Deflagration to detonation transition in weakly confined conditions for a type of potentially novel green primary explosive:Al/Fe_(2)O_(3)/RDX hybrid nanocomposites

The properties of the combustion and deflagration to detonation transition(DDT)of Al/Fe_(2)O_(3)/RDX hybrid nanocomposites,a type of potentially novel lead-free primary explosives,were tested in weakly confined conditions,and the interaction of Al/Fe_(2)O_(3)nanothermite and RDX in the DDT process was studied in detail.Results show that the amount of the Al/Fe_(2)O_(3)nanothermite has a great effect on the DDT properties of Al/Fe_(2)O_(3)/RDX nanocomposites.The addition of Al/Fe_(2)O_(3)nanothermite to RDX apparently improves the firing properties of RDX.A small amount of Al/Fe_(2)O_(3)nanothermite greatly increases the initial combustion velocity of Al/Fe_(2)O_(3)/RDX nanocomposites,accelerating their DDT process.When the contents of Al/Fe_(2)O_(3)nanothermite are less than 20 wt%,the DDT mechanisms of Al/Fe_(2)O_(3)/RDX nanocomposites follow the distinct abrupt mode,and are consistent with that of RDX,though their DDT processes are different.The RDX added into the Al/Fe_(2)O_(3)nanothermite increases the latter's peak combustion velocity and makes it generate the DDT when the RDX content is at least 10 wt%.RDX plays a key role in the shock compressive combustion,the formation and the properties of the DDT in the flame propagation of nanocomposites.Compared with RDX,the fast DDT of Al/Fe_(2)O_(3)/RDX nanocomposites could be obtained by adjusting the chemical constituents of nanocomposites.

Application of Two-dimensional Viscous CE/SE Method in Calculation of Two-phase Detonation

The method of two-dimensional viscous space-time conservation element and solution element (CE/SE) can be used to calculate the gas-liquid two-phase interior flow field in pulse detonation engine (PDE). In this paper, the evolution of the detonation wave and the distribution of its physical parameters were analyzed. The numerical results show that the change of axial velocity of gas is the same as that of detonation pressure. The larger the liquid droplet radius is, the longer the time to get stable detonation wave is. The calculated results coincide with the experimented results better.

Effects of nano-sized aluminum on detonation characteristics and metal acceleration for RDX-based aluminized explosive

Nano-sized aluminum(Nano-Al)powders hold promise in enhancing the total energy of explosives and the metal acceleration ability at the same time.However,the near-detonation zone effects of reaction between Nano-Al with detonation products remain unclear.In this study,the overall reaction process of 170 nm Al with RDX explosive and its effect on detonation characteristics,detonation reaction zone,and the metal acceleration ability were comprehensively investigated through a variety of experiments such as the detonation velocity test,detonation pressure test,explosive/window interface velocity test and confined plate push test using high-resolution laser interferometry.Lithium fluoride(LiF),which has an inert behavior during the explosion,was used as a control to compare the contribution of the reaction of aluminum.A thermochemical approach that took into account the reactivity of aluminum and ensuing detonation products was adopted to calculate the additional energy release by afterburn.Combining the numerical simulations based on the calculated afterburn energy and experimental results,the parameters in the detonation equation of state describing the Nano-Al reaction characteristics were calibrated.This study found that when the 170 nm Al content is from 0%to 15%,every 5%increase of aluminum resulted in about a 1.3%decrease in detonation velocity.Manganin pressure gauge measurement showed no significant enhancement in detonation pressure.The detonation reaction time and reaction zone length of RDX/Al/wax/80/15/5 explosive is 64 ns and 0.47 mm,which is respectively 14%and 8%higher than that of RDX/wax/95/5 explosive(57 ns and 0.39 mm).Explosive/window interface velocity curves show that 170 nm Al mainly reacted with the RDX detonation products after the detonation front.For the recording time of about 10 ms throughout the plate push test duration,the maximum plate velocity and plate acceleration time accelerated by RDX/Al/wax/80/15/5 explosive is 12%and 2.9 ms higher than that of RDX/LiF/wax/80/15/5,respectively,indicating that the aluminum reaction energy significantly increased the metal acceleration time and ability of the explosive.Numerical simulations with JWLM explosive equation of state show that when the detonation products expanded to 2 times the initial volume,over 80%of the aluminum had reacted,implying very high reactivity.These results are significant in attaining a clear understanding of the reaction mechanism of Nano-Al in the development of aluminized explosives.

