气氧/气甲烷针栓喷注器孔型设计仿真研究

为解决针栓喷注器易烧毁的问题,就圆形喷孔孔径比对气氧/气甲烷针栓喷注器头部传热环境和燃烧特性的影响进行了数值仿真研究.结果表明:在给定几何条件下,双排圆形喷孔的针栓喷注器头部最高温度随孔径比增大而减小,而燃烧效率变化微小且均在96％以上.在燃烧室内存在两个大回流区的传统认识之上,研究发现孔径比不小于1时针栓喷注器头部下方还存在一小回流区,该区域轴向推进剂的质量分数较大,对隔绝高温燃气回流避免喷注器烧毁具有重要作用.     

直流互击式喷注器的实验与数值研究

针对一种直流互击式喷注器做了冷态实验和数值研究。应用Fluent软件对火箭发动机的直流互击式喷注器的内部流道流场进行了仿真,并与实验结果做了对比,验证了该数值模拟方法的正确性;通过数值模拟研究得到喷注器流道的压力云图、速度矢量图及流量分布折线图;分析了产生压降及出口流量不均匀的原因;提出改善压降和流量均匀性的方法。结果表明:为直流互击式喷注器的数值仿真、结构设计和优化提供了参考。     

改进过渡级喷注器计划/过渡级-多用途上面级

改进过渡级喷注器计划/过渡级继1981年10月31日和1982年3月6日大力神ⅢC获得高度成功的飞行之后已经进入了飞行验证阶段。改进过渡的喷注器计划(ITIP)研制的是AJ10-138A型发动机,该发动机在性能上较1964年以来使用的AJ10-138型过渡级发动机有很大的提高。性能的提高是通过重新设计喷注器后实现的。此外,采用15穴双调谐声腔实现了动力燃烧稳定性。改进过渡级喷注器计划/过渡级研制成功后,其主要设计用于德尔它运载火箭和日本的N-Ⅱ运载火箭上。该两种运载火箭选用了改进过渡级喷注器计划来提高其第二级的性能,以便运载更重的有效载荷。这种改进过渡级喷注器计划发动机在当前和未来的上面级应用上还具有相当大的性能增长潜力。本文综述了改进过渡级喷注器计划发动机的设计、过渡级首次成功飞行的结果、在德尔它和N-Ⅱ运载火箭上的应用、以及该发动机性能进一步增长的潜力。     

具有薄层过滤筛的改进型过渡级发动机(AJ10-138A型发动机)

为使自1964年来一直在使用的过渡级发动机(AJ10—138)性能有显著的提高,进行了一项改进过渡级喷注器的计划(ITIP),该项计划最后导致AJ10一138A发动机的研制成功。性能的提高是由重新设计喷注器获得的。用一种15空腔槽的双调谐声腔达到了燃烧的动态稳定性。使用了航空喷气通用公司研制的薄层过滤筛消除了喷注器外圈燃料喷嘴可能发生的杂质堵塞。具有先进技术的薄层过滤筛的采用使设计得到改进,而又不改变发动机的工作特性。本文将介绍ITIP设计概况及讨论薄层过滤筛。     

信息动态

小推力液氧/甲烷发动机以及变推力发动机一直是火箭发动机领域研究的热点内容.从推进剂物性和发动机主要部件,包括点火器、燃烧室和推进剂供应系统等方面介绍了液氧/甲烷小推力发动机的研究历史和现状,并对针栓式变推力发动机技术进行了阐述,最后提出了针栓式变推力液氧/甲烷发动机的关键技术和应用前景.     

氢氧火箭发动机预燃室喷注器特性研究

为发展高性能分级燃烧氢氧火箭发动机技术，对４种预燃室单元喷注器进行了理论和试验研究。利用相位多普勒粒度仪研究了气／液喷嘴压降比、液体流量及反压对不同结构形式喷嘴的喷雾特性的影响，通过理论计算和燃烧试验，揭示了不同单元喷注器之间的性能、燃气温度分布、燃烧稳定性和点火性能差异。     

幂律型煤油凝胶在不同几何构型管道的流动特性数值研究

为了优化煤油凝胶供给管道和锥形喷注器设计,构建出幂律流体的二维/三维稳态层流的求解方法,采用基于FLUENT平台的SIMPLE算法进行求解,开展煤油凝胶的流动特性数值研究。推导出了推进剂在直圆管中各参数的解析解以及层流的动能修正系数。研究结果表明：直圆管的柱塞流区域在管径不变时是固定的;为降低喷注器出口截面的平均表观粘度,需减小出口段长度;喷注器的收缩角选择在40°左右是较为合理的;弯管内存在双涡旋形式的二次流,且剪切速率和表观粘度的非对称性比速度的非对称性显著。为了优化煤油凝胶供给管道和锥形喷注器设计,构建出幂律流体的二维/三维稳态层流的求解方法,采用基于FLUENT平台的SIMPLE算法进行求解,开展煤油凝胶的流动特性数值研究。推导出了推进剂在直圆管中各参数的解析解以及层流的动能修正系数。研究结果表明：直圆管的柱塞流区域在管径不变时是固定的;为降低喷注器出口截面的平均表观粘度,需减小出口段长度;喷注器的收缩角选择在40°左右是较为合理的;弯管内存在双涡旋形式的二次流,且剪切速率和表观粘度的非对称性比速度的非对称性显著。     

