UDMH/NTO火箭发动机尾焰流场特性数值仿真

采用AUSM(advection upstream splitting method)空间离散格式,探究了常用的3种k-ε湍流模型和2阶、3阶迎风格式对激波捕捉效果的影响。采用标准k-ε双方程模型和2阶迎风格式对不同高度和不同来流马赫数下的偏二甲肼/四氧化二氮(UDMH/NTO)火箭发动机尾焰流场进行喷管-尾焰流场一体化仿真。复燃反应采用12组分18步化学反应模型,喷管入口参数由热力计算给出。结果表明:随着来流马赫数的增加,波节数逐渐降低;随着飞行高度的上升,尾焰影响区域逐渐扩大;复燃反应造成混合区中的O2、N2质量分数大幅下降,而混合区中O、OH、NO质量分数则有所上升。      

高层大气模型对空间站轨道漂移和寿命的影响分析

本文以轨道摄动分析方法一阶理论为基础，其中大气阻力摄动采用数值积分方法，给出一种可利用各种大气模型进行轨道摄动分析的计算方法，并利用三种高层大气模型（ＣＩＲＡ—７２，ＣＩＲＡ—８６和ＤＴＭ）和三个太阳活动水平（Ｆ１０．７＝１００，１５０和２００）分析比较了大气阻力振动对高度为４００ｋｍ的空间站轨道漂移和寿命的影响，以及估算修正轨道漂移所需的能量。给出的定量分析结果将为空间站或航天飞行器的轨道设计和能量估算提供依据。     

返回式航天器轨道周期变率确定及预报的数值方法

对返回式航天器进行变轨控制计算时要用到平均轨道周期变率,而数值法定轨通常求解的是大气阻力系数,无法直接得到平均轨道周期变率。文章通过建立航天器精密动力学模型、数值积分器、瞬时轨道根数到平均轨道根数的转换算法和平均周期序列多项式拟合算法,提出了一种基于数值法精密轨道确定和预报计算平均轨道周期变率的数值方法。     

Electric sail,photonic sail and deorbiting applications of the freely guided photonic blade

We consider a freely guided photonic blade (FGPB) which is a centrifugally stretched sheet of photonic sail membrane that can be tilted by changing the centre of mass or by other means. The FGPB can be installed at the tip of each main tether of an electric solar wind sail (E-sail) so that one can actively manage the tethers to avoid their mutual collisions and to modify the spin rate of the sail if needed. This enables a more scalable and modular E-sail than the baseline approach where auxiliary tethers are used for collision avoidance. For purely photonic sail applications one can remove the tethers and increase the size of the blades to obtain a novel variant of the heliogyro that can have a significantly higher packing density than the traditional heliogyro. For satellite deorbiting in low Earth orbit (LEO) conditions, analogous designs exist where the E-sail effect is replaced by the negative polarity plasma brake effect and the photonic pressure by atmospheric drag. We conclude that the FGPB appears to be an enabling technique for diverse applications. We also outline a way of demonstrating it on ground and in LEO at low cost.     

“微藻-小白鼠”二元生态系统气体交换规律研究

为探讨“微藻-小白鼠”二元生态系统中氧气和二氧化碳交换规律,进一步评价空间微藻光生物反应器地面试验样机生产螺旋藻的能力,开展了螺旋藻和小白鼠的整合试验研究。将微藻光生物反应器和动物活动室组成气路闭环系统,试验期间连续监测系统中氧气和二氧化碳含量、小白鼠的活动状况、藻液pH变化以及藻体浓度含量等指标。试验结果表明,螺旋藻生长良好,系统闭环后促进了藻体的生长;从小白鼠的体征来看,小白鼠生活正常,但对小白鼠的生理影响还需深入研究。螺旋藻和小白鼠间能实现氧气和二氧化碳的完全交换,螺旋藻具有较强的吸收二氧化碳和放氧能力,可作为未来受控生态生保系统中的重要生物部件。     

激波波后氮分子发射光谱的测量

利用多通道光学分析仪测量激波波后不同时刻高温氮气的辐射光谱发现,辐射随时间发生强烈的变化。在非平衡态和平衡态,光谱的各条谱线强度有明显的差别。光谱的结构特征也依赖于激波的速度。     

一种高效的计算卫星轨道寿命的方法

关于在大气阻力作用下卫星生存寿命的估计 ,提出了一种高效的数值方法 ,称为微分 -积分法。它的实质是以轨道要素的平均变化率为基础的微分方程 ,而方程的右端包含定积分。与传统方法比较验证了此新方法的正确性 ,并且显示了它的极高效率。在诸如空间碎片减缓这种需要非常大量的计算卫星寿命的问题中 ,新方法的价值得到充分体现。     

A numerical model approximating extreme energetic electron events involved in the physical and chemical processes of the middle atmosphere

Relativistic electrons (with energies >150 keV) which originate in the outer radiation belt and detected by the Russian ‘Meteor’ series of satellites have been correlated with the atmospheric total ozone data compiled by almost 90 stations located around the world within the latitude zone 40°–70°N. In more than 60% of the stations examined we have detected a clear decrease of the ozone 3–5 days after the electron flux excess. A numerical model has been applied to approximate this effect based on relativistic electron initiated nitric oxides creation in the upper mesosphere with subsequent atmospheric transport (both vertical and horizontal) towards the upper stratosphere. A first attempt of local and temporal prediction of ozone depletion because of energetic electrons impact in the middle atmosphere has been illustrated.     

The Mars Environment Analogue Platform long duration balloon flight

The MEAP (Mars Environment Analogue Platform) mission was to fly a stratospheric balloon on a semicircular trajectory around the North Pole in summer 2008. The balloon platform carried the high-resolution neutral gas mass spectrometer P-BACE (Polar Balloon Atmospheric Composition Experiment) as scientific payload. MEAP/P-BACE is a joint project between the Esrange Space Center, Sweden, the University of Bern, Switzerland and the Swedish Institute of Space Physics (IRF), Kiruna, Sweden. Mission objectives were to validate the platform for future long duration flights around the North pole, to validate the P-BACE instrument design for planetary mission applications (conditions in the Earth stratosphere are similar to the conditions at the Mars surface), to study variation of the stratospheric composition during the flight and to gain experience in balloon based mass spectrometry. All objectives were fulfilled.     

空间环模设备液氮系统中文丘利管的研究

通过对文丘利管的工作原理的分析，阐明了文丘利管在液氮系统中所起的作用，提出了文丘利管的设计计算方法。通过对现有设备液氮系统的改造，对该系统及文止利管进行了试验验证工作。这些工作所得到的结论对新型环境模拟设备液氮系统的设计提供了重要的参考依据。