流动不稳定性对沸腾临界触发机制的实验研究  

Experimental Investigation on Trigger Mechanism of Flow Instability on Critical Boiling

作　　者：陆祺 周铃岚[1,2] 沈才芬[1,2] 刘伟[1,2] 刘卢果 何航行 LU Qi;ZHOU Ling-Lan;SHEN Cai-Fen;LIU Wei;LIU Lu-Guo;HE Hang-Xing(Science and Technology on Reactor System Design Technology Laboratory,Chengdu 610041,China;Nuclear Power Institute of China,Chengdu 610041,China)

机构地区：[1]中国核动力研究设计院核反应堆系统设计技术重点实验室,成都610041 [2]中国核动力研究设计院,成都610041

出　　处：《工程热物理学报》2020年第4期966-975,共10页Journal of Engineering Thermophysics

基　　金：国家自然科学基金(No.11905212)。

摘　　要：本文以Din=2.15 mm的带旁通小流道为对象,分别在不同液相质量流速以及不同入口水温条件下开展沸腾临界实验,结合汽泡动力学行为以及两相界面形态特征,探讨流动不稳定性对沸腾临界的触发机制。在本文工况范围内,在流动状态由稳定阶段转变为不稳定阶段后,进一步增大热流密度会触发沸腾临界,且所有沸腾临界均属于DO型沸腾临界。当液相质量流速较高时,环状流近壁液膜主要在汽芯强烈的扰动作用下迅速破裂;当入口水温较低时,近壁液膜主要由于强烈的蒸发现象迅速破裂;因此沸腾临界与流动不稳定性几乎同步被触发。本文分别通过引入受限系数(Nconf)、过冷数(Nsub)、以及Weber数(We)来反映壁面的限制作用、入口过冷度、以及惯性力与表面张力对沸腾临界的影响,建立了适用于Din=2.15 mm带旁通小流道的CHF模型。In this study,the mini channel with bypass(Din=2.15 mm) was selected as the object,and the critical boiling experiment was carried out with different liquid mass fluxes and inlet temperatures.Meanwhile,the trigger mechanism of the flow instability on the critical boiling was researched combined with the bubble dynamics and the two-phase interface morphology.Within the working conditions in this paper,the critical boiling might be triggered with the heat flux continuously increasing as the flow state transferred from the stable stage to the unstable stage.Also,all the critical boiling occurred in this study belonged to DO type critical boiling.As for the working conditions with high liquid mass fluxes,the liquid film near the heating wall was rapidly broken up mainly due to the intense entrainment caused by the vapor core.As for the working conditions with low inlet water temperatures,the fracture of liquid film was mainly attributed to the intense evaporation.Therefore,the critical boiling and the flow instability were nearly simultaneously triggered.Finally,Confinement number(Nconf),Subcooling number(Nsub),and Weber number(We)were considered in CHF model to reflect the confinement of channel wall,the inlet subcooling,and the inertia force as well as the surface tension,respectively.

关 键 词：带旁通小流道 可视化实验 两相界面特征 流动不稳定性 沸腾临界 

分 类 号：TL334[核科学技术—核技术及应用]