• 反应堆工程 •

### 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

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

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.