安全壳内置换料水箱内自然对流现象试验研究

以第3代核电技术中广泛采用的安全壳内置换料水箱（IRWST）为对象，通过比例分析获得了自然对流现象的相似准则，设计了缩比试验装置，对事故条件下IRWST内的自然对流现象进行了试验研究，分析了IRWST内自然对流的演变规律及初始条件的影响。结果表明：相似格拉晓夫数、相似雷诺数和相似普朗特数是IRWST自然对流现象试验装置设计应遵循的相似准则；加热初期，IRWST内以轴向上升羽流为主，随冷热分层的形成，流体的轴向上升运动被抑制，转变为以IRWST中下部区域的径向横流为主；不同初始条件下IRWST内自然对流的演变规律基本一致，但流场演变过程的快慢、流体速度的大小不同。

Experimental Study of Natural Convection Phenomena in In-containment Refueling Water Storage Tank

Taking the in-containment refueling water storage tank (IRWST), which is widely used in generation Ⅲ nuclear power technology, as the object of study, the similarity criteria for natural convection phenomena were obtained by scaling analysis in terms of normalized control equations. The scaled down facility was designed, the natural convection phenomena in IRWST under accident conditions were experimentally studied and the natural convection evolution process and the influences of initial condition on it were analyzed. The results show that modified Grashof number, modified Reynolds number and modified Prandtl number are the similarity criteria for design of test facility on natural convection in IRWST. In the initial heating stage, the axial rising plume is the dominant flow in IRWST. With the formation of thermal and cold stratification, the upward motion of fluid is suppressed, and the upward motion is transformed to the radial cross flow in the middle and lower regions of IRWST. The evolution of natural convection in IRWST is basically the same under different initial conditions, but the evolution rate of flow field and fluid velocity are different.