真空失效下变密度多层绝热传热性能试验研究  

Experimental study on the insulation performance of variable density multilayer insulation under vacuum failure

作　　者：张尚武 陈叔平[1] 陈联[2] 马晓勇 李棉峰 ZHANG Shangwu;CHEN Shuping;CHEN Lian;MA Xiaoyong;LI Mianfeng(College of Petrochemical Engineering,Lanzhou University of Technology,Lanzhou 730050,China;Lanzhou Institute of Physics,Lanzhou 730000,China)

机构地区：[1]兰州理工大学石油化工学院,兰州730050 [2]兰州空间技术物理研究所,兰州730000

出　　处：《压力容器》2024年第9期23-30,共8页Pressure Vessel Technology

基　　金：甘肃省科技计划项目(22ZD6GA026)。

摘　　要：为探究真空失效条件下,不同气体和夹层真空度对多层绝热传热性能的影响,搭建了真空失效实验平台,针对反射层为50层的变密度多层绝热,采用N_(2),Air,Ar,CO_(2)作为破空气体,开展了真空度为10^(-1),10,102,103 Pa的真空失效试验,并测得低温液体蒸发率和热边界温度的变化,获得了变密度多层绝热表观导热系数。结果表明:对于同种气体,表观导热系数随夹层真空度降低而增大,尤其是当真空度介于10^(-1)~102 Pa时,表观导热系数上升更明显;对于不同气体,夹层真空度为10^(-1)Pa时,Air为破空气体时表观导热系数最大,其次为CO_(2),N_(2),Ar,而夹层真空度在10~103 Pa时,表观导热系数大小依次为N2,Air,CO_(2)和Ar,不同破空气体在不同真空度时表现出不一致的表观导热系数关系,此差异是由于气体的物性以及不同真空度下的传热机理不同引起的。该研究为探究真空失效下多层绝热传热机理提供理论支持和数据参考。To study the impact of different gases and annular space vacuum levels on the thermal performance of multilayer insulation under vacuum failure conditions,an experimental platform was established.For a vessel wrapped with 50 reflective layers of variable density multilayer insulation,vacuum failure experiments were carried out at pressures of 10^(-1),10,102 and 103 Pa using N_(2),Air,Ar and CO_(2).The boil-off rates of cryogenic liquid and the warm boundary temperatures were measured,and the apparent thermal conductivity of the variable density multilayer insulation was obtained.The results indicate that,for the same gas,the apparent thermal conductivity increases with the decrease of vacuum level,especially obvious when the vacuum level is between 10^(-1)to 102 Pa.For different gases,when the vacuum level is 10^(-1)Pa,the apparent thermal conductivity of the multilayer insulation is highest when the interlayer atmosphere is air,followed by CO_(2),N2 and Ar.The magnitude order of apparent thermal conductivity is sequentially N_(2),Air,CO_(2)and Ar at the vacuum levels between 10 to 103 Pa.The relationship between the apparent thermal conductivity of different gases at various vacuum levels is inconsistent,which is caused by physical properties of the gases and the different heat transfer mechanisms under varied vacuum levels.This study provides theoretical support and data reference for exploring the mechanism of multilayer insulation under vacuum failure.

关 键 词：低温容器 真空失效 变密度多层绝热 表观导热系数 绝热性能 

分 类 号：TH49[机械工程—机械制造及自动化] TB658[一般工业技术—制冷工程] TB66