共查询到20条相似文献,搜索用时 62 毫秒
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通过对现役预警机研制过程中,载机选择的一般原则和几种雷达天线罩布局形式优缺点的分析,论述了预警机雷达天线罩布局设计中的若干技术问题,总结了雷达天线罩布局设计的发展趋势。 相似文献
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介绍了机载雷达罩复合材料结构的力学和电磁学性能的分析设计方法,以某型飞机雷达天线罩设计为实例,对天线罩等效平板试验件的电性能进行了计算分析,对天线罩的强度、刚度进行了分析和试验验证,结果表明计算结果与试验结果基本一致,能够满足工程设计要求. 相似文献
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飞机上的雷达罩是容易受损坏的部位,因此弄清雷达罩的结构、损伤种类,掌握其检查、修理、维护和喷漆技术对维修人员非常重要。了符合飞机的空气动力的需要和保持飞机整个外形的美观,同时保护雷达的天线,需要安装雷达天线罩。这就要求雷达天线罩不但要保护雷达天线,同时还要保证雷达发射接收的全部电性能要求,也就是尽量减少雷达发射功率的衰减。B737飞机电性能要求是透波率平均为84%,最小要达到78%。下面分别介绍B737的雷达罩的结构,损伤及其修理。雷达罩的结构雷达天线罩采用蜂窝夹层结构,其前端采用柔性蜂窝材料,后部加强结… 相似文献
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基于EKF的天线罩误差斜率多模型估计方法 总被引:2,自引:0,他引:2
提出一种新的滤波器结构,利用基于扩展卡尔曼滤波(EKF)的多模型(MM)算法,对天线罩误差斜率进行估计,降低天线罩误差对雷达自寻的导弹的影响,提高系统性能。在三维坐标下,创建包含导弹运动方程、目标运动方程、弹目相对运动方程的滤波模型。采用EKF算法,对包含天线罩误差的非线性观测方程进行线性化处理;依照多模滤波的思想,对天线罩误差进行离散建模,构建伪观测方程,更新模型概率,得到天线罩误差斜率的估计值;将斜率估计结果代入EKF,得到滤除天线罩误差影响的系统状态量估计结果并形成制导指令。仿真结果表明,所提方法可以有效地估计天线罩斜率,提高系统制导精度。 相似文献
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针对导弹雷达导引头天线罩生产过程中的质量偏差问题,利用六西格玛的改进模式——DMAIC,借助统计软件MINITAB,分析并提出了天线罩的生产过程改进方法。结果表明:天线罩厚度是影响生产质量的关键因素,通过控制生产过程中的压力、温度等直接影响因素,能显著提高天线罩生产的质量水平。 相似文献
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有翼高超声速再入飞行器气动设计难点问题 总被引:2,自引:1,他引:2
有翼高超声速再入飞行器是近年来的研究热点,气动设计是飞行器设计的关键。为了更清楚地认识有翼高超声速再入飞行器气动设计的难点问题,对有翼高超声速再入飞行器的发展、优势及总体任务剖面进行了介绍,从5个方面详细介绍了该类飞行器气动设计的难点问题,包括多约束复杂面对称气动布局设计、高温真实气体效应对气动特性影响、天地差异与天地换算方法、反作用控制系统(RCS)喷流干扰对气动特性的影响以及气动数据不确定度等,简要阐明了这些难点问题对总体设计的重要性以及初步的解决思路,为有翼高超声速再入飞行器气动设计提供了一些参考。 相似文献
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LUO Cheng LIU Hua YANG Jia-ling LIU Kai-xin 《中国航空学报》2007,20(3):230-235
Crashworthiness requirement of fuel tanks is one of the important requirements in helicopter designs. The relations among the protection frame, textile layer and rubber layer of the fuel tank are introduced. Two appropriate FE models are established, one is for an uncovered helicopter fuel tank without protection frame, and the other is for fuel tank with protection frame. The dynamic responses of the two types of fuel tanks impinging on the ground with velocities of 17.3 m/s are numerically simulated for the purpose of analyzing energy-absorbing capabilities of the textile layer and protection frame. The feasibility of the current crashworthiness design of the fuel tank is examined though comparing the dynamic response behaviors of the two fuel tanks. 相似文献
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The effect of inlet conditions on the flow and heat transfer in multiple rotating cavity with axial throughflow 总被引:1,自引:0,他引:1
This paper discusses experimental results from two different build configurations of a heated multiple rotating cavity test rig.Measurements of heat transfer from the discs and tangential velocities are presented.The test rig is a 70% full scale version of a high pressure compressor stack of an axial gas turbine engine.Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air.Tests were carried out for a range of non-dimensional parameters representative of high pressure compressor internal air system flows(Re up to 5×106 and Rez up to 2×105).Two different builds have been tested.The most significant difference between these two build configurations is the size of the annular gap between the(non-rotating) drive shaft and the bores of the discs.The heat transfer data were obtained from thermocouple measurements of surface temperature and a conduction solution method.The velocity measurements were made using a two component,LDA system.The heat transfer results from the discs show differences between the two builds.This is attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity.There are also significant differences between the radial distributions of tangential velocity in the two builds of the test rig.For the narrow annular gap,there is an increase of non-dimensional tangential velocity V/Ωr with radial location to solid body rotation V/Ωr=1.For the wider annular gap,the non-dimensional velocities show a decrease with radial location to solid body rotation. 相似文献
