七孔变燃速发射药内弹道性能的数值计算

基于经典内弹道理论建立了七孔变燃速发射药的内弹道模型。在Ф30mm火炮装填条件下,用C语言编写的计算程序,对标准七孔发射药以及不同内外层火药力和不同内外层燃速比的七孔变燃速发射药的内弹道性能进行了数值计算。结果表明,七孔变燃速发射药比标准七孔发射药具有更好的燃烧渐增性,在膛压变化较小的情况下,弹丸初速有较大提高,约5%左右。调节七孔变燃速发射药内外层火药力可以有效控制膛压和提高弹丸初速。随着内外层燃速比的增大,膛内最大压力和弹丸初速逐渐降低,燃烧分裂点和结束点向后推移,七孔变燃速发射药的内外层燃速比一般取2左右为宜。     

片状多层发射药的内弹道性能

制备了片状多层发射药,内层选用燃速较高的高能发射药,外层为含有高分子阻燃材料的低燃速配方发射药.对不同阻燃剂含量和不同厚度比的片状多层发射药进行了密闭爆发器实验和30 mm模拟弹道炮试验.结果表明,外层阻燃剂含量不同的MD1和MD2多层发射药均有较好的燃烧渐增性,外层阻燃剂含量较高的MD2多层发射药的燃烧渐增性要优于MD1多层发射药;在保证最大膛压基本不变的情况下,外内层厚度比为1∶10的MD1发射药的初速较5/7单基药的初速提高77.4 m/s,外内层厚度比为1∶5的MD2初速较5/7单基药的初速提高108.7 m/s.因此得出,通过调节多层发射药外层阻燃剂含量和外内层的厚度比,可以实现增加装药量、提高炮口初速而保持最大膛压不变.     

多层发射药内弹道模型及数值求解

基于经典内弹道理论建立了多层发射药的内弹道模型,用MATLAB编写了计算程序,以59式100mm高炮发射装药为基础进行了数值模拟.计算结果表明,在假定各层发射药为双芳-3、单基药、高能硝胺药、双迫药,发射药层数由1层依次增加到4层时,初速分别增加了3%、3.63%、3.69%;当燃烧层的燃速比为1:1.4:1.8:2.2,燃烧层的厚度比为5.5:1.5:1:2时,最大膛压为306.4 MPa,初速为932.4m/s,此时初速增加3.69%,且最大膛压未变,压力平台效果明显.从内弹道过程和工艺技术的可行性方面考虑,多层发射药采取3层即可达到较好的效果;对于多层发射药,当武器选定后,最优化的燃烧层厚度比和燃烧层燃速比存在唯一确定的关系,此时,在保持最大膛压不变的情况下,初速增加最多.     

基于密闭爆发器试验的发射装药内弹道性能预估

为了预估发射装药的内弹道性能,建立了一种基于密闭爆发器试验检测发射药的静态燃烧性能参数进而预测其装药内弹道性能的方法,采用不同批次的单樟-5/7发射药进行了装药性能预估计算,并基于30 mm火炮对内弹道性能预估精度进行了试验验证。结果表明,采用所建立的基于密闭爆发器试验的发射装药内弹道性能预估方法计算获得的最大膛压为376.0 MPa,与试验测试的膛压平均值388.7 MPa的计算误差为3.27%;计算的炮口初速为1143.5 m/s,与试验测试的炮口初速平均值1156.3 m/s的计算误差为1.11%。所建立的基于密闭爆发器试验的发射装药内弹道性能预估方法具有较高的精度,可对发射药样品不同批次间的内弹道性能进行高效精确的预估,为长期贮存发射药使用寿命的判定及发射药产品的出厂校验提供了一种高效低成本的弹道性能评价方法。     

多层高能硝胺发射药研究

设计并制备出了高能硝胺圆环多层发射药,通过恒压燃速和密闭爆发器试验测试了缓燃材料对高能硝胺发射药燃速的影响;通过中止燃烧试验考察了多层发射药的燃烧稳定性.结果表明,缓燃材料可有效降低发射药的燃速,并有显著增强其燃烧渐增性,且燃烧稳定.30mm内弹道试验表明,与粒状高能硝胺发射药相比,在不增加最大膛压的前提下,高能硝胺多层发射药能使炮口动能提高15%左右.     

颗粒密实模块药的弹道性能

采用含能材料对高能硝胺发射药药粒进行表面处理并模压,得到一种新型颗粒密实模块药。利用30mm高压模拟试验火炮,研究其弹道性能。结果表明,不同密度颗粒密实模块药弹道试验稳定性均较好,与散粒药相比相同膛压下初速提高4.1%。另外,该颗粒密实模块药还具有明显的低温度系数效果,低温(-40℃)初速降为-0.13%,高温(50℃)膛压升为0.37%,而散粒药低温(-40℃)初速降为0.26%,高温(50℃)膛压升为9.04%。因此,将散粒药制成颗粒密实模块药,在保持最大膛压不变的条件下可以实现增加装药量,降低温度系数,达到大幅度提高炮口初速的目的。     

变燃速发射药线膨胀系数关系的实验研究

为了解双层变燃速发射药的热膨胀性能规律,采用膨胀系数测定仪测定了一种类双基型中心开孔双层变燃速发射药的线膨胀系数,结果表明,外层药的线膨胀系数大于内层药的线膨胀系数.推导了变燃速药型的轴向线膨胀系数与内、外层药的线膨胀系数以及几何尺寸之间的理论关系式,并计算了变燃速发射药的线膨胀系数,与实测值的相对误差小于10%.     

