Joule-Thomson cryocooler for space applications

A J-T cryocooler is being developed for space applications. It is under laboratory testing and will be flight-tested aboard the Space Shuttle in middle to late 1997. A seal-ability study confirmed that the EDM design is robust and can accommodate a wide range of heat loads while maintaining the development heritage.     

空间斯特林制冷机失效分析

针对空间用的"牛津型"斯特林制冷机的结构特点,对其早期失效模式和正常失效模式等主要失效模式进行了较深入分析,提出了改进措施.通过结构设计、工艺等改进,可以消除早期失效模式、延长正常失效的时间.     

液化空气(中国)投资有限公司

法国液化空气集团成立于1902年，是全球领先的工业气体和医疗气体以及相关服务的供应商，业务遍及72个国家，拥有近4万名员工。集团借助不断更新的技术为各方提供创新的解决方案，并生产各种空气产品（氧气、氮气、稀有气体）以及氢气等其他气体。法国液化空气集团为众多日常生活用品的生产也做出了贡献：饮料中的气泡，食品封装的保护气体，医院和家庭理疗所需的氧气，电子工业所需的超纯气体以及燃油脱硫所需的氢气等。法国液化空气集团2007年的销售额为118亿欧元，其中近80％的销售额都是在法国以外实现的。法国液化空气集团在巴黎证券交易市场上市，同时是法国股指CAC40和Eurostoxx50indices的成员企业。在福布斯2007年公布的世界500强中排名第339位。     

空间吸附制冷技术的研究进展

吸附制冷机具有工作寿命长、无运动部件、不会产生振动、可靠性较高、无电磁干扰的特点,是未来空间制冷技术中最重要的制冷技术之一.介绍了美国和欧洲空间吸附式制冷技术的发展和研究热点,结合中国深空探测对低温制冷技术的需求提出了发展空间吸附制冷技术的建议.     

法国液化空气集团经营动向和发展战略的研究

介绍了法国液化空气集团近期在全球和中国的业务发展情况及发展战略。     

6 W@90 K星载斯特林制冷机的热环境适应性

针对某空间任务要求,分析了热试验温度取值.基于1台6 W@90 K星载斯特林制冷机,开展了常压热循环和热真空试验研究,得到了制冷机在不同温区下的制冷性能参数.从6个方面对比分析了两个试验中性能参数的变化,最后得出:环境温度对6 w制冷机性能影响较大,从50 ℃到-20℃温区,制冷温度为90 K时,冷量增大约1.4 W,功耗减小约17 W;在50至-20℃温区内,制冷机未发生结构热变形失效.该6 W型制冷机在合理设计辅助散热(卫星总体热控调节)之后,可满足空间应用时-20℃-40 ℃温区热环境适应性;压缩机和膨胀机通过良导热体连接散热,可平衡温差,便于控温.     

Low-power cryocooler survey

A cryocooler survey has been performed on data of 235 cryocoolers, with cooling powers below some tens of watts and operating between 4 and 120 K. The state-of-the-art is discussed and trends are investigated on cooling performance, mass and size, cost, lifetime and reliability. The data were compared with earlier surveys to explore historical trends. Improvements in cooling performance were mainly in 80 K cryocoolers, an increase in efficiency by about a factor of 5. Coolers did not reduce in size significantly. Main reduction was in 80 K coolers because of the higher efficiency. In the survey, cost is related to input power, cooling power and operating temperature. Cost development is considered and related to learning curves. Since the mid-90s, the lifetime of Stirling-type cryocoolers has increased by one order of magnitude from typically 0.5 to 5 years or more. The confusion that exists on the term “reliability” is discussed.     

NASA cryocooler technology developments and goals to achieve zero boil-off and to liquefy cryogenic propellants for space exploration

NASA’s interest in human exploration of Mars has driven it to invest in 20 K cryocooler technology to achieve zero boil-off of liquid hydrogen and 90 K cryocooler technology to achieve zero boil-off liquid oxygen or liquid methane as well as to liquefy oxygen or methane that is produced on the surface of Mars. These investments have demonstrated efficiency progress, mass reductions, and integration insights. A history of the application of cryocooler technology to zero boil-off propellant storage is presented. A trade space on distributed cooling is shown, along with the progress of reverse turbo-Brayton cycle cryocoolers, where the specific power and specific mass have dropped, decreasing the mass and power of these cryocoolers. Additionally, the cryocooler technology advancements of recuperators and compressors are described. Finally, NASA’s development ideas with respect to zero boil-off technology are discussed.     

Finite waiting space bulk queueing systems

Summary This paper extends earlier work on the stationary queue length distribution of a bulk service system with finite waiting space by considering two queueing systems. The first system incorporates the feature of batch arrivals with group service; it has compound Poisson input, general service times and a single server with variable batch capacity. The second system has individually arriving customers with Erlangian interarrival time distribution, general service times and a single server with variable batch capacity.The financial support of the National Research Council of Canada, under Research Grants No. 3-644-189-60; NRC-A5639 and No. 3-641-189-10; NRC-A2796, is acknowledged.     

空间用斯特林制冷机的寿命评价

介绍了空间用斯特林制冷机的主要失效模式和失效机理,国内外寿命评价研究的状况和进展,分析了几种加速寿命评价方法.针对中国空间用制冷机寿命评价研究的现状,提出了加速寿命评价的一些见解和思路.     

双级斯特林制冷机热力分析

基于热力学第一定律,分析了双级斯特林制冷机两级之间冷量分配的关系式,以及冷量与压缩机功耗之间的关系.通过商业计算软件,对制冷机内部能量流进行模拟计算,结合实例定量给出制冷机各部分的损失.     

