总收缩比对RBCC进气道影响数值研究

为研究火箭基组合循环发动机（Rocket Based Combined Cycle,RBCC）进气道隔离段内激波串传播规律,利用数值模拟研究分析了在高、低反压作用下总收缩比变化对激波串驻留位置及流动分离区范围的影响,并进一步开展了总收缩比对进气道气动性能影响的仿真研究。研究结果表明：在承受额定反压作用下,进气道总收缩比存在临界值,在临界值下提高总收缩比能显著增强进气道抗反压能力,并影响激波串驻留位置。在临界值上提高总收缩比对进气道抗反压能力无明显作用,进气道流动状态不受总收缩比变化的影响。此外,提高总收缩比能显著提高被捕获冲压空气流所承受的压缩程度,但会承受额外的空气流量损失和气动阻力。     

Flow control of double bypass variable cycle engine in modal transition

To study the change mechanism and the control of the variable cycle engine in the process of modal transition, a variable cycle engine model based on component level characteristics is established. The two-dimensional CFD technology is used to simulate the influence of mode selection valve rotation on the engine flow field, which improves the accuracy of the model. Furthermore, the constant flow control plan is proposed in the modal transition process to reduce the engine installed drag. The con...     

航空发动机全生命周期碳排放计量方法研究

航空是碳排放八大重点行业之一,航空产业的碳排放主要受航空发动机碳排放的影响,因此亟需开展航空发动机碳排放计量方法研究。以生命周期评价作为航空发动机碳足迹的量化方法,将航空发动机全生命周期碳排放分为燃料周期碳排放与材料周期碳排放,并分别进行统计;将航空发动机系统边界进行划分,提出各个阶段应进行的数据收集,并对数据做出要求,得到一套相对完整的航空发动机碳排放计量方法。本文得到的方法可以从生命周期的角度全面评估航空发动机碳排放,可为航空发动机全生命周期碳排放计量提供指引,从燃料角度与材料角度为减排提供理论基础。     

关于飞船的动态稳定问题

本文研究了以平衡攻角为中心作俯仰振荡的飞船,其动态稳定形态随来流马赫数Ｍ∞Ｒ ＹＯ ＷＸ 。     

Thoughts and Research on Technical Economic Design of the Equipment

装备在研制阶段的设计方案决策和研制工作,决定了其全寿命周期费用的 90%,在装备研制阶段开展目标价格管理和技术经济性设计是提高装备经济可承受性的关键。但目前装备技术经济性设计仍存在认知不够、建设能力不足、投入不足等问题。针对上述问题进行分析,提出相应措施辅助建立装备经济性管理新模式以实现装备的经济可承受性。     

液氧煤油补燃发动机泵间管路高温富氧燃气掺混冷凝特性数值研究

针对液氧煤油补燃发动机液氧预压泵和主泵间管路富氧燃气掺混冷凝现象,建立了大过热度下富氧燃气和液氧两相流动掺混冷凝特性的全三维数值仿真方法,并以常温制冷剂R123为工质,通过气液掺混冷凝实验验证了数值仿真模型对管内两相流型和气液再液化性能的精确预测能力.仿真结果表明:弯管段气液两相在离心力作用下发生横向相对流动,强化了相...     

航空发动机涡轮盘低循环疲劳寿命研究

结合某型涡轴发动机一级涡轮盘低循环疲劳寿命研究的工程实践,阐述了对涡轮盘低循环疲劳寿命研究的一般过程和方法,提出了涡轮盘低循环疲劳寿命试验的加载程序和方法,对开展同类型的涡轮盘疲劳寿命研究具有借鉴作用。     

多用途战斗机/涡扇发动机一体化循环参数优化

 针对多用途战斗机的特点,发展了基于飞/发一体化的涡扇发动机循环参数优化设计模型和相应的计算程序,优化设计模型中包括双变量控制涡扇发动机特性计算模型、进排气系统安装特性计算模型、飞机气动特性分析模型、重量组成分析模型、任务剖面分析模型、约束分析与任务分析模型和优化计算模型等。重点研究了多用途战斗机约束边界的获得方法,利用多岛遗传算法和自适应模拟退火优化算法,分别对现役多用途战斗机、不加力超声速巡航多用途战斗机以及下一代先进多用途战斗机用涡扇发动机循环参数进行了优化计算,对计算结果进行了分析,获得了对多用途战斗机用涡扇发动机循环参数选择有指导意义的结论。     

Trends in foF2 and the 24th solar activity cycle

The trends in foF2 are analyzed based on the data of Juliusruh and Boulder ionospheric stations. It is shown that using the traditional solar activity index F10.7 leads to an impossible trend in foF2 when the data for the 24th solar activity cycle are included into the analysis. It is assumed that the F10.7 index does not describe correctly the solar ultraviolet radiation variations in that cycle. A correction of this index using the Rz (sunspot number) and Ly (intensity of the Lyman-α line in the solar spectrum) is performed, and it is shown that in that case reasonable values of the foF2 trends are obtained.     

Joining of SiO2 ceramic and TC4 alloy by nanoparticles modified brazing filler metal

Nano-Al₂O₃ particles modified AgCuNi filler was adopted to braze the SiO₂ ceramic and TC4. The effects of filler size as well as the brazing temperature on the interfacial microstructure and mechanical property of the joints were investigated. Nanoscale filler reduced the phases dimension and promoted the homogeneous distribution of microstructure, obtaining a higher joint strength when compared to microscale filler. The increase of brazing temperature made the accelerating dissolution and diffusion of Ti, which promoted the increase of thickness of Ti₄O₇ + TiSi₂ layer adjacent to SiO₂ ceramic and diffusion layer zone nearby TC4 alloy. The hypoeutectic structure was produced in the brazing seam due to the high Ti content. The maximum shear strength of ∼40 MPa was obtained at 950 °C for 10 min.