含硝酸铵发射药内弹道过程数值模拟

通过分析不同硝酸铵含量的发射药的能量示性数,在φ30 mm火炮装填条件下,采用传统的经典内弹道模型,模拟计算出不同硝酸铵含量的七孔火药发射药的膛压、弹丸初速等弹道参数,研究硝酸铵含量对硝酸铵发射药内弹道参数的影响。结果表明,随着硝酸铵含量的增加,膛内压力和弹丸速度先增加后降低,硝酸铵含量存在一个最优点使二者达到最大值。     

端面不堵孔包覆对多孔发射药燃烧和弹道性能的影响

用密闭爆发器测量了相同装填密度下37孔硝基胍发射药不堵孔包覆前后的燃烧性能,并以100mm加农炮弹道诸元为参考,对包覆前后发射药的弹道性能进行了预估。结果表明,发射药药粒包覆后其密闭爆发器试验最大动态活度增加约23%。在0.7kg/dm3的装填密度下,采用不堵孔包覆药装药的示压效率比未包覆药粒装药提高了约4%。包覆药粒装药装填密度0.759kg/dm3时的膛压与原药装药装填密度为0.700kg/dm3时的膛压相同,但初速提高16m/s,并与未包覆药粒装药具有相同的燃烧结束点。     

DAGQ发射药膛内静态和动态燃烧性能

为了研究DAGQ发射药在膛内的燃烧性能,以经典内弹道理论为基础,建立了发射药膛内燃烧测试系统和处理方法,通过密闭爆发器燃烧试验和微波干涉法发射药膛内动态燃烧性能试验,研究了DAGQ发射药的静动态燃烧规律及不同温度下的动态燃烧特性。结果表明,所建立的试验系统和处理方法,能够很好地获得弹丸在膛内的运动过程。DAGQ发射药的静动态燃速都存在转折现象,静态燃速在转折点前压力指数大于1,转折点后压力指数都远小于1,动态燃速压力指数基本都小于1。在膛内燃烧过程中,由于高速气流对发射药的燃面冲刷,使得膛内的动态燃速要大于密闭爆发器内的静态燃速,并且随着膛内压力的增大,燃速相差越来越大。     

Interior Ballistics Two‐Phase Reactive Flow Model Applied to Small Caliber Projectile‐Gun System

Multi‐dimensional multi‐component two‐phase flow modeling of solid propellant combustion in weapons is the new trend of the interior ballistics codes. Most of these codes are designated to large caliber guns and rockets simulation. Only a small number of investigations on small‐caliber gun have been recently reported, where the need of high‐performance and reliable small‐caliber guns stimulated significant interest in developing techniques to understand the phenomenology of small‐caliber ballistics and predict the behavior and the performance of this type of weapons. In this paper, a numerical model describing the combustion of solid propellant in small‐caliber gun is presented. The governing equations with customize parameters were derived in the form of coupled, non‐linear axisymmetric partial differential equations. They were further implemented into the CFD code Fluent. A numerical test showed that Fluent is able to handle correctly the interaction between the moving projectile and the combustion gases in the chamber. The interior ballistics curves along with the performance of small‐caliber gun 5.56 mm were adequately predicted. The numerical results were in agreement with the experimental results.     

发射药中钝感剂含量与分布的测定

利用气相色谱法对某新型发射药中钝感剂含量与分布进行了测定。借助一些假设和萃取时间及所萃取樟脑含量数据,建立了钝感剂在发射药中的含量分布模型。分析了结果误差,计算了含樟脑发射药的内弹道性能。讨论了钝感剂含量及其分布对内弹道性能主要指标pm,v0的影响。结果表明,所提出的基本假设是合理的,钝感剂含量及分布显著影响内弹道性能。     

Numerical Prediction of Interior Ballistics Performance of Projectile Accelerator Using Granular or Tubular Solid Propellant

Two‐dimensional axisymmetric interior ballistics simulations in projectile acceleration systems that use granular or long slotted tubular solid propellants are performed using the solid/gas two‐phase fluid dynamics code of the Euler‐Lagrange approach. For validation, the simulation results are compared with experimental data for tubular solid propellants. In the series of the interior ballistics simulations, the propellant grain size and shape effects on the firing performance of 50 mm gun are numerically investigated. The propellant grain size and shape affect the energy release rate of the solid propellant charged in the chamber, the projectile kinetic energy at the muzzle, and even the fluctuations of the chamber pressure history. An appropriate burning surface area of the propellant grain exists, so that the projectile can achieve the maximum kinetic energy from the released energy of the solid propellant. Based on the simulation results, guidelines are proposed for the grain size design that enables the propellant energy to be used efficiently.     

