Attitude control system design and on-orbit performance analysis of nano-satellite––‘‘Tian Tuo 1’’

‘‘Tian Tuo 1'(TT-1) nano-satellite is the first single-board nano-satellite that was successfully launched in China. The main objective of TT-1 is technology demonstration and scientific measurements. The satellite carries out the significant exploration of single-board architecture feasibility validation, and it is tailored to the low-cost philosophy by adopting numerous commercialoff-the-shelf(COTS) components. The satellite is featured with three-axis stabilization control capability. A pitch bias momentum wheel and three magnetic coils are adopted as control actuators.The sun sensors, magnetometers and a three-axis gyro are employed as the measurement sensors.The quaternion estimator(QUEST) and unscented Kalman filter(UKF) method are adopted for the nano-satellite attitude determination. On-orbit data received by ground station is conducted to analysis the performance of attitude determination and control system(ADCS). The results show that the design of ADCS for TT-1 is suitable, robust and feasible.     

Dynamic analysis of C/C composite finger seal

A seal device as an important component of aeroengines has decisive influence on per- formance, reliability, and working life of aeroengines. With the development of aeroengines, demands on the performance characteristics of seal devices are made strictly. Finger seal as a novel kind of sealing device, recently attracts more and more attentions in academic circles and engineer- ing fields at home and abroad. Research on finger seals has been extensively developed, especially on leakage and wear performances under dynamic conditions. However, it is a pity that the work on finger seals has been limited with a single approach that is improving the performance by structural optimization; in addition, the technology of dynamic analysis on finger seals is weak. Aiming at the problems mentioned above, a distributed mass equivalent dynamic model of finger seals considering the coupling effect of overlaid laminates is established in the present paper, the dynamic perfor- mance of 2.5 dimension C/C composite finger seal is analyzed with the model, and then the effects of fiber bundle density and fiber bundle preparation direction on finger seal＇s dynamic performance are discussed, as well as compared with those of Co-based alloy finger seal. The current work is about dynamic analysis of finger seals and application of C/C composite in this paper may have much academic significance and many engineering values for improving research level of finger seal dynamics and exploring feasibility of C/C composite being used for finger seals.     

基于技术参数评估的涡扇发动机总体性能设计分析

为了充分掌握各代涡扇发动机技术参数水平及其发展趋势,统计包括现役型号在内的15台2～4代涡扇发动机的总体性能参数、循环参数和部件参数,采用考虑涡轮冷却的总体性能计算和重量预测相结合的发动机技术参数综合评估模型并利用计算程序绘制趋势曲线,评估技术参数的发展趋势,结果表明技术参数逐年改善的趋势是比较稳定的,并用曲线趋势外推法取得下一代关键参数的定量数据。在此基础上探索下一代高推重比涡扇发动机可能的总体性能方案,为下一代先进涡扇发动机的预研和设计提供参考。     

多尾鳍仿生航行器推进性能的三维数值研究

采用格子波尔兹曼方法及浸没边界法,发展了一套适用于自由游动的三维数值研究程序。进而以多尾鳍推进仿生航行器为原型,讨论了尾鳍数目、形状、材料刚度等构型参数及振幅、频率等尾鳍摆动参数对推进性能的影响。结果表明对称布置、反对称摆动的双尾鳍能够明显消除侧向力而避免航行器主体的横向晃动,且推力大于两个单独尾鳍的简单加和;在中等Reynolds数下,具有波动性质的柔性尾鳍不论是推进速度还是推进效率均优于刚性尾鳍;当尾鳍单纯摆动推进时,具有完整鳍面的半椭圆形尾鳍的推进性能优于后部有缺口的深叉形尾鳍。     

