低RCS飞行器外形设计实践

 在鸭式布局的基础上 ,对飞行器各部件及部件间的连接方式进行了外形隐身设计。对初步形成的鸭翼 -翼身融合体改变机身头部形状和立尾配置等进行 RCS优化。给出了飞行器各种状态下的 RCS平均值和迎头± 45°区内的 RCS值。测试结果表明 ,尖头机身、 30°双立尾 (立尾与垂直平面成± 30°角 )的鸭翼 -翼身融合体的 RCS值最小。对 RCS优化后的外形 ,风洞测力试验表明其气动性能也较好 (最大升阻比达到 8,失速迎角超过 2 6°)     

水下强声波脉冲引发的空化气泡运动和声辐射

通过建立由等离子体声源、PCB压力传感器和高速相机等构成的实验测量系统,研究了强声波脉冲引发的空化气泡运动和二次声辐射。通过实验,观察到了强声波脉冲特有的波形结构,空化气泡的成长、膨胀和坍缩过程以及气泡坍缩时辐射的声信号。其次,利用Gilmore方程和Bernoulli方程,从理论上对空化气泡的运动和声辐射进行了数值模拟和分析。研究结果表明：（1）在强声波脉冲正压区的作用下,空化气泡将受到压缩并围绕＂准平衡态半径＂振荡;在强声波脉冲负压区的作用下,空化气泡将出现膨胀、坍缩和回弹的物理过程。（2）空化气泡坍缩时周期性辐射的声脉冲持续时间极短,具有＂冲击波＂的特点。     

燃油射流横流穿透深度试验和数值模拟

采用激光粒子成像测速仪(PIV),试验研究了不同动量比下燃油射流在横向空气流中的穿透深度特性。同时,采用数值计算方法,对射流穿透特性进行了模拟,并将试验和计算结果,分别与已有的经验关系式,及考虑气动韦伯数影响修改后的关系式进行对比。结果表明:燃油射流上边界深度与幂指数关系式较吻合;采用VOF两相流模型能较准确地模拟出燃油射流的喷雾核心深度;修改后的关系式与不同燃油-空气动量比范围下的喷雾核心深度较吻合;燃油-空气动量比和气动韦伯数,是影响燃油射流横流穿透深度的主要参数。     

高功率微波极化方式与入射方向对微带线耦合特性影响分析

针对高功率微波（HPM）耦合效应分析需求,采用时域多分辨分析法（MRTD）模型,给出了微带线端口电压和电流方程,验证了模型的适用性。基于MRTD,仿真分析了HPM作为入射波时其极化方式、入射方向对微带线电磁耦合特性的影响。结果显示：垂直线极化波和平行线极化波耦合系数峰值出现在不同的频率,且峰值相差约15 dB,采用圆极化波时耦合系数最大;入射方向变化时,耦合系数以水平入射最小,垂直入射时最大,高频段微带线边缘有绕射现象产生。该分析采用了分析计算电大尺寸HPM耦合效应的MRTD数学模型,提高了HPM与复杂结构的耦合计算效率。     

低损耗介质材料复介电常数的变温测试

采用TE015模高Q圆柱腔对X波段低损耗介质材料的复介电常数进行了变温测试,电场的极化方向平行于样品表面.可测温度范围为常温到200℃.在所有温度点上,空腔的无载品质因数均大于40000.复介电常数的测试范围为εr1.05～10,tanδ3×10-2～5×10-5,测试系统的最可几误差为|Δεr / εr|=1.5% ,|Δtanδ|=10% tanδ+3.0×10-5.     

Type II Solar Radio Bursts: Theory and Space Weather Implications

Recent data and theory for type II solar radio bursts are reviewed, focusing on a recent analytic quantitative theory for interplanetary type II bursts. The theory addresses electron reflection and acceleration at the type II shock, formation of electron beams in the foreshock, and generation of Langmuir waves and the type II radiation there. The theory's predictions as functions of the shock and plasma parameters are summarized and discussed in terms of space weather events. The theory is consistent with available data, has explanations for radio-loud/quiet coronal mass ejections (CMEs) and why type IIs are bursty, and can account for empirical correlations between type IIs, CMEs, and interplanetary disturbances. This revised version was published online in August 2006 with corrections to the Cover Date.     

