冷中子源两相氢热虹吸回路流动极限试验研究

针对中国先进研究堆冷中子源两相氢热虹吸回路传递管的流动极限,以R113 为工质进行了垂直管内气液两相逆流流型和液泛发生界限的试验研究.通过可视化试验发现,随着气液两相流量的增加,依次可出现平稳的下降液膜流、入口有液滴夹带的下降液膜流、入口附近局部乳沫流和全管搅拌乳沫流4 种流型.依据不同管径(32、34、45 mm)、不同压力(70~820 kPa)下的液泛试验数据,提出了一个新的预测液泛发生的关联式,并和一些著名的液泛关联式进行了比较,发现试验数据以及新关联式的预测结果和McQuillan修正关联式的预测值最为一致.所提出的关联式适用于闭式系统中具有锐边入口几何结构的垂直管内气液两相逆流液泛的预测.

Experimental Investigation of Two-Phase Countercurrent Flow Limit in Hydrogen Thermosiphon Loop of Cold Neutron Source

The flow pattern and flooding phenomena in vertical vapor-liquid countercurrent flow were experimentally investigated using a two-phase thermosiphon loop and R113 as working fluid for developing China Advanced Research Reactor (CARR) Cold Neutron Source (CNS). Four flow patterns, i.e. falling film flow, falling film flow with droplet entrainment at vapor entrance, churn flow near the vapor entrance, and the churn flow through the whole tube, were observed. New data of the onset of flooding in a closed system were obtained for three vertical tubes with inner diameters of 32, 34,and 45 mm under pressures of 70- 820 kPa. A new correlation was developed and compared with existing correlations.The result shows that this new correlation agrees very well with the data and the McQuillan correlation.The new correlation presented can predict the onset of flooding in the vertical tube with a sharp end in a closed system.