空间低温杜瓦瓶凯夫拉支撑结构多约束优化设计

采用新型凯夫拉纤维作为某空间用小型低温杜瓦瓶的支撑材料，在验证其力学性能的基础上，设计了杜瓦瓶的支撑结构，建立了一种新的热力学耦合优化模型，给出支撑结构固有频率、热应力及发射环境下的约束条件，通过一种“离散点加密”新约束优化法计算出了支撑结构满足约束条件范围内的要求的最优设计参数。     

Remote-controlled flexible pose measurement system and method for a moving target in wind tunnel

The measurement of position and attitude parameters for the isolated target from a high-speed aircraft is a great challenge in the field of wind tunnel simulation technology. This paper proposes a remote-controlled flexible pose measurement system in wind tunnel conditions for the separation of a target from an aircraft. The position and attitude parameters of a moving object are obtained by utilizing a single camera with a focal length and camera orientation that can be changed based on different measurement conditions. Using this proposed system and method, both the flexibility and efficiency of the pose measurement system can be enhanced in wind tunnel conditions to meet the measurement requirements of different objects and experiments, which is also useful for the development of an intelligent position and attitude measurement system. The position and the focal length of the camera also can be controlled remotely during measurements to enlarge both the vertical and horizontal measurement range of this system. Experiments are conducted in the laboratory to measure the position and attitude of moving objects with high flexibility and efficiency, and the measurement precision of the measurement system is also verified through experiments.     

Numerical Analysis of Dry Friction-Induced Vibration of Moving Slider-Elastic Annular Beam System

A disc-pad friction system is modelled as that two moving pads act symmetrically on an annular beam with flexible boundary condition.Simulation procedure is proposed to deal with the moving interactions and calculation is carried out by using the finite difference method,which shows that only the first-order mode vibration of the beam can be induced.Then the partial differential equation of motion of the disk is reduced to a first-order mode vibration system with time-varying stiffness.As the disk speed is decreased below the critical speeds,the relative equilibrium of the pad on the disk loses its stability and stick-slip type limit cycle vibrations are resulted in all directions′movements.Acceleration of the disk motion on the frictional instability is also investigated.The period of stick-slip vibration with large amplitude will be shortened with higher moving deceleration.     

高温声表面波器件Pt电极的制备研究*

针对高温声表面波(SAW)器件中的Pt电极制备需求,采用电感耦合等离子体干法刻蚀工艺实现Pt电极的干法刻蚀。通过采用纯Ar气源,研究不同ICP功率/RF功率下Pt电极的刻蚀,采用优化的刻蚀参数实现SAW中Pt叉指电极的制备。针对Pt溅射刻蚀中出现的再沉积问题,分析沉积物对电极制备的影响,通过后处理实现沉积物的去除,实现高温SAW器件的制备。     

高校新媒体环境下大学生意识形态教育新路径

意识形态关乎社会稳定和国家前途,必须得到足够的重视。而意识形态教育中青年学生的问题又尤为突出,当代大学生思想活跃,自我意识强烈,对意识形态领域的教育较为反感,因此意识形态教育工作必须创新其内容和形式。高校新媒体平台因为其新颖性和碎片化的特点,可以很好的作为意识形态教育工作的载体,承担意识形态教育工作的重任。     

热等静压对激光选区熔化成形GH4169合金持久性能的影响

采用激光选区熔化(SLM)成形技术制备了GH4169合金,运用金相显微镜(OM)、扫描电子显微镜(SEM)、电子背散射衍射(EBSD)和透射电镜(TEM)等分析手段分析了热等静压对SLM成形GH4169合金组织及持久性能的影响规律。结果表明:沉积态合金组织中,沿沉积方向的晶粒为柱状晶,晶粒内枝晶组织细小,枝晶间分布大量Laves相;热等静压处理可有效消除组织中气孔缺陷,溶解大部分Laves相,促使组织晶粒等轴化,并减少后续980℃固溶处理过程中δ相在晶内的析出;热等静压处理能提高合金的持久寿命,但会降低合金的持久塑性。     

重型燃气轮机高雷诺数CDA叶型转捩特性数值计算

为研究重型燃气轮机的压气机叶片在高雷诺数工况下的气动性能,基于Gamma-Theta转捩模型的雷诺时均方程对某可 控扩散叶型进行了数值计算。通过对比不控制马赫数与控制马赫数,分析高雷诺数对可控扩散叶型气动性能及转捩特性的影响。 结果表明：在不控制马赫数条件下,在零攻角时,雷诺数从7×10 5 增大为9×10 5 ,总压损失增加了约391.95%;在高雷诺数工况下随 着雷诺数的增大,叶片流动损失不断增大,叶片可用攻角范围减小,同时在叶片吸力面出现激波,干扰转捩的产生。在控制马赫数 条件下,当Ma=0.6时,在零攻角工况下,雷诺数从8.2×10 5 增大为1×10 7 ,总压损失减小了约38.98%,吸力面转捩起始点从4.78%弦 长处前移至1.11%弦长处;在高雷诺数工况下,叶片流动损失随着雷诺数的增大不断减小,吸力面转捩位置前移。     

超临界RP-3航空煤油喷嘴内部流动与相变特性研究

未来航空燃气轮机采用燃油作为冷却剂,对发动机冷却空气及热端部件进行冷却,使得燃油在进入燃烧室之前超过其热力学临界点,燃油的热力学性质发生巨大变化,将对燃油在喷嘴内的流动和喷嘴下游的喷射掺混过程产生重要的影响,因此有必要对超临界RP-3在喷嘴内的流动与相变特性展开研究。本文采用自主设计的喷嘴内部收缩通道模拟试验件,对超临界RP-3在喷嘴内的沿程压力分布进行测量,并采用基于一维等熵假设的计算方法进行数值模拟。试验首次获得了超临界航空煤油RP-3在喷嘴收缩通道内的沿程静压分布随喷射压力、温度变化的规律。通过与模型对比,发现未发生相变时,计算结果与试验值拟合精度较高,可以较好地预测RP-3在喷嘴内的流动参数,喷嘴内的静压分布也趋于一致;发生冷凝相变时,计算结果与试验值产生误差较大,喷射参数对于静压分布存在着较大的影响。本文试验获得的超临界RP-3航空煤油在喷嘴内的流动与相变特性,为航空发动机超临界RP-3喷射的喷嘴设计提供了重要的设计依据。     

嫦娥五号探测器推进系统研制与飞行

本文介绍了嫦娥五号探测器推进系统的任务特点、研制要求、设计方案、主要单机技术以及在轨飞行表现。嫦娥五号推进系统由三部分组成：轨道器推进子系统、着陆器推进子系统、上升器推进子系统,均采用氦气恒压挤压式双组元统一推进系统。为实现探测器的目标,推进系统在以往技术基础上开发了一系列新技术和新产品,大幅减轻了系统干质量、提高了相关性能,并采取了一系列技术加强了产品可靠性和月面环境适应性,最终圆满实现了探测器的任务目标。