燃料包壳表面沉积层对气泡脱离直径与气泡脱离频率影响的实验研究  

Experimental Study of the Influences of CRUD layer on Bubble Departure Diameter and Bubble Departure Frequency on Fuel Cladding Surface

作　　者：蔡杰进[1] 胡致平 邓日宁 Cai Jiejin;Hu Zhiping;Deng Rining(School of Electric Power,South China University of Technology,Guangzhou,510640,China)

机构地区：[1]华南理工大学电力学院,广州510640

出　　处：《核动力工程》2024年第4期118-126,共9页Nuclear Power Engineering

基　　金：国家自然科学基金面上项目(12275088);广东省基础与应用基础研究基金资助项目(2021A1515010340)。

摘　　要：燃料包壳在压水堆运行中会形成表面沉积,其对包壳沸腾传热行为的影响机理尚不清楚。为探究包壳表面沉积层对气泡脱离直径和气泡脱离频率的影响规律,本研究基于常压下的流动沸腾可视化实验台架,采用包壳材料Zr-4合金为基板,对其进行逐层沉积得到不同厚度的SiO_(2)沉积层来模拟燃料包壳表面沉积。通过开展流动沸腾实验对气泡脱离直径和气泡脱离频率进行气泡动力学分析,关注其与壁面过热度的变化规律,并与现有预测模型进行对比。研究发现:相比没有SiO_(2)沉积层的表面,有SiO_(2)沉积层的表面气泡脱离直径和气泡脱离频率更大,同时壁面过热度的增高会引起气泡脱离直径变大并加快气泡脱离壁面,在相同条件下工质过冷度和雷诺数对于气泡脱离频率的影响比气泡脱离直径更大;提出了符合本实验所有工况条件下改进的气泡脱离直径预测公式,改进后的预测计算式预测值与实验值的误差小于30%。Chalk River Unidentified Deposits(CRUD)is naturally formed on the fuel cladding during the routine operation of pressurized water reactor(PWR),and its influence mechanism on the boiling heat transfer behavior of cladding is still unclear.In order to investigate the influence of CRUD on the bubble departure diameter(BDD)and bubble departure frequency(BDF),based on the flow boiling visualization experimental platform under atmospheric pressure,the cladding material Zr-4 alloy is used as the substrate,and SiO_(2) deposition layers with different thicknesses are deposited layer by layer to simulate the CRUD.The bubble dynamics analysis of BDD and BDF is carried out through the flow boiling experiment,with their relationship with the wall superheat considered,and compared with the existing prediction model.It is found that compared with the surface without SiO_(2) deposit,the BDD and BDF on the surface with SiO_(2) deposit are larger,and the increase of wall superheat will cause the BDD to become larger and accelerate the bubble departure.Under the same conditions,the influence of fluid subcooling and Reynolds number on the BDF is greater than that on the BDD.The improved prediction equations of BDD for all conditions in this experiment are put forward.The error between the predicted value of the improved prediction equations and the experimental value is less than 30%.

关 键 词：流动沸腾实验 表面沉积层 气泡脱离直径 气泡脱离频率 

分 类 号：TL331[核科学技术—核技术及应用]