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波音公司面临着来自空客公司的巨大挑战,企业战略性创新才是公司成功的关键。为此波音公司的全部战略性研究集中在扩大产品的差异性上,体现在3个方面:电子化(e-Enabled)运营环境、整体复合材料机身部件的制造技术和支持波音787客机的全球协同环境(GCE)。 相似文献
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临近空间飞行器测控与信息传输系统频段选择 总被引:7,自引:0,他引:7
临近空间飞行器是高性能信息化武器平台,测控(TT&;C)与信息传输系统是其信息保障的核心,而选择合理、可行的频段是展开系统设计的前提和基础。频段选择影响到整个技术方案的制定,是一个需综合考虑、影响深远并具有战略意义的关键问题,从国际电联(ITU)国际标准、高速数传、接收信噪比(SNR)、“三抗”、超视距中继、黑障、雨衰以及设备研制成熟度8个方面全面、细致论证了近空间平台测控系统的频段选择问题,最终得出在视距链路中以Ka频段为宜,在超视距链路中以Ku/Ka双频段为宜的结论。 相似文献
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基于弯曲激波压缩系统的高超声速进气道反设计研究进展 总被引:3,自引:0,他引:3
总结了近十年来弯曲激波压缩研究的主要成果。提出了弯曲激波压缩系统的新概念,即利用特殊设计的楔形弯曲压缩面或空间弯曲压缩面,产生一系列与前缘弱激波相互交汇或叠加的压缩波系,从而使前缘激波弯曲,形成特殊的弯曲激波,它与波后的等熵压缩波来共同完成对气流的压缩。在此基础上,实现了由给定出口气动参数的超声速内流道反设计,实现了由给定压缩面压力分布和给定压缩面马赫数分布要求的型面反设计,实现了由给定激波波面的压缩型面反设计。研究证明,弯曲压缩面-弯曲激波压缩系统具有良好的综合气动性能,为高性能高超声速进气系统的气动设计提供了一种全新的设计方法。 相似文献
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Wu Xianyu Li Xiaoshan Ding Meng Liu Weidong Wang Zhenguo 《中国航空学报》2007,20(6):488-494
In order to investigate the effects of fuel injection distribution on the scramjet combustor performance, there are conducted three sets of test on a hydrocarbon fueled direct-connect scramjet test facility. The results of Test A, whose fuel injection is carried out with injectors located on the top-wall and the bottom-wall, show that the fuel injection with an appropriate close-front and centralized distribution would be of much help to optimize combustor performances. The results of Test B, whose fuel injection is performed at the optimal injection locations found in Test A, with a given equivalence ratio and different injection proportions for each injector, show that this injection mode is of little benefit to improve combustor performances. The results of Test C with a circumferential fuel injection distribution displaies the possibility of ameliorating combustor performance. By analyzing the effects of injection location parameters on combustor performances on the base of the data of Test C, it is clear that the injector location has strong coupled influences on combus- tor performances. In addition, an inner-force synthesis specific impulse is used to reduce the errors caused by the disturbance of fuel supply and working state of air heater while assessing combustor performances. 相似文献
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(高)超声速流动试验技术及研究进展 总被引:1,自引:1,他引:1
近年来,与高速飞行器相关的(高)超声速流动受到了极大的关注。这类流动所具有的非定常性、强梯度和可压缩性对试验方法和风洞设计技术提出了挑战。超声速纳米示踪平面激光散射(NPLS)技术是由作者所在团队研发的非接触光学测试技术。它能够以较高的空间分辨率来揭示超声速三维流场的一个瞬态剖面的时间解析的流动结构。介绍了NPLS技术以及基于NPLS开发的密度场测量、雷诺应力测量和气动光学波前测量等方法,并回顾了这些技术在超声速边界层、超声速混合层、超声速压缩拐角、激波/边界层相互作用和光学头罩绕流等流动中的应用,清晰地再现了边界层、混合层、激波等典型流场结构及其时空演化特性。另外,为了模拟和研究高空大气条件下边界层自然转捩和超声速混合层的转捩特性,介绍了高超声速静风洞、超-超混合层风洞的设计技术以及层流化喷管的设计方法。 相似文献
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Research on Auto-detection for Remainder Particles of Aerospace Relay Based on Wavelet Analysis 总被引:2,自引:0,他引:2
GAO Hong-liang ZHANG Hui WANG Shu-juan 《中国航空学报》2007,20(1):75-80
Aerospace relay is one kind of electronic components which is used widely in national defense system and aerospace system. The existence of remainder particles induces the reliability declining, which has become a severe problem in the development of aerospace relay. Traditional particle impact noise detection (PIND) method for remainder detection is ineffective for small particles, due to its low precision and involvement of subjective factors. An auto-detection method for PIND output signals is proposed in this paper, which is based on direct wavelet de-noising (DWD), cross-correlation analysis (CCA) and homo-filtering (HF), the method enhances the affectiv-ity of PIND test about the small particles. In the end, some practical PIND output signals are analysed, and the validity of this new method is proved. 相似文献