AP1000稳压器波动管竖直管段空气-水CCFL实验研究

Experimental Research of Air-Water CCFL in Vertical Pipe Section of AP1000 Pressurizer Surge Line

使用竖直管代替波动管模型开展稳压器波动管竖直管段内空气-水两相逆流限制(CCFL)特性可视化实验研究。实验现象表明:竖直管与上容器接口处的局部CCFL决定了进入竖直管内的液相流量;竖直管内的局部CCFL决定了从竖直管流出的液相流量;两处局部CCFL均随空气流量的增大而增强。在较低气量情况,进入竖直管内的液相能够完全或大部分流出,竖直管内的局部CCFL较弱,上容器和竖直管接口处的局部CCFL在整体CCFL中占主导地位,整体CCFL程度随着上容器液位升高而略有增强。在高气量情况,从上容器进入竖直管的液相大部分或者完全被限制而不能向下流出,竖直管内的局部CCFL强烈,在整体CCFL中占主导地位,整体CCFL特性不受上容器液位变化的影响。通过实验数据拟合得到了新的稳压器竖直管CCFL模型。稳压器波动管CCFL数据和稳压器竖直管CCFL数据基本重合,表明波动管CCFL主要由CCFL-U决定。

In this study the pressurizer surge line model is replaced by a vertical pipe, and visual experiments have been carried out to investigate the characteristics of air-water Counter-Current Flow Limitation(CCFL) in the vertical pipe section. The visualization experimental phenomena shows that: local-CCFL occurring at the junction between vertical pipe and upper tank limits the liquid penetration to vertical pipe;local-CCFL occurring in the vertical pipe restricts the liquid flowing out from the vertical pipe;both local-CCFL extent increases with the increasing of air flow rate. Under low gas flow condition, the water entering the vertical pipe can flow out entirely or mostly;the local-CCFL in the vertical pipe is weak, and local-CCFL at the junction between vertical pipe and upper tank dominates the overall CCFL;the overall CCFL extent in the test section increases slightly with the increasing of the upper tank water level. Under high gas flow condition, the water entering the vertical pipe is restricted partially or completely from downwards flowing out;local-CCFL in the vertical pipe is intense, dominating the overall CCFL;the effect of upper tank water level on CCFL extent disappears. New pressurizer vertical pipe CCFL model is obtained by fitting the experimental data. The present pressurizer vertical pipe air-water CCFL data overlaps essentially with our pressurizer surge line experimental data, which indicates that CCFL-U plays a dominant role on the pressurize surge line CCFL characteristics.