程序控制燃烧发射药的概念和原理

从提高发射药燃烧渐增性和提高发射装药总能量角度,提出了一种新概念发射药及装药--程序控制燃烧发射药及装药.通过总结和归纳大量密闭爆发器和内弹道试验结果,得到了3个经验公式.根据经验公式可推断出高初速发射装药应同时具备高能量和高燃烧渐增特性,验证了程序控制燃烧发射药概念原理上的正确性.     

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。     

基于密闭爆发器试验的发射装药内弹道性能预估

为了预估发射装药的内弹道性能,建立了一种基于密闭爆发器试验检测发射药的静态燃烧性能参数进而预测其装药内弹道性能的方法,采用不同批次的单樟-5/7发射药进行了装药性能预估计算,并基于30 mm火炮对内弹道性能预估精度进行了试验验证。结果表明,采用所建立的基于密闭爆发器试验的发射装药内弹道性能预估方法计算获得的最大膛压为376.0 MPa,与试验测试的膛压平均值388.7 MPa的计算误差为3.27%;计算的炮口初速为1143.5 m/s,与试验测试的炮口初速平均值1156.3 m/s的计算误差为1.11%。所建立的基于密闭爆发器试验的发射装药内弹道性能预估方法具有较高的精度,可对发射药样品不同批次间的内弹道性能进行高效精确的预估,为长期贮存发射药使用寿命的判定及发射药产品的出厂校验提供了一种高效低成本的弹道性能评价方法。     

七孔发射药内外弧厚差异对其燃烧性能的影响

为了研究七孔发射药内外弧厚差异对其燃烧性能的影响,通过密闭爆发器静态燃烧试验及火炮发射药装药内弹道试验研究了内外弧厚一致性及弧厚偏差对高能低烧蚀叠氮硝胺七孔发射药燃烧性能的影响。结果表明,当发射药的内外弧厚差异较大时,密闭爆发器试验中发射药增面燃烧阶段结束点提前,增面燃烧阶段已燃百分数由85.46%降至70.76%,燃烧时间由23.40ms增至27.75ms;发射药燃烧时间随着温度变化的敏感性逐渐加大。装药发射试验中,当外弧厚大于内弧厚时,加大了装药的初速温度系数,初速温度系数由0.54m/(s·℃)增至0.78m/(s·℃),装药质量由9.4kg增至9.8kg,最大膛压由266.9MPa降至262.6MPa。     

端面不堵孔包覆对多孔发射药燃烧和弹道性能的影响

用密闭爆发器测量了相同装填密度下37孔硝基胍发射药不堵孔包覆前后的燃烧性能,并以100mm加农炮弹道诸元为参考,对包覆前后发射药的弹道性能进行了预估。结果表明,发射药药粒包覆后其密闭爆发器试验最大动态活度增加约23%。在0.7kg/dm3的装填密度下,采用不堵孔包覆药装药的示压效率比未包覆药粒装药提高了约4%。包覆药粒装药装填密度0.759kg/dm3时的膛压与原药装药装填密度为0.700kg/dm3时的膛压相同,但初速提高16m/s,并与未包覆药粒装药具有相同的燃烧结束点。     

加固参数对加固发射装药燃烧的影响——第一阶段

已广泛开展加固和装药设计参数对高装填密度加固装药燃烧性能影响的研究。本文论及密闭爆发器技术,其目的在于尽可能用定量的方法获得加固装药主要变量对燃烧性能的影响。为了确定粘结剂组成和加固对燃烧性能的影响,用三种形式的IMR4895发射药在密闭爆发器内进行试验:(1)松散,不包复的发射药;(2)松散的,用胶/丙酮或用胶/苯二甲酸二丁酯(DBP)型的粘结剂包复的发射药;(3)用每一种粘结剂成分加固的发射药。本文对三种不同发射药的压力对时间和dp/dt对P/P_(max)曲线进行比较。由此可计算出有效燃速与压力的关系和画出相应的曲线。此外,从实验及结构数据中可算出有效燃烧表面积。也可以计算出三种形式发射药的相对速度(RQ)和相对力(RF)。粘结剂的组成极大地影响加固装药的燃烧性能。本文详细讨论了加固对加固装药燃烧性能的影响,也提出了将来的工作计划。     

