侵蚀燃烧在发射装药内弹道中的应用研究

侵蚀燃烧是具有内孔燃烧火药的一种普遍现象，应用侵蚀燃烧可改变火药燃烧的规律。由于火炮发射装药装填密度的变化，不同装填密度发射药所受的内孔与外部压力也不同，这种压力差使发射药内孔在火炮膛内燃烧时发生侵蚀燃烧。利用发射药内孔燃气流动的流速、传热和冲刷对燃速的影响，研究了火炮发射装药的侵蚀燃烧对发射药燃速的影响，建立了发射装药侵蚀燃烧数学模型，分析了发射药装填密度、内孔的孔径、药粒长度等变化所引起的侵蚀燃烧变化及对发射装药内弹道性能的影响。提出了在变装药中，利用侵蚀燃烧提高小装药量、小射程用发射装药膛压的方法。     

发射药药型结构对燃速测试结果的影响

为了研究药型结构对发射药燃速测试结果的影响,以高能硝胺发射药为研究对象,采用密闭爆发器燃烧实验和数据处理的分析方法,研究了4种药型及其不同内孔长径比发射药的燃速特性及其变化规律;采用中止燃烧实验研究了发射药内孔长径比对侵蚀燃烧的影响,并与太根发射药对比研究了燃速特性对侵蚀燃烧的影响关系。结果表明,多孔药的燃速压力指数明显小于单孔药,在内孔长径比相同的条件下,随着发射药内孔数量的增加,正比式燃速系数减小,燃速压力指数减小;在药型相同的条件下,随着内孔长径比增大,发射药侵蚀燃烧现象加剧,正比式燃速系数增大,燃速压力指数减小;燃速较高的发射药,侵蚀燃烧现象对燃速参数测试结果的影响更大。     

炮膛内底排装置燃烧特性计算分析

为了研究内弹道过程中底排装置的燃烧特性,基于两组不同底排药剂试样装填密度下的密闭爆发器燃烧试验数据,优化计算得到了高压工况下某底排药剂燃速模型为de/dt=8.51×10-8p0.579.建立了底排装置膛内燃烧模型与火炮-底部排气弹内弹道零维模型.针对某155 mm底排装置,在理想发射环境下,计算分析表明:膛内底排装置...     

考虑管状药束轴向运动的大口径平衡炮二维内弹道模型的建立与仿真

传统的两相流内弹道模型将火药颗粒作拟流体假设,对于采用长管状药装药的大口径高速平衡炮来说误差较大。为解决这一问题,针对管状药模块化装填的某480 mm口径高速平衡炮提出在欧拉坐标系中考察火药气体的流动情况,在拉格朗日坐标系中追踪管状药束的运动规律;同时针对药束径向运动方程难以建立的问题,提出药束沿径向线性排布药束的思想,建立了考察管状药束沿轴向的运动规律并能够描述火药气体沿轴向和径向的流动情况的内弹道模型,编制程序进行了数值模拟。通过计算结果与试验结果的对比分析,证明了建立的模型有效,得到了火药气体在轴向和径向的压力分布以及药束模块的运动轨迹,为平衡炮内弹道性能的深入研究提供了新的思路。     

某压裂火药燃烧速度特征与温度关系的密闭爆发器实验研究

为模拟某压裂火药在油井作业中燃气的压力变化规律,需要确定火药的燃烧速度与其温度的关系。利用密闭爆发器实验系统,获得不同温度条件下火药燃气的压力随时间的变化曲线。基于内弹道火药燃烧特征量静态分析方法,计算出不同温度下火药的燃烧速度定律,并进一步计算燃速系数与温度的关系。通过拟合得出火药的燃速随温度增长的指数式变化函数,通过误差分析判定该函数适用于30 ℃～150 ℃的温度变化区间,为不同温度下的井下模拟计算提供了理论支持。     

一种新型大弧厚六翼星孔棒状发射药的燃烧特性

设计并制备了一种新型大弧厚六翼星孔棒状发射药,利用密闭爆发器研究了不同长径比(L/D=1,2,6)、不同端面封堵层厚度/发射药弧厚比(s/e_1=0,0.05,0.1)的星孔棒状发射药燃烧特性,并结合某大口径火炮进行了试验验证。结果表明,星孔棒状发射药燃烧稳定,呈平行层燃烧。长径比L/D由1增加至6时,燃烧渐增性因子Pr由0.285增加至0.447,增加了56.8%,而且最大压力点滞后。端面封堵发射药的L-B曲线显示了明显的降低起始燃烧活性和燃烧破孔特征。s/e_1由0增加至0.05、0.1时,星孔棒状发射药的起始气体生成量降低了约1/2,破孔时间介于燃烧10%~20%(已燃份数)发射药所需燃烧时间之间。选择合适封堵层厚度,可实现发射药燃气生成规律的可控调节。s/e_1由0增加至0.05、0.1时,最大膛压pm分别下降1.3%和3.5%,而离炮口32.5m处的弹丸初速分别提高0.28%和1.4%。     

