泡孔结构对泡沫发射药燃烧性能的影响

通过配方调节与工艺控制得到3种不同结构的泡沫发射药,讨论了泡孔结构形成的影响因素;采用密闭爆发器实验和恒压燃速测试实验研究了不同结构泡沫发射药的燃烧性能。结果表明,控制气体生成速率、添加RDX颗粒、调节NC含氮量和发泡时间能够有效控制泡沫发射药的泡孔结构;皮芯结构泡沫发射药具有渐增燃烧特性,发泡区的动态活度可达不发泡皮层的2.4倍以上;独立泡孔结构的泡沫发射药在100MPa下燃速可达未发泡样品的30倍;非独立孔隙结构的泡沫发射药不同方向上的燃速差异显著,密度为1.37g/cm~3的样品100MPa下轴向燃速最高可达3.860m/s。     

变燃速发射药的燃烧性能

介绍了变燃速发射药的原理和实现方法。内层采用高燃速发射药．外层为低燃速发射药．从而达到变燃速的目的;分析了双层结构变燃速发射药的密闭爆发器燃烧性能及30mm火炮内弹道试验结果。与高分子包覆单基发射药相比,双层结构变燃速发射药具有较好的燃烧渐增特性和明显的低温度系数效果。     

用密闭爆发器测定发射药实际燃速的原理和方法

提出一种采用密闭爆发器测定发射药实际燃速的原理和方法,通过设计标准结构药型发射药、并对形状函数进行修正,可消除燃面变化对燃烧性能测试的影响;运用数学变换方法对测试数据进行处理,可消除压力变化对燃烧性能测试的影响.通过实验对该方法进行了验证,结果表明,用该方法可获得发射药的实际燃速.     

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%.     

LOVA发射药点火燃烧性能

制备了含有两种不同黏结剂的低易损性发射药(即LOVA发射药),并应用点火燃烧模拟装置与密闭爆发器对其点火燃烧性能进行了研究。结果表明,LOVA发射药难点火,但在点火药中添加高氯酸铵后可有效改善LOVA发射药的点火性能。LOVA发射药燃烧具有燃速系数低、燃速压力指数高等特点。     

变燃速发射药的研究进展

综述了变燃速发射药的种类、性能及应用研究现状,指出发射药钝感包覆技术中表面钝感剂与包覆层的分布及迁移控制问题是该技术的关键。管状变燃速发射药由于制备工艺易于实现、能量性能较优而被广泛使用。分析了国内在变燃速发射药的种类、制备工艺及应用等方面存在的差距,并提出了建议。     

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。     

溶剂含量对变燃速发射药的流变性影响研究

用MLW-90防爆流变仪测试不同溶剂含量下变燃速发射药内、外层的流变性能.得出结论,随着溶剂含量的增加,其表观黏度降低,流动性增强;乙基硝化纤维素(EC)、黑索今(RDX)的加入降低了变燃速发射药的表观黏度.     

超多孔圆片(MPD)发射药定容燃烧特性的数值计算（英文）

为模拟并优化超多孔圆片发射药的燃烧性能,建立了一种超多孔圆片发射药的定容燃烧模型。在几何燃烧定律条件下,计算了超多孔圆片发射药的燃烧压力曲线和动态活度曲线与超多孔圆片的关系;分析了超多孔圆片厚度、内孔孔径、燃速系数及燃烧压强指数对其燃烧性能的影响。结果表明,超多孔圆片发射药的药型结构与配方共同影响其燃烧性能;超多孔发射药圆片厚度的增加及内孔孔径的降低可提高超多孔圆片发射药最大动态活度以及燃烧时间;但超多孔圆片发射药药型尺寸对其燃烧性能的影响较弱;相对而言,发射药配方燃速系数及压强指数对其燃烧影响较大,燃速系数及压力指数较大的超多孔圆片发射药的燃烧特性更优。     