加固参数对加固发射装药燃烧的影响——第一阶段

已广泛开展加固和装药设计参数对高装填密度加固装药燃烧性能影响的研究。本文论及密闭爆发器技术,其目的在于尽可能用定量的方法获得加固装药主要变量对燃烧性能的影响。为了确定粘结剂组成和加固对燃烧性能的影响,用三种形式的IMR4895发射药在密闭爆发器内进行试验:(1)松散,不包复的发射药;(2)松散的,用胶/丙酮或用胶/苯二甲酸二丁酯(DBP)型的粘结剂包复的发射药;(3)用每一种粘结剂成分加固的发射药。本文对三种不同发射药的压力对时间和dp/dt对P/P_(max)曲线进行比较。由此可计算出有效燃速与压力的关系和画出相应的曲线。此外,从实验及结构数据中可算出有效燃烧表面积。也可以计算出三种形式发射药的相对速度(RQ)和相对力(RF)。粘结剂的组成极大地影响加固装药的燃烧性能。本文详细讨论了加固对加固装药燃烧性能的影响,也提出了将来的工作计划。     

发射药床初始堆积形态对破碎程度的影响

用发射装药动态挤压破碎试验和发射装药破碎程度表征试验,研究了在相同冲击载荷下,发射药床初始堆积形态对药床破碎程度的影响。结果表明,在装药质量相同的情况下,发射药床随机堆积形态对破碎程度的影响很小,试验的重复性较好;但当发射药床的堆积为竖排和横排时,发射药床的破碎程度有较大的差异,且横排的发射药床破碎程度明显大于竖排。     

炮射导弹发射药燃烧表象规律

首先对炮射导弹的发射特点进行了分析,认为炮射导弹发射药的特殊性在于燃烧压力介于固体推进剂和常规固体发射药之间;针对炮射导弹发射过程中小于100MPa的压力范围,采用密闭爆发器在相应的压力条件下对其燃烧特性进行测试与评价,并与常规枪炮发射药的测试结果进行比较,认为两者之间具有不同的特征表现,对新型炮射导弹发射药的装药设计具有指导意义。     

一种低易损固体发射药的等离子体点火及燃烧特性

采用密闭爆发器实验对低易损性(LOVA)发射药等离子体点火和燃烧性能进行了实验研究,通过分析P-t曲线和dP／dt-P／P-曲线的变化规律,探讨了等离子体对该种火药作用机理,以便进一步研究它用于电热化学炮发射试验中的装药结构和增强燃烧的机理。     

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。     

新型高能叠氮硝胺发射药高压燃烧稳定性研究

为了研究高能发射药膛内燃烧规律,通过半溶剂法制备了一种火药力高达1240J/g的新型高能叠氮硝胺发射药(ADR),采用高压密闭爆发器和30mm高压模拟试验装置,分别研究了不同温度下ADR发射药定容高压燃烧性能和装填密度、温度以及石墨光泽处理对ADR发射药膛内高压燃烧稳定性的影响。结果表明,不同温度条件下(-40、20和50℃)ADR发射药静态及动态燃烧性能稳定性良好,燃烧过程无异常;随着温度的增加,ADR发射药点火性能提高,增加了膛内燃烧稳定性;装填密度0.48~0.64g/cm³范围内,随着装填密度的增加,ADR发射药膛内压力波强度逐渐增加,但增长幅度减小;对发射药进行石墨光泽处理,增加了ADR发射药起始缓燃效果,使不同温度下膛内压力波强度明显降低;与RGD7发射药相比,ADR发射药火药力较高,爆温较低,发射装药膛内高压燃烧稳定性相当,在高膛压环境中应用前景较好。     

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.     

A Study of Solid Propellant Containing Titanium Hydride

The burning rate characteristics of the propellant containing TiH₂ have been examined in order to understand the effect of TiH₂ addition on the combustion wave structure. The burning rate increases and the pressure exponent of burning rate decreases as the addition of TiH₂ increases. Using very fine thermocouples which were embedded within the propellant samples, the heat transfer process in the combustion wave was determined. The results indicate that the heat flux feedback from the gas phase to the burning surface increases when TiH₂ is mixed within the propellants.     

Mathematical Simulation of Airbag Inflation by Low Temperature Gas Generator Products

A mathematical model is described analyzing the processes during the combustion of a solid propellant gas generator for airbags. Results on parameter variations are presented. For porous and granulate charges the dynamic parameters of the gas flow and the progress of the ignition of the propellant are determined.     

