一种新型评价发射药点火性能的试验方法

为了科学评价发射药的点火性能,建立了一种以特征点火药量为评价指标的新型试验方法。在密闭装置中调整点火药量进行点火试验,得到最低点燃点火药量,作为评价发射药的点火性能。该方法可以区分不同发射药的点火性能,对比不同点火药的点火能力。     

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。     

硝基胍对硝胺发射药点火性能影响的实验研究

采用差示扫描量热仪（ Ｄ Ｓ Ｃ）和点火燃烧模拟装置,研究了硝基胍（ Ｎ Ｇｕ）对 Ｎ Ｃ Ｎ Ｇ Ｒ Ｄ Ｘ 系列发射药点火性能的影响。实验证明： Ｎ Ｇｕ 可以改善 Ｎ Ｃ Ｎ Ｇ Ｒ Ｄ Ｘ 类硝胺火药的点火性能,且当 Ｎ Ｇｕ 与 Ｒ Ｄ Ｘ 之比大于１ 时效果才更显著。     

发射药的等离子体点火燃烧中止试验研究

用等离子体点火中止燃烧装置,研究了等离子体点火太根药、双基药、硝胺药及单基药的燃烧中止现象,借助所得回收样品的显微照片和中止压力-时间曲线分析了等离子体与发射药的相互作用规律.结果表明,由于等离子体的侵蚀和辐射作用,发射药的燃烧表面不规则;不同配方发射药的点火延迟时间不同,太根发射药等离子体点火的延迟时间最短,容易实现等离子体点火.发射药的理化性质,包括配方和添加剂成分、表面状况、热传导系数和光学吸收系数等对等离子体点火有着显著影响.     

发射药初温和热物性参数对点火性能影响的研究

采用点火模拟试验装置，对几种发射药在常，低温情况下的点火性能进行试验，获得了这几种发射药在不同温度下的点火特征曲线及重要参数，得出了这几种发射药在不同温度下的点火性能差异，并结合火理论作数值计算，分析了发射药初温对点火性能影响的内在原因，为进一步研究低温下发射药膛内的点火特性及燃烧过程提供依据。     

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。     

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.     

边界条件对尾部点火性能的影响

通过模拟点火空间、改变点火药量及喷管堵片厚度的技术措施，解决了某发动机尾部点火装置研制过程中出现的点火延迟等技术问题，试验研究表明，对尾部点火设计而言，单靠增加点火药量并不是解决发动机点火延迟问题的有效途径。通过改变点火边界条件，使得点火药量与喷管堵片设计厚度协调、匹配，在解决发动机点火延迟等技术问题中起着重要作用。     

火炮同步点火管的燃烧实验和数值模拟

为增加火炮点火的同步性,对一种爆轰波传火的火炮同步点火管进行了燃烧实验,测量了点火管不同位置的压力-时间曲线.在考虑火药燃烧过程中同步点火特征、气体湍流和新增燃气质量流流入的基础上,建立了点火管内的燃烧计算模型,用CFD软件对点火管的燃烧过程进行了三维数值模拟计算,并将计算得到的压力-时间曲线与实验曲线进行对比分析.结果表明,点火管具有很高的点火同步性,模拟计算的压力-时间曲线与实验结果基本吻合.     

苦味酸钾对含RDX硝铵火药热行为与点火性能的影响

为改善含RDX硝胺火药存在的低压点火难、燃烧压力前沿上升慢的问题,采用差示扫描量热仪(DSC)和小型密闭爆发器装置,研究了苦味酸钾(KP)对含RDX硝铵火药热行为及其点火性能的影响.结果表明,KP分解放热补偿了RDX的熔融吸热,调整了含RDX硝铵火药体系的热行为,改善了硝铵火药的点火性能,且当体系中KP与RDX的质量比大于1时效果更显著;随着体系中KP含量的增加,火药的点火延迟时间明显下降.     

