基于气泡动力学的过冷流动沸腾边界层模型研究  

Boundary Layer Model for Subcooled Flow Boiling Based on Bubble Dynamics

作　　者：何雯 赵陈儒[1] 薄涵亮[1] HE Wen;ZHAO Chenru;BO Hanliang(Institute of Nuclear and New Energy Technology,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学核能与新能源技术研究院,北京100084

出　　处：《原子能科学技术》2022年第7期1219-1229,共11页Atomic Energy Science and Technology

基　　金：中核集团领创科研项目;中核集团“青年英才”项目。

摘　　要：过冷流动沸腾中的流动和传热特性对反应堆的安全运行和经济性都具有重要意义。过冷流动沸腾起始于ONB点,结束于Tsat点,中间被OSV点划分为高过冷流动沸腾段和低过冷流动沸腾段,不同阶段流场情况以及气泡行为存在较大区别。目前关于过冷流动沸腾过程的研究主要基于宏观实验、理论研究和数值模拟,随着气泡动力学的发展,从微观层面揭示沸腾机理变得可行。本文基于气泡动力学和气泡边界层模型,提出了一套预测过冷流动沸腾的理论模型,采用分相模型,将流场在径向上划分为多个区域,通过1组准二维控制方程,将各区域内的气泡行为,区域间的质量、动量和能量交换以及两相参数沿轴向的变化情况考虑在内,利用获得的边界层流场信息,可确定ONB点和OSV点。模型与空泡份额和流体温度的实验结果符合良好,并成功应用于核反应堆燃料元件通道的过冷流动沸腾计算。Generally,the subcooled flow boiling can be divided into two parts along the channel direction,which are the highly subcooled flow boiling and the slightly subcooled flow boiling.There exist large differences in bubble behaviors and interactions in each part.Modelling of the subcooled flow boiling is very important in many industrial fields,such as in nuclear steam generators,satellites,and space vehicles.However,subcooled flow boiling is a very complex process which contains various bubble behaviors,such as sliding,lift-off,and condensation.Currently,the prediction of this process mainly relies on experiments,theoretical analysis and numerical simulations.With the development of the research on bubble dynamics,it becomes possible to analyze the heat transfer mechanisms at the micro level.Therefore,based on the bubble dynamics and the bubble boundary layer model,a theoretical model was developed for the prediction of the subcooled flow boiling which divided the flow field into different regions in the radial direction.According to the concept of the separated flow model,bubble behaviors in each region,mass and energy exchanges at the interfaces of different regions,and variations of parameters along the channel direction were considered and analyzed through a new set of two-dimensional steady-state conservation equations.Once the flow field in the bubble layer region was obtained,the ONB point and OSV point were also determined through this model.The present model was verified with experimental data of void fraction and liquid temperature with the mean absolute error equal to 22.3%and 0.3%respectively.The application ranges of the present model are 0.827-4.5 MPa for pressure,520-1440 kg/(m^(2)·s)for mass flux,243-888 kW/m 2 for heat flux,6.1-15.4 mm for hydraulic diameter.This model was also applied to the prediction of subcooled flow boiling in the fuel element channel of nuclear reactors.The results show that the length of the whole subcooled boiling section accounts for 52.6%of the total length,and the positi

关 键 词：过冷流动沸腾 气泡动力学 气泡边界层模型 分相模型 ONB点 OSV点 

分 类 号：TB126[理学—工程力学]