谐振式燃油密度传感器振动筒的设计与分析

飞机燃油密度高精度的测量对精确控制燃油量有重要作用.本文通过理论分析及ANSYS有限元分析软件对谐振式燃油密度传感器振动筒进行了振动模态分析,并利用正交实验设计法优化了不同振动模态、不同振动频率下振动筒的设计.分析结果表明:采用基本振型m=1,n=4,几何尺寸为L=2.9 cm,R=0.8 cm,t=0.20 mm的振动筒时,在密度范围为700～900 kg/m3的航空煤油环境下,其谐振频率范围为7.5～8.5 kHz.符合设计目标频率在2～10 kHz的要求,可作为谐振式燃油密度测量系统振动筒的设计参考.     

利用质子强度变化对太阳质子事件进行短期预报方法初步研究

采用GOSE-10卫星4～9 MeV(P2),9～15 MeV(P3),15～40 MeV(P4),40～80 MeV(P5)能段上的质子通量数据,结合质子能谱,对太阳质子事件发生前各能谱参数的变化特征进行分析,详细介绍利用能谱参数的变化特征及能量E>10 MeV的质子通量数据对太阳质子事件进行预报的新方法,并运用这种方法对2002-2006年期间太阳质子事件进行了预报.预报结果显示,预报提前量最多达到100 h以上,对质子事件的报准率达97.5%,预报方法具备一定的有效性和实用性.      

A new modeling method of solar energetic proton events for ISO specification

Solar energetic protons degrade performance and reliability of spacecraft systems due to single-event effects, total dose effects and displacement damage in electronics components including solar cells. On designing a solar cell panel, a total fluence of solar energetic protons (SEPs) which cause solar cell damage is needed to estimate power loss of the solar cells over mission life. Nowadays a solar panel area of spacecraft is increasing as spacecraft mission life becomes longer (15–18 years). Thus an accurate SEP model is strongly required for the cost-minimum design from the aerospace industry. The SEP model, JPL-91 proposed by Feynman et al., is currently used widely for solar cell designing. However, it is known that the JPL-91 model predicts higher fluences of protons than values actually experienced in space, especially after 7 years on orbit. In addition, the model is based on several assumptions, and also needs Monte-Carlo simulations for calculating fluences. In this study, we propose a new method for modeling SEPs especially focused on solar cell degradation. The newly-proposed method is empirical, which constructs a model based directly upon proton flux measurement data taken by instruments onboard spacecraft. This method has neither assumptions nor dependence on SEP event selection, both of which are needed in JPL-91. The model fluences derived from this method show lower fluences in longer missions compared to JPL-91. This method has been proposed to ISO (International Organization for Standardization) and has been discussed for a new standard SEP model.     

IPX实时通信软件的设计与实现

分析了基于IPX(Internetwork Packet eXchange)协议的实时通信编程原理,讨论了针对某网络所开发的实时通信软件IPXSR的设计思想、特点、实现技术和调用方法.目前该软件已经通过了验收和鉴定,在实际系统中得到应用,效果良好.并能够方便地移植到其他的物理网络系统中,具有较大的实用价值.      

一种富氧中空纤维膜组件的温度特性

通过实验研究温度对中空纤维膜组件氧/氮分离性能的影响,结果表明温度能够明显影响膜的分离特性,并且不影响富氧浓度,可以通过控制膜组件的使用温度来增加富氧产量.      

预混湍流燃烧的level-set小火焰库方法研究

针对燃气涡轮发动机中贫燃预混预蒸发燃烧室,考虑详细化学反应机理,结合Level-set方法与小火焰模型模拟预混火焰,计算了甲烷/空气贫燃预混燃烧的火焰面的位置,并比较了在贫燃条件下各当量比的NO排放值,计算与实验结果吻合较好。      

微流体动力学研究发展与现状

在分析微流体流动特性基础上,介绍了微流体动力学研究的发展与现状,包括临界雷诺数、固液界面速度滑移、微流体热传导特性等基本问题的研究结果。     

储箱平铺多燃料卫星平台的主承力构架结构

为实现携较多燃料并能传递较大载荷的卫星平台,根据贮箱上下叠放、环向平铺和主承力结构与大容量贮箱一体化等典型贮箱布局介绍了一种储箱平铺的主承力构架结构。该结构可减小平台高度,降低卫星质心,且便于有效载荷扩展,并使工艺更简单。对两卫星平铺主承力结构的有限元数值模拟结果表明,其结构能满足卫星结构的力学性能要求,可作为未来相关卫星研制的参考构型。     

水基推进系统综述

水基推进系统的发展为航天器推进、供电、能量储存、系统构建提供了新的选择。这一系统的核心是一体化可再生燃料电池,它利用太阳能电池帆板提供的电能电解水．产生的氢氧气体既可以用于燃烧推进,又可以通过燃料电池反应重新复合为水进行供电。介绍了水基推进系统的基本组成与工作原理,通过质量估算与性能分析,评估了水基推进系统的工作能力、适用范围及空间应用优势。     

Numerical Simulation of Characteristics of CEX Ions in Ion Thruster Optical System

Charge exchange(CEX) ions could inflict severe damages on the ion thruster optical system. This article is aimed at investigating the characteristics of the CEX ions and their influences upon the optical system by means of particle-in- cell(PIC) ion simulation and Monte Carlo collision(MCC) methods. The results from numerical simulation indicate that despite the fact that CEX ions appear in the entire beamlet region near the ion optical system, the ones that present themselves downstream of the accelerator grid have good reason for attracting more attention. As their trajectories are significantly affected by the local electric field, a great number of CEX ions are accelerated toward grids resulting in sputtering erosion. When the influences of the CEX ions are considered in the numerical simulation, there could hardly be observed augments in the screen grid current, but the accelerator grid current increases from zero to 1. 4% of the beamlet current. It can be understood from the numerical simulation that the CEX ions formed in the region far downstream of the accelerator grid should be blamed for the erosion on the downstream surface of the accelerator grid.