Spectral Acquisition and Calibration Techniques for the Measurement of Radiative Flux Incident upon Propellant

A technique for the absolute calibration of a time‐resolved spectrographic system has been developed at QinetiQ, specifically designed to be relevant to spectral acquisition from within the interior of translucent gun‐propellant samples. The technique has shown itself to be particularly useful in the realm of propellant ignition as it allows for the precise determination of the moment that propellant combustion processes begin, as well as measuring the incident radiative flux leading up to ignition. Scope exists to extend its use for high‐pressure measurements of the incident radiative flux during both conventional propellant burn and high‐powered electrothermal‐chemical (ETC) discharges. This paper sets out to describe both the technique and some of the pitfalls encountered during the development of the technique. The use of this technique in some of the experimental work performed at QinetiQ, including the results of measurements that compare the incident radiative flux with propellant ignition during both ETC discharges and conventional gunpowder burn, have been published separately; references for this experimental work are given in this paper.     

Study on Unsteady Combustion Behaviors of AP/HTPB Base‐Bleed Propellants under Transient Depressurization Conditions

As the base‐bleed projectile flies out of the muzzle, the environmental pressure in the base‐bleed combustion chamber suddenly decreases and AP/HTPB base‐bleed propellant suffers intense unsteady combustion. To further study the unsteady combustion characteristics of base‐bleed propellants, a semi‐closed bomb as was designed experimental device and transient depressurization conditions of the muzzle were simulated. Measurements of the transient combustion characteristics of the base‐bleed propellant under high depressurization rate were carried out by using a high speed digital camera system. In the experiments, the combustion chamber pressure of the semi‐closed bomb was controlled from 20 to 90 MPa and the depressurization rate was controlled from 400 to1.12×10⁴ MPa s⁻¹. The experimental results indicate that, the out‐of‐phase blowing effect is intense under rapid depressurization condition, leading to the reaction layer thickened. The thermal feedback to the solid surface decreases and thus the combustion reaction of gas phase is so difficult to maintain that it begins to extinguish. However, the thermal decomposition of the solid phase is still continuing and a yellow fog can be observed above the combustion chamber nozzle. Depending on the maximum pressure in the combustion chamber and depressurization rate, the transient combustion behavior of AP/HTPB base‐bleed propellant displays three patterns, i.e., automatic reignition, oscillating combustion (a critical type) and permanent extinguishment. Three unsteady combustion behaviors are preliminarily analyzed based on the thermal feedback. If the initial pressure in the combustion chamber before depressurization is larger or the depressurization rate is smaller, the base‐bleed propellant tends to automatically reignite earlier and the combustion process is more stable.     

Al2O3在发动机燃烧室中尺寸分布的实验研究

采用压力可控式 T形燃烧室及实时脉冲微粒取样系统 ,结合微粒粒度分析技术 ,分析了在无铝双基推进剂中原始添加剂 Al2 O3在燃烧过程中随燃烧室压强变化的粒度及粒度分布的变化情况 ,结果发现 :燃气微粒呈单峰分布 ,燃烧室压强升高 ,趋于使推进剂燃烧产物微粒之间发生凝聚 ,但是燃气微粒与 Al2 O3原始粒径基本相符 ,未发生明显的凝聚现象     

Investigation of the Burning Behavior of Cryogenic Solid Propellants

Cryogenic Solid Propellant (CSP)‐technology is a new approach to develop more powerful rocket motors. CSPs include the advantages of classical solid propellants to save weight as well as those of a high energy content and safety of modern liquid propellants. The charges consist of liquid and/or gaseous fuels and oxidizers, both frozen. Two main versions of CSP‐technology can be realised: 1. Mono‐CSPs show the burning behavior of solid propellants. Experiments with mono‐CSPs have been carried out under inert pressure conditions in a window bomb. Mono‐CSPs have a stable burning behavior with a constant regression rate which follows the Vieille's law under varying pressure conditions. 2. The advantage of high safety is obtained by assembling oxidizer and fuel in sandwich configurations. The grain geometry governs the burning behavior. Such systems can be externally controlled, e.g. by the heat from a gas generator or they can work self‐sustained. A Rod‐in‐Matrix burner shows self‐sustained combustion in an inert pressure atmosphere with overall burning rates in a similar range as solid rocket propellants which obey also a Vieille‐like pressure law. Disc stack burners have also been investigated, the combustion of which is strongly dependent on the disc thickness. For a short time Mach's nodes have been observed in the exhaust plume of a disc stack burner. Currently, the temperature ranges are limited to the boiling temperature of liquid nitrogen. Therefore, liquid oxidizers like H₂O₂ have been used. However, for the first time a propellant strand of polymer rods embedded in solid oxygen was prepared and burnt. The experiments with CSPs end in the combustion of a small rocket motor showing no serious technical obstacles. Simplified models based on the heat flow equation can simulate the burning characteristics of the frozen energetic materials including phase transitions.