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航空发动机燃烧室主燃区特性的研究 总被引:1,自引:0,他引:1
采用FLUENT6.1软件对某型机燃烧室主燃区的各个典型工作状态进行三维两相湍流燃烧的速度场、温度场、油滴轨迹进行了数值模拟计算。通过对计算结果的分析,得出了主燃区的特性:主燃区的冷热区决定了出口温场冷热区,其效率决定了燃烧室的效率;随着负荷增加,油滴轨迹明显呈缩短趋势,模拟计算结果与试验结果及燃烧室工作特点比较吻合。 相似文献
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利用晶格动力学理论计算了二维三角晶格的Peierls相变前后的声子能谱。并且在第一布里渊区绘制了声子色散曲面。通过对Peierls相变前后的声子能谱比较可知,随其对称性降低,声子能谱的简并度被破缺。二维三角晶格的Peierls相变前只有两支声频支声子能谱,Peierls相变后有两支声频支声子能谱与两支光频支声子能谱,并且声频支声子能谱与光频支声子能谱不相交,两支光频支声子沿ky轴平缓地变化。 相似文献
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杨居奎 《运载火箭与返回技术》2006,27(2):14-17
文章介绍了3种平行光管中大口径反射镜的安装方法,并通过力学分析进行比较,给出了各自的优缺点。 相似文献
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F. Sabri N. Leventis J. Hoskins A.C. Schuerger M. Sinden-Redding D. Britt R.A. Duran 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Room temperature vulcanizing (RTV)-based components have been used on Mars Pathfinder, the Mars rovers, Spirit and Opportunity, as well as the Phoenix Lander as a support matrix for pigmented panoramic camera calibration targets. RTV 655 has demonstrated superiority to other polymers due to its unique range of material properties namely mechanical stability between −115 and 204 °C and UV radiation tolerance. As a result, it has been the number one choice for many space-related missions. However, due to the high mass density and the natural tendency for electrostatic charging RTV materials have caused complications by attracting and retaining dust particles (Sabri et al., 2008). In the current project we have investigated the relevant properties of polymer-reinforced (crosslinked) silica aerogels with the objective of substituting RTV-based calibration targets with an aerogel based design. The lightweight, mechanical strength, ability to accept color pigments, and extremely low dust capture makes polyurea crosslinked aerogels a strong candidate as a chromatic standard for extraterrestrial missions. For this purpose, the reflection spectra, gravimetric analysis, and low temperature response of metal oxide pigmented, polyurea crosslinked silica aerogels have been investigated and reported here. 相似文献
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Dmitri Nikolaevich Severov Valentina Pshennikov Alexsandr Vasilievich Remeslo 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
Fronts and thermohaline structure of the Brazil–Malvinas Confluence System (BMCS) are studied from climatic data, “Marathon Exp. Leg.8, 1984” data, and Sea surface temperature (SST) data base “ds277-Reynolds” (1981–2000). The South Atlantic Central Water (SACW) is divided in two main types: tropical (TW) and subtropical water (ST). Water masses, Fronts, Inter-Frontal and Frontal Zones are analysed and classified: (a) the water masses: Tropical Low-Salinity Water, Tropical Surface Water, Tropical Tropospheric Water, Subtropical Low-Salinity Water, Subtropical Surface Water, Subtropical Tropospheric Water. T,S characteristics of intermediate, deep and bottom water defined by different authors are confirmed and completed; (b) the Inter-Frontal Zones: Tropical/Brazil Current Zone, Subtropical Zone and Subantarctic Zone; (c) the Frontal Zones: Subtropical, Subantarctic and Polar, and (d) the Fronts: Subtropical Front of the Brazil Current, Principal Subtropical Front, North Subtropical Front, Subtropical Surface Front, South Subtropical Front, Subantarctic Surface Front, Subantarctic Front and Polar Front. Several stable T–S relationships are found below the friction layer and at the Fronts. The maximum gradient of the oceanographic characteristics occurs at the Brazil Current Front, which can be any of the subtropical Fronts, depending on season. Minimum mean depth of the pycnocline coincides with the Fronts of the BMCS, indicating the paths of low-salinity shelf waters into the open ocean. In the work it is shown how to recover the horizontal and vertical thermohaline structure of waters from satellite data RSMAS SST. 相似文献
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建立了墙面反射模型,用于根据雷达精度试验的要求计算微波暗室单个墙面的最大反射系数。进而可据此选择具有相应吸波性能的吸波材料。模型验证结果表明,计算结果比传统方法更具有工程应用价值。 相似文献
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使用我国2009-2017年286个地级市数据和双重差分模型,将设立自由贸易试验区视作一项准自然实验,评估其对试点城市高端服务业集聚的政策影响.结果显示:(1)自由贸易试验区的设立对高端服务业专业化集聚存在显著的正向影响,但对多样化集聚的作用并不明显;(2)自由贸易试验区的设立对高端服务业专业化集聚的促进作用,在短期内... 相似文献
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