Combustion Mechanism of Azide Polymer

The combustion wave structure and thermal decomposition process of azide polymer were studied to determine the parameters which control the burning rate. The azide polymer studied was glycidyl azide polymer (GAP) which contains energetic – N₃ groups. GAP was cured with hexamethylene diisocyanate (HMDI) and crosslinked with trimethylolpropane (TMP) to formulate GAP propellant. From the experiments, it was found that the burning rate of GAP propellant is significantly high even though the adiabatic flame temperature of GAP propellant is lower than that of conventional solid propellants. The energy released at the burning surface of GAP propellant is caused by the scission of N N₂ bond which produces gaseous N₂. The heat flux transferred back from the gas phase to the burning surface is very small compared with the heat generated at the burning surface. The activation energy of the decomposition of the burning surface of GAP propellant, E_s, is determined to be 87 kJ/mol. The burning rate is represented by r = 9.16 × 10³ exp(–E_s/RT_s) where r (m/s) is burning rate, T_s (K) is the burning surface temperature, and R is the universal gas constant. The observed high temperature sensitivity of burning rate is correlated to the relationship of (∂T_s/∂T₀)_p = 0.481 at 5 MPa, where T₀ is the initial propellant temperature.     

无烟交联改性双基推进剂的高、低压燃烧特性

分析了无烟交联改性双基推进剂样品的火焰结构、燃烧波温度分布和熄火表面成分,初步研究了无烟交联改性双基推进剂在高、低压力下的燃烧特性。结果表明,压力升高,无烟交联改性双基推进剂的燃烧模式由双基推进剂的燃烧模式转变为与复合推进剂类似的燃烧模式。     

多层发射药的燃烧特性

利用已建立的圆环状多层发射药燃烧模型得到多层发射药的理论燃烧猛度Γ-Ψ曲线,并通过密闭爆发器实验测试了不同结构的多层发射药的静态燃烧性能,讨论了结构对多层发射药燃烧渐增性的影响。结果表明,火药燃去量处于0.2~0.8时,实验L-B曲线与理论Γ-Ψ曲线之间有着相同的变化趋势;过大(或过小)的内外层燃速比K和缓燃层厚度比X均对多层发射药的燃烧渐增性不利,只有在合理的范围里选择,多层发射药的燃烧渐增性才会呈现增强的趋势;随着药片宽厚比W的增大,多层发射药表现出恒面燃烧的特征,燃烧渐增性变佳。     

高能硝胺发射药的膛内基本燃烧特征

针对高能硝胺发射药在静态下燃速压力指数大的特殊燃烧性能，通过３０ｍｍ高压模拟炮试验，采用与制式单基药相对比的研究分析方法，对高能硝胺发射药在火炮膛内条件下的基本燃烧特征进行了研究分析。     

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。     

DAGR125发射药的燃烧特征

采用密闭爆发器静态试验和30mm高压模拟炮的动态试验,以制式单基药作为对比发射药,研究了DAGR 125发射药的静态燃烧特性及膛内燃烧特征。结果表明,DAGR 125发射药具有低压下起始缓燃的燃烧特性,随压力的升高呈渐增性燃烧特征;在高膛压装药条件下DAGR 125发射药燃烧正常、稳定,膛内p-t曲线光滑,起始负压差小。     

新型高能高强度JMZ发射药的燃烧特性

为探索混合硝酸酯增塑的聚醚聚氨酯黏合剂体系的新型发射药的燃烧性能,通过密闭爆发器常规实验和高压实验．研究分析了JMZ发射药在不同压力范围的燃烧特性。结果表明,JMZ发射药在低压下的燃速压力指数较大,具有高含量RDX硝胺发射药的共同特征,但在高压下的燃速压力指数逐渐变小,与制式发射药相当,在燃速压力指数的变化过程中不存在明显的转折现象。另外,JMZ发射药在起始阶段表现出了良好的燃烧渐增性,对身管武器的应用是十分有利的。     

