低冰点推进剂对液体火箭发动机性能影响研究

针对低冰点推进剂在液体火箭发动机性能研究中的重要性,对使用MON25/DT3组合的低冰点推进剂液体火箭发动机的启动过程及稳态过程进行研究.建立了发动机系统的数学模型,采用Matlab/Simulink构造系统的仿真模型.根据仿真结果比较和分析了不同初温的推进剂对燃烧室压强、发动机比冲和推力等各方面性能的影响,得出了这三个参量与推进剂初温的拟合关系式.     

含硼贫氧推进剂固体火箭冲压发动机性能

含硼贫氧推进剂固体火箭冲压发动机的性能预示是在热力计算基础上进行的,其热力计算就是贫氧推进剂在给定一、二次燃烧条件下的热力计算。本文简要介绍了贫氧推进剂非化学平衡体系热力计算的原理,分别对壅塞式和非壅塞式固体火箭冲压发动机进行了不同情况的热力计算。结果说明:用能量高的含硼推进剂,固体火箭冲压发动机的比冲显著提高。燃气流量不可调的壅塞式固体火箭冲压发动机的性能随工作高度和飞行马赫数的变化会有较大的变化,非壅塞式固体火箭冲压发动机的变化较小。     

固体火箭发动机比冲估算及界面程序实现

依据某推进剂热力计算结果和基于FLUENT软件平台的固体火箭发动机燃烧室和喷管两相流流场仿真得到的相关参数,根据比冲计算的相关理论,利用MATLAB图形用户界面(Graphical User Interface,GUI)软件编制了发动机比冲预估算程序,利用该程序对某型号固体火箭发动机的比冲进行了预估。预估结果与实验值对比表明,该程序可以对发动机比冲进行较准确和快速的估算。     

F-1火箭发动机的发展史

F-1火箭发动机是在美国航宇局(NASA)和马竭尔航天飞行中心(MSFC)领导下于1958～1967年由洛克达因公司研制和生产的。发动机在1967到1973年服役。在整个F-1发动机计划期间完成了设计、试验和工作三个里程碑。 F-1发动机是推力最大的液体火箭发动机。五台F-1并联用于NASA的土星V火箭第一级,其推力为750万磅。土星V火箭发射载三人的阿波罗飞船,并完成登月。 F-1发动机是一次起动、固定推力、液体双组元推进剂发动机。其海平面推力为152.2万磅,比冲265.4秒。发动机所使用推进剂为液氧、煤油(RP-1),推进剂混合比为2.27∶1。RP-1为常平座作动器工质及发动机控制系统工质,并用做涡轮泵轴承润滑剂。F-1由七个工作系统组成。     

液体火箭推进剂发展远景

一、前言液体火箭发动机的特点是不靠外部能源而利用飞行器上推进剂诸组元的化学能建立推力。推进剂诸组元之间经过反应的物质(即燃烧产物)构成高速喷射物质。这样,火箭发动机的主要参数:喷射速度(比冲)就取决于单位质量推进剂所含的化学能。实际上,单位质量推进剂所含化学能的上限等于12.10~6焦耳/千克。具体说,双组元推进剂F_2/H_2在其燃烧产     

液体火箭发动机羽烟紫外辐射特性分析

通过分析火箭发动机羽烟的紫外辐射机理,建立了适用于热发射、CO + O 化学发光、OH 自由基化学发光的液体火箭发动机羽烟紫外辐射模型,可以考虑热发射、CO + O 化学发光、OH 自由基化学发光等紫外辐射机理。在分别计算流场和辐射传输的基础上,分别采用二维和三维网格计算流场参数和辐射传输,既节省了计算时间,还可得到羽烟在不同视角的紫外光谱辐射强度分布和二维辐亮度分布。利用火箭发动机羽烟紫外辐射模型,计算了液氢/ 液氧和航空煤油/ 液氧两种双组元液体推进剂火箭发动机羽烟的紫外光谱辐射强度分布和二维辐亮度分布,并以液氢/ 液氧推进剂为例,研究了液体混合比对液体火箭发动机羽烟紫外辐射分布的影响。研究结果可以为紫外导弹预警系统判断导弹所采用的液体火箭发动机类型,以及液体火箭发动机导弹紫外隐身性能的改进提供参考。     

微型续航固体火箭发动机设计及试验方法研究

介绍了毫米级固体推进剂火箭发动机的设计和试验方法,并将其用作一次性的执行微型传感器网络节点系统的展开平台.此火箭发动机由燃烧室、推进剂燃料、喷管、点火器组成.点火器采用电点火方式.对微型化后需解决的火箭设计问题进行了讨论,提出了相应的设计原则和方法.用这种方法设计的火箭质量仅为2 g,比冲在230～860 N·s/kg范围内,测量到的推力达到24～230 mN.     

