液体火箭发动机诱导轮空化热力学效应研究

为了研究空化热力学效应,以模型诱导轮为研究对象,改变流量、水温等条件,对其内部空化流动进行了可视化实验研究,完整记录了从空化初生至性能断裂点各工况的空化区形态。结果表明:温度对诱导轮无空化水力性能没有显著影响,但是高温下诱导轮的空化性能断裂点被显著延后,体现了热力学效应的影响。对比不同温度下的空化区形态,发现热力学效应的强弱与流动工况密切相关,在小空化数下体现得更为显著。同时引入一种半经验的理论模型预测热效应对空化性能的影响,小流量(Φ=0.071)下预测结果与实验结果平均偏差为5.5%,大流量(Φ=0.088)下平均偏差为10.8%,验证了模型在本文应用条件下的可靠性。     

气体注入压力激励法测量卫星液体推进剂剩余量的热力学模型

通过对气体注入压力激励法测量卫星液体推进剂剩余量系统的详细热力学过程分析,建立了能满足实际测量需求的等温和绝热两种热力学模型,对具体测量模型的选用及相关问题进行了分析。     

The relationship between plasma effects and cosmic radiation studied with TriTel-LMP measurements during the ESEO mission

The main point of the paper is to use the simultaneous measurements of the energetic particle flux by TriTel and those of electron density by a Langmuir probe to study the question of to what extent solar electromagnetic and corpuscular radiation (galactic cosmic rays, particle precipitation from the radiation belts) are responsible for the ionization of the atmosphere. The electron density measured by the Langmuir probe is the sum of the ionization produced by the solar electromagnetic radiation and that due to the corpuscular radiation. The ionization produced by the solar electromagnetic radiation may be computed. The flux of energetic particles in an energy range may be determined by taking the difference between the threshold energy of the TriTel telescopes and the energy corresponding to the local cut-off rigidity. As the ESEO satellite will have a quasi-polar and circular orbit, the cut-off rigidity will change from low to high latitudes, thus enabling the assignment of different energy bands for the telescopes. Thus, it will be possible to determine which energy bands of particle produce ionization at different latitudes.     

空间电子攻击的体系作战效用及发展对策

通过分析空间电子攻击在打击对象多、方式灵活多样,打击速度快、隐蔽突然,效果等同于火力打击、太空安全隐患小等方面的优势,得出了"空间电子攻击具有很大的发展潜力,是未来空间对抗力量发展的重心"的结论。通过分析空间电子攻击在遮态势感知耳目、断信息分发链路、破精确打击能力、实施战略威慑方面发挥体系作战效用的机理,论证了空间电子攻击的体系作战效用。通过分析还提出空间电子攻击力量的发展对策。     

Coupling behavior between adhesive and abrasive wear mechanism of aero-hydraulic spool valves

Leakage due to wear is one of the main failure modes of aero-hydraulic spool valves. This paper established a practical coupling wear model for aero-hydraulic spool valves based on dynamic system modelling theory. Firstly, the experiment for wear mechanism verification proved that adhesive wear and abrasive wear did coexist during the working process of spool valves. Sec-ondly coupling behavior of each wear mechanism was characterized by analyzing actual time-variation of model parameters during wear evolution process. Meanwhile, Archard model and three-body abrasive wear model were utilized for adhesive wear and abrasive wear, respectively. Furthermore, their coupling wear model was established by calculating the actual wear volume. Finally, from the result of formal test, all the required parameters for our model were obtained. The relative error between model prediction and data of pre-test was also presented to verify the accuracy of model, which demonstrated that our model was useful for providing accurate prediction of spool valve’s wear life.     

Detonation engine fed by acetylene–oxygen mixture

The advantages of a constant volume combustion cycle as compared to constant pressure combustion in terms of thermodynamic efficiency has focused the search for advanced propulsion on detonation engines. Detonation of acetylene mixed with oxygen in various proportions is studied using mathematical modeling. Simplified kinetics of acetylene burning includes 11 reactions with 9 components. Deflagration to detonation transition (DDT) is obtained in a cylindrical tube with a section of obstacles modeling a Shchelkin spiral; the DDT takes place in this section for a wide range of initial mixture compositions. A modified ka-omega turbulence model is used to simulate flame acceleration in the Shchelkin spiral section of the system. The results of numerical simulations were compared with experiments, which had been performed in the same size detonation chamber and turbulent spiral ring section, and with theoretical data on the Chapman–Jouguet detonation parameters.     

纳米硅薄膜的氧化特性

将ｎｃ－Ｓｉ：Ｈ薄膜进行等离子和高温氧化处理，测量了样品的氢，氧含量，Ｒａｍａｎ谱，红外吸收谱，光致发光（ＰＬ），结果表明两种氧化方式都将氧掺入薄膜中，但不同处理方式氧在薄膜中的键合形式不同Ｒａｍａｎ谱表明氧化处理对薄膜中晶粒大小及晶态比没有影响，用晶粒－表面模型对氧化引起的光致发光（ＰＬ）蓝移进行了解释。     

Kinetic Excitation Mechanisms for ION-Cyclotron Kinetic Alfvén Waves in Sun-Earth ConnectionI

We study kinetic excitation mechanisms for high-frequency dispersive Alfvén waves in the solar corona, solar wind, and Earth's magnetosphere. The ion-cyclotron and Cherenkov kinetic effects are important for these waves which we call the ion-cyclotron kinetic Alfvén waves (ICKAWs). Ion beams, anisotropic particles distributions and currents provide free energy for the excitation of ICKAWs in space plasmas. As particular examples we consider ICKAW instabilities in the coronal magnetic reconnection events, in the fast solar wind, and in the Earth's magnetopause. Energy conversion and transport initiated by ICKAW instabilities is significant for the whole dynamics of Sun-Earth connection chain, and observations of ICKAW activity could provide a diagnostic/predictive tool in the space environment research. This revised version was published online in August 2006 with corrections to the Cover Date.     

基于SRAM型FPGA单粒子效应综合防护技术

为解决基于SRAM(Static Random Access Memory,静态随机存储器)型FPGA(Field Programmable Gate Array,现场可编程门阵列)的扩频应答机在空间环境中时常发生功能故障的难题,提出了一种低轨卫星基于SRAM型FPGA的应答机的单粒子综合防护方案。该方案在代码级、器件级、单机级、整星级综合采用器件优选、结构屏蔽设计、巡检自愈、自主复位等多种方法,有效杜绝了单粒子事件带来的种种危害,已成功应用于某在轨卫星。在轨测试结果表明:遥测、遥控、跟踪测量等功能、性能指标满足任务要求,且未发生需要地面干预的问题或现象。该技术还可推广应用于其他采用低等级器件及其他类型FPGA、DSP(Digital Signal Processing,数字信号处理)等大规模集成电路的星载单机防护。     

考虑真实气体效应的一维非定常平衡流的随机选取法计算

本文提出一种近似随机选取法,计算一维非定常的高温平衡流动。采用稀疏激波替代等熵稀疏波,选用拟合经验方程计算高温热力学性质,并利用切割迭代方法加快收敛,从而计算大为简化,并有很好精度。