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。     

适应高压强的HTPB推进剂的燃烧性能

为改善高压强下HTPB推进剂的燃烧特性,研究了碳酸盐复合调节剂、二茂铁衍生物G、高氮化合物M、纳米铝粉和纳米金属氧化物对HTPB推进剂燃烧性能的影响.结果表明,碳酸盐复合调节剂能够降低推进剂的燃速和压强指数;二茂铁衍生物G能够提高推进剂的燃速,同时将推进剂在8.60～17.12MPa下的压强指数降至0.27;高氮化合物也可降低推进剂的燃速和压强指数;将高氮化合物M与二茂铁衍生物G配合使用可将推进剂在8.63～16.48MPa下的压强指数降至0.24; 纳米铝粉和包覆的纳米金属氧化物可明显降低推进剂的燃速压强指数.     

Development of Polyurethane‐Based Solid Propellants Using Nanocomposite Materials

Mechanically‐activated nanocomposites (MANCs) of nano‐aluminum (nAl)/X (X=Cu, Ni, Zn, Mg, and graphite) were used as replacements for reference nAl powder and as catalytic ingredients in polyurethane (PU) propellants. The effects of their use on combustion heat, burning rate, and thermal decomposition were investigated. It was found that MANCs have catalytic effects and the modified propellants have enhanced the released heat, burning rate, and thermal decomposition properties. MANCs‐based propellants have improved the processing and the mechanical properties with acceptable safety aspects. They can be used for catalytic applications in solid propellants to improve their energetic, burning rate, and thermal decomposition characteristics.     

Thermal Decomposition of RDX Composite Propellants

The thermal decomposition characteristics of RDX, binders, and RDX composite propellants were studied using thermal analytical techniques. Three kinds of binders were tested to elucidate the role of binder on the burning rate of the propellants. There were no apparent correlations between the thermal decomposition rates of binders and the burning rates of propellants, whereas there was a correlation between the decomposition temperature and the burning rate of the propellants. It is found that the major factor which controls the burning rate is the initial thermal-decomposition stage of the binders. Thus, the burning rate of nitramine composite propellants appeared to be largely dependent on the physical and chemical properties of binder.     

On-demand microwave growth of porosity within a granular composite energetic material: Void formation via a dielectric loss phase change binder additive for propellant burning rate control

This study demonstrates, for the first time ever, the ability to grow, in an on-command fashion, porosity within a granular composite energetic material to effect a change in energy output rate. Specifically, the study investigates the change in burning rates of ammonium perchlorate composite propellants as a result of porosity created in situ via microwave field-driven volatilization of the low boiling point binder additive, ethylene glycol. Theoretical mass densities were measured before and after microwave irradiation finding that the maximum observed %TMD change for tested propellants is 6 %. Propellants were burned at 1.72 MPa to 6.89 MPa pressures, finding that for all propellants, microwave irradiation produced a change in ballistic characteristics. Most propellant formulations demonstrate acceptable burning rate parameters for use within rocket motors; some exhibited a large change in their pressure exponent as well as slope breaks attributed to the onset of convective burning, while microwave irradiation produced no change in burning rate or density in reference propellants without the additive. Microwave heating simulation results are presented to gain insight into the thermal environment of the propellant during microwave irradiation. These results provide valuable insight into propellant formulations that can have their burning rates (and thus the thrust profile for motor grains) altered after casting via microwave irradiation.     

Burning Characteristics of Consolidated Gun Propellants

To improve the combustion behaviors of conventional consolidated propellants, consolidated propellants were prepared using porous propellant grains as fast‐burning filler. The porous propellant grains were prepared by supercritical fluid foaming process and exhibited the high burning rate. The multi‐perforated structure of the consolidated propellants was designed and adopted to obtain high burning progressivity. To investigate the burning characteristics of the consolidated propellants, closed vessel and quenched combustion experiments were carried out. The results show that deconsolidation of the consolidated propellants does not occur, and that the consolidated propellants exhibit high burning rates and high burning progressivities. Besides, the results show that the consolidated propellants burn steadily even at low (−40 °C) and high temperatures (50 °C).     

