定位格架对单棒通道欠热流动沸腾影响的数值研究  

Numerical Investigation to Effect of Spacer Grid on the Subcooled Flow Boiling in Single Rod Channel

作　　者：张廷 吕梦欣 刘洪江 支长双 陈鹏帆 刘迎文[1] ZHANG Ting;L Mengxin;LIU Hongjiang;ZHI Changshuang;CHEN Pengfan;LIU Yingwen(School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学能源与动力工程学院,西安710049

出　　处：《西安交通大学学报》2020年第12期116-124,共9页Journal of Xi'an Jiaotong University

基　　金：国家重点研发计划资助项目(2018YFB1900402);国家自然科学基金资助项目(51976164)。

摘　　要：为了研究定位格架对燃料棒束通道内冷却剂热工水力特性的影响规律,选取5×5棒束通道中心的一根燃料棒及定位格架进行数值研究。建立了基于欧拉两流体六方程的带定位格架的竖直单燃料棒通道内冷却剂欠热沸腾多相流模型,并实验比较验证了模型的准确性,获得了带定位格架与不带定位格架的单燃料棒通道内发生欠热沸腾时相关热力参数的空间分布特征,揭示了定位格架对欠热沸腾流动及换热特性的影响规律。结果发现:相较无定位格架结构,引入定位格架及搅混翼后,流场和温度场发生了不同程度的逆时针旋转,平均二次流最大值能达到进口速度的13.5%,局部二次流强度可达到60%,整体压降仅增加5%;定位格架显著增大了液相对流热流密度,最大增幅为44.3%,导致液相过冷度、壁面过热度和气体体积分数的进一步降低,从而增强了核反应堆的安全性。To investigate the influence of spacer grid on the thermal-hydraulic characteristics of coolant in fuel rod bundle channel,a single fuel rod and a spacer grid in the center of 5×5 bundle channel are selected for the numerical analysis.Following Eulerian theory,a mathematical model of multiphase flow for the subcooled boiling of coolant in a vertical single rod channel is established.The accuracy of the model is verified by a comparison of numerical simulation results with experiment data.The spatial distribution characteristics of the relevant thermal parameters in the single rod channel with or without spacer grid are obtained,and the influence of spacer grid on the flow and heat transfer characteristics of subcooled boiling is revealed.The results show that compared with the rod channel without spacer grid,the flow field and temperature field rotate anticlockwise in a certain degree after passing through the spacer grid and the mixing wings.The maximum value of the average secondary flow can reach 13.5%of the inlet velocity,and the local secondary flow can reach 60%.The pressure drop of the whole device with spacer grid is only 5%higher than that without spacer grid.The spacer grid can significantly make liquid phase convection heat flux increase,and the maximum increase can reach 44.3%.As a result,the liquid subcooling,wall superheat and vapor volume fraction are further reduced,thus enhancing the safety of nuclear reactor.

关 键 词：欠热沸腾 计算流体动力学 定位格架 热工水力 

分 类 号：TL333[核科学技术—核技术及应用] TK172[动力工程及工程热物理—热能工程]