军用直升机雷达隐身性能仿真与评估

采用高频方法计算了某型通用直升机及其隐身改型的RCS数据,基于现有雷达隐身性能计算方法和直升机低空飞行特点,对直升机在单部雷达和雷达组网两种情况下的雷达隐身性能进行仿真分析,给出了单部雷达和雷达组网发现目标的判定准则,分析了直升机可探测范围曲线、平均综合检测概率和暴露时间等隐身指标。通过仿真分析,评估了不同飞行高度下RCS减缩与直升机隐身性能的定量关系,为直升机的隐身设计提供了参考依据。     

高超声速二元进气道前体曲线激波逆向设计

为实现高超声速二元进气道前体激波的压缩能力、压缩效率、流量捕获特性和结构长度可控,提出了平面曲线激波逆向设计方法。采用B-Spline曲线控制激波形状。利用有旋特征线法,求解激波的影响域及决定激波的壁面。设计了一凹激波,并对波后流场进行CFD无黏数值模拟,CFD结果和设计结果一致,验证了设计方法的可行性。此外,还设计了直激波、凹激波和凸激波3种激波,并对其在设计点和非设计点处的性能开展了数值研究。在设计点处,分析了激波的压缩比、激波的总压恢复系数、激波压缩区的压升、激波压缩区出口马赫数和流动角随激波控制角的变化规律。在非设计点处,分析了激波压缩区的流量系数和总压恢复系数随攻角和马赫数的变化规律。     

置氢TC4钛合金粉末热等静压制件组织与性能研究

采用置氢钛合金粉末热等静压成形与钛合金热氢处理技术相结合的新工艺路线制备合金,研究了置氢量及热等静压工艺参数对置氢TC4合金粉末热等静压制件组织性能的影响规律。结果表明:随着置氢量的增加,置氢TC4合金粉末热等静压后制件的密度呈逐渐增高的趋势;热等静压制件的片层状组织尺寸变薄、针状的组织变细,等轴颗粒组织愈来愈多;退火后制件的显微组织中等轴状的颗粒增多,压缩屈服强度和抗压强度均逐渐增大;热等静压制件与粉末原料的氢含量及相组成基本相近,真空退火除氢后氢含量则达到了安全使用水平,置氢量0.42%TC4合金粉末热等静压制件致密效果好、综合力学性能高。     

不同工艺粉末对超音速火焰喷涂WC-10Co-4Cr涂层性能的影响

对比分析了采用烧结破碎和团聚烧结工艺制备的两种WC-10Co-4Cr粉末的物理性能和物相组成。采用超音速火焰喷涂技术对两种粉末进行了涂层制备,并对两种涂层的性能进行对比评价,结果表明:团聚烧结粉末制备涂层的硬度、孔隙率和抗冲蚀磨损性能均优于烧结破碎粉末制备涂层,但其结合强度略低于烧结破碎粉末制备涂层。     

篦齿封严流动及其对压气机静子性能的影响

为研究工程上广泛采用的3平齿型篦齿封严泄漏流动,以1台多级压气机第3级静子为例,利用数值模拟技术进行了计算分析.结果表明：篦齿封严间隙与泄漏流量成线性正比关系,但对静子流通能力和总压损失等的影响不是线性的;篦齿封严泄漏导致静子端壁区流动产生角区分离,并催生强的二次流动,是静子封严泄漏能够影响主流大范围流动的内在机制.为此提出将篦齿封严间隙控制在1％叶高左右的建议,以将篦齿封严泄漏对压气机静子的影响控制在可接受的范围之内.     

航空发动机用M210石墨材料耐湿热老化性能研究

为适应海洋环境高温、高湿的气候条件,对航空发动机用高性能抗氧化石墨材料M210,选取不浸渍不浸油、浸渍不浸油、浸渍后浸油3种不同处理方式的试样进行湿热老化试验,对比研究湿热环境对不同处理方式的M210石墨材料在外观形貌、抗压强度和抗折强度等方面的影响.研究表明：M210石墨材料表现出良好的抗湿热老化性能,浸渍处理可以增强M210石墨材料在湿热环境下的抗压强度,且不受浸油的影响.3种处理方式的试样在湿热环境下均表现出优异的抗折性能.