Solar Sources of Heliospheric Energetic Electron Events—Shocks or Flares?

Electrons with near-relativistic (E≳30 keV, NrR) and relativistic (E≳0.3 MeV) energies are often observed as discrete events in the inner heliosphere following solar transient activity. Several acceleration mechanisms have been proposed for the production of those electrons. One candidate is acceleration at MHD shocks driven by coronal mass ejections (CMEs) with speeds ≳1000 km s⁻¹. Many NrR electron events are temporally associated only with flares while others are associated with flares as well as with CMEs or with radio type II shock waves. Since CME onsets and associated flares are roughly simultaneous, distinguishing the sources of electron events is a serious challenge. On a phenomenological basis two classes of solar electron events were known several decades ago, but recent observations have presented a more complex picture. We review early and recent observational results to deduce different electron event classes and their viable acceleration mechanisms, defined broadly as shocks versus flares. The NrR and relativistic electrons are treated separately. Topics covered are: solar electron injection delays from flare impulsive phases; comparisons of electron intensities and spectra with flares, CMEs and accompanying solar energetic proton (SEP) events; multiple spacecraft observations; two-phase electron events; coronal flares; shock-associated (SA) events; electron spectral invariance; and solar electron intensity size distributions. This evidence suggests that CME-driven shocks are statistically the dominant acceleration mechanism of relativistic events, but most NrR electron events result from flares. Determining the solar origin of a given NrR or relativistic electron event remains a difficult proposition, and suggestions for future work are given.     

混合总线测控系统在R0110燃气轮机低排放试验中的应用

针对R0110燃气轮机低排放试验内容的要求,提出了对试验平台的测试与控制系统的设计方案,并详细介绍了该试验平台测试系统与控制系统的硬件与软件结构和功能的实现,其中通过利用混合总线方式将原测试系统与新测试系统相结合,扩展了试验器的测试能力.根据试验中多路燃料供给规律的要求,提出燃料供给手动、自动2种控制方式,进一步提高了试验控制上的智能性.在自动控制程序设计中,充分考虑了燃料供应的风险,并制定了相应的处理方案,保障了试验的顺利完成,而且提高了该试验器的智能化水平和整体测控能力.     

三旋流器加装外套环对燃烧性能的影响

对带有两种不同头部结构（基准型为方案1,头部加装外套环为方案2）的三旋流单头部燃烧室进行了研究,对有两种头部结构的燃烧室进行了流场和燃烧场的数值模拟,在相同的进口试验条件下,用燃气分析法和15点测温耙分别测量了两种头部的燃烧效率、出口冒烟数和出口温度场.结果表明:三旋流器的燃烧效率超过了99.7%,加装外套环后其流场、温度场分布均较基准型有所改善,回流区更加饱满,油气混合和燃油雾化效果增强,出口温度分布系数（OTDF）和出口冒烟数分别降低了36%和25%.      

煤基喷气燃料在地面单管燃烧室内燃烧和排放特性研究

为研究煤基喷气燃料的燃烧和排放特性,通过改造的单管燃烧室评估了煤基喷气燃料和石油基RP-3喷气燃料的燃烧和排放特性差异.试验结果表明:煤基喷气燃料具有更加优异的贫油点火和贫油熄火性能,两种喷气燃料的燃烧和排放特性随燃油流量和燃烧室出口温度的改变呈现出一致的变化趋势,在相同质量流量下,煤基喷气燃料的燃烧和排放性能要低于RP-3,在相同燃烧室出口温度时,煤基喷气燃料燃烧时的壁温要低于RP-3.