液氧/碳氢燃料喷注器的性能

本文以试验的方法评定了液氧/碳氢燃料喷注器的设计对性能和燃烧室传热的影响。对于液氧/丙烷和液氧/乙醇两种推进剂,给出了两种不同类型喷嘴的数据。试验是在室压为200～400磅/英寸~2(绝)和各种不同混合比的条件下进行的。燃料薄膜冷却流量在燃料总流量的0～15%范围内变化。在选择喷注器的设计条件以及分析多喷嘴喷注器的数据时,单个喷嘴燃烧的摄影数据是有意义的。冷流混合与热点火的混合有很大差别。而这种趋向与以前对自燃“可贮存”推进剂所取得的结果很相似。本文介绍的多喷嘴喷注器的数据,可为前面所说的趋向提供定量的证据,并为发动机的应用提供原始的设计资料。这些数据是在 NASA 的合同下获取的,目的在于为先进的、可重复使用的空间运输系统发动机的设计提供数据基础。     

喉栓式固体火箭发动机喷管性能影响研究

对喉栓式固体火箭发动机内流场进行了稳态数值模拟,分析了喉栓头部型面、喉栓尺寸、喉栓位置对发动机性能的影响规律,结果表明发动机效率受喉栓头部型面、尺寸、位置等因素影响显著,所提供的结论可为喉栓式变推力固体火箭发动机的设计、试验及应用提供参考依据.     

氢喷前温度递降对液氧/气氢燃烧特性的影响

为了研究氢喷前温度对液氧/气氢同轴直流式喷嘴燃烧特性的影响,分别通过单喷嘴热试验和缩比喷注器热试验两种途径,对氢氧发动机推力室用大流量喷嘴进行了氢喷前温度递降试验.其中单喷嘴热试验中氢喷前温度范围90～230 K,在温度递降过程中未发生不稳定燃烧.缩比喷注器热试验中氢喷前温度范围65～145 K,在温度递降到70 K时激发了不稳定燃烧.研究表明:液氧/气氢同轴直流式喷嘴燃烧存在一个稳定工作氢温的下限,如果在低于该下限的温度下工作,则将激励燃烧不稳定性.所选用的大流量喷嘴具有一定的燃烧稳定性裕度,氢喷前温度递降试验可以作为氢氧发动机燃烧稳定性评定的一套可行方法.     

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.     

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.     

Stability of the Third Generation Intensifier under Illumination

The stability under illumination of transmission-mode GaAs photocathode sealed in the third generation intensifier is investigated by use of spectral response testing instruments. The variations of spectral response with the illumination times under weak and intense illumination are compared. The variations of photoemission performance parameters are also characterized. The results show that during initial several weak illuminations photocathode behaves no evident decay and a maximum sensitivity is achieved, while under intense illumination the sensitivity of photocathode begin to decrease largely at the first illumination. The calculated performance parameters show that the variation of surface escape probability with illumination times is a direct cause of instability of photocathode. It is also found that under intense illumination peak wavelength is moved towards short-wave and peak response is decreased, which shows that the ability of long-wave response of photocathode is decreased.     

An Experimental Study on Electro Chemical Machining of Microelectrode

Puts forward a new method in machining microelectrode by electro chemical machining （ECM） and plastic deformed theory. The procedure of this method is to machine the microelectrode according to the basic rule of ECM theory at first. Then, with the change of ECM machining parameters, one of the microelectrode ends is exerted by a load. As a result, the elastic and plastic deformation is produced at the machining section and the microelectrode diameter is reduced. It has been proved that the proposed method can determine the optimum machining parameters to machine the microelectrode of Cu.     

Unscented Kalman Filter for Autonomous Warship Attitude Determination

To address a problem of autonomous attitude determination algorithm using gravitational field and geomagnetic field observation, a new recursive optimization autonomous attitude estimation algorithm is proposed. The algorithm is based on unscented Kalman fiher(UKF), and can synchronously provide the attitude rate information. The simulated results show that the measurement precision of the method could be increased by 2 times compared to that of the common methods.     

Error Coefficient Estimation of Inertial Platformin Its Calibration

The error coefficient estimation of inertial platform in the course of its consecutive ground calibration is studiedA separate-bias algorithm is adopted to estimate the error parameters effectively. The ill-conditioning problem of the equation solution caused by the huge state dimension is also resolved. And the simulation result shows its validity.