Study of detonation wave contours in EFP warhead

An analytical model for calculating the propagation time of shock wave in a wave shaper is presented in this study. The calculated results show that the contours of three typical detonation waves, such as conical detonation wave, spherical detonation wave, and planar detonation wave, can be formed in the main charge by changing the thickness of wave shaper.The results show that the planar detonation wave do better than the conical detonation and the spherical detonation wave in increasing the length–diameter ratio of explosively-formed projectiles(EFP) and keep the nose of EFP integrated. The detonation wave can increase the length–diameter ratio of EFP when the wave shaper has the suitable thickness.

Confinement Effect and Diameter Effect on the Non-ideal Detonation Parameters of Small Charge

An expanding model of the confinement of non-ideal detonation of small charge is established on the basis of the nozzle theory.Making use of the expanding model,the analytic relationship of small charge detonation velocity and the semi-empirical relationship of detonation pressure that both change with charge diameter and confinement condition are established.The detonation velocity and pressure of small charges are calculated and experimentally verified,and the detonation velocity deviation is less than 7% while the detonation pressure deviation is less than 9%.

Analysis on damage characteristics and detonation performance of solid rocket engine charge subjected to jet

To further explore the damage characteristics and impact response of the shaped charge to the solid rocket engine(SRE) in storage or transportation, protective armor was designed and the shelled charges model(SCM)/SRE with protective armor impacting by shaped charge tests were conducted. Air overpressures at 5 locations and axial acceleration caused by the explosion were measured, and the experimental results were compared with two air overpressure curves of propellant detonation obtained by related scholars. Afterwards, the finite element software AUTODYN was used to simulate the SCM impacted process and SRE detonation results. The penetration process and the formation cause of damage were analyzed. The detonation performance of TNT, reference propellant, and the propellant used in this experiment was compared. The axial acceleration caused by the explosion was also analyzed.By comprehensive comparison, the energy released by the detonation of this propellant is larger, and the HMX or Al particles contained in this propellant are more than the reference propellant, with a TNT equivalent of 1.168-1.196. Finally, advanced protection armor suggestions were proposed based on the theory of woven fabric rubber composite armor(WFRCA).

A quasi-isentropic model of a cylinder driven by aluminized explosives based on characteristic line analysis

A quasi-isentropic study on the process of driving a cylinder with aluminized explosives was carried out to examine the influence of the aluminum(Al) reaction rate on cylinder expansion and the physical parameters of the detonation products. Based on the proposed quasi-isentropic hypothesis and relevant isentropic theories, the characteristic lines of aluminized explosives driving a cylinder were analyzed,and a quasi-isentropic model was established. This model includes the variation of the cylinder wall velocity and the physical parameters of the detonation products with the Al reaction degree. Using previously reported experimental results, the quasi-isentropic model was verified to be applicative and accurate. This model was used to calculate the physical parameters for cylinder experiments with aluminized cyclotrimethylenetrinitramine explosives with 15.0 % and 30.0 % Al content. The results show that this quasi-isentropic model can be used not only to calculate the cylinder expansion rule or Al reaction degree, but also to calculate the physical parameters of the detonation products in the process of cylinder expansion. For explosives with 15.0 % and 30.0 % Al, 24.3 % and 18.5 % of the Al was found to have reacted at 33.9 μs and 34.0 μs, respectively. The difference in Al content results in different reaction intensity, occurrence time, and duration of two forms of reaction(diffusion and kinetic) between the Al powder and the detonation products;the post-detonation burning reaction between the Al powder and the detonation products prolongs the positive pressure action time, resulting in a continuous rise in temperature after detonation.

