Experimental Study on Heat Transfer Characteristic for Natural Circulation Flow Instability

被引:0
|
作者
Wang Q. [1 ]
Gao P. [1 ]
Tan S. [1 ]
Wang Z. [1 ]
Chen X. [1 ]
Huang Y. [1 ]
机构
[1] Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, Harbin
关键词
Critical boiling; Dryout; Flow boiling; Flow instability; Natural circulation;
D O I
10.7538/yzk.2018.youxian.0464
中图分类号
学科分类号
摘要
A series of natural circulation experiments were carried out in order to explore the flow instability mechanism. The flow boiling mechanism and local heat transfer characteristics were analyzed for different natural circulation oscillation modes. The experimental results show that the periodic and regular oscillation is induced by flow boiling under low and/or medium heat flux. Meanwhile, the wall superheat varies within a small range when flow rate oscillates. Under high heat flux conditions, an irregular but periodic oscillation is observed in the experiment. The transition of different boiling regimes is not the unique reason for this oscillatory circulation mode. Large amplitude oscillation is likely to trigger transient critical boiling. Periodic dryout occurs near the outlet and gives rise to the decrease of local heat transfer coefficient and the fly-up of wall temperature. With the increase of heat flux, continuous dryout might take place in natural circulation system. © 2019, Editorial Dept. of JA. All right reserved.
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页码:632 / 640
页数:8
相关论文
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