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。     

黑火药和单基发射药的电热丝点火实验研究

用实验方法研究了黑火药和单基发射药在电热丝作用下的点火问题 ,测出了实验条件下两种药剂的临界点火电流及点火延滞期 ,并推算出了点火的电热丝温度。     

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。     

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。     

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。     

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。     

液体发射药在模拟火炮使用条件下压缩点火特性研究

采用液体发射药绝热压缩感度测试装置，试验研究两种液体发射药ＨＹ９１１和鱼推－Ⅱ含气泡与不含气泡两种状态下的绝压缩点火特征，阐述了液体发射药在火炮上安全使用的可能性。     

发射药点火燃烧测温技术探索研究

采用六通道光学高温计,对两种发射药的点火燃烧温度进行试验,获得了这两种发射药在不同压力点的点火燃烧温度,并对所获得的测温结果进行了分析,为进一步开展发射药的点火燃烧温度研究打下基础。     

钝感发射药的热分解性能实验研究

运用热重法（TG）及差示扫描量热法（DSC）研究了不同钝感剂种类及浓度对钝感发射药的热分解性能的影响。以TG曲线和DSC曲线的临界热分解温度来定性地表征钝感发射药的点火难易程度,传统观点认为发射药经钝感处理后其点火温度应当升高;而实验结果表明对于本文所述钝感剂及其不同浓度处理的钝感药,其TG曲线和DSC曲线的临界热分解温度并未升高,而是略有下降,DSC曲线的吸热量有显著的降低,并对这一实验结果给出了简要的分析。     

Laser-induced ignition of solid propellants for gas generators

An experimental study was conducted to evaluate the ignitibility of a family of potential gas-generator solid propellants under different CO₂ laser heat fluxes and chamber operating conditions. Six types of solid propellant were tested: one baseline and five variations. The ingredients of the baseline propellant were ammonium nitrate, guanidine nitrate, potassium nitrate, and polyvinyl alcohol. The other five propellant variations were obtained by adding different amounts of carbon black, ammonium perchlorate, RDX, and triamino guanidine nitrate to the baseline formulation. The propellants were tested in a high-pressure windowed strand burner, which was pressurized with either air or argon purge gases. Propellant ignition was accomplished by a 50-W CO₂ laser. The ignition delay times of the propellants were measured at pressures of 1 and 69 atm using high-speed video cameras. In this paper, the test results and comparison of the ignition and combustion characteristics of these propellants were presented.     

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.     

固体含能工质等离子体单药粒点火特性分析

作为固体工质电热化学（SPETC）炮等离子体点火特性的基础性研究,本文利用等离子体切割机提供的等离子体源,对单基、多基火药的等离子体点火特性进行了实验研究,得出了不同类型火药在不同点火强度条件下的点火特性,为后续的等离子体内弹道环境点火特性研究提供了基础。     

Effects of NTO Oxidizer Temperature and Pressure on Hypergolic Ignition Delay and Life Time of UDMH Organic Gel Droplet

Organic gel propellants are promising candidates for a variety of rocket motor and scramjet applications, since they are intrinsically safe and provide high performance. It is well known that organic gel fuel droplets exhibit distinct combustion characteristics compared with conventional liquid fuel droplets, and furthermore an understanding of the ignition delay and lifetime of these droplets is critical to the improvement of combustor design. In this work, investigations of the combustion of unsymmetrical dimethylhydrazine (UDMH) organic gel droplets in different nitrogen tetroxide (NTO) oxidizing atmospheres were conducted using two sets of experimental apparatus. The combustion characteristics under different conditions of temperature and pressure were compared and analyzed based on the flame shapes observed during experimentation. From these trials, an unsteady combustion model was developed and used for the numerical simulation of spray‐sized UDMH organic gel droplet combustion in an NTO atmosphere. The hypergolic ignition and burning characteristics of the organic gel droplets under conditions simulating either engine startup or steady state combustion were compared, and changes in ignition delay and droplet lifetime with ambient temperature and pressure were analyzed. The experimental and numerical results show that the UDMH organic gel droplets exhibit periodic swell‐burst behavior following the formation of an elastic film at the droplet surface. Each droplet burst results in fuel vapor ejection and flame distortion, the intensity of which declines with increasing ambient pressure. However, the swell‐burst period is extended with increasing ambient pressure, which results in potential flameout. Under conditions of low temperature and pressure similar to those at engine startup, the ignition delay and lifetime of spray‐sized gel droplets decrease with increasing temperature or pressure, although there is a sharp increase in droplet lifetime when the ambient pressure reaches a critical value associated with flameout. The ignition delay was found to be a rate‐limited phenomenon linked to the droplet heating rate. The proportion of ignition delay and droplet lifetime due to droplet heating‐up decreased with increasing temperature or decreasing pressure. Conversely, at high temperatures and pressures simulating the engine’s steady state operating conditions, the droplets were observed to flameout after several swell‐burst periods and both ignition delay and lifetime decreased monotonically with increasing temperature or pressure. The ignition delay time was determined to be rate‐limited by gas phase chemical reactions and contributed very little to the overall droplet lifetime compared with the engine startup condition.     