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。     

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。     

不同气氛对铝粉点火燃烧特性的影响分析

为了研究流化气体对粉末推进剂点火燃烧性能的提高作用,采用CO_2激光点火器和光纤光谱仪相结合的实验方法,研究了不同气氛条件下Al粉的点火燃烧特性。采用光谱信号拟合测温法计算了Al粉在不同气氛环境中的点火温度。结果表明,常压环境下,粒径1μm的Al粉在N_2O和空气氛围下的点火延迟时间分别为10ms和359ms,从点火成功过渡到全面燃烧的时间分别为829ms和1 579ms,说明Al粉在N2O环境中点火阶段的表面异相反应速率与燃烧阶段的反应速率均快于在空气中;粉径1μm的Al粉在N2O和空气环境下的点火温度分别为1 550~1 650K和1 450~1 500K,两者相近,但都明显低于毫米级Al粉的点火温度(2 300K),说明Al粉的点火温度受粒径影响较大。     

Experimental Investigation on Laser Ignition and Combustion Characteristics of NEPE Propellant

The ignition and combustion property of solid propellant is the main content in internal ballistic research, which has a great significance for propulsion application and combustion mechanism. In this study, the detailed gas‐phase reaction mechanism of Nitrate Ester Plasticized Polyether Propellant (NEPE) was developed. It is helpful to understand the intricate processes of solid‐propellant combustion. The factors which may have influences on ignition delay time and temperature distribution of propellant surface was analyzed by laser ignition experiment. Using high‐speed camera and an infrared thermometer, the ignition and combustion process and the surface temperature distribution of NEPE propellant under laser irradiation were measured. Laser heat flux, ambient pressure and initial temperature of NEPE propellant have an influence on the ignition delay time and the surface temperature. Results show that the ignition delay time decreases with the increase of laser heat flux, ambient pressure and initial temperature of NEPE propellant. At the same time, with the increase of laser heat flux, the influences of ambient pressure and initial temperature on the ignition delay time decrease. Besides, laser irradiation, ambient pressure and initial temperature have significant influences on the surface temperature distribution of the propellant.     

环境气体氧含量对NEPE推进剂激光点火过程的影响

为研究环境气体氧含量对硝酸酯增塑聚醚(NEPE)推进剂激光点火过程的影响,采用CO2激光辐射点火并利用高速摄影仪记录NEPE推进剂的点火过程,讨论了环境气体氧含量对NEPE推进剂初焰位置与点火延迟时间的影响。结果表明,当环境气体氧含量小于NEPE推进剂热解产物中氧化性气体含量时,NEPE推进剂点火的气相反应发生在推进剂热解产物的分散区,初焰紧靠NEPE推进剂表面,环境气体氧含量变化不影响NEPE推进剂的点火延迟时间;当环境气体氧含量大于NEPE推进剂热解产物中氧化性气体含量时,NEPE推进剂点火的气相反应发生在推进剂热解产物与环境气体的扩散区,初焰远离NEPE推进剂表面,此时由于扩散区氧含量高于NEPE推进剂热解产物分散区氧含量,NEPE推进剂的点火延迟时间减小。     

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.     

Plasma Ignition and Combustion

Electro‐thermal‐chemical (ETC) initiation and combustion offers the possibility to increase the performance of guns substantially as new propellant formulations and high loading densities (HLD) can be safely ignited and burnt in an augmented way. This paper reports investigations of burning phenomena in the low pressure region for JA2 and the effects of plasma interaction on ignition and study its influence on the burning rate. The comparison of transparent and opaque versions of the propellant is of special interest. Electrically produced plasma can strongly influence the ignition and combustion of solid propellants. Predominantly, plasma arcs influence strongly the burning of propellants by its radiation. The high intensity of the radiation initiates burning with short time delays in the µs‐range and high conversion during exposure also in the case of a stable burning. Radiation can penetrate into the propellant interior and partially fragment at absorbing structures which could be artificially introduced or be inherently present as in the case of a JA2 propellant. Simplified approaches based on the heat flow equation and radiation absorption can explain these effects at least on a qualitative scale. Dynamic effects are understood by more sophisticated models.     

Ignition of Propellant by Metallic Vapour Deposition for an ETC Gun System

The Defence Evaluation and Research Agency are exploring the potential of electrothermal‐chemical (ETC) gun technology. An important area is that of plasma ignition of solid propellant gun charges. An understanding of the energy transfer mechanisms from the metallic plasma to the propellant grain is central for optimisation of an ETC ignition system. This paper explores, both theoretically and experimentally, the energy transfer mechanisms involved in plasma–propellant interactions during plasma ignition of a conventional charge system, with a view to minimising the electrical energy requirements of an ETC gun system. A mechanism of energy transfer due to the condensation of metallic vapour onto the propellant grain is advanced and experimentation provides some evidence for this. In principle, it should be possible with vapour deposition to initiate self‐sustaining combustion using very small quantities of electrical energy, provided the power transfer is greater than that required to accomplish self‐sustained combustion processes. A ‘vapour generator’ may be required rather than a plasma generator for ETC ignition.