摘要
受海洋条件影响,浮动核反应堆(FNR)回路冷却剂会发生周期性流量波动现象,影响系统热工水力特性。为研究这一现象,对脉动流条件下5×5燃料棒束的阻力特性进行了试验研究。试验的周期平均雷诺数Re_(ta)=0.8×10^3^9×10^3,脉动幅值A_u=0.2^0.8,无量纲频率ω′^(1/2)=1.26~2.81。试验结果表明:脉动流条件下流体加速会导致瞬时阻力系数大于对应雷诺数的稳态值,减速会使瞬时阻力系数小于稳态值,且这一偏离值随流体流速的减小而增大。此外,在脉动流过程中,周期平均摩擦阻力系数λ_(ta)和局部阻力系数k_(ta)都大于对应平均雷诺数下的稳态值。通过提出无量纲参数C_f=λ_(ta)/λ_(st)和C_(sg)=k_(ta)/k_(st)来评价脉动流对周期平均阻力系数的影响。C_(f)和C_(sg)随A_u和ω′^(1/2)的增加而增加,随Re_(ta)的增加而减少。且在相同的脉动流参数下,C_(sg)小于C_f,说明流体波动对定位格架局部阻力的影响较小。最后,通过量纲分析,根据阻力系数的变化规律建立了预测λ_(ta)和k_(ta)的计算关系式,得到了较好的预测结果。
Under the ocean conditions,the coolant in the loop of floating nuclear reactor(FNR)would fluctuate periodically,which would affect the thermal and hydraulic characteristics of the system.In order to study this phenomenon,the resistance characteristics of 5×5 fuel rods under pulsating flow conditions were experimentally studied.The ranges of the cycle-averaged Reynolds number Reta=0.8×10^(3) to 9×10^(3),pulsating amplitude Au=0.2 to 0.8 and dimensionless frequencyω′1/2=1.26 to 2.81 were covered in this experimental study.The results show that under the pulsating flow,the instantaneous flow resistance will be greater than the steady-state value due to the acceleration,and the flow resistance will be less than the steady-state value due to the deceleration,and the deviation value will increase with the decrease of the velocity.In addition,during the pulsating flow,the cycle-average friction factor and local resistance coefficient in the whole cycle are larger than the steady-state value under the corresponding Reynolds number.The normalization parameters of C_(f)=λ_(ta)/λ_(st )and C_(sg)=k_(ta)/k_(st) are proposed to evaluate the effect of pulsating flow on the cycle-averaged flow resistance.Cf and C_(sg) increase with the increase of Au andω′1/2,and decrease with the increase of Reta.Finally,by dimensional analysis,the prediction relation ofλ_(ta)and k_(ta) is established,and a better prediction result is obtained.
作者
祁沛垚
李兴
邓坚
于晓勇
谭思超
QI Peiyao;LI Xing;DENG Jian;YU Xiaoyong;TAN Sichao(Fundamental Science on Nuclear Safety and Simulation Technology Laboratory,Harbin Engineering University,Harbin 150001,China;Wuhan Second Ship Design and Research Institute,Wuhan 430205,China;Science and Technology on Reactor System Design Technology Laboratory,Nuclear Power Institute of China,Chengdu 610213,China)
出处
《原子能科学技术》
EI
CAS
CSCD
北大核心
2021年第5期840-848,共9页
Atomic Energy Science and Technology
基金
国家重点研发计划资助项目(2017YFE0106200)
中央高校基础研究——博士生研究与创新基金资助项目(3072020GIP1517)。
关键词
脉动流
棒束通道
定位格架
流动阻力
pulsating flow
rod bundle
spacer grid
flow resistance
