共查询到16条相似文献,搜索用时 187 毫秒
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国家微重力实验室介绍 总被引:2,自引:0,他引:2
微重力科学是当前空间科学的前沿领域,主要研究微重力环境下的流体物理、物理化学、材料科学及生物科学和技术.微重力科学的发展将促进自然科学某些领域取得突破性的进展,并为空间技术的商业化应用奠定一定的基础.为了适应我国航天事业发展,由国防科工委和中国科学院共同投资建立了国家微重力实验室,这是国家高技术研究发展计划航天领域专家委员会的一个重大的应用基础性建设项目.文章简要介绍了国家微重力实验室的研究方向、组织结构和有关实验室的情况. 相似文献
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文章报道了三次α-碘酸锂晶体空间生长实验.该实验是在我国返回式科学技术探测卫星上完成的.为研究空间微重力环境对于晶体生长和物性的影响,应用X射线衍射、X射线形貌、X射线荧光分析、光学透过率和介电测量等技术,对在微重力和常重力条件下生长的晶体结构、完整性、杂质分布以及介电常数等参数进行了研究.研究结果表明:微重力条件下,晶体中β-碘酸锂的含量比地面低;微重力对α-碘酸锂的晶体形态和结构没有影响;微重力条件下生长的晶体的完美性优于地面晶体;微重力环境使碘酸锂晶体的介电常数增高 相似文献
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A. A. Lobykin 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2009,3(1):154-160
It is shown that none of the domestic spacecrafts on which microgravity experiments can be performed satisfy the requirements for experiments on the physics of liquid and space materials science by the level of their onboard microgravity environment. The necessary level of microgravity environment for such experiments is ~10?7 g 0. Procedures for decreasing the microgravity onboard a prospective spacecraft intended for microgravity studies to a level necessary level are proposed. 相似文献
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Andrew J. Lock Ranjan Ganguly Ishwar K. Puri Suresh K. Aggarwal Uday Hegde 《Proceedings of the Combustion Institute》2005,30(1):511-518
While premixed and nonpremixed microgravity flames have been extensively investigated, the corresponding literature regarding partially premixed flames (PPFs) is sparse. We report the first experimental investigation of burner-stabilized microgravity PPFs. Partially premixed flames with multiple reaction zones are established in microgravity on a Wolfhard–Parker slot burner in the 2.2 s drop tower at the NASA Glenn Research Center. Microgravity measurements include flame imaging, and thermocouple and radiometer data. Detailed simulations are also used to provide further insight into the steady and transient response of these flames to variations in g. The flame topology and interactions between the various reaction zones are strongly influenced by gravity. The flames widen substantially in microgravity. During the transition from normal to microgravity, the flame structure experiences a fast change and another relatively slower transient change. The fast response is due to the altered advection as the value of g is reduced, while the slow response is due to the changes in the diffusive fluxes. The radiative heat loss from the flames increases in microgravity. A scaling analysis based on a radiation Damköhler number is able to characterize the radiation heat loss. 相似文献
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在常重力下模拟微重力燃烧对载人航天器的火灾安全具有重要意义.窄通道就是这样一种可以有效限制自然对流的模拟设施.但是,不同重力下火焰传播的相似性仍然是有待研究的问题.本文用实验和数值模拟的方法,比较了不同重力下有限空间内热薄材料表面的逆风传播火焰.不同重力下火焰形状和火焰传播速度的比较表明,1cm高的水平窄通道可以有效地限制自然对流,在常重力下用这种通道能够模拟微重力下相同几何尺寸的通道中的火焰传播.因此,在地面上首先利用水平窄通道,模拟相同环境中的微重力火焰传播,然后考虑通道尺寸变化对火焰传播的影响,有可能成为地面模拟其他尺寸的空间中的微重力燃烧的方法. 相似文献
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Fengshan Liu Gregory J. Smallwood 《Journal of Quantitative Spectroscopy & Radiative Transfer》2011,112(7):1241-1249
The importance of radiation heat loss in laminar and turbulent diffusion flames at normal gravity has been relatively well recognized in recent years. There is currently lack of quantitative understanding on the importance of radiation heat loss in relatively small scale laminar diffusion flames at microgravity. The effects of radiation heat transfer and radiation absorption on the structure and soot formation characteristics of a coflow laminar ethylene/air diffusion flame at normal- and microgravity were numerically investigated. Numerical calculations were conducted using GRI-Mech 3.0 combustion chemistry without the NOx mechanism and complex thermal and transport properties, an acetylene based soot formation model, and a statistical narrow-band correlated-k non-grey gas radiation model. Radiation heat transfer and radiation absorption in the microgravity flame were found to be much more important than their counterparts at normal gravity. It is important to calculate thermal radiation transfer accurately in diffusion flame modelling under microgravity conditions. 相似文献
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This paper describes applications of computed tomography (CT) to combustion phenomena under microgravity conditions. Infrared Thermography (IT) has been considered as a promising method for two-dimensional measurement of flames. We have applied IT to CT for a butane flame under microgravity conditions. The method joining spectroscopy to CT for diffusion flame of hydrogen has also been carried out. Intensity of chemical luminescence, which is originated from combustion-chemical reaction in the flame, can be measured by scanning a spectrometer with collimator. The effectiveness of the CT applications to microgravity combustion has been confirmed from two method. 相似文献