A 9 K conical stirling-cycle cryocooler

A low power closed cycle Stirling refrigerator with a conical glass-fibre reinforced epoxy displacer/regenerator, and an external compressor has been built in our laboratory. The single stage device has demonstrated cooling to 9 K directly from room temperature, and may be used for cooling SQUID systems.     

Northrop Grumman Aerospace Systems cryocooler overview

Mechanical long life cryocoolers are an enabling technology used to cool a wide variety of detectors in space applications. These coolers provide cooling over a range of temperatures from 2 K to 200 K, cooling powers from tens of mW to tens of watts. Typical applications are missile warning, Earth and climate sciences, astronomy and cryogenic propellant management. Northrop Grumman Aerospace Systems (NGAS) has delivered many of the US flight cooler systems and has 12 long life pulse tube and Stirling coolers on orbit with two having over 11 years of continuous operation. This paper will provide an overview of the NGAS cryocooler capabilities.     

Experimental results for a cryocooler regenerator

In this work some experimental results obtained on a single stage Gifford McMahon cryocooler developed at the Officine Galileo for ir thermal vision applications are presented. The difference in thermodynamic behaviour of three ordinary and easy to find meshed nets used in our cryocoolers as a matrix for the thermal regenerator has been checked. The method used to detect the regenerator performance is indirect but very simple to put into practice and useful for an overall evaluation. A clear indication for the choice of the regenerator material comes from the experimental data.     

斯特林制冷机的自寻优前馈振动控制

研究采用自寻优前馈方案实现斯特林制冷机的主动减振。斯特林制冷机是提供空间大制冷量的最佳手段。从减轻重量、减小体积和功耗的角度出发,提出了一种基于前馈控制的主动减振方案,用直线电机推动一个质量平衡块以抑制制冷机的振动,并设计了控制器参数的在线自寻优算法,实现整套系统的全自动运行。该减振系统的控制算法由DSP实现,将制冷机的基频振动水平降低到原来的2.87%。     

Aerogel insulation systems for space launch applications

New developments in materials science in the areas of solution gelation processes and nanotechnology have led to the recent commercial production of aerogels. Concurrent with these advancements has been the development of new approaches to cryogenic thermal insulation systems. For example, thermal and physical characterizations of aerogel beads under cryogenic-vacuum conditions have been performed at the Cryogenics Test Laboratory of the NASA Kennedy Space Center. Aerogel-based insulation system demonstrations have also been conducted to improve performance for space launch applications. Subscale cryopumping experiments show the thermal insulating ability of these fully breathable nanoporous materials. For a properly executed thermal insulation system, these breathable aerogel systems are shown to not cryopump beyond the initial cooldown and thermal stabilization phase. New applications are being developed to augment the thermal protection systems of space launch vehicles, including the Space Shuttle External Tank. These applications include a cold-boundary temperature of 90 K with an ambient air environment in which both weather and flight aerodynamics are important considerations. Another application is a nitrogen-purged environment with a cold-boundary temperature of 20 K where both initial cooldown and launch ascent profiles must be considered. Experimental results and considerations for these flight system applications are discussed.     

Adapting space vehicle systems to measurement conditions

A method is proposed for stabilizing the operation of a measurement system while adapting it to the on-board measurement conditions. __________ Translated from Izmeritel’naya Tekhnika, No. 11, pp. 3–9, November, 2006.     

Vibration-free stirling cryocooler for high definition microscopy

The normal operation of high definition Scanning Electronic and Helium Ion microscope tools often relies on maintaining particular components at cryogenic temperatures. This has traditionally been accomplished by using liquid coolants such as liquid Nitrogen. This inherently limits the useful temperature range to above 77 K, produces various operational hazards and typically involves elevated ownership costs, inconvenient logistics and maintenance. Mechanical coolers, over-performing the above traditional method and capable of delivering required (even below 77 K) cooling to the above cooled components, have been well-known elsewhere for many years, but their typical drawbacks, such as high purchasing cost, cooler size, low reliability and high power consumption have so far prevented their wide-spreading. Additional critical drawback is inevitable degradation of imagery performance originated from the wideband vibration export as typical for the operation of the mechanical cooler incorporating numerous movable components.Recent advances in the development of reliable, compact, reasonably priced and dynamically quiet linear cryogenic coolers gave rise to so-called “dry cooling” technologies aimed at eventually replacing the traditional use of outdated liquid Nitrogen cooling facilities. Although much improved these newer cryogenic coolers still produce relatively high vibration export which makes them incompatible with modern high definition microscopy tools. This has motivated further research activity towards developing a vibration free closed-cycle mechanical cryocooler.The authors have successfully adapted the standard low vibration Stirling cryogenic refrigerator (Ricor model K535-LV) delivering 5 W@40 K heat lift for use in vibration-sensitive high definition microscopy. This has been achieved by using passive mechanical counterbalancing of the main portion of the low frequency vibration export in combination with an active feed-forward multi-axes suppression of the residual wideband vibration, thermo-conductive vibration isolation struts and soft vibration mounts. The attainable performance of the resulting vibration free linear Stirling cryocooler (Ricor model K535-ULV) is evaluated through a full-scale experimentation.     

牛津型斯特林制冷机的动力特性分析

为了提高牛津型斯特林制冷机的制冷效率,提出了一种应用数值软件进行动力特性研究的方法。总结分析了压缩机、膨胀机的板弹簧刚度和活塞质量,充气压力,膨胀机位移相位角,膨胀机活塞行程以及制冷温度对制冷机动力特性的影响规律。优化了制冷机的动力系统,实验验证了该方法的可行性。研究结果表明,优化后制冷机的压缩机电机效率和整机效率均有所提高。