发展小型空间环境模拟设备是未来的一种趋势

大型空间环境模拟设备已成系列化,完全能满足大型航天器发展的需要。航天器小型化将是一种发展趋势,空间环境模拟设备必须适应这种发展要求。小型空间环境模拟设备除了能保证微小型航天器的试验需要外,在开展空间环境影响机理的研究、预先研究和降低试验成本上有其优势。     

微小卫星平台公共总线技术——CAN网络应用

对局域控制网络(CAN)协议在“清华一号”微小卫星平台上的应用作了描述。提出了微小卫星对平台公共总线的要求,介绍了CAN网络的特点,阐述了CAN协议的帧结构,并在此基础上提出了针对卫星子系统数据通讯所作的改进协议。还给出了微小卫星星载计算机子系统的CAN节点硬件设计结构和软件控制流程。     

地面长时间微重力装置原理及设计

采用串联的Maxwell摆作为主机构，可以实现地面上长时间、低速度的连续失重环境，解决了地面上长时间失重伴随的速度无限增大及加速度反弹问题。     

贮箱内推进剂微重力下晃动的有限元模拟及试验

采用有限体积(VOF)法 任意拉格朗日．欧拉(ALE)法，建立分析液体火箭贮箱内推进剂大幅晃动的数学模型，给出了计算的基本方程。对常重力和低重力下不同形状贮箱内推进剂的非线性晃动进行了数值模拟，并用落塔法进行了微重力下贮箱内液体晃动试验。结果表明，数值模拟法与落体试验的结果相近，在工程上有一定的实用价值。     

微重力落塔试验技术及其应用（Ⅱ）

本文研究落塔试验技术中的３个重要问题。落舱的释放技术，落舱的回收和缓冲技术、试验的测量技术。讨论了有关的技术要求，给出了解决这些问题的若干技术途径及其特点，评价了不同技术途径的适用性。     

Aerodynamic performance of hovering micro revolving wings in ground and ceiling effects at low Reynolds number

Numerous investigations have been conducted to understand the wall effects on rotors. The purpose of this study is to further investigate the aerodynamic performance of revolving wings, especially when it is very close to the ground and ceiling (i.e., less than half the wingspan) at low Reynolds numbers. Hence, the ground and ceiling effect for hovering micro revolving wings at low Reynolds numbers are investigated by improving the theoretical models. The theoretical model for the ground effect is established based on the wall-jet assumption, and that for the ceiling effect is improved by considering the uneven spanwise distribution of induced velocity. These two models are validated by comparing the results of experiments and CFD simulations with the Lattice-Boltzmann Method (LBM). Both ground and ceiling effects are found helpful to enhance the thrust, especially with small wing-wall distances, by making a difference to the induced velocity and the pressure distribution. By comparing the thrust generation and aerodynamic efficiency between the ground and ceiling effects, the former is found more helpful to the thrust augmentation, and the latter is more beneficial for the aerodynamic efficiency promotion.     

电火花型腔加工中加工余量分配的优化研究

在电火花型腔加工中,加工余量的确定及分配对电火花的加工效率有很大的影响,本文提出了一种加工余量及分配的优化模型,实验结果表明,该模型明显地提高了加工效率。     

电火花加工用微型压电换能器的研制

在电火花加工中,沿电极的轴向采用微幅超声振动可明显改善微小孔的加工性能,本试验对该系统Φ２０Ｘ５５的微型换能器进行了设计和有限元分析,在频率３９～４５ｋＨｚ范围内获得无侧向振动的轴向振动和对加工有利的振幅     

回热器性能对微小型燃气轮机总体性能影响分析研究

为分析回热器性能对微小型回热燃气轮机总体性能的影响,基于回热器性能实验,提出了一种改进回热器仿真模型,开展了燃气轮机性能仿真与控制规律优化研究。结果表明:变转速控制能改善燃气轮机部分工况热效率,且控制涡轮出口温度于设计值是提高燃气轮机部分工况性能的有效控制策略,但亦使燃气轮机性能受回热器性能恶化的影响更为严重;变转速控制下,回热器内部泄漏、堵塞使回热器换热有效度降低14.80%,将造成热效率降低4.38%。     

Research on windmill starting characteristics of MTE-D micro turbine engine

Micro turbine engine (MTE) is an important kind of propulsion system for miniature unmanned aircraft or missiles, because of its better high-speed performance (than propeller propulsion) and higher propulsion efficiency (obviously than rockets). Windmill start is a common air-starting mode used in micro turbine engine. The windmill starting characteristics are important to the practical use of micro turbine engine. In this paper, the windmill starting characteristics research for a 12 cm diameter (MTE-D) micro turbine engine is carried out by experiment and numerical simulation. The characteristic of rotor mechanical losses at low-speed condition is stud- ied, and the engine common working line of windmill starting process is obtained. Based on the engine windmill characteristics, the propane ignition characteristics under different inflow conditions are researched, and the envelope of propane ignition and propane flameout is determined. The experimental research of fuel supply and ignition characteristics is completed, and the envelope of fuel supply and ignition is obtained. The windmill stage, propane ignition stage, fuel ignition stage and acceleration process from idling-speed to 80% full speed of MTE-D micro turbine engine is optimized, and the optimization windmill starting parameters are collected. The successful wind-mill starting experiment under this condition with engine speed up to 80% full speed indicates that these starting parameters are reasonable. All the starting parameters of MTE-D micro turbine engine obtained in this work are dimensionless parameters, and the conclusions obtained in this study have some reference to other micro turbine engines with the similar structural form and starting process.