3种典型炸药水中爆炸初始冲击波的近场参数测试

为了探索水中爆炸初始冲击波近场的传播特性和衰减差异,扩展水箱法测爆压试验的研究范围,采用高速摄影狭缝扫描测试方法,对3种典型的柱状炸药(TNT、JH-14、JO-9159)水中爆炸过程进行了测试研究,测量获得了一维正平面水中初始冲击波传播的时间历程演化曲线;由此拟合计算出柱状炸药的水中初始冲击波传播速度随时间的变化曲线,进一步由水的冲击雨果尼奥方程和冲击波动量方程、界面上压力和质点速度连续的条件及声学近似理论,计算得到了水中爆炸初始冲击波阵面压力的衰减曲线和炸药试样的爆压、多方指数等爆轰参数。结果表明,水中爆炸初始冲击波阵面压力近似以指数形式衰减,初始阶段衰减极快;当炸药爆压为20~37 GPa时,水中冲击波初始速度处于5.66~6.81 km/s的范围,波阵面初始压力与炸药的爆压近似成线性关系;虽然JO-9159的爆速和爆压均高于JH-14和TNT,但其水中初始冲击波传播仅在7μs后,其冲击波速度与波阵面压力下降至最低,说明以HMX为基的理想炸药水中爆炸初始冲击波速度和波阵面压力的衰减率要高于以RDX为基的理想炸药和TNT,高爆速、高爆压类理想炸药在水中初始冲击波性能方面优势不显著。

硝酸铵细度对铵胺炸药性能的影响

为研究硝酸铵细度对铵胺炸药性能的影响,以六亚甲基四胺作为可燃剂制备了一种胶状炸药—铵胺炸药;对多孔粒状硝酸铵进行破碎,分别过20、40、60、80目筛区分不同的细度,对混合各细度硝酸铵颗粒铵胺炸药基质的黏度、炸药的爆速和猛度进行了测试,对炸药进行了储存稳定性实验。结果表明,当硝酸铵细度由0~20目增至80目以上时,铵胺炸药基质的混合均匀性增加,基质的初始黏度由92828mPa·s增至148637mPa·s,基质黏度随着剪切时间增加而逐渐降低,铵胺炸药基质属于触变性流体;炸药的爆速由3569m/s增至4316m/s,猛度由26.00mm增至30.50mm,能量释放更集中,对周围介质的的冲击力提升;分别储存2d和120d的铵胺炸药,爆速降幅均小于5%;说明硝酸铵细度的增加可以提高铵胺炸药的爆轰性能和储存稳定性。

六元氮杂芳环构建方法及含能材料合成研究

综述了吡啶,哒嗪、嘧啶、吡嗪环、三嗪以及四嗪等六元氮杂芳环骨架构建方法,探讨了相应的六元氮杂芳环环化反应机理,概述了典型含能材料的物化与爆轰性能;重点从合成角度总结了缩合反应与环加成反应在构建六元氮杂芳环结构中的应用,讨论了在相应氮原子中心位点实现氮氧化或氮氨化反应的方式。其中,六元氮杂芳环氮氧化片段的引入主要包括两类途径:一是以氧化剂与氮杂芳环中氮原子中心发生反应,形成N-氧化物片段;另一类是利用环化反应,将相应的氮氧双键等结构转化为N-氧化物片段。附参考文献91篇。

带隔板复合装药结构对双层罩毁伤元成型的影响

针对带隔板复合装药爆轰波控制问题,利用LS-DYNA软件仿真研究了不同隔板参数及复合装药结构参数对爆轰波传播及作用过程的影响;结合X光成像试验验证并通过仿真研究了双层药型罩在不同装药结构参数下的成型规律。结果表明,随着隔板厚度及复合装药高度的增加,复合装药爆轰波由球面波向V形波转化,使得双层药型罩从包覆式侵彻体向杆式侵彻体转换;其中侵彻体的头部速度和长径比与隔板厚度、装药高度、炸药性能呈正相关,与隔板半径、隔板底部距起爆中心位置、内外层炸药直径比呈负相关,当隔板厚度为0.114~0.142倍装药口径、隔板半径为0.400~0.429倍装药口径、隔板底部距起爆中心位置为0.100~0.129倍装药口径、复合装药高度为0.971~1.257倍装药口径、内外层炸药直径比为0.77~0.83时,杆式侵彻体成型较好。

