原子能科学技术 ›› 2019, Vol. 53 ›› Issue (4): 624-631.DOI: 10.7538/yzk.2018.youxian.0828

• 反应堆工程 • 上一篇    下一篇

物理模型及边界条件对直流蒸发管两相流不稳定性边界影响研究

苏阳;李晓伟*;阎慧杰;吴莘馨;梁骞   

  1. 清华大学 核能与新能源技术研究院,先进核能技术协同创新中心,先进反应堆工程与安全教育部重点实验室,北京100084
  • 出版日期:2019-04-20 发布日期:2019-04-20

Influence of Physical Model and Boundary Condition on Two-phase Flow Instability Boundary in Once-through Evaporation Tube

SU Yang;LI Xiaowei*;YAN Huijie;WU Xinxin;LIANG Qian   

  1. Institute of Nuclear and New Energy Technology, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Tsinghua University, Beijing 100084, China
  • Online:2019-04-20 Published:2019-04-20

摘要:

本文研究不同边界条件及物理模型对两相流不稳定性边界的影响。采用RELAP5程序模拟直流蒸发管内的两相流不稳定性实验工况,对计算程序和模型进行验证,分析恒定流量及恒定压降两种边界条件、并联管数量、轴向功率分布形式和传热管热容等不同边界条件和物理模型对不稳定性边界的影响。结果表明:恒定压降边界条件下,单根管、2根并联管和多根并联管的不稳定性边界差别小于5%;恒定流量边界条件下,多根并联管不稳定性边界和2根并联管相比差别小于5%,而与单根管不稳定性边界的差别则超过100%;并联管根数相同时,恒定流量边界条件的稳定性好于恒定压降边界条件;沿流动方向(轴向)功率递增分布时,系统稳定性好于沿流动方向功率均匀分布,沿流动方向功率均匀分布时,系统稳定性好于沿流动方向功率递减分布;当管壁厚度为0~20 mm时,管壁热容对不稳定性边界几乎没有影响。

关键词: 蒸汽发生器, 两相流不稳定性, 不稳定性边界, 恒定流量, 恒定压降, 功率分布

Abstract:

The effects of different boundary conditions and physical models on two-phase flow instability boundary were studied in this paper. In order to verify the code and model, the RELAP5 code was used to simulate two-phase flow instability experiments in once-through evaporation tube. Then the influences of constant flow rate and constant pressure drop boundary conditions, the number of parallel tubes, the axial power distribution patterns and the heat capacity of the heat transfer tubes on the instability boundary were analyzed. The results show that the instability boundary differences among single tube, two tubes and multiple tube models are less than 5% under constant pressure drop boundary conditions. Under constant flow rate boundary conditions, the instability boundary of multiple tube models differs from that of two tubes model by less than 5%, while the instability boundary of single tube model differs from that of two tubes models by more than 100%. When the numbers of parallel tubes in the models are the same, the stability of the model with the constant flow rate boundary conditions is better than that with the constant pressure drop boundary conditions. The stability of the system with increasing power distribution along the flow direction (axial direction) is better than that with uniform power distribution, and the stability of the system with uniform power distribution along the flow direction is better than that with decreasing power distribution. When the wall thickness varies from 0 to 20 mm, the wall heat capacity has little effect on the instability boundary.

Key words: steam generator, two-phase flow instability, instability boundary, constant flow rate, constant pressure drop, power distribution