不同种类破空气体对高真空多层绝热低温容器真空丧失后传热的影响

通过实验,分别利用氮气、空气、氧气和氦气作为破空气体,对高真空多层绝热低温容器在真空完全丧失后的漏热进行了研究。结果表明,多层绝热结构对于绝热真空完全丧失后的低温容器能够起到一定的保护作用,初始和最终漏热和渗入到绝热真空夹层中气体的性质密切相关。     

高真空多层绝热低温容器真空丧失后的传热试验

利用一个工业化的高真空多层绝热低温量热器,以液氮为介质研究了真空突然丧失对高真空多层绝热低温容器漏热量的影响.主要研究了低温量热器绝热层的变化及破空气体(空气和干燥氮气)的不同对真空丧失后低温容器漏热量的影响,指出绝热层数和破空气体种类都是影响真空丧失后低温容器漏热量的重要因素.     

高真空多层绝热二氧化碳低温容器真空寿命与绝热性能分析

首先介绍了影响真空绝热低温容器真空寿命的影响因素和常用的吸气剂,然后针对高真空多层绝热二氧化碳低温容器,进行了真空寿命和绝热性能的分析研究。     

低温绝热气瓶真空丧失后内容器热流场分析

建立了真空丧失后低温液体在金属表面上的核态沸腾模型,并用于计算液氮充满率为90%的175L立式低温绝热气瓶真空丧失后容器内的液体流动、传热及沸腾过程.研究表明,真空丧失后液体温度出现明显分层,且温度分层的方向会随着时间的增加而发生变化;容器内液体在整个容器内形成环状自然循环,而沸腾产生的汽泡主要集中在近壁区和气液界面.     

卧式高真空多层绝热低温容器无损贮存规律

介绍了卧式低温容器的传热特点,以及低温液体无损贮存的传热模型.通过2m3卧式高真空多层绝热低温容器在90%、85%和80%初始充满率下的静态无损贮存试验,拟合现有的传热模型,对升压过程中不同规律的3个阶段进行了分析,得到了第一、第三阶段升压的初步规律.     

低温容器在水蒸气膜态凝结前后的绝热效果分析

绝热失效严重影响了低温容器的经济和安全运行。膜态凝结的出现是绝热失效最直接的表现。提出了用低温容器表面温度与空气露点温度的比较来判别低温容器的绝热是否失效的方法。理论上,分析了低温容器表面水蒸气膜态凝结出现前后的换热机理。在一个高真空多层绝热低温容器上进行了实验,测量并分析了水蒸气膜态凝结前后低温容器表面温度和液氮蒸发速度的变化。理论分析和实验均验证该方法对于判别绝热效果的有效性和可行性。     

高真空多层绝热低温容器整体热分析及试验验证

对35 m'高真空多层绝热低温容器在满载液氧的状态下进行热分析,得到标准状态下该容器漏热量的分布范围及相应的静态蒸发率分布,分析了导热和辐射漏热在总漏热的比重.将计算结果和静态蒸发率试验进行对比,结果符合较好,说明计算的准确性和有效性.进而分析了冷态下玻璃钢支承件和罐体的接触情况.结果可为高真空多层绝热低温容器的设计、...     

几种高真空多层绝热结构低温绝热性能试验分析

介绍了在低温容器上最新应用的两种高真空多层绝热结构,发表了新型多层绝热结构与传统多层绝热结构的导热率试验测试比较数据。详细介绍了新结构所应用的材料及排列组合方法,其导热率可低于0.4W/m2,比传统结构至少降低了50%。     

6 m3高真空多层绝热液氧容器真空性能

对高真空多层绝热液氧容器的真空寿命影响因素进行了分析和研究,提出了解决问题的技术方案,分析了吸附剂,吸气剂在获得和保持夹层真空度中的重要作用。     

应用逐层传热模型分析高真空多层绝热中的传热过程

本文在量热研究所得到的实验数据的基础上,通过建立逐层传热模型,对高真空多层结构中的传热过程进行了分析.计算结果和实验数据的比较表明:模型较好的解决了反射屏间固体传热量难以用特定的公式进行计算的难题,计算得到的当量热导率与实验值的误差在30%以内,符合工程计算的要求.由此可见,逐层传热模型可以较好地反映层间的传热过程,这为以后的高真空多层绝热结构的理论研究打下了坚实的基础.     