含调整器装药结构破片形成影响因素研究

为有效改善柱壳断裂位置并产生形状规则的大质量破片,该文设计了一种由柱壳装药以及嵌入其中的爆轰波调整器构成的新型破片战斗部结构,并研究了爆轰波调整器结构参数对破片输出的影响。采用AUTODYN-3D有限元计算软件,分析了爆轰波碰撞叠加切割柱壳形成破片的过程,找出了柱壳切割效果优良的调整器结构参数取值范围,并开展了最优结构的验证试验。研究结果表明:有效破片生成率随内外层装药厚度比、调整器厚度的增加以及沟槽数量的减小,由一定值逐渐达到100%;当内外层装药厚度比为5、调整器厚度为10 mm或15 mm且开有8或12个沟槽时,有效破片在生成率达到100%的同时兼具较大的平均质量;水井试验回收率为96.3%,获得的有效破片生成率为100%,破片平均长度和宽度分别为39.75 mm和14.2 mm,与仿真结果的误差分别为6.25%和11.25%。该文研究结果可为实现破片战斗部智能可选择化提供借鉴思路。

Detonation Mechanism in Double Vertical Explosive Welding of Stainless Steel/Steel

One-dimensional detonation model and two-dimensional P-M （Prandtl-Meyer） expanding model of double vertical explosive welding were established. A one-dimensional formula of flyer plate velocity was obtained and the bending angle curve representing flying attitude of flyer plate in double vertical was deduced as well. Compared with single parallel explosive welding, the double vertical explosive welding combines two cladding plates in one explosion. Due to closed charging structure, the influence of rarefaction wave on the plate＇s surface in double vertical explosive welding is eliminated and explosion loading time and displacement are increased, resulting in the increase of flyer velocity and energy utilization rate by 1.3 times to 1.6 times in different mass ratios. The analysis of microstructure in bonding zone of double vertical cladding plate under traditional charging shows that there is a clear over-melting near the interface, which is in line with the conclusion of detonation mechanism.

Propagating Characteristic of Premixed Methane-Oxygen Deflagration in the Coal Mine Lane Including a Refuge Chamber

In order to investigate detonation propagation and distribution problems of premixed CH_4 ＋ 2O_2 mixture around a concrete structure such as a refuge chamber,detonation experiments in one small size tube were conducted. A simulation method was developed to obtain the flow field load distribution in the coal mine lane and pressure load of each part for the refuge chamber. Firstly,a physical model of a full-size explosiontest lane was established,which included the refuge chamber. With the calculations of the exact initial detonation pressure,the propagation characteristics of CH_4 ＋ 2O_2 premixed mixture detonation in the lane was simulated. Simulation results of various parts from AUTODYN are recorded,and the shock wave arrival time and the pressure peak can be observed from the detonation pressure-time curve over the changing propagation distance. So curve differences in different locations cannot be ignored. Then by detonation experiments in the small size tube,detonation pressure-time curves and velocity were obtained. Finally the simulation waveform of variation curve agreed well with the experimental results,which validated the detonation simulation method. The difference between shockwaves of the two sensors confirmed that detonation wave changed along with distance and time. These results should be taken into serious consideration for the detonation progration and distribution problem in future researches.

Research on Matching Relationship Between Number of Initiation Points and Charge Diameter

For shaped charges,LS-DYNA software was adopted to explore the influence of number of initiation points on the penetrator formation numerically.Changed the number of initiation points from 4 to 36,the performance of penetrator under four different kinds of typical charge diameter was analyzed,and the effect of detonation wave pressure on the liner was discussed.The minimum number of initiation points to substitute for annular initiation was obtained for each of four warheads with different charge diameters,and the curve representing the relation between the number of initiation points and charge diameter was found out also by using polynomial fitting.The simulation result provides a reference for the design of multimode warhead.

多孔粒状硝酸铵含量对现场混装乳化炸药的性能影响

为提高现场混装乳化炸药的性能,在其中加入质量分数分别为0%、3%、6%、9%、12%、15%的多孔粒状硝酸铵,制备6组炸药样品;通过扫描电镜分析了多孔粒状硝酸铵的微观形貌结构;使用B-W法计算了炸药的爆热和爆速,测试了炸药样品的黏度、密度与爆速,并将该炸药在金堆城钼矿进行工程应用。结果表明,炸药的黏度随着多孔粒状硝酸铵含量增加而上升,当质量分数为0~12%时,黏度为1.75×10^(5)~2.97×10^(5)mPa·s;理论爆热由2382.95kJ/kg升至2790.89kJ/kg;理论爆速由4229m/s升至4683m/s;实际爆速受装药密度影响,先由4198m/s升至5294m/s,后下降至4578m/s。当多孔粒状硝酸铵质量分数为9%时,炸药实际爆速达到最高,应用于矿山爆破中,爆后岩石块度下降,矿石粉矿率由30%增加到45%。