Study of Confined Pyrotechnic Compositions for Medium/Large Calibre Gun Igniter Applications

With the continued shift towards more insensitive munitions and the subsequent development of low vulnerability propellants, the study of novel gun igniters is playing a significant role in the design of future direct and in‐direct fire charge systems. Previously, concepts such as electrothermal plasma ignition have offered high performance ignition solutions. However, using current technology they lack practical, in‐service applicability and will be difficult to incorporate into near future combat systems at a low cost.     

Ignition behaviour of different rank coals in an entrained flow reactor

An experimental study to determine the temperature and mechanism of coal ignition was carried out by using an entrained flow reactor (EFR) at relatively high coal feed rates (0.5 g min⁻¹). Seven coals ranging in rank from subbituminous to semianthracite, were tested and the evolved gases (O₂, CO, CO₂, NO) were measured continuously. The ignition temperature was evaluated from the gas evolution profiles, and it was found to be inversely correlated to the reactivity of the coal, as reflected by the increasing values of the ignition temperature in the sequence: subbituminous, high volatile bituminous, low volatile bituminous and semianthracite coals. The mechanism of ignition varied from a heterogeneous mechanism for subbituminous, low volatile bituminous and semianthracite coals, to a homogeneous mechanism for high volatile bituminous coals. A thermogravimetric analyser (TGA) was also used to evaluate coal ignition behaviour. Both methods, TGA and EFR, were in agreement as regards the mechanism of coal ignition. From the SEM micrographs of the coal particles retrieved from the cyclone, it was possible to observe the external appearance of the particles before, during and after ignition. The micrographs confirmed the mechanism deduced from the gas profiles.     

Decomposition and Ignition of the High‐Nitrogen Compound Triaminoguanidinium Azotetrazolate (TAGzT)

The high‐nitrogen compound triaminoguanidinium azotetrazolate (TAGzT) belongs to a class of C, H and N compounds that are free of both oxygen and metal, but retain energetic material properties as a result of their high heat of formation. Its decomposition thus lacks secondary oxidation reactions of carbon and hydrogen. The fact that TAGzT is over 80% nitrogen makes it potentially useful as a gas generant and energetic material with a low flame temperature to increase the impulse in gun or rocket propellants. The burning rate, laser ignition and flash pyrolysis (T‐jump/FTIR spectroscopy) characteristics were determined. It was found that TAGzT exhibits one of the fastest low‐pressure burning rates yet measured for an organic compound. Both the decomposition and ignition behavior of TAGzT are dominated by condensed phase reactions. T‐Jump/FTIR spectroscopy indicates that condensed phase reactions release about 65% of the energy, which helps to explain the high burning rate at low pressure.     

An experimental study of biomass ignition

An experimental study has been conducted to determine the ignition temperature of biomass at 21% O₂, both under pulse ignition conditions and under thermogravimetric conditions. In the pulse ignition experiments, samples of about 2 g wheat straw were placed in an isothermal reactor. The ignition temperature was determined from the transient CO and CO₂ profiles to approximately 255 °C at a superficial gas velocity of 14 cm/s (STP). The ignition temperature increased for decreasing superficial gas velocity.Thermogravimetric experiments at 20% O₂ and heating rates of 5 °C/min with finely milled biomass indicated ignition temperatures of approximately 220 °C for wheat straw, 235 °C for poplar wood, and 285 °C for eucalyptus wood. These values are significantly lower than values obtained for coal under similar conditions and confirm the relationship between volatile matter content and ignition temperature previously reported for coal.A mechanistic model for ignition of biomass is proposed. We believe that the ignition process is initiated by oxidation reactions on the straw surface. These reactions raise the surface temperature above that of the surrounding gas and promote ignition of the volatiles. Once ignited, the volatiles may form a homogeneous diffusion flame away from the particle surface. The superficial gas velocity affects the particle heating rate as well as the transport of oxygen to the surface. For this reason the ignition process is not entirely controlled by kinetics at low temperatures.