叠氮硝酸酯对硝胺改性双基推进剂燃烧性能的影响

研究了一种叠氮硝酸酯PDADN对硝胺改性双基推进剂燃烧性能的影响。结果表明添加叠氨酸酯是一种提高硝胺改性双基推进剂燃速与能量的切实可行途径。     

ETPE发射药等离子体点火的燃烧特性

为解决ETPE发射药点火延迟时间长及难点火的问题,用高功率脉冲电源通过等离子体发生器产生电弧等离子体点燃ETPE发射药,并研究了ETPE发射药在等离子体作用条件下的点火燃烧特性.结果表明,与常规点火方式相比,等离子体作用使ETPE发射药的燃速显著增强,点火延迟期缩短,点火的一致性改变.分析认为,等离子体高温高速射流的强作用使得RDX颗粒快速越过吸热熔融过程达到分解放热阶段,所以ETPE发射药点火延迟期缩短以及燃烧初期燃速提高.     

超高燃速推进剂的限燃包覆层

研究了超高燃速推进剂的侧面限燃包覆。通过包覆层厚度、中止燃烧、间接证明实验,证实了采用硬质PVC黏合剂为内层,添加石棉粉的醋酸纤维素为外层的包覆层,可以使超高燃速推进剂侧面不发生窜火,达到稳定对流燃烧,燃速可达1000mm／s以上。     

无铝低燃速NEPE推进剂的燃烧性能

采用水下声发射法测定了无铝低燃速NEPE推进剂的燃速,研究了增塑剂种类、高氯酸铵(AP)与奥克托今(HMX)含量、AP粒度级配以及降速剂对无铝NEPE推进剂燃烧性能的影响。结果表明,通过选择合适的增塑剂、调整AP/HMX的相对含量、AP粒度级配以及采用有效的降速剂可使推进剂基础配方在3.5MPa下静态燃速达到4.0~5.5mm/s,2~5MPa下静态压强指数可降至0.30以下;NEPE推进剂燃烧时,NO2的生成速度越慢或NO2的含量越低,则推进剂的燃速越小,反之则越高。     

EI发射药的燃烧特性

为研究EI发射药的燃烧性能,基于EI发射药的制备过程及药形结构特征,对EI发射药的浸渍层分布、燃烧过程中药型尺寸及能量特性的变化进行了理论分析和实验验证.建立了EI发射药的燃速计算数学模型.制备了NG浸渍量分别为10％和15％的EI-1和EI-2样品.进行了密闭爆发器试验、显微切片照相.结果表明,NG浸渍量为15％时,火药力提高了10.14％,浸渍深度为0.168 mm;根据实验数据计算EI发射药的u-p曲线,150 MPa前EI发射药的燃速高于单基发射药,在150 MPa后两者重合;由L-B曲线知EI-2发射药的燃烧渐增性较好.只要NG浸渍量和聚酯浸渍量配比合适,EI发射药的火药力和燃烧渐增性在一定范围内可以同步增加.     

ETPE发射药的热分解特性与燃烧机理

通过DSC、PDSC分析了点火延迟时间长及难点火ETPE发射药燃烧过程中的热分解特性。用中止燃烧实验装置、SEM电镜观察研究了ETPE发射药燃烧表面的形貌变化及燃烧规律。结果表明,ETPE发射药热分解过程主要由其配方中含能添加剂RDX的热分解过程决定,RDX组分与含能黏结剂BAMO/AMMO聚合物体系之间的燃烧不同步性是造成ETPE发射药点火燃烧性能不佳的主要原因。根据ETPE发射药燃烧过程的特点,归纳出该类发射药的燃烧机理。     

高效含能燃烧催化剂对双基推进剂燃烧性能的影响

研究了含能有机铅、铜盐即3-硝基-1,2,4-三唑-5酮(NTO)和4-硝基咪唑铅、铜盐及其复配体系对双基推进剂燃烧性能和燃烧残渣率的影响.结果表明,NTO和4-硝基咪唑铅、铜盐及其复配体系均可明显提高双基推进剂的燃速,降低推进剂的压强指数;NTO和4-硝基咪唑铅、铜盐与炭黑形成的铅/铜/炭燃烧催化剂复配体系使双基推进...     

