新型空间站氢/氧变轨发动机研究

基于气动谐振点火技术的氢／氧变轨发动机是一项新型的液体火箭推进技术,尤其适用于空间站应用。通过氢氧推力室理论热力计算以及同轴氢氧谐振点火试验研究,采用了同轴氢氧谐振点火器加氧气补燃喷嘴的发动机头部结构方案。在同轴氢氧谐振点火器进行性能试验研究基础上,依次成功进行了发动机头部的谐振点火及氧气补燃试验。最后,成功完成了包括单脉冲、连续双脉冲及3．0S持续工作几种形式下的发动机地面试车试验,验证了发动机工作的可靠性及可行性。发送机起动时间达到0．2S以内。     

辉光放电等离子体对边界层流动控制的机理研究

本文求解电位势方程得到电场分布,假定电场强度大于击穿阈值的区域为等离子体区,给定电荷密度,得到了作用于流体上的电场力。通过求解带源项的NS方程,研究了一个大气压下的均匀辉光放电等离子体对边界层流动的影响,考察了电场力做功对流动的影响。本文研究结果同文献[6]一致,即电场力总体上使边界层流动加速。另外,电场力做功对流动参数的影响可以忽略。文献[6]给出的线化电场模型和本文得到的电场相比,具有较大的差别,该差别引起了流动参数显著差别。     

EUV and Radio Observations of an Equatorial Coronal Hole

An equatorial coronal hole has been observed on 18 and 19 October 1996 with SOHO-CDS and with the Nancąy Radioheliograph (RH). The CDS EUV line intensities are used to determine the coronal hole Differential Emission Measure (DEM); in turn this is used to compute the radio brightness temperature T_b at the observed frequencies, leaving the coronal electron temperature and density as free parameters. EUV line intensities, calculated from the derived models, show a good agreement with EUV observations. This revised version was published online in June 2006 with corrections to the Cover Date.     

冷等离子体接枝处理对碳纤维织物／环氧复合材料界面性能的影响

采用冷等离子体接枝法对碳纤维织物进行表面处理,在纤维表面产生活性官能团,研究了冷等离子体接枝处理对碳纤维织物/环氧复合材料的层间剪切强度的影响。实验结果表明,冷等离子体接枝处理提高了碳纤维表面活性,从而改善了碳纤维织物/环氧复合材料的界面粘结性能,进而改善了复合材料的界面性能。     

小型微波等离子推力器研究

 介绍约100W 功率微波等离子推力器的系统结构, 谐振模式, 电磁场分布, 电磁场、等离子体和流场的耦合, 喷管中的等离子体复合流动, 真空羽流, 原理实验样机性能及应用前景。     

The local bubble

Recently, observations with the rosat PSPC instrument and the spectrometers onboard the euve satellite have given new detailed information on the structure and physical conditions of the Local Bubble. From the early rocket experiments, and in particular from the WISCONSIN Survey, the existence of a diffuse hot gas in the vicinity of the solar system, extending out to about 100 pc, has been inferred in order to explain the emission below 0.3 keV. The higher angular resolution and sensitivity of rosat made it possible to use diffuse neutral clouds as targets for shadowing the soft X-ray background. Thus, in some directions, more than half of the flux in the 0.25 keV band appears to come from outside the Local Bubble. Further, measurements of the diffuse EUV in the LISM, show surprisingly few emission lines. These findings are in conflict with the standard LHB model, which assumes a local hot (T 10⁶ K) plasma in CIE. Model calculations, based on the non-equilibrium cooling of an expanding plasma, show a promising way of reconciling all available observations. Thus the present temperature within the LB may be as low as 4 × 10⁴ K and its number density as large as 2 × 10^–2 cm ^–3, giving a total pressure that is roughly in agreement with the Local Cloud.Abbreviations CIE collisional ionization equilibrium - ISM Interstellar Medium - LHB Local Hot Bubble - LB Local Bubble - LISM Local ISM - SB superbubble - SXR soft X-ray - SXRB SXR Background - VLISM Very Local ISM Heisenberg Fellow     

激光等离子体点源减阻技术中入射能量对气动阻力的影响

数值模拟了来流马赫数为5时的圆球绕流冷流场,以及来流与头部驻点附近注入激光能量而产生的等离子体相互耦合形成的流场的演化过程。计算结果表明:施加局部能量点源能够改变原有的弓形激波结构,使其变为斜激波,从而减小气动阻力;气动阻力随入射激光能量的增大而逐渐减小,当入射激光能量为1.1 J时,气动阻力减小的百分比高达40%。     

等离子体隐身结构机翼的RCS分析

等离子体隐身是利用等离子体回避雷达探测系统的一种技术.本文介绍了飞机等离子体隐身的原理,提出了一种在飞机机翼封闭前缘内产生离子体的隐身结构设计方案,进而采用CST NWS高频电磁分析软件,对等离子体隐身结构机翼与金属机翼的RCS进行了分析、对比.研究表明,在前缘设置等离子体隐身结构可以改善机翼的总体雷达散射特性.     

液体姿控火箭发动机地面试验热结构分析

以液膜冷却结合辐射冷却的液体姿控火箭发动机为研究对象,采用一体化计算模型分析传热,同时应用有限元方法对给定温度条件的热结构进行了耦合分析,最后讨论了推力室在外压作用及温度载荷条件下结构的屈曲稳定性.计算结果与参考的试验结果接近,最高温度误差为3.67%,说明该一体化计算传热模型的有效性.考虑热载荷作用得到的屈曲载荷值较...     

叶型附面层分离流动控制技术研究进展

叶型附面层分离流动控制技术,通过流动控制方法减小和控制叶片吸力面附面层的分离气流和低能流团,提高压气机或涡轮的效率和工作稳定性。主要介绍了国外研发的涡流发生器、射流注入、附面层抽吸、叶片附面层转捩控制和等离子体气动激励等流动控制技术的特点、作用机理和实验验证结果,以及国内在叶型附面层分离流动控制技术方面的研究进展。