密闭爆发器实验技术的进展

密闭爆发器实验是一个重要的内弹道实验。直到现在,人们仍然沿用这个经典的实验测定发射药的火药力、余容、最大压力等一系列内弹道特征量,以及根据记录的压力—时间曲线,研究密闭爆发器中的点火燃烧过程,确定发射药的燃烧特性。近卄年来,密闭爆发器实验在国外取得了一系列重大进展,其中主要是一直采用记录的dp/dt—p曲线(或由记录的p—t曲线经转换而成dp/dt—p曲线)计算四个压力的dp/dt的     

存在侵蚀燃烧的发射药高、低温内弹道性能研究

为研究存在侵蚀燃烧的发射药高、低温内弹道性能,分析了发射药初温变化引起的火药热焓变化及对侵蚀燃烧的影响,修正了常温发射药的侵蚀函数,得到了高、低温多孔药燃速的数学表达式,建立了多孔发射药高、低温内弹道数学模型。应用该模型对某大口径舰炮高、低温内弹道进行仿真,计算结果和试验值一致性较好。通过对比仿真研究可得结论:考虑火药热焓变化对侵蚀燃烧影响的多孔发射药高、低温内弹道仿真结果更接近试验值。     

影响低温度系数装药弹道性能的装填参数

从理论上分析了影响低温度系数装药弹道性能的装填参数，并具体讨论了主装药和包覆火药的混合比，燃面比及燃面温度系数等对该装药弹道温度系数的影响。研究表明，在一定范围内，包覆火药与主装药的混合比增加，主装药和包覆火药的燃面比减小或燃面温度系数的绝对值增大，有利于降低该装药的弹道温度系数。     

低温感包覆火药装药的内弹道势平衡理论模拟

为了进一步研究低温感包覆火药装药的内弹道特征及其内弹道数值计算方法,运用内弹道势平衡理论,对制式装药和低温感包覆火药装药的势平衡点参数进行了比较。分析了低温感包覆火药装药势平衡点处燃去火药相对量ψE随装填密度变化的原因,并拟合了低温感包覆火药装药的实际燃气生成函数。在此基础上利用势平衡方程对内弹道过程进行了数值模拟。结果表明,计算曲线与实验曲线基本一致,应用内弹道势平衡理论描述低温感包覆火药装药的膛内燃烧规律可行。     

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.     

Expert Systems Aimed at General Design of Projectiles

Expert systems aimed at the general design of projectiles can implement a series of intelligent designs, such as the design of HE shell, the scheme expounded and proved, the emulation analysis and calculation, etc. Aiming at the product design feature, the expert system adopts the object-oriented knowledge representation and all kinds of inference control engines to describe and reason the relevant knowledge regarding the product through the microcomputer. It embodies the foundation of emulation analysis and simulated manufacturing of the shell. It makes use of the method that knowledge expression is combined with condition of inference to carry out the overall design and emulation and reference.The paper gives the ways through which the functions can be achieved, gives the modularization of reference and the design methods of systematization, puts forward the method of knowledge expression and working interface, and supplies a platform for similar products of the shell category that can be quickly designed.     

Parameter Identification for the Valve Control Cylinder System of a Hydraulic Manipulator

In mechanical, hydraulic and electronic systems, the determination of system parameters is often challenging because liquid parameters often change significantly, due to variations in working and environmental conditions. Therefore, it is of significant practical importance to identify those parameters through experimental procedures. A systematic approach to identifying parameters in the valve controlling cylinder system of hydraulic manipulators is provided. It first derives the transfer function of the system, and then uses P control of PID control to predict system parameters. The predicted parameters are further validated using PID control. The prediction through simulation using MatLab language is utilized, which agrees well with experimental results.     

Three-dimensional Numerical Simulation of Combustion Field in the Combustion Chamber

In order to study the effect of rotation on the combustion in the underwater vehicle, a two-phase turbulent combustion process is described with Reynolds stress turbulence model, eddy-dissipation turbulent combustion model, P-1 radiation model and particle tracking model of liquid. The flow in the rotating combustion chamber is simulated at two different working speeds, 0 r/min and 1 000 r/min by Fluent software. The temperature, gas velocity, static pressure of wall and fuel concentration are computed and compared. The results show that the combustion in rotating combustor is faster and more effective.     