基于丙二腈的含能化合物的合成研究进展

丙二腈是一种重要的有机合成原料。介绍了丙二腈分子中亚甲基和氰基的反应特性。利用氰基的反应活性可以构建氮杂环母体骨架,可进一步赋予能量,设计并合成多种性能优异的含能化合物。丙二腈作为原料可以合成3,4-二(3’-硝基呋咱-4’-基)氧化呋咱(DNTF)和1,1’-二羟基-5,5’-联四唑二羟胺盐(HATO)等新型含能材料。系统综述了构建呋咱、四唑、异呋咱、偶氮桥联、醚桥联等含氮含能化合物的合成方法。同时,重点介绍了典型含能化合物的爆轰性能等物理化学性能。对基于丙二腈的含能化合物的合成思路和方法进行总结并提出建议,为未来设计、合成具有自主知识产权且性能优异的新型含能材料提供参考。

约束对DNAN基熔铸炸药点火反应特性的影响

为了探究约束对2,4-二硝基苯甲醚(DNAN)基熔铸炸药点火反应特性的影响,设计了不同壁厚条件下单端点火试验和相同壁厚的爆轰试验;基于爆炸相似理论,通过对比爆轰试验与点火试验产生的冲击波超压,估算了炸药在点火试验中产生的等效反应药量。结果表明,DNAN基熔铸炸药在一般约束条件下(壁厚小于10mm),经黑火药引燃后仅发生燃烧反应;在强约束条件下(壁厚20、30、40及50mm)反应更为剧烈,但未发生典型的燃烧转爆轰过程,反应烈度为爆燃或爆炸级。DNAN基熔铸炸药发生反应的等效反应药量随着管体壁厚增大,爆炸百分比从23.9%依次增加至34.8%、77.3%及78.7%。可知在一定范围内增强约束条件,炸药燃烧进程会随之加快,反应更为剧烈,但当约束条件足够强时,这种促进作用将不再明显。

CL-20/HMX共晶及其混合炸药机械感度和能量性能研究

CL-20与HMX形成共晶,在能量损失相对较小的前提下有利于降低CL-20的感度,是目前CL-20基共晶材料研究的热点之一。为了促进CL-20/HMX共晶在混合炸药中的应用,采用水悬浮法分别制备了含HMX、CL-20、CL-20/HMX共晶的混合炸药,测试了不同炸药配方的机械感度、密度和爆速。以炸药配方的爆速测试结果为基础,对Kamlet公式进行修正,通过修正Kamlet公式及Urizar公式分别计算了HMX、CL-20、CL-20/HMX共晶的标准生成焓和特征爆速。结果表明,三种混合炸药中,含CL-20/HMX共晶的混合炸药机械感度低于40%,爆速大于8800 m/s,综合性能最好;三种单质炸药中,CL-20/HMX共晶的标准生成焓和特征爆速计算值较大,分别为851 kJ/mol、9335 m/s。

Simulative Calculation of Mechanical Property, Binding Energy and Detonation Property of TATB/Fluorine-polymer PBX

Molecular dynamics （MD） method was used to simulate 1,3,5-triamino-2,4,6-trinitrobenzene （TATB） coated with fluorine containing polymers. The mechanical properties and binding energies of PBXs were obtained. It was found that when the number of chain monomers of fluorine containing polymers was the same, the elasticity of TATB/F2314 was increased more greatly than others and the binding energy of TATB/F2311 was the largest among four PBXs. Detonation heat and velocity of such four PBXs were calculated according to theoretical and empirical formulas. The results show that the order of detonation heat is TATB〉TATB/PVDF〉TATB/F2311〉TATB/ F2314 〉 TATB/PCTFE while the order of detonation velocity is TATB/PVDF 〈 TATB/F2311 〈 TATB/F2314 〈 TATB/PCTFE 〈TATB.