Dimensional analysis of critical heat flux in subcooled water flow under one-side heating conditions for fusion application
Dimensional analysis of critical heat flux in subcooled water flow under one-side heating conditions for fusion application
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DOI：
10.1016/s0920-3796(98)00387-1
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发表时间：
1998-12
影响因子：
1.7
通讯作者：
J. Boscary;M. Araki;J. Schlosser;M. Akiba;F. Escourbiac
中科院分区：
文献类型：
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作者：
J. Boscary;M. Araki;J. Schlosser;M. Akiba;F. Escourbiac
通过临界热流(CHF)实验，设计了一种面向等离子体的部件在单面加热条件下，采用加压过冷水的高性能冷却装置。旋流、螺杆和超蒸汽管是去除高入射热流的最有效的几何形状。量纲分析表明，CHF现象可由临界沸腾、埃克特数、雷诺数、质量热质和液汽密度比等无量纲组表征。对均匀受热的光滑管和旋流管在单面加热条件下的最大壁面热流密度进行了关联，得到了比较准确的预测结果。文中还引入了单侧加热与均匀加热不同的强化因子。单侧加热下CHF的发生具有归一化温度，即最高壁面温度与核沸腾起始温度之比，它只与压力有关。通过对光滑管和旋流管的有限元计算，得到了单面加热条件下冷却通道内壁的温度和热流密度分布。这些分布由每个几何形状的两个无量纲数表征：峰值因子，即冷却通道内壁最大热流密度与入射热流密度之比，以及冷却通道内壁热流密度半极大处的全宽角。本研究不仅在均匀加热条件下，而且在单侧加热条件下，都得到了具有CHF现象的无量纲群，这些无量纲群包含附加的归一化参数。
Critical heat flux (CHF) experiments have been carried out to design a high performance cooling device with pressurized subcooled water flow under one-side heating conditions for plasma facing components. Swirl, screw and hypervapotron tubes are the most efficient geometries to remove high incident heat fluxes. A dimensional analysis shows that CHF phenomenon can be featured by dimensionless groups that are the critical Boiling, the Eckert and the Reynolds numbers, the mass enthalpic quality and the ratio between liquid and vapor densities. CHF for uniformly heated smooth tubes, the maximum wall heat flux for smooth and for swirl tubes under one-side heating conditions are predicted with a reasonable accuracy by correlating these five dimensionless groups. An enhancement factor featuring the difference between one-side and uniform heating is also introduced. CHF occurrence under one-side heating is characterized by a normalized temperature, ratio between the maximal wall temperature and the onset of nucleate boiling temperature, which only depends on the pressure. According to finite element calculations performed for smooth and swirl tubes, temperature and heat flux are distributed along the inner wall of the cooling channel under one-side heating conditions. These distributions are characterized by two dimensionless numbers for each geometry: a peaking factor, which is the ratio between the maximal heat flux at the inner wall of the cooling channel and the incident heat flux, and a full width angle at half maximum of wall heat flux at the inner wall of the cooling channel. This study draws the dimensionless groups featuring CHF phenomenon not only under uniform heating, but also under one-side heating, which involve additional normalized parameters.