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针对采用下颌式进气道的固体火箭冲压发动机,建立了二次燃烧性能计算模型,对掺混燃烧性能进行了仿真研究。研究表明,采用掺混装置可大幅提升下颌式进气道的固冲发动机补燃室一次燃气和空气的掺混均匀度,并通过数值仿真对掺混装置进行了优化。结合数值仿真优化结果,通过地面直连试验,验证了不采用与采用掺混装置的补燃室二次燃烧性能。试验结果表明,合理设计掺混装置,可显著提高补燃室二次燃烧性能,特征速度燃烧效率均在93%以上;空燃比在6~20之间的发动机高空比冲提升了55%以上,空燃比在20~30之间的发动机高空比冲提升了75%以上。 相似文献
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进行了后置燃气发生器的新型固体火箭冲压发动机直连式试验,并对实验演示用发动机补燃室三维内流场进行了数值模拟,将试验结果与数值模拟结果进行对比,验证了数值模拟的准确性。采用单因素比较分析的方法,研究了一次燃气喷射方式与补燃室长度对固冲发动机性能的影响。结果表明,一次燃气喷射角度为150°时的燃烧效率比60°时高14%,补燃室燃烧效率在一次燃气喷射角度为180°时达到最大值;8喷口的燃烧效率高于4喷口;补燃室长度增加,燃烧效率增大,补燃室长度为149 mm时的燃烧效率比99 mm仅高5%。 相似文献
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膏体冲压发动机构型对燃烧效率的影响研究 总被引:1,自引:0,他引:1
膏体冲压发动机是在膏体发动机和冲压发动机基础上提出的一种新型组合动力装置.探讨了膏体冲压发动机的多种构型.并对其反应流场进行了数值模拟和燃烧效率分析.结果表明,采用将膏体富燃料直接喷射到补燃室的方式燃烧效率较高;随着进气道轴向距离的增加,补燃室头部的燃烧效率有所降低;随着进气道夹角的增加,补燃室燃烧效率略有增加. 相似文献
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A string moving with geostationary angular velocity in its radial relative equilibrium configuration around the Earth, reaching from the surface of the Earth far beyond the geostationary height, could be used as track for an Earth to space elevator. This is an old dream of mankind, originating about 100 years ago in Russia. Besides the question of feasibility from a technological point of view also the question concerning the stability of such a configuration has not yet been completely solved. Under the assumption that a proper material (carbon nanotubes) is available, making the connection possible technologically, we address the question of existence and stability of the radial relative equilibrium of a tapered string on a circular geosynchronous trajectory around the Earth, reaching from the surface of the Earth far beyond the geostationary height. 相似文献
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本文介绍了“三位一体”教育模式的内容,描述亍我们实施该模式所采取的措施及取得的成效。实践表明,“三位一体”教育模式能够提高学生的综合素质,为学生毕业后的发展打下坚实基础,对教育模式的改革具有一定的指导意义。 相似文献
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In this paper, we analyze the illumination conditions, the thermal regime, and the possibility of deposits of volatile compounds existing in the vicinity region (NSR S5 region) near the southern pole of the Moon. It has been found that there are no permanently shadowed zones near the Scott crater and the NSR S5 region, though the temperature conditions allow the of compounds such as CH3OH, SO2, NH3, CO2, H2S, C2H4, and water to remain stable relative to evaporation for a long time (≥1 Gyr). It has been also shown that compounds like CO and CH4 cannot stably exist in these regions. 相似文献
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电阻式传感器的核心部件——电阻应变计是目前最常用的应力分析的敏感元件。也常用于测量力、压力、扭矩和加速度等物理量。作者简要回顾了电阻应变计的发展历史,介绍了电阻应变计的结构、分类及现状,展望了电阻式传感器的前景。 相似文献
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The results of an investigation of the distribution of plasma pressure, pressure gradients, and magnetic field near the equatorial plane in the plasma ring surrounding the Earth under magneto-quiet conditions are presented. Observational data obtained during the international THEMIS mission are used. The picture of the distribution of transverse-current density near the equatorial plane was obtained under assumption of observing the magnetostatic balance condition at geocentric distances from 6 to 12R E. In estimating the integral transverse current it was accepted that in daytime sector the magnetic-field minima on magnetic field lines are not localized in the equatorial plane. Estimates of the integral transverse current were obtained, which demonstrate the possibility of closing nighttime transverse currents at geocentric distances of up to ~12R E inside the magnetosphere, which form a high-latitudinal continuation of the ring current. 相似文献
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文章基于阿列纽斯经验公式,利用相关标准中的数据,拟合得到硅集成电路老炼试验温度和时间的关系,根据这种关系可以确定在标准未规定的高温下硅集成电路的老炼时间,同时预计了硅集成电路的工作寿命。最后基于经典的温度应力加速试验模型进行了分析,并与前者进行了对比。 相似文献
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对老年人体育锻炼负荷量监控方法的探讨 总被引:2,自引:0,他引:2
石丹青 《桂林航天工业高等专科学校学报》2004,9(4):66-69
通过对老年人体育锻炼活动的情况进行相关调查,发现目前老年人体育锻炼中存在一些误区。因此本文针对这些现实情况提出,应根据实际情况运用一些简单易行的方法来对老年人体育锻炼实施医务监督,达到提高老年人体育锻炼的科学性。 相似文献
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周艳华 《华北航天工业学院学报》2009,(1):58-60
诚信是中华民族的传统美德,是社会生活正常运行的道德基础,是市场经济有序发展的基本要素,是和谐社会构建的重要标尺。但近年来,在大学生无视诚信的现象不容忽视。为此要发扬传统文化之精髓,弘扬当代大学生的诚信精神,并且实行知行统一。 相似文献