Burning Characteristics of Ammonium Nitrate‐based Composite Propellants Supplemented with Ammonium Dichromate

Ammonium nitrate (AN)‐based composite propellants have attracted much attention, primarily because of the clean burning nature of AN as an oxidizer. However, such propellants have some disadvantages such as poor ignition and low burning rate. Ammonium dichromate (ADC) is used as a burning catalyst for AN‐based propellants; however, the effect of ADC on the burning characteristics has yet to be sufficiently delineated. The burning characteristics of AN/ADC propellants prepared with various contents of AN and ADC have been investigated in this study. The theoretical performance of an AN‐based propellant is improved by the addition of ADC. The increase in the burning rate is enhanced and the pressure deflagration limit (PDL) becomes lower with increasing amount of ADC added. The increasing ratio of the burning rate with respect to the amount of ADC is independent of the AN content and the combustion pressure. The optimal amount of ADC for improving the burning characteristics has been determined.     

Burning Rate Augmentation of BAMO Based Propellants

Thermal decomposition and the burning properties of BAMO based propellants with HMX or AN/HMX have been investigated. The heat generated by the azide binder decomposition initiated and accelerated the thermal decomposition of HMX and AN. Ammonium perchlorate (AP) and lead stearate with carbon black significantly altered the mechanisms of the thermal decomposition and the burning properties of the HMX based propellants. AP showed an increase in burning rate with a slight decrease in burning rate pressure exponent. The lead catalyst yielded high value of the burning rate with the lowest pressure exponent. The ammonium dichromate also influenced the mechanisms of the thermal decomposition and the burning properties of the AN/HMX samples. The combination of ammonium dichromate and copper chromite was the most effective on the burning rate augmentation of AN/HMX based propellants. AN sublimed and evaporated from the condensed phase and mainly reacted exothermically in the gas phase HMX and AN/HMX based propellants showed smokeless burning characteristics in the small rocket motor combustion tests.     

含黑索今酮的火药热分解及燃烧性能研究

用ＤＳＣ技术考察了７种含黑索今酮（Ｋｅｔｏ－ＲＤＸ）火药的热分解特性,并对其中３种进行了密闭爆发器测试。将ＤＳＣ数据对动力学方程进行拟合以求得动力学参数。从密闭爆发器测试结果转换得到了该３种火药的燃速－压力曲线,并对其进行了转折性分析。结果表明,向火药中加入Ｋｅｔｏ－ＲＤＸ可提高火药燃速并降低其热分解表观活化能。含Ｋｅｔｏ－ＲＤＸ的火药其燃速压力指数在低压区较在高压区为高。在火药中同时存在有Ｋｅｔｏ－ＲＤＸ和ＲＤＸ对火药热分解和燃烧的稳定性是不利的。仅由Ｋｅｔｏ－ＲＤＸ与双基粘结剂组成的火药,其燃速压力指数较由ＲＤＸ与双基粘结剂组成的火药为低。     

碳硼烷类燃速催化剂的研究进展

综述了国内外碳硼烷类燃速催化剂的研究情况,介绍了各种碳硼烷类催化剂的性能特点,指出碳硼烷类燃速催化剂是适用于高燃速和超高燃速推进剂配方的燃速催化剂,具有显著提高推进剂燃速的作用,对压强指数的影响依据配方组成的不同而有区别.     

Measurement and Analysis of the Burning Rate of HAN‐Based Liquid Propellants

A new device for measuring the linear burning rate of liquid propellants at high pressures is reported. High‐pressure environments were generated by the combustion of solid propellants. The coated propellants, which burn progressively, were introduced to maintain the approximate constant‐pressure environments. By use of ion probe transducers, measurements were made of the spread velocity of the flame surface, i.e. the apparent linear burning rate of the HAN‐based liquid propellant LP1846 (HAN =hydroxylammonium nitrate) was measured quantitatively at pressures from 6 to 28 MPa. The results show that it follows the exponential burning rate law. The burning rate coefficient and exponent were fitted by least‐squares methods. Based on the experiment, a simplified model of the linear burning rate of HAN‐based liquid propellants at high pressures was developed. The numerical simulation is found to be in good agreement with the experimental data.