竖直向下浸没式蒸汽直接接触冷凝流型研究  

Investigation on Regime of Vertical Downward Submerged Steam Direct Contact Condensation

作　　者：刘海强 郭张鹏 邱美铭 王升飞[1] 牛风雷[1] 黄彦平[2] LIU Haiqiang;GUO Zhangpeng;QIU Meiming;WANG Shengfei;NIU Fenglei;HUANG Yanping(Beijing Key Laboratory of Passive Safety Technology for Nuclear Energy,North China Electric Power University,Beijing 102206,China;CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology,Nuclear Power Institute of China,Chengdu 610041,China)

机构地区：[1]华北电力大学非能动核能安全技术北京市重点实验室,北京102206 [2]中国核动力研究设计院中核核反应堆热工水力技术重点实验室,四川成都610041

出　　处：《原子能科学技术》2022年第8期1559-1565,共7页Atomic Energy Science and Technology

基　　金：国家自然科学基金(U1867218,11805068);国家重点研发计划(2020YFB190140403)。

摘　　要：直接接触冷凝直接影响核反应堆安全壳抑压系统的性能。本文针对竖直向下浸没式直接接触冷凝流型开展实验研究,采用高速摄影仪记录不同湿阱过冷度条件下的蒸汽冷凝过程,依据流型特征划分了喘振、管外颈缩、向上球型脱落、向上T型脱落4种冷凝流型。研究了各流型对湿阱热分层的影响。实验结果表明,喘振流型和管外颈缩流型会增强湿阱内流体搅混,不易发生热分层,而向上球型脱落流型和向上T型脱落流型易引起热分层。理查森数(Ri)可作为流型转变的无量纲数,Ri<1时为管外颈缩流型,Ri>1时为向上脱落流型。Direct contact condensation affects the performance of pressure suppression system of nuclear reactor.Since the heat and mass transfer varies with the condensation regimes as well as steam-water interface shapes,the identification and classification of the condensation regimes are important.The experiment of steam direct contact condensation was carried out and the corresponding condensation regimes were studied.Specifically,the experiment was studied by injecting steam vertically into a wet well with subcooled water.The physical process of steam condensation phenomenon with varying undercooling degree of wet well was recorded by high-speed camera.According to the location of the steam-water interface and the shape of the steam bubble,the four condensation regimes were studied,namely internal chugging,external necking,spheroidal upward bubble and T-shaped upward bubble.Besides,it is found that thermal stratification occurs in the wet well at low steam mass flux,the influence of each condensation regime on the thermal stratification of wet well was studied.The experimental results show that the internal chugging and external necking cause a large downward circulation of subcooled water,which enhance the flow mixing around the discharge tube and the bottom of the wet well.Consequently,the thermal stratification phenomenon does not happen in those condensation regimes.However,the regimes like spheroidal upward bubble and T-shaped upward bubble cause the upward circulation of subcooled water in wet well,which cause the thermal stratification.The critical Richardson number(Ri)determines the condensation regimes.Furthermore,when the Ri is smaller than 1,the condensation regime is external necking.Besides,when the Ri is greater than 1,the condensation regimes are spheroidal upward bubble and T-shaped upward bubble.

关 键 词：直接接触冷凝 竖直向下 冷凝流型 理查森数 

分 类 号：TK172[动力工程及工程热物理—热能工程]