鸭舵位置参数对弹箭滚转特性的影响

采用数值模拟方法,研究了一尾翼固定的鸭式布局弹箭舵尾间距以及鸭舵安装位置对滚转特性的影响。分析了其流场特性与气动特性,结果显示,固定尾翼鸭式布局弹箭的舵尾间距对滚转控制特性有较大的影响,且舵尾间距越小,鸭舵下洗诱导尾翼产生反向滚转力矩越大,鸭舵滚转控制效率越低; 鸭舵安装位置对滚转特性亦有较大的影响,安装在圆柱段上较安装在圆锥段上,其滚转力矩系数在跨音速得到提升,在亚音速和低超音速都有所下降,超音速时几乎不变。     

旋转体制下鸭式布局弹箭正弦打舵气动特性分析

为了研究鸭式布局弹箭正弦打舵滚转控制时非对称姿态飞行的气动特性,根据滚转周期内的飞行姿态建立了4组模型,进行风洞实验,得到全弹的气动力变化规律; 采用基于三维Navier-Stokes方程求解的时空二阶精度的隐式迭代算法,建立数值计算模型,对流场进行数值模拟,得到不同攻角下飞行时的弹箭各部件气动力数据。结果表明数值模拟气动力数据与风洞实验结果有相似的变化规律。采用后处理软件分析了鸭舵下洗对尾翼的影响,得到结论:鸭式布局弹箭鸭舵洗流对尾翼干扰明显,非对称姿态下鸭舵对尾翼的洗流会使弹箭产生诱导滚转力矩,且该滚转力矩随攻角增大而增大。     

鸭舵后掠角对火箭弹尾翼的滚转性能研究

根据具有较大翼面的鸭式布局火箭弹难以进行滚转控制的特性,文中采用数值流体力学分析手段,建立鸭式布局火箭弹外流场模型,仿真分析了鸭舵滚转效应产生机理、鸭舵下洗对尾翼气动耦合规律以及后掠角对火箭弹滚转性能的影响.仿真结果表明由于鸭舵下洗作用,在尾翼上诱导出一个舵控方向相反的滚转力距,使滚转控制能力降低甚至反效;在后缘后掠角x≠0°时,随着后缘后掠角的减小火箭弹的滚转控制能力基本不变.     

制导炮弹滚转控制系统设计

某鸭式布局的制导炮弹,采用自旋尾翼的方式可实现鸭舵对弹体的滚转控制。基于小扰动假设推导出制导弹滚转运动的扰动方程,分析了滚转运动特性及鸭舵偏转对滚转运动的影响,建立了相应的滚转运动稳定回路模型,回路中滚转控制用比例微分(PD)控制方式来实现。采用Matlab/Simlink软件建立了制导弹滚转控制的仿真模型,根据系统的性能要求用Simulink中的Simulink Response Optimization模块对控制系统进行了优化设计。结果显示弹体滚转位置0.2s可以控制到位,设计结果较好地满足了滚转控制系统品质指标的要求。     

侧滑角对大长细比鸭式布局弹箭俯仰操纵性的影响

大长径比鸭式布局制导弹箭进行倾斜转弯控制时,受侧滑角、攻角和滚转角影响,鸭舵产生的斜吹洗流会引起尾翼和弹身产生额外的面外力和力矩。因此为研究侧滑角对大长细比弹箭操纵性的影响,将流场域划分六面体-多面体网格,采用CFD方法对鸭式布局弹箭在不同攻角、马赫数、舵偏角和侧滑角下的气动特性进行了数值模拟,得到了弹箭气动特性的变化规律,绘制出了弹箭的流线图、涡量图和压力云图,进行流场分析研究。利用风洞实验获得相关空气动力学参数,对实验结果作对比分析,发现风洞实验与数值模拟得到的结果都有较高的吻合度,验证了数值模拟方法的可行性。研究表明多数情况下侧滑角不为零时,由于弹箭的弹体较长,鸭舵的洗流向弹体一侧偏移,使得鸭舵的洗流对部分尾翼没有产生干扰,尾翼的当地攻角增大,尾翼法向力变大,弹箭的压心后移,平衡攻角减小,静稳定度变大,进而弹箭的俯仰操纵效率降低;而在少数情况下弹箭尾翼当地攻角却降低,尾翼法向力有所降低,静稳定度变小,弹箭的操纵效率有所提高。     

