一种双基站低轨道区域覆盖δ星座设计

在双基站理论研究基础上 ,进行了定倾角区域性覆盖双基站δ星座设计 ,采用倾角为 41°的回归轨道 ,用点覆盖数值仿真的方法设计了对地面站与空间站的一重覆盖与二重覆盖下的星座构型。且星座中各星之间 ,各星与空间站之间均可建立星际链路 ,保证数据在空间站、地面站及星座之间连续传递     

Towards intelligent design optimization: Progress and challenge of design optimization theories and technologies for plastic forming

Plastic forming is one of enabling and fundamental technologies in advanced manufacturing chains. Design optimization is a critical way to improve the performance of the forming system, exploit the advantages of high productivity, high product quality, low production cost and short time to market and develop precise, accurate, green, and intelligent (smart) plastic forming technology. However, plastic forming is quite complicated, relating to multi-physics field coupling, multi-factor influence, multi-defect constraint, and triple nonlinear, etc., and the design optimization for plastic forming involves multi-objective, multi-parameter, multi-constraint, nonlinear, high-dimensionality, non-continuity, time-varying, and uncertainty, etc. Therefore, how to achieve accurate and efficient design optimization of products, equipment, tools/dies, and processing as well as materials characterization has always been the research frontier and focus in the field of engineering and manufacturing. In recent years, with the rapid development of computing science, data science and internet of things (IoT), the theories and technologies of design optimization have attracted more and more attention, and developed rapidly in forming process. Accordingly, this paper first introduced the framework of design optimization for plastic forming. Then, focusing on the key problems of design optimization, such as numerical model and optimization algorithm, this paper summarized the research progress on the development and application of the theories and technologies about design optimization in forming process, including deterministic and uncertain optimization. Moreover, the applicability of various modeling methods and optimization algorithms was elaborated in solving the design optimization problems of plastic forming. Finally, considering the development trends of forming technology, this paper discusses some challenges of design optimization that may need to be solved and faced in forming process.     

一种涡轮发动机加速控制规律设计的新方法

 提出了一种涡喷、涡扇发动机加速控制规律快速设计的新方法：在发动机稳态特性计算模型的基础上,通过额外增加转子提取功率,使得发动机稳态工作点（线）靠近喘振边界,在同时考虑燃烧室富油熄火边界、涡轮进口总温限制以及压气机喘振裕度限制的条件下,利用适当的控制规律描述形式并结合发动机工程研制中的经验,能够快速而准确地获得涡喷、涡扇发动机加速控制规律。对某型涡喷发动机加速控制规律的改进的计算结果表明,提出的加速控制规律的设计方法准确而有效。     

合成孔径雷达卫星构型设计

合成孔径雷(Synthetic Aperture Radar,简称SAR)卫星的构型与其它卫星相比具有一定的特殊性,主要体现在大面积的相控平面SAR天线在工作时需侧视(长度方向沿飞行方向)和SAR天线与太阳电池阵之间的相容性.通过分析SAR卫星构型的特点,根据卫星构型设计的原则,结合SAR卫星的构型实例,给出SAR卫星构型设计的基本思路和方法.     

Air-LUSI: A robotic telescope design for lunar spectral measurements

This paper presents the mechanical design of a new robotic telescope that was designed and built to acquire lunar spectral measurements from the science pod of NASA's ER-2 aircraft while flying at an altitude of 70,000 feet (21.34 km). The robotic telescope used a double gimbal design that allowed for target tracking in azimuth and elevation. In addition to the challenging and restrictive geometry of the science pod, each component needed to be carefully selected to ensure that they could withstand the operating conditions at high altitude such as harsh temperatures extending as low as −54 °C and atmospheric pressure less than 1.05 psi (7.23 kPa). Due to the cold temperatures, low atmospheric pressure and the likely exposure to moisture, high strength industrial linear actuators were used to create an adjustable linkage system that controlled the pointing and tracking of the telescope. Although unconventional, this allowed for a robust design that outperformed the team's expectations by tracking the Moon for 40 min with an average tracking error under 0.05°. The results presented within this paper were acquired during a first set of engineering test flights, with further scientific missions to follow.     

直升机贴地飞行时的驾驶员诱发振荡研究

主要阐述直或机贴地飞行时的驾驶员诱发振荡问题，导出了贴地突防和迅速停止动作、地形跟踪时的“海豚”运动和贴地飞行时滑雪运动条件下诱发振荡时操纵位移和稳定裕度的计算公式，计算了Ｚ－８直长机的纵向试验结果，并进行了误差分析。计算结果表明，所研究的方法是可行的，可推广应用于各种直升机的闭环分析和计算。     

空调冷水变流量设计改进

本文对常规空调冷水变流量系统进行了节能分析，指出按传统设计方法设计的变水量系统不能充分发挥新技术的节能潜力，并提出了改进的设计做法。     

Design and examination of a turboprop inlet with scavenge duct

The inlet with scavenge duct is an important part of turboprop aircraft engine. This type of inlet normally has a complex shape, of which the design is challenging and directly affects the flow field quality of the engine entrance and thus the engine performance. In this paper, the parametric design method of a turboprop aircraft inlet with scavenge duct is established by extracting and controlling the transition law of the critical characteristic parameters. The inlet’s performance and internal flow characteristics are examined by wind-tunnel experiment and numerical simulation. The results indicate that a flow tendency of winding up on both sides is formed due to the induction of the inlet profile, as well as a vortex pair on the back side of the power output shaft. The vortex pair dominates the pressure distortion index on the Aerodynamic Interface Plane (AIP). In addition, with the increase of freestream angle of attack, the total-pressure recovery coefficient of the inlet increases gradually while the total pressure distortion index decreases slightly. On the basis of the experimental results under different working conditions, the parametric design method proposed in this paper is feasible.     

跨声轴流压气机等离子体控制实验

为了能有效地拓宽压气机的失稳裕度,在一台跨声轴流压气机上进行了基于介质阻挡放电（DBD）等离子体激励扩稳的实验研究.实验中分别选取了正弦交流电源和纳秒脉冲电源提供激励,并在跨声压气机40%设计转速和65%设计转速下对其扩稳效果和效率进行了对比分析.结果表明:在40%设计转速时,正弦交流电源和纳秒脉冲电源均能有效拓宽压气机流量范围,其中正弦交流电源激励方式能够使压气机综合失速裕度改善（SMI）达到15.33%.在65%设计转速时,两种激励方式的扩稳效果明显减弱,此时纳秒脉冲电源激励方式的扩稳效果更好.在压气机效率方面,纳秒脉冲电源对压气机设计点的效率影响更小,在40%设计转速时甚至能略微提升其设计点效率.实验结果表明,合理地选择激励方式有助于提高等离子体激励的扩稳效果,为实际压气机中基于介质阻挡放电等离子体激励扩稳措施的设计提供参考.      

压差控制器的稳定性分析和设计参数的研究

压差控制器是航空发动机燃油计量的重要部件,用于保持计量活门前后的压差恒定.为探究其控制压差能力的因素,研究了某型发动机加力系统中压差控制器的性能,分析并推导出其影响控压差能力的主要因素,并在AMESim仿真环境下对所得结果进行建模仿真,验证了所得结论的正确性.在此基础上对其进行合理的改型,为保证改型不影响系统稳定性,用小偏差原理对改型前后的压差控制器辨识,得到传递函数,确保改型并未损失其动态性能.最终得到改进压差控制器控压差能力的理论依据.