含绕丝棒束低流速时阻力特性的实验研究  

Experimental Investigation of Frictional Pressure Dropof Wire-wrapped Bundle at Low Velocity

作　　者：周志伟[1] 李虹锐 薛秀丽[1] 曾泽华 刘瑞 刘健 罗锐[2] ZHOU Zhiwei;LI Hongrui;XUE Xiuli;ZENG Zehua;LIU Rui;LIU Jian;LUO Rui(Department of Nuclear Engineering Design,China Institute of Atomic Energy,Beijing 102413,China;Department of Energy and Power Engineering,Tsinghua University,Beijing 100084,China;Power Engineering Department,North China Electric Power University,Baoding 071003,China)

机构地区：[1]中国原子能科学研究院核工程设计研究所,北京102413 [2]清华大学能源与动力工程系,北京100084 [3]华北电力大学动力工程系,河北保定071003

出　　处：《原子能科学技术》2023年第5期960-967,共8页Atomic Energy Science and Technology

摘　　要：钠冷快堆含绕丝棒束组件低流速时的摩擦阻力特性,是设计钠冷快堆非能动事故余热排出系统的重要参数。使用水作为测量介质,采用改进的液柱测压方法,准确测量了一个有机玻璃材质37棒绕丝棒束组件雷诺数Re=200~1 100时的摩擦阻力特性。结果表明,被测量组件从层流向湍流转捩的临界Re为370。组件的入口段长度随着流速的增加而增大,随着流动开始向湍流转变而减小。现有的绕丝棒束摩擦阻力系数经验公式中,UCTD公式与实验值最接近:在层流区,UCTD公式高估了约7%,在层流向湍流转换区,UCTD公式计算值与实验值基本一致。同时,UCTD和CTS公式还高估了组件从层流向湍流转捩的临界Re。During decay heat removal,the sodium flow rate through the core of sodium-cooled fast reactors(SFRs)determines the removal ability.This flow rate is a balance between the buoyancy-driven force generated by the sodium density variation in the primary loop and the flow resistance during the natural circulation.The resistance loss consumption in wire-wrapped bundles occupies more than 90%of the total head loss in the natural circulation loop.Consequently,the frictional resistance in wire-wrapped bundles at low velocities is one of the essential parameters in designing passive residual heat removal systems(PRDRS)for SFRs.However,there are a few experimental data in this regard.In this paper,a liquid column manometer was improved by adopting image processing techniques,and volumetric flow rates were obtained by measuring the mass flow rates.In addition,a constant-head tank replaced the pump to drive water through the assembly,reducing the fluctuations significantly in water flow during frictional resistance measurements.Then,the frictional pressure drops of a 37-pin wire-wrapped bundle assembly made from polymethyl methacrylate were accurately measured using a water medium at Re=200-1100.Experimental results show that the frictional factors of the measured assembly decrease with increasing Re and are 0.337-0.094 for Re=200-1100.The transition Re from laminar to transition flow of the measured assembly is 370,and the friction factors of the assembly decrease faster with the increasing Re in the laminar flow region.The rate of decrease decelerates in the critical zone.At low flow rates,the entrance length of the assembly increases as the flow velocity increases and decreases as the flow begins to transform from laminar flow in the assembly.Although the flow channel inside the assembly is very narrow and complex,at low flow rates,the flow inside the assembly still exhibits the same frictional resistance characteristics as inside simple geometries,such as a circular tube.Among several available empirical formulas for the

关 键 词：绕丝棒束 摩擦阻力 非能动余热排出 层流 

分 类 号：TL33[核科学技术—核技术及应用]