A~3NPL推进剂的燃烧

在过氯酸铵(以下简称AP)系推进剂的燃气中,含有大量的酸性氯化氢(HCI)。降低燃气中的这种有害气体甚为必要。本文探讨了硝酸铵(以下简称AN)作为推进剂氧化剂的实用性。硝酸铵推进剂价格低廉,燃气中不含有害物质。AN系复合推进剂的缺点是比冲低,在理论上添加金属铝可以提高比冲。为了提高点火性能及燃烧效率,在本研究中还探讨了由AN、AP、AI组成的推进剂的燃烧特性。这种称为A~3 NPL推进剂的燃烧特性,可以借助AN、AP、AI的不同添加量来调节。小型火箭发动机的燃烧实验结果表明:(1)AN系复合推进剂中添加的AI在燃烧室内熔融成层状物附着于喷管内壁,不能完全燃烧,致使比冲下降;(2)用AP取代AN系复合推进剂中的部份AN,可以提高AI的燃烧效率和增加比冲,并大幅度减少燃烧产物中的酸性气体。     

新型乙炔氨推进剂热力性能计算分析

采用吉布斯最小自由能法计算了不同乙炔含量的乙炔氨推进剂的热力参数,选定了乙炔氨中乙炔的含量并计算了液氧(LO X)分别与选定浓度的乙炔氨、火箭煤油、甲烷等组合的6种推进剂热力性能。结果表明:乙炔含量为25%的乙炔氨推进剂在比冲和安全性两方面最优,可作为下一步研究目标;液氧(LO X)/乙炔氨组合较其它推进剂组合具有很好的空间应用物性和较高的热力性能,在燃烧室压强/喷管出口压强为180∶1、喷管出口面积/喷管喉部面积为35∶1时,比组合冲达到372.63s,比现有的LO X/火箭煤油比冲高14 s。     

气氧/酒精推进剂组合的点火特性

本报告介绍了为确定气氧/酒精推进剂组合的点火特性和推力室的脉冲工作性能而进行的研完工作的结果。确定了利用火炬点火器产生的火花点火时,可以点燃的混合比范围和冷流压力范围。在冷流压力、推进剂温度和混合比变化范围很大的情况下,进行了点火器试验。利用冷流压力和点火器直径的乘积把点火状态下和非点火状态下的混合比范围联系起来。利用推力为620磅并装有组合火炬点火器的推力室验证了发动机的可靠性和脉冲工作性能。燃烧室额定工作压力和混合比分别为150磅/英寸~2·绝压和1.8·在燃烧室压力和混合比变化范围很大的情况下进行了推力室试验。通过试验证明,推力室可以以非自燃的气氧/酒精为推进剂可靠地进行脉冲工作。     

Nitrosation and Nitration of Tetraacetyldibenzylhexaazaisowurtzitane

Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.     

A Robust Algorithm for Watermarking 2D Vector Maps with Low Shape-Distortions

The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS （geographical information system） data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.     

Method for Measuring Velocity of Warhead Fragments Based on Photoelectric Detection

For measuring velocity and impacting position of single fragment of warhead, a non-contact measuring method is proposed, in which a six-light-screen array, a position indicator, a multi-channel chronograph and a computer are used.The principle of measurement is described. The key device of the system is a light screen array sensor which consists of six light screens allocated with certain geometrical parameters. When the fragment flies through the light screen array, the time of passing through each of the screens is recorded by the multi-channel chronograph. According to the time data and the geometrical parameters of the array, the velocity vector and the location of the fragment can be calculated immediately. The presented method can be used to locate the fragment and to measure the real velocity on its flying direction. It can also be used to measure the velocity of a fragment swarm after the system is engineered further.     

数码电子雷管中影响点火头性能因素分析

阐述了数码电子雷管中,点火药剂细结晶三硝基间苯二酚铅（LTNR）的制备工艺;从点火药剂的种类、加入黏合剂的质量分数、桥丝直径、点火头的电阻值、防潮漆的蘸涂等方面对点火头性能的影响因素进行了探讨;通过震动试验、并联起爆试验、延期精度检测与考核,试验结果表明：一次性合成的细结晶LTNR是制造数码电子雷管点火头较为理想的点火药剂,按技术要求生产的点火头性能指标能够满足行业标准要求。     

Open Rule-setting System Applied to Conceptual Design of Engines

Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.     

Research on Linux Network Device Driver

By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux （kernel version 2.6.11 ） is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.     

Design and Implementation of One Missile Visual Simulation System Based on OpenGL

The implementation of a missile＇s visual simulation system is explained that is developed with OpenGL（open graphic library） and the flight path and flight carriage in different stages of the missile are displayed. The establishment problems of the 3D scene are circumstantiated including the construction and redeployment of the model, creation of the virtual scene, setting of the multi-viewports and multi-windows etc. The missile＇s data driver, system flow, the modules and their mutual relations of the missile visual simulation system are discussed. The missile flight simulation results and effect of the scenes are given.     

Improvement and Experiment of the Reamer in Vibra Cutter Against Wave Edge of Titanium Sheet Alloy Parts

By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.     

Dynamic Encryption Technology in Ad-hoc Networks

A new dynamic encryption application in ad-hoc networks is proposed. The advantages of this method are its being able to use the previous ciphertext as a seed of a new encryption process, rendering the encryption process effective in all communication process by continuous dynamic key generation together with synchronization, and its capability to cut back on system bandages to a greater extent, which is valuable for the ad-hoc circumstance. In addition, the rationality and effectiveness of this novel encryption method have been verified by the test results.     

Experimental Study on the Small Flyer Initiating Behavior of Fine-grained Explosives

The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite.