SF-3发射药的等离子体点火中止燃烧试验

采用有剪切膜片控压的密闭爆发器分别在等离子体点火和常规点火条件下进行该发射药的燃烧性能和中止燃烧两种比较试验.用扫描电镜观测了SF-3发射药的燃面变化情况.结果显示,在底喷式等离子体发生器作用下,SF-3发射药的燃烧表面存在大量微坑,使燃烧表面积大大增加,并导致SF-3发射药等离子体点火燃烧在一定程度上偏离几何燃烧规律.在常规点火条件下,SF-3发射药中止燃烧表面的Cu、C、O三种元素的归一化质量分数分别为0.7%、30.0%、69.3%,而在等离子体点火条件下则分别为3.0%、35.5%、61.5%,表明等离子体发生器所产生的高温C颗粒和Cu颗粒对SF-3发射药的燃烧有显著影响.     

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。     

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.     

等离子体点火发射药中止燃烧试验原理与装置设计

试验装置是由等离子体发生器、半密闭爆发器本体和一个专用螺栓以及其他附件组成。中止压力和燃烧室的容积可调,等离子体输出参量如输出能量、峰值电流、充电电压、脉冲宽度等可以根据试验要求在一定的范围内变动。该装置可以研究在等离子体点火条件下,发射药燃烧中止后的表面微观变化和燃烧反应机理,从而了解等离子体能量辐射与发射药吸收关系以及等离子体与发射药相互作用时的能量传递方式及其影响因素。     

空气电弧等离子体作用下发射药的燃烧特性

为了研究发射药等离子体点火作用机理,用扫描电子显微镜研究了不同强度电弧放电等离子体揭示的3种制式发射药及新型ETPE发射药在等离子体作用后的燃烧表面变化规律,得到等离子体点火后发生燃烧反应的质量.结果表明,电弧等离子体输入电能对发射药的点火有着重要影响,随着输入电能的增加,参加反应的发射药质量逐渐增加.ETPE发射药燃烧表面与常规制式发射药燃烧表面有较大差别.发射药对电弧等离子体的相对敏感程度不同,双基发射药最强,ETPE发射药最弱.     

带延迟点火部件的发射药点火性能试验研究

为了更好地研究发射药的点火性能,在基于密闭爆发器原理的点火性能测试装置基础上增加了一个延迟点火部件,构建了一个新型点火性能模拟试验装置,根据该装置建立了简单的火药分层点火过程模型,模拟并对比了高能太根-18/1、双芳-3-18/1及NR11-18/1三种发射药的点火性能。结果表明,NR11-18/1发射药较易点火,双芳-3-18/1发射药最难点火,点火时间分别为19和45ms。增加延迟点火部件后,可将点火药的燃烧和发射药的燃烧阶段有效区分,不仅有利于对比点火性能差异较小的发射药之间的区别,还有助于分析发射药低压段的燃烧速度。随着延迟点火部件长度的增加,点火时间也增长。     

双基发射药热碎片传导点火实验及影响因素

为研究发射药在高温碎片作用下的点火和燃烧行为,选热钢材圆柱体作模拟碎片,模拟高温碎片作用于发射药的点火和燃烧过程,建立了用于发射药热碎片传导点火的实验装置,确定了在热碎片作用下易损性的表征参数,研究了双基发射药在热碎片作用下的点火和燃烧行为。结果表明,碎片温度、碎片尺寸、药型尺寸及样品环境条件是影响同一配方发射药热碎片传导点火的主要因素。     

一种新型LOVA发射药点火性能的研究

采用点火模拟试验方法，对新型LOVA发射药的点火性能进行了研究，提出了一种预估发射药点火难易的方法。结果表明：在相同的试验条件下该LOVA发射药较单基药难点燃；在密闭爆发器实验中延迟时间短的发射药相应地在点火实验中较容易点燃。     

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。     

适用于硝胺发射药的点火药

采用NC,NH4ClO4,BP常用点火材料组成不同的点火剂配方，考察其对含RDX的硝胺火药的点火能力，以点燃性能较好的硝化棉，单基药（SL）作基准，通过点火模拟对比试验，获得了可提高硝胺发射药点火效能的新型点火药配方，点火剂E（含NC23．1％，38．5％，NH4ClO438.5%）在低温（－40℃）条件下点燃硝胺药的点火延迟时间（tig）与制式单基药tig相当。     

Response of TEGDN Propellants to Plasma Ignition with the Same Magnitude of Ignition Energy as Conventional Igniters in an Interrupted Burning Simulator

In order to consider the potential influence of ignition energy factors on the response of double base propellants plasticized with triethyleneglycol dinitrate (TEGDN propellants), the influence of different ignition methods at the same magnitude of ignition energy level on the response of TEGDN propellants was investigated in an interrupted burning simulator. Compared to conventional ignition methods, plasma ignition exhibits a significantly shorter ignition delay and lower ignition energy. There are stronger ablation and impact interactions of plasma flow with the surface of propellants. For TEGDN propellants coated with titanium dioxide, a greater amount of melted white layer is deposited on the surface of propellants. The content of copper on the surface of recovered plasma‐ignited samples observed by X‐ray Fluorescence (XRF) spectroscopy is much larger than that on the surface of recovered conventionally ignited samples, indicating more deposition of copper wire discharge on the surface of the samples. The test results will benefit the design of plasma generator and electrical parameters of pulse power to satisfy certain propellant compositions.     

铝镁贫氧推进剂的点火性能

为研究镁铝富燃料固体推进剂组分对点火性能的影响,采用改进的靶线法燃速测试系统对多种含镁铝富燃料固体推进剂在常压和加压下进行了通电金属丝点火性能的对比实验。被测试推进剂的镁铝合金含量为20%～40%,或者同时含镁铝合金及硼,氧化剂含量为30%～53%。实验表明,在固定外界输入热源的情况下,推进剂的点火性能主要与氧化剂含量和粒度有关;金属的含量和种类也有一定的影响;催化剂对点火延迟时间影响很小;压强对此种点火方式几乎无影响。该点火延迟测试方法简单易行,并具有一定的可靠度,适于配方调试。     

高分子钝感发射药的低温感机理

为研究聚二甲基丙烯酸已二醇酯(D1)钝感的单基发射装药的低温度系数机理,在不同温度条件下,采用动态机械分析仪、材料试验机等研究了D1和单基发射药的物化性能(线膨胀系数及力学性能),通过密闭爆发器、中止试验等,对钝感多气孔单基发射药的燃烧性能进行了分析.结果表明,D1和单基药的热膨胀系数有较大的差异,中止燃烧破孔率常温小于低温.高分子钝感发射药的低温感效果是两种作用的综合结果:(1)由于发射药和钝感剂在不同温度下膨胀系数的差异,导致低温下钝感剂和发射药之间界面产生空隙,从而增加了发射药的低温燃面;(2)对于多孔钝感发射药,其低温破孔机理也发挥了一定的降低温度系数的效果.     

一种随行装药定容燃烧性能研究

为了在静态环境下模拟某新型随行装药的内弹道燃烧性能,采用将小粒发射药进行钢筒中压制成型,端面封堵延时处理的方法得到了一种新型随行装药试样。并将制得的随行药与单樟6/7混合进行密闭爆发器实验,测试了其燃烧性能。实验结果表明:与单樟6/7单独装药相比,其燃烧过程分为2个阶段,且第二阶段燃烧速率远大于第一阶段,通过延迟装置质量和装药密度的调节可以实现对随行药点火延迟时间的控制。随行药具有很高的燃速和较强的燃烧渐增性,在内弹道过程中可有效改善膛内压力分布。     

The Effects of Porous Structure on the Burning Characteristics of Foamed NC‐Based Gun Propellants

The effects of porous structure on the burning characteristics of foamed NC‐based (nitrocellulose‐based) gun propellants were investigated by closed vessel and quenched combustion experiments. The foamed NC‐based TEGDN (triethylene glycol dinitrate) gun propellants with different porous structures were prepared by adjusting the process parameters in the foaming process. SEM (scanning electron microscopy) was used to observe the morphologies of foamed TEGDN propellants, and the densities of the foamed propellants were also measured to evaluate the porosities of foamed propellants. The experimental results showed that the burning characteristics of the novel foamed propellants are totally different from combustion characteristics of parallel‐layer. Further investigations revealed that the burning characteristics of the foamed NC‐based propellants largely depend on the porous structure, larger pores and higher porosity would lead to higher burning rate of the foamed TEGDN propellants.     

Experiment study of the altitude effects on spontaneous ignition characteristics of wood

This paper has studied the influence of ambient pressure and oxygen content on spontaneous ignition of wood by conducting contrastive experiments with wood slab exposed to high temperature radiation at two different altitudes. The measurement of mass loss, time to ignition, and surface temperature of wood are carried out. Results show that mass loss rate of wood at high altitudes (3650 m) is higher than the one at low altitudes (50 m), while ignition delay time of the sample at high altitude is shorter. The surface temperatures at the time of ignition in the two different places are both close to each other, which indicates that the pressure did not affects the ignition temperature. The theoretical analysis on the phenomenon of different ignition behavior of wood in these two altitude environments has been presented.     

Laser Ignition of Various Pyrotechnic Mixtures – an Experimental Study

Ignition of several pyrotechnic mixtures by diode‐laser was studied experimentally using a novel combustion chamber. The ignition delay times dependence on laser intensity could be fit by the expression t_ign=aI⁻ⁿ for all compositions, with I being the laser intensity at target and n=1.4–2.1. This is roughly in accordance with thermal ignition theories assuming a semi‐inert solid. Differences in ignition delay times did not depend on fuel alone or oxidizer alone. The temperature of oxidizer decomposition does not correlate with ignition delay time. Furthermore, the steady state combustion temperature, deduced from emission spectra of the composition products are not correlated with ignition delay time. It is proposed that chemical reactions, taking place in the gas‐phase or in the solid‐phase, play a significant role, but are not solely responsible for ignition delay time. The seemingly uncorrelated ignition delay results between pyrotechnics containing either the same fuel or oxidizer hamper the construction of a “unified theory” for laser ignition of pyrotechnic mixtures.