率无关。此外，随着热通量的增加，最高温度变得更高。