信息技术在航空发动机设计体系集成平台建设中的应用

设计体系是航空发动机设计经验的总结归纳和深化结晶。其集成平台的全面应用,将有助于科研工作的层次清晰化、设计协同化、管理规范化及质量精细化,推进科研水平上升一个新的台阶。阐述了充分利用现代信息技术,融汇自主创新研制思路,以设计规范和数字化设计流程为依据,以专业技术设计软件为基本元素,以工程数据库为支持,利用集成技术建立支持多专业协同、信息共享的以数字化为特征的发动机设计体系,初步建造了一套融发动机设计、仿真、优化等于一体的综合集成平台,为航空发动机设计体系建设奠定基础。     

某型直升机机务训练模拟器的设计与实现

针对某型直升机座舱维修训练需求,设计了机务训练模拟器的几项主要功能,并从硬件和软件实现方面加以论证。     

民用涡扇发动机预测控制器设计

对一定包线范围内的稳态预测控制器和加速减速过渡态控制器设计展开研究.针对某大涵道比民用涡扇发动机,根据发动机进口参数的相对变化指标对控制区域进行划分,以标称点处发动机线性模型为对象设计了相应的预测控制器,利用提出的多层参数调度方案实现了不同飞行条件及不同发动机状态下预测控制器参数的自适应调整.仿真结果表明:所设计的发动机预测控制系统在控制区域内的设计点和非设计点均具有良好的性能,为全包线设计提供了有效方法.     

大涵道比发动机多级低压涡轮气动设计

基于大涵道比航空发动机多级低压涡轮设计研究,分析了大涵道比发动机多级低压涡轮气动设计特点和主要设计参数的设计选取原则以及发展趋势,研究了过渡流道设计参数的选取标准、过渡流道优化设计方法以及对多级低压涡轮子午流道设计与功率分配方法,综合分析了多级低压涡轮功率分配需要考虑的各项因素,并探讨了高升力涡轮叶型设计方法。研究表明:过渡流道方案设计可以采用长高比及当量扩张角作为初步选取标准;多级低压涡轮功率分配要综合考虑不同工况性能及气动设计参数;完成设计的大转折角后加载叶型能够有效地控制涡轮叶栅内的流动损失。     

高可靠性陶瓷轴承技术研究进展

陶瓷轴承具有长寿命、耐高温、耐腐蚀和超高速等优异的综合性能,已经在航空航天及装备制造领域中得到应用.介绍了陶瓷轴承的发展背景,归纳了陶瓷材料技术研究进展,概括了陶瓷滚动体毛坯和成品的无损探伤技术和方法,阐述了陶瓷滚动体表面低损伤加工的必要性,探讨了陶瓷轴承的润滑行为和热行为,提出了陶瓷轴承的失效模式和设计准则,分析了陶瓷轴承的结构和性能设计方法,给出了部分典型应用和极限性能试验情况,展望了高性能陶瓷轴承技术的发展趋势.为继续深化陶瓷轴承技术研究、攻克极限工况下的陶瓷轴承关键技术、发展面向工况的轴承设计制造技术、实现高性能陶瓷轴承的技术转化和推广应用、解决高端装备的公共轴承技术难题提供技术基础.     

定子双绕组异步发电机的电磁优化设计

新型的基于静止励磁调节器控制的定子双绕组异步发电机系统适用于航空、坦克、舰船、汽车等独立电源系统。文章提出了变速变负载运行下的静止励磁调节器控制的双绕组异步发电机的优化设计策略,系统地讨论了带整流型负载的电机计算容量的确定方法,并以此针对一种应用于坦克电源的双绕组异步发电机进行了电磁优化设计。计算结果表明,该方法可以有效地降低控制绕组功率变换器的无功容量。     

小型无人机翼型优化设计

采用类别形状函数变换（CST）方法对翼型参数化描述;利用Fluent软件,进行翼型升力系数和阻力系数的气动计算;以升阻比最大为优化目标,通过拉丁超立方设计生成样本点,建立了径向基神经网络（RBF）代理模型;使用粒子群优化算法（PSO）,在Isight平台上,实现对Clark Y翼型优化的整个过程。优化翼型升阻比比原始翼型提高了约10%,表明此种方法是可行的,可用于小型无人机设计的工程中。     

基于类云模型的c均值聚类航迹关联算法

针对多传感器多目标航迹关联的特点,提出了将类云模型和c均值聚类联合应用于航迹关联的解决方法。将表征航迹特征的参量构成聚类中心和待分类的样本空间,利用类云模型和c均值聚类算法对来自不同传感器的航迹进行分类和收敛判断,构建了基于类云模型的c均值聚类航迹关联模型,有效地解决了目标密集环境下的航迹关联问题,通过仿真研究说明了该算法的有效性和鲁棒性。     

Ionospheric electron density over Resolute Bay according to E-CHAIM model and RISR radar measurements

In this study, predictions of the E-CHAIM ionospheric model are compared with measurements by the incoherent scatter radars RISR at Resolute Bay, Canada, in the northern polar cap. Reasonable coverage was available for all seasons except winter for which no conclusions were drawn. It is shown that ratios of the model-to measured electron densities are close to unity in the central part of the F layer, around its peak. This is particularly evident for summer daytime. Distributions of the ratios are wider for other seasons indicating larger number of cases when the model underestimates or overestimates. E-CHAIM underestimates the electron density at ionospheric topside and bottomside by ～ 10–20 %. At the bottomside, the underestimations are strongest in summer and equinoctial nighttime. At the topside, the underestimations are strongest in autumn nighttime. Model overestimations are noticeable in the middle part of the F layer during dawn hours in autumn. Overall, the model tends to not predict highest-observed peak electron densities and the largest-observed heights of the peak.     

Variations in cosmic ray cutoff rigidities during the great geomagnetic storm of November 2004

A very strong interplanetary and magnetospheric disturbance observed on 7–13 November 2004 can be regarded as one of the strongest events during the entire period of space observations. In this paper we report on the studies of cosmic ray cutoff rigidity variations during 7–13 November 2004 showing how storm conditions can affect the direct cosmic ray access to the inner magnetosphere. Effective cutoff rigidities have been calculated for selected points on the ground by tracing trajectories of cosmic ray particles through the magnetospheric magnetic field of the “storm-oriented” Tsyganenko 2003 model. Cutoff rigidity variations have also been determined by the spectrographic global survey method on the basis of experimental data of the neutron monitor network. Relations between the calculated and experimental cutoff rigidities and the geomagnetic Dst-index and interplanetary parameters have been investigated. Correlation coefficients between the cutoff rigidities obtained by the trajectory tracing method and the spectrographic global survey method have been found to be in the limits 0.76–0.89 for all stations except the low-latitude station Tokyo (0.35). The most pronounced correlation has been revealed between the cutoff rigidities that exhibited a very large variation of ∼1–1.5 GV during the magnetic storm and the Dst index.