铜盐对RDX-CMDB推进剂燃烧性能的影响

研究了6种铜盐(DBC、CNI、NT-Cu、B-Cu、S-Cu、A-Cu)以及铜盐/炭黑复配体系对RDX-CMDB推进剂燃烧性能的影响,用扫描电镜和元素分析测试了推进剂的熄火表面.结果表明,铜盐可降低RDX-CMDB推进剂在16～22 MPa的压强指数;在10～22 MPa,铜盐和铜/炭黑混合物对RDX-CMDB推进剂燃烧特性的影响不显著.铜盐催化剂以及铜盐和炭黑复配催化剂对推进剂的燃烧反应有一定的促进作用.     

片状变燃速发射药燃烧性能的数值计算

为研究包覆方式对片状发射药燃烧性能的影响,建立了不同包覆方式下多层片状发射药的物理模型,并推导了形状函数和燃气生成猛度表达式,利用Matlab软件对不同的宽厚比、长厚比及多层结构的片状发射药进行了数值计算;制备了不同长厚比的片状变燃速发射药,并进行了密闭爆发器实验。结果表明,四面包覆和全包覆可以很好地消除临界宽厚比对片状发射药燃烧性能的影响;与两面包覆的片状发射药相比,四面包覆和全包覆的片状发射药能够延缓内层药减面燃烧的时间,其燃气生成猛度的阶跃程度分别提高了1.17%和1.23%,呈现出良好的燃烧渐增性。     

Mechanical Properties of Plateau Burn Azide Composite Propellants

The effects of cure ratio, crosslinking density, ammonium perchlorate (AP) particle size, and other additives on the mechanical properties of azide polymer composite propellants were characterized. The equivalence ratio of 1.0 and IPDI/TPA=7/3 were effective on low temperature mechanical properties. Relatively high amount of plasticizer was required in BAMO/NMMO binder and preferred the equivalence ratio of 1.0 to retain itself in the three-dimensional binder matrix. Excellent elasticity was obtained at a temperature range between −20°C and 2°C and normal strain rate dependency was obtained at from 54°C to −20°C. Glass transition occurred at −30°C to −35°C in Sample 17. The increase in contact area between AP particle and binder and in bonding strength played an important role on the prevention of the propagation of crack around a boundary and, therefore, ϵ_m was increased with decrease of particle size. Almost exactly the same σ_m, however, was observed in whole temperature range with increment of 5% to 10% in ϵ_m.     

Synthesis and Characterization of Glycidyl Azide Polymer with Enhanced Azide Content

ABSTRACT

The present study reports the preparation of glycidyl azide polymer with enhanced azide content. This process involves the cationic ring-opening polymerization of epichlorohydrin (ECH) using borontrifluoride etherate (BF₃-etherate) and 2,2-bis(bromomethyl)1,3-propane diol (BMPD) as initiator and co-initiators, respectively, followed by subsequent azidation of the product. For both the products, poly(epichlorohydrin)s (PECHs) and glycidyl azide polymers (GAPs) the substituted 1,3-propane diol units were characterized by spectroscopic as well as thermal analysis. Vapor pressure osmometer studies indicated that as the diol concentration increased in the polymerization the formed PECH molecular weight decreased. The spectral analysis indicates the presence of corresponding diol units in their polymeric chains. The differential scanning calorimetry and elemental analysis of the GAPs developed in this investigation indicated the presence of higher azide content in the polymer.     

含团聚硼富燃料推进剂的能量特性及燃烧性能

用最小自由能计算程序计算了含硼富燃料推进剂的能量性能,探讨了不同压力时硼粉的质量分数对富燃料推进剂能量性能的影响,采用靶线法和化学滴定法研究了富燃料推进剂的燃烧特性和燃烧残渣中硼粉的燃烧效率。结果表明,随着硼粉含量的增加,推进剂的能量增大;大粒径的团聚硼对富燃料推进剂的燃速和压强指数影响较大,随着团聚硼含量的增加,推进剂的燃速提高;含硼富燃料推进剂中的硼粉燃烧后单质硼和硼化物的摩尔比发生了明显的变化,无定形硼粉经团聚后燃烧效率明显提高。