旋转尾翼鸭式布局导弹数值模拟

通过数值方法求解三维非定常N-S方程组,对旋转尾翼鸭式布局导弹绕流流场进行了数值模拟。研究了时间步长、旋转角速度对导弹气动特性的影响,并比较了与准定常计算结果的差异,重点分析了尾翼旋转的滚转控制特性。数值计算结果表明:尾翼旋转对纵向气动特性影响较小,对横向气动特性影响较大,滚转力矩随转速的增大而增大;尾翼旋转可以有效提高鸭式布局导弹的滚转控制能力。     

简控火箭弹舵翼气动干扰特性研究

为了研究固定鸭舵简控火箭弹舵翼气动干扰特性,在验证数值方法适用性和可靠性的基础上,采用数值模拟方法对该弹气动特性进行仿真分析。计算得到不同弹长和不同舵翼相对夹角(鸭舵组件反旋角)工况下由鸭舵和尾翼产生的空气动力参数,仿真获得火箭弹外流场压力分布。研究分析了弹体长径比和舵翼相对夹角对鸭舵和尾翼气动特性的影响规律。结果表明:鸭舵与尾翼之间的气动干扰受弹体长径比影响,当弹体长径比达到一定数值时鸭舵对尾翼的气动干扰消失,且这种舵翼气动干扰特性对不同舵翼相对夹角情况同样适用; 研究结果可用于简化固定鸭舵火箭弹气动特性的研究方法,提高火箭弹气动外形设计效率。     

固定鸭舵双旋火箭弹超声速侧向气动特性

为研究加装了固定鸭舵修正组件的双旋火箭弹的气动特性,采用ANSYS Fluent软件计算弹体周围流场,采用滑移网格方法模拟弹箭旋转运动,在验证数值方法的基础上,对超声速下无鸭舵、鸭舵修正组件不旋和鸭舵修正组件反旋3种状态的双旋火箭弹进行数值模拟,重点分析了鸭舵修正组件对全弹和部件侧向力的影响。计算结果表明:加装鸭舵修正组件后,全弹阻力系数和法向力系数增加,侧向力系数随攻角大幅增加; 弹体侧向力受鸭舵的影响最大,也是全弹侧向力的主要组成部分,尾翼次之,修正组件产生的侧向力最小; 加装修正组件后,鸭舵尾涡与弹体体涡相互干扰是弹体和尾翼侧向力增加的主要原因。     

简易制导弹滚转控制研究

研究了鸭式布局简易制导弹的滚转控制方案,在对固定尾翼弹滚转控制进行分析的基础上提出了一种自适应式自旋尾翼设计方案,实现了可根据转速自适应改变尾翼滚转控制方式的结构布局。分析了自适应自旋尾翼自动解锁的原理与可行性,通过对固定尾翼与自旋尾翼滚转气动特性进行比较,表明了用鸭舵可实现对自旋尾翼弹滚转的有效控制。对全弹道进行了弹体转速的仿真计算,得到了理想的滚转控制性能。     

旋转稳定二维修正弹鸭舵法向力计算模型研究

为了研究修正组件滚转条件下二维修正弹鸭舵的法向气动力非线性规律,建立了鸭舵坐标系,考虑弹丸攻角、舵偏角、弹丸运动和迎风区与背风区等影响因素,采用多元泰勒展开理论,建立了动态鸭舵法向力计算模型; 采用数值计算分析了不同攻角、舵偏角组合的鸭舵法向力特性,得到了不同舵偏角下鸭舵法向力随攻角的变化规律,分析了滚转条件下舵偏角和攻角对4个鸭舵法向力系数的影响规律。结果表明:鸭舵法向力计算模型的计算结果与数值计算结果吻合较好,该模型为二维修正弹的气动力计算提供了参考。     

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。     

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.     

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.     

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.     

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.     

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.     

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.