变燃速发射药的低温感性能

根据银纹厚度随温度的变化,改变火药燃烧面和建立一个补偿系统,使变燃速发射药具有低温度系数。通过扫描电镜观察变燃速发射药的微观结构,观察到外层的银纹和银纹厚度随温度的变化情况;通过密闭爆发器实验,对发射药高、低、常温的燃烧性能进行了对比;在30mm火炮上进行内弹道试验,观察其温度系数的变化。结果表明。银纹厚度随温度的变化改变火药的燃烧面积,从而改变了变燃速发射药的气体生成速率;变燃速发射药高、低、常温燃烧性能变化不大;变燃速发射药具有较低的温度系数。     

枪用发射药燃烧残渣的测试方法

研究了发射药的燃烧残渣特性及残渣对内、外弹道的影响。提出将枪药燃烧残渣分为附着性残渣、漂浮性残渣和沉降性残渣,有害燃烧残渣主要是漂浮性残渣和附着性残渣。为探索充氮氧弹法用于测试附着性燃烧残渣方法的可行性,进行了8种发射药样品的烟室法、充氮氧弹法和TG残渣测试。结果表明,充氮氧弹法测试可区分不同枪用发射药燃烧附着性残渣的大小,漂浮性残渣用烟室法测定;不同发射药的残渣生成量差异很大,附着性残渣较大时,其漂浮性残渣也较大。     

混合装药内弹道性能优化及应用

为了研究混合装药结构对内弹道性能的影响,以某舰炮为工程背景,提出内弹道多目标优化设计方案,研究了目标函数、设计变量及约束条件.采用e-约束法对次要目标函数进行简化处理,利用当前流行的进化算法—遗传算法进行优化计算,并针对内弹道数学模型特性,对算法进行改进.最后,通过进化计算得到的优化方案为一组非劣解集,同时验证了该改进...     

Pressure Profile Prediction of Dual‐Thrust Rocket Motors under Uncertainties

Mathematical models that simulate the internal ballistics of solid propellant rocket motors are widely used in lieu of the expensive, hazardous, time‐consuming static firing experiments. Since they rely on the input of various measured data, these models are vulnerable to uncertainties that may deteriorate their prediction accuracy. Improving the accuracy of internal ballistics prediction can be achieved by coupling the mathematical models with optimization algorithm. This paper discusses the issues of uncertainties and their impact on prediction accuracy of developed mathematical models. The model handles two types of dual thrust rocket motors, where the impact of uncertainties is more pronounced since they include more geometric and ballistic parameters. The model is developed based on the fundamental principles of internal ballistics and is coupled with a commercial genetic algorithm optimization tool. Two static firing tests are conducted to assess the proposed optimized prediction model. It is found that prediction optimization via tuning the uncertain parameters has led to significantly improving the prediction accuracy. More importantly, the tuned uncertain parameters give better understanding and clearer insight of the phenomena taking place inside dual thrust solid propellant rocket motors.     

Flamespreading during Base Ignition of Propellant Charge: Theoretical and experimental studies

In the paper theoretical modeling of flamespreading through granular propellant charge during base ignition is given. The theoretical model includes the balance equations for the gas and solid phase, as well as necessary constitutive laws. The stable convergent numerical procedure for solution of the system of equations is developed. This procedure is included in computational program FSPC (Flame-spreading through Propellant Charge). The program FSPC enables investigations of influence of ignition material, physical and chemical characteristics of propellant and propellant charge loading density on the flamespreading process. The experimental investigations by an especially designed apparatus are performed. The verification of the theoretical-numerical access through the comparison with the experimental data (pressure vs. time and locations, flamespreading velocity, propellant grains displacements) is carried out. The entire access makes possible more successful solutions of many interior ballistics problems.     

Comparative Analysis of Methods for Measuring the Transient Burning Rate. I. Research Methods

This paper considers two independent methods for measuring the transient burning rate of solid propellants-high-speed photography and a method based on solving the inverse problem of interior ballistics. Comparative analysis shows that these methods are mutually complementary. Evaluation of the ranges of application of the inverse methods of identifying the transient burning rate shows that their use is promising not only in laboratory tests but also in measurements in large solid propellant gas generators.     

Comparative Analysis of Methods for Measuring the Transient Burning Rate. II. Research Results

This paper considers two independent methods for measuring the transient burning rate of solid propellants-high-speed photography and a method based on solving the inverse problem of interior ballistics. Comparative analysis shows that these methods are mutually complementary. Evaluation of the ranges of application of the inverse methods of identifying the transient burning rate shows that their use is promising not only in laboratory tests but also in measurements in large solid propellant gas generators.