共查询到19条相似文献,搜索用时 171 毫秒
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高真空多层绝热低温容器真空丧失试验研究 总被引:2,自引:0,他引:2
通过高真空多层绝热容器真空丧失试验,分析了不同绝热结构下容器真空丧失后的升压规律,同时讨论了容器内气液状态变化。利用试验数据计算了容器真空丧失后的热负荷变化,并综合比较分析了不同绝热结构下的漏热量、气体升压、液体温度变化。经研究发现,容器夹层真空丧失后气液相处于不平衡态,气相空间压力变化呈现出三种不同状态,夹层的漏热量决定了液体升温和容器升压速度。 相似文献
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为解决高真空多层绝热超低温容器漏热的设计难点,通过对高真空多层绝热超低温容器支撑结构、容器接管、残余气体传热、辐射传热进行漏热分析,介绍了理论计算和数值模拟计算过程,同时提出了以机械构件和多层绝热结构优化为主的降低漏热的措施,最后将超低温容器蒸发率转化为允许漏热量,并以此作为性能考核指标,建立高真空多层绝热超低温容器漏热设计流程图,分析结果可为工程中的漏热设计提供参考。 相似文献
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真空粉末绝热低温液体贮槽是用于液氧、液氮、液氩等低温液体贮存的一种大型容器,广泛用于化工、冶金、玻璃制造等行业,由于其绝热方式为真空环境下的粉末(一般为珠光砂)绝热,因此决定了检漏在这类贮槽制造过程中是一个必不可少的重要环节。检漏方法有很多,如氦质谱... 相似文献
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真空多层绝热管道漏放气速率是考核管道绝热性能的重要指标,在生产过程中,影响其漏放的因素有抽空机组本身的泄漏情况、加热温度、加热时间、氮气置换、抽空周期等.到目前为止,真空多层绝热管道的生产工艺没有明确的标准及规范,为得到较为优化的生产工艺,论文介绍了其中一个重要的因素-氮气置换技术,对其进行了理论与试验分析,研究了氮气置换的注氮温度、注氮时间、注氮次数对真空多层绝热管道的影响,通过理论与实践总结出氮气置换相关参数的优化值,为进一步工艺理论规范化提供借鉴. 相似文献
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通过改进优化真空多层绝热软管外软管、内软管、支撑、法兰热桥及绝热层的结构研制出一种高柔性真空多层绝热软管,兼顾了管道的柔性和绝热性能,使得真空软管的结构更加紧凑。 相似文献
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文章通过分析充填于绝热低温储罐夹层中膨胀珍珠岩的特性、充填中的重点技术问题,介绍了一种膨胀珍珠岩的真空充填技术。 相似文献
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液氢截止阀按绝热形式分主要有外堆积绝热和真空多层绝热,本文主要针对该液氢阀门结构进行了分析。阀门在整体上采用了真空夹层结构,阀杆选用了波纹管密封结构,阀座和阀体一体加工成形,并且阀盖组件可以从阀体中整体抽出,方便的实现了阀瓣的快速更换和维修。该阀门结构形式已经申请国家专利(申请号:200720186326.3)。 相似文献
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论文综述了真空多层绝热管道发展过程和现状,阐明了其具有绝热性能好、重量轻、损失小等优点,是航天试车台和发射场长距离低温输送管道的最佳选择,介绍了目前常用的三种连接方式的性能和阐述了其各自应用特点,重点介绍了采用CO_2冷凝真空技术,展望了真空多层绝热管道的发展方向。 相似文献
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论文介绍了一种粉末真空液氮/液氧贮箱,用于承担某液体火箭发动机试验。该低温储存容器采用立式夹套结构。使用珠光砂真空绝热,几何容积6.2m3综合考虑该压力容器工作环境、制造工艺性、安装条件及空间的限制以及维护成本等诸多因素,详细介绍了研制中材质的选择、结构特点以及漏热计算、相关试验等关键技术。 相似文献
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China’s High-speed steel cutting tools hold a considerable share in the global market.However,the overproduction of low-end HSS tools causes serious resource waste and low efficiency,which has become one of the major problems in the tool industry in China.So a new Surface Modification technology is developed,which can make the low-end HSS tools into the high-end ones.On the analysis of the mechanism of cryogenic and quenching-polish-quenching(QPQ),the cryogenic and QPQ compound treatment are studied by using φ8 HSS(M2) drills.The nitriding layer and the base of the drill bit are Studied and analyzed,and the mechanism of compound treatment is discussed by the technological parameters adjustment and the combination test of cryogenic,nitrogen,tempering procedures,and several analysis methods such as the optics metallographic microscope,the scanning electronic microscope (SEM),X-ray diffraction and micro hardness.The cutting test is done on the drills by cryogenic treatment,QPQ treatment and cryogenic and QPQ compound treatment separately.The results indicates that the cutting life of HSS (M2) drill can be increased dramatically by cryogenic and QPQ compound treatment. 相似文献
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Paritosh P. Ambekar S. Wang R. Torii D. DeBra 《International Journal of Precision Engineering and Manufacturing》2009,10(3):37-42
We describe the design and development of a cryogenic tilt table that will be used to test the flight hardware for NASA’s
Satellite Test of the Equivalence Principle (STEP). Our table can tilt the hardware around two axes and is part of a test
bed that has 6-degree-of-freedom controllability. The goal was to build a tilt table with a resolution better than ∼5 μrad
(1 arcsec). Our table consists of three aluminum plates. The outermost plate is attached to the cryogenic probe and is fixed.
The middle and inner plates rest on the outer and middle plates, respectively, using knife edges and knife edge holders made
of silicon nitride that are glued to the aluminum plates. A cryogenic tilt sensor was also developed and integrated with the
table. The sensor consists of an electrically grounded copper cube hanging from a support, and is placed between two pairs
of capacitive electrodes. Any motion of the cube caused by tilting is measured differentially using a Wheatstone bridge circuit.
The table is connected to the bottom of a cryogenic probe. A voice coil actuator, located on top of the probe at room temperature,
is used to create the necessary tilt. A thin fiber is used to connect the actuator and the table. The system is controlled
using a dSPACE control card. A test of the table at cryogenic temperatures (4.5 K) and low pressure (1 μTorr) showed a noise
level of ∼0.7 μrad (150 marcsec), which is nearly an order of magnitude better than the required resolution. 相似文献