Software Communication Architecture Implementation and Its Waveform Application

This paper attempts to do a research on the development of software defined radio（SDR） based on software communication architecture（SCA）. Firstly, SCA is studied and a whole reference model of SCA3.0 core framework （CF） is realized; Secondly, an application-specific FM3TR waveform is implemented on the platform of common software based on the reference model; Thirdly, from the point of view of real-time performance and software reuse, tests and validations are made on the above realized CF reference model and FM3TR waveform. As a result, the SCA-compliant SDR has favorable interoperability and software portability and can satisfy the real-time performance requirements which are not too rigorous.     

Dynamic Simulation of the Tank Gun Recoil Response

By using the ATV module of MSC. ADAMS, the dynamic simulation of recoil response of tank gun is analyzed.How the recoil force affects the bodywork and the suspension during gun firing, as well as the changing status of the gun muzzle‘s velocity are gained. All results and analyzing methods are offered for the designing basis of optimizing tank vehicle-gun match. The constructive exploration is beneficial to improving the general capability of tank.     

Survey of Controllable Suspension System for Off-road Vehicles

The controllable suspension system can improve the performances of off-road vehicles both on road and cross-country. So far, four controllable suspensions, that is, body height control, active, semi-active and slow-active suspensions, have been developed. For off-road vehicles, the slow-active suspension and the semi-active suspension which have controllable stiffness, damping and body height are more appropriate to use. For many years, some control methodologies for controllable suspension systems have been developed along with the development of modern control theory, and two or more original control methods are integrated as a new control method. Today, for military or civilian off-road vehicles, the R&D of controllable suspension systems is ongoing.     

Passive Acoustic Radar for Detecting Supersonic Cruise Missile

A Passive Acoustic Radar is presented as a necessary complement to electromagnetic wave radar, which will be expected to be an effective means for detecting cruise missiles. Acoustic characteristics of supersonic flying projectiles with diverse shapes are expounded via experiment. It is pointed out that simulation experiment could be implemented using bullet or shell instead of cruise missile. Based on theoretical analysis and experiment, the ““acoustic fingerprint““ character of cruise missile is illustrated to identify it in a strong noise environment. After establishing a locating mathematical model, the technique of acoustic embattling is utilized to resolve a problem of confirming the time of early-warning, considering the fact that velocity of sound is much slower than that of light. Thereby, a whole system of passive acoustic radar for detecting supersonic cruise missile is formed.     

Super-resolution Restoration of Remote-sensing Images

A novel image restoration scheme, which is super-resolution image restoration algorithm Poisson-maximum-afterword-probability based on Markvo constraint （MPMAP） combined with evaluating image detail parameter D, has been proposed. The advantage of super-resolution algorithm MPMAP incorporated with parameter D lies in the fact that superresolution algorithm MPMAP model is discrete, which is in accordance with remote-sensing imaging model, and the algorithm MPMAP is proved applicable to linear and non-linear imaging models with a unique solution when noise is not severe. According to simulation experiments for practical images, super-resolution algorithm MPMAP can retain image details better than most of traditional restoration methods; at the same time, the proposed parameter D can help to identify real point spread function （PSF） value of degradation process. Processing result of practical remote-sensing images by MPMAP combined with parameter D are given, it illustrates that MPMAP restoration scheme combined PSF estimation has a better restoration result than that of Photoshop processing, based on the same original images. It is proved that the proposed scheme is helpful to offset the lack of resolution of the original remote-sensing images and has its extensive application foreground.     

Design and Simulation of TF and TA Controller for Missile

A nonlinear terrain following(TF) and terrain avoidance(TA) controller is proposed for missile control systems. Based on classical TF algorithm (adaptive angle method), a new method for TF controller is proposed by using angle of attack. A method of obtaining terrain outline data from digital elevation map (DEM) for TF control is discussed in order to save store space. A TA algorithm is proposed by using bank-to-turn technique. The block control model, which is suitable for backstepping design, is given for nonlinear model of missile. Making full use of the characteristics of the system and combining block control principle and backstepping technique, a robust controller design method is proposed. Uncertainties in every sub-block are allowed, and can be canceled by using the idea of nonlinear damping. It is proved that the state tracking errors are converged to a neighborhood of the origin exponentially. Finally, nonlinear six-degree-of-freedom simulation results for the missile model are presented to demonstrate the effectiveness of the proposed control law.