轴流风扇旋转失速时的流场测量与分析

针对渐近型旋转失速在一轴流风扇上进行了一些测量工作,包括失速时的激光平均流场测量和热丝动态测量两大类。激光平均流场研究表明失速团主要活动在风扇转子前缘,而转子叶片通道中的流场则主要表现为叶尖间隙流的横向堵塞流动。      

低雷达散射目标的RCS分析与求解

利用Ｃ－Ｒ样条对目标进行建模和求解爬行波短程线,通过ＧＲＥＣＯ与爬行波混合法求解低散射目标后向ＲＣＳ。获得令人满意的结果。     

一种自适应的曲面剖分算法的实现与性能分析

根据曲面求交的基本原理,结合自适应理论,构造出了一种新的剖分算法。这种算法提高了曲面求交的精度和效率,简化了曲面求交算法的复杂性,同时有效地解决了曲面求交中的漏点漏线、自交等各种问题。     

弹性基础上预应力任意四边形中厚板的横向振动

本文研究弹性基础上任意四边形中厚板在预加面内荷载作用下的横向振动问题。通过坐标变换将任意四边形区域映照到一个2×2的单位方板区域。用一组数学上完备的二元多项式作为位形函数,采用pb-2Ritz法求得板的自振频率。并通过算例考察了基础刚度参数、预加面内荷载、边界条件、横向剪切变形等对板振动特性的影响。     

离子推力器放电室参数在线优化实验研究

为了改进氙离子推力器传统优化实验方法,针对环切场放电室设计多维优化调节机构,通过步进电机配合电磁铁实现放电室设计参数的在线实时调节。实验中在线调节放电室长径比、中间磁极靴位置、阴极顶位置等参数,得到了放电室性能影响规律,经迭代实验获取了优化后的放电室构型及磁场参数。优化后的推力器性能曲线"膝点"较正交实验结果更加靠后,在工质利用率80%~90%区间内,束离子电离能耗低于正交实验优化结果。在线优化实验方法极大缩短了离子推力器设计周期,降低研制成本,并弥补了传统方法需多次破空导致参数一致性差的不足。     

基于安全性的航空发动机控制软件测试技术

针对航空发动机控制软件安全性需求的验证问题,提出了基于需求模型与安全性分析结果的软件测试技术。从软件需求的结构化描述和软件安全性分析结果中的失效和危险因果关系链出发,研究并制定了符合航空发动机控制软件特点的测试用例生成方案,给出了程序化的自动实现算法,并描述了在某重点发动机型号的工程实践情况。     

涡扇发动机低压部件通流耦合计算

为了研究各部件匹配与过渡段几何参数对发动机总体性能的影响,针对某涡扇发动机风扇、低压涡轮、内外涵道、掺混段和尾喷管等部件,基于周向平均Navier-St okes通流控制方程,采用时间推进有限体积法进行了部件耦合计算求解,将沿程各部件性能计算参数与试验做了对比,结果表明:在设计状态下发动机沿程各截面计算特征参数与试验值最大误差不超过5.0%,说明该通流耦合计算方法能够快速预估发动机总体性能,完善各部件匹配关系,在发动机总体设计初期有一定工程应用价值。     

含金属相变材料温控组件的研究

研究使用一种含有金属相变材料（Phase Change material,PCM）的温控组件（Thermal Control Component,TCC）对航天器上的有效载荷进行温度控制。通过对载荷的温控需求分析,设计并制备了以Ga-Sn合金为PCM的TCC,并通过地面模拟实验对TCC的温控性能进行测试。实验结果表明这种含有Ga-Sn合金的TCC满足载荷的温控需求。最后在仿真软件中建立了TCC的相变传热仿真模型用于预测TCC的温控性能。结果表明：仿真模型计算所得结果与实验结果基本一致,可用于预测TCC的温控性能。     

An innovative navigation scheme of powered descent phase for Mars pinpoint landing

Pinpoint landing (within 100 m from the target) is essential for future Mars exploration missions. This paper deals with one aspect of the pinpoint landing architecture—the navigation performance improvement during the powered descent phase, and proposes an innovative navigation scheme to obtain the vehicle complete and accurate states. On the basis of dead reckoning relying on the Inertial Measurement Unit, measurements of the Integrated Doppler Radar are adopted to correct the vehicle velocity and altitude. Distance between the vehicle and one Mars Orbiter as well as their line-of-sight relative velocity is measured by a radio sensor, and integrated in the filter to correct the vehicle horizontal position. The innovative navigation system is based on an Extend Kalman Filter. Two observation schemes are developed. One considers measurements of the Integrated Doppler Radar and radio range measurement. Another further considers radio velocity measurement. The performance of the innovative navigation scheme is greatly influenced by the position of the Mars Orbiter with respect to the target. Stochastic analyses are performed to obtain optimal locations of Mars Orbiter. Finally, the innovative navigation scheme performances are assessed through stochastic simulations. Its performance improvements are demonstrated by comparison with the Integrated Doppler Radar only navigation scheme.     

Study on O2 generation and CO2 absorption capability of four co-cultured salad plants in an enclosed system

The ability to generate O₂ and absorb CO₂ of several co-cultured vegetable plants in an enclosed system was studied to provide theoretical reference for the future man-plant integrated tests. Four kinds of salad plants (Lactuca sativa L. var. Dasusheng, Lactuca sativa L. var. Youmaicai, Gynura bicolor and Cichorium endivia L.) were grown in the CELSS Integration Test Platform (CITP). The environmental factors including O₂ and CO₂ concentration were continuously monitored on-line and the plant biomass was measured at the end of the test. The changing rules of O₂ and CO₂ concentration in the system were basically understood and it was found that the O₂ generated by the plants could satisfy the respiratory needs of 1.75 persons by calculation. It was also found that the plants could absorb the CO₂ breathed out by 2 persons when the light intensity was raised to 550 mmol m⁻² s⁻¹ PPF. The results showed that the co-cultured plants hold good compatibility and excellent O₂-generating and CO₂-absorbing capability. They could also supply some fresh edible vegetable for a 2-person crew.