CFM56系列发动机高压涡轮面向维修的设计改进分析

分析了主动间隙控制活门漏油、高压涡轮叶片榫头裂纹、高压涡轮叶片腐蚀和高压涡轮冷却部件堵塞等四个典型故障的解决方法,总结出高压涡轮主动间隙控制系统、高压涡轮叶片、高压涡轮导向器及高压涡轮罩环的设计改进措施,为我国设计出维修性好和性能高的大涵道比涡扇发动机的高压涡轮提供了参考。     

扇翼流动机理数值模拟研究

以扇翼的气动特性(高升力)为关注焦点,对扇翼流动的流场结构细节进行了数值模拟研究。对有推力二维Lockheed C-141超临界翼型进行数值模拟,验证和确认了扇翼流场的数值模拟方法,并数值模拟了扇翼旋转时的流场结构。结果表明,其高升力来源于固定翼部分上表面高速流动的射流,而这种射流正是由叶片旋转带动扇翼内部流体不断加速喷射得到的。扇翼内部的流动是复杂的非定常流动,存在多种尺度的旋涡、湍流边界层及二者的相互干扰等,使气动力高频振荡,进而可以预测相当的气动噪声是不可避免的。将算法应用于扇翼飞行器的外形设计优化阶段,得到了若干构型的气动性能,为下一步开展的无人机研制工作提供了指导。     

低轨航天器长期轨道预报的初步研究

低轨航天器的长期管理和维护需要较高精度的长期轨道预报,影响长期预报精度最主要的因素来自低轨航天器所受的大气阻力摄动.借助平均大气密度模型,以340 km高度的低轨航天器为例,研究了低轨长期轨道预报问题.利用基于长弧段的逐天精密定轨,可以修正参考点的平均密度.根据目前积累的数据,通过引入太阳自转周期27 d和半年180 d这2个周期拟合平均密度序列,未来的平均密度可以预报到较高精度.目前的计算结果表明,在此基础上低轨航天器的长期轨道预报精度可以得到保证,在不同算例中表现基本稳定可靠.     

大展弦比飞机模型边界层转捩模拟技术

针对大展弦比飞机模型高速风洞试验需求,进行了边界层转捩模拟技术研究.研究表明:与传统的金刚砂粗糙带相比,柱状转捩带具有粘贴牢靠、可操作性强等优势,已经推广应用于大展弦比飞机模型高速风洞试验;边界层转捩对大展弦比飞机模型气动特性有重要影响,不仅影响阻力,而且对升力与俯仰力矩均有明显影响;在目前国内低雷诺数风洞条件下建议在边界层固定转捩条件下进行风洞试验,以提高风洞试验精度.     

变结构制导规律及其实现

由于变结构控制的滑动模态具有完全的自适应性,不必全面研究系统的各种摄动及外干扰,只需根据高速度大机动目标的特点,对其实现自适应,将各种干扰及偏差的影响归人有关增益系数上加以考虑。应用变结构滑膜控制理论,推导了出一种适用于拦截高速大机动目标的空间制导规律,该制导规律能将系统引向滑动面并保持在其上运动。算例仿真证明,变结构项保证了对目标机动的鲁棒性,简单易行利于工程实现。     

高海拔环境直升机吊装组塔作业技术研究

应用直升机进行高海拔环境下输电线路吊装组塔作业受自然条件影响较大,本文将从高海拔环境特征及其对直升机工作性能的影响、直升机选型、吊装组塔作业方法等方面深入的研究在高海拔环境下应用直升机进行吊装组塔作业技术,促进了青藏高原输电线路搭建技术和效率的提高。     

冬季高原复杂机场对CFM56-7B发动机的起动影响

分析了CFM56-7B型发动机在冬季高原多次发生航前第一次起动不成功的原因,并针对该故障提出了相关的维护建议,以供同行借鉴。     

SAR卫星用能量功率兼顾型锂离子电池研究

未来大功率合成孔径雷达(SAR)卫星的发展对储能电池组提出了轻量化、倍率高及在轨寿命长等要求,而现有的SAR卫星用功率型锂离子电池产品已无法满足未来需求。通过优化正极材料和电池设计,加入功能电解液,在保证电池功率特性的同时,显著提升了电池的能量密度和循环稳定性。本文研制出的新一代能量功率兼顾型锂离子蓄电池,额定容量为25.0 Ah,初期放电比能量达到180.0 Wh·kg~(-1),2 C放电容量为0.2 C容量的91.0%,1 C-100%放电深度(DOD)和2 C-30%DOD循环性能优异,可以满足下一代大功率SAR卫星的供配电需求,且大幅降低了电源系统重量,提高了卫星储能系统的利用率和平台有效载荷能力。     

Advances in Researches on the Middle and Upper Atmosphere in 2008-2010

This paper summarizes the results of the researches on the middle and upper atmosphere obtained by Chinese scientists in 2008-2010. The focuses are specifically placed on the researches being associated with ground-based observation capability development, dynamical processes, the property of atmospheric circulation and the chemistry-climate coupling of the middle atmospheric layers.     

Exploration life support technology challenges for the Crew Exploration Vehicle and future human missions

As NASA implements the U.S. Space Exploration Policy, life support systems must be provided for an expanding sequence of exploration missions. NASA has implemented effective life support for Apollo, the Space Shuttle, and the International Space Station (ISS) and continues to develop advanced systems. This paper provides an overview of life support requirements, previously implemented systems, and new technologies being developed by the Exploration Life Support Project for the Orion Crew Exploration Vehicle (CEV) and Lunar Outpost and future Mars missions. The two contrasting practical approaches to providing space life support are (1) open loop direct supply of atmosphere, water, and food, and (2) physicochemical regeneration of air and water with direct supply of food. Open loop direct supply of air and water is cost effective for short missions, but recycling oxygen and water saves costly launch mass on longer missions. Because of the short CEV mission durations, the CEV life support system will be open loop as in Apollo and Space Shuttle. New life support technologies for CEV that address identified shortcomings of existing systems are discussed. Because both ISS and Lunar Outpost have a planned 10-year operational life, the Lunar Outpost life support system should be regenerative like that for ISS and it could utilize technologies similar to ISS. The Lunar Outpost life support system, however, should be extensively redesigned to reduce mass, power, and volume, to improve reliability and incorporate lessons learned, and to take advantage of technology advances over the last 20 years. The Lunar Outpost design could also take advantage of partial gravity and lunar resources.