Study on the heat transfer of high-vacuum-multilayer-insulation tank after sudden, catastrophic loss of insulating vacuum

One of the worst accidents that may occur in a high-vacuum-multilayer-insulation (HVMLI) cryogenic tank is a sudden, catastrophic loss of insulating vacuum (SCLIV). There is no doubt that the gases leaking into the insulation jacket have some influence on the heat transfer process of it. However, this issue has not been thoroughly studied so far. In this paper, a test rig was built up and experiments were conducted using a SCLIV cryogenic tank and with nitrogen, helium and air as the working medium, respectively. The venting rates of the tank and temperature in the insulation jacket were measured respectively after the three different gases leaking into the jacket. A heat transfer model describing the heat transfer process of a SCLIV tank was also presented. The calculated results using this model were compared against the experimental data. It is found that the heat transfer performance of the HVMLI cryogenic tank after SCLIV is strong relevant to the type of gas leaking into the insulation jacket.     

高真空多层绝热低温液体运输半挂车的开发研制

简述高真空多层绝热低温液体运输半挂车的基本结构、绝热特性 ,并阐述了该车在低温液体运输的应用前景。     

Wrapped multilayer insulation design and testing

New vehicles need improved cryogenic propellant storage and transfer capabilities for long duration missions. Multilayer insulation (MLI) for cryogenic propellant feedlines is much less effective than MLI tank insulation, with heat leak into spiral wrapped MLI on pipes 3–10 times higher than conventional tank MLI. Better insulation for cryogenic feed lines is an important enabling technology that could help NASA reach cryogenic propellant storage and transfer requirements. Improved insulation for Ground Support Equipment could reduce cryogen losses during launch vehicle loading. Wrapped-MLI (WMLI) is a high performance multilayer insulation using innovative discrete spacer technology specifically designed for cryogenic transfer lines and Vacuum Jacketed Pipe (VJP) to reduce heat flux.The poor performance of traditional MLI wrapped on feed lines is due in part to compression of the MLI layers, with increased interlayer contact and heat conduction. WMLI uses discrete spacers that maintain precise layer spacing, with a unique design to reduce heat leak. A Triple Orthogonal Disk spacer was engineered to minimize contact area/length ratio and reduce solid heat conduction for use in concentric MLI configurations.A new insulation, WMLI, was developed and tested. Novel polymer spacers were designed, analyzed and fabricated; different installation techniques were examined; and rapid prototype nested shell components to speed installation on real world piping were designed and tested. Prototypes were installed on tubing set test fixtures and heat flux measured via calorimetry. WMLI offered superior performance to traditional MLI installed on cryogenic pipe, with 2.2 W/m² heat flux compared to 26.6 W/m² for traditional spiral wrapped MLI (5 layers, 77–295 K). WMLI as inner insulation in VJP can offer heat leaks as low as 0.09 W/m, compared to industry standard products with 0.31 W/m. WMLI could enable improved spacecraft cryogenic feedlines and industrial hot/cold transfer lines.     

真空保温孔板式低温流量计

一种真空保温孔板式低温流量计用于4米高温超导电缆制冷系统。在结构上它与真空输液管做成一体，焊在输液管内管上．没有多余的接头连接。因而有效地减少了热量损失。它具有热损小、寿命长、能工作于气液两相等优点，减少了系统预冷期间的诸多麻烦。介绍了低温流量计的技术要求、设计方案和应用情况。     

用于低温存储系统的多层绝热性能分析

真空多层绝热的性能好坏直接影响到低温贮箱的安全性。根据修正的Lockheed模型,计算冷边界温度、热边界温度、层密度等对均匀层密度多层绝热性能影响,并对三区域变密度的多层绝热性能进行分析,最后针对在轨、地面状态时对低温贮箱漏热方面的要求提出采用复合多层绝热的概念,得出复合多层绝热具有优良的隔热性能。     

绝热材料放气速率测试台研制

高真空条件下,绝热材料的放气速率会影响低温容器的真空性能,从而影响其绝热性能。根据GB/T31480-2015,搭建了绝热材料放气速率测试平台。通过本底放气速率的测定,验证了该测试平台的可靠性;利用静态法测试了某型号多层绝热材料的放气速率,给出了试验数据。本试验台将为绝热材料的应用及低温容器的设计提供数据支撑。     

聚甲基丙烯酰亚胺(PMI)泡沫塑料在可重复使用低温贮箱绝热结构中的应用研究进展

介绍了国外以聚甲基丙烯酰亚胺(PMI)泡沫塑料为绝热材料的可重复使用低温贮箱绝热结构的研究情况,通过温度-载荷联合试验、热导率试验验证,用于试验的绝热结构可承受重复使用必须的多次温度循环冲击。     

两种绝热型式低温液体槽车的分析比较

文章从绝热性能、外形尺寸与重量、有效载液容积、制造工艺难度及槽车价格五个方面对真空粉末绝热与高真空多层绝热低温液体槽车进行了比较 ,分析了各自在使用上的优势与不足 ,并对具体运用时槽车的选择提出一些建议