炸药爆轰波光谱发射率及爆温的虚拟辅助光源反射法测量

依据光学原理,提出了爆轰波光谱发射率及爆温的虚拟辅助光源反射测量方法,克服了单波长或双波长光学测试装置不能同时测量两参量的困难,利用该方法对液体炸药ＮＭ爆轰波光谱发射率及其爆温进行了实验测量,结果与文献报道相吻合。     

Computer controlled detonation spraying of WC/Co coatings containing MoS2 solid lubricant

Composite WC/Co + MoS₂ coatings were deposited onto steel substrates by Computer Controlled Detonation Spraying using three spraying modes: very cold, cold and normal. Maximal content of MoS₂ in a sprayed powder was 10 wt.%. Characterization of coatings was made with chemical and phase analyses, microhardness measurement, morphology and microstructure investigation. X-ray diffraction study shows that residual MoS₂ exists only in coatings obtained at very cold and cold spraying modes. At normal spraying mode complete decomposition of the solid lubricant occurs during spraying. From the engineering point of view, the coating applied at the cold mode using a powder containing 10 wt.% MoS₂ is the most promising. Such a coating has microhardness of 650 HV_0.2 and a porosity of 10%.     

爆轰技术在纳米碳材料制备中的应用进展

在综合分析国内外文献的基础上,介绍了爆轰技术的特点,重点阐述了多项爆轰技术在纳米碳材料制备中的应用以及所得爆轰产物的形貌特征。目前,爆轰技术已广泛应用于纳米金刚石、纳米石墨、纳米碳管、富勒烯以及纳米碳包覆金属等多种新型纳米碳材料的制备,发展前景广阔。     

一种低爆速粉状乳化炸药的研制

介绍了一种低爆速粉状乳化炸药制备方法,通过乳化、钢带冷却、固化、粉化的工艺流程,采用控制炸药粒度的方法得到1种低爆速炸药。该炸药外观为细颗粒状,粒度1.2～2.5mm、装药密度0.90～1.05 g/cm~3。试验证明,该低爆速炸药具有雷管起爆感度,爆速2200～2700 m/s、猛度8～12 mm、传爆长度>12 m(装药直径32mm),储存期>6个月。该低爆速炸药生产工艺简单、爆速调节方便、安全性好,可满足特殊控制爆破的需要。     

水下爆破中乳化炸药抗水性能的实验研究

研究乳化炸药的抗水性能对水下爆破和乳化炸药的研制都有一定的指导作用。本文利用设计的乳化炸药抗水实验装置,对三种乳化炸药进行了实验研究;利用爆速和猛度的变化来衡量其抗水性能的优劣,三种乳化炸药在深水中浸泡72h后,依然有较好的抗水性能。     

The initiation and propagation of detonation in supersonic combustible flow with boundary layer

Adaptive simulations solving the Navier-Stokes equations have been conducted in order to get a better understanding on the detonation initiation and propagation in a stoichiometric H₂/O₂/Ar supersonic mixture with boundary layer. The detonation is initiated by a continuous hot jet. When reflecting on the wall, the jet induced bow shock interacts with the boundary layer and forms the shock boundary layer interaction phenomena, while in Euler result the bow shock forms Mach reflection. The investigation shows that the Navier-Stokes simulation result is structurally in better agreement with the experiment compared with that of the inviscid Euler simulation result. The bow shock interacts with the separation shock, forming the shock induced combustion behind the interaction zone. Then the combustion front couples with shock and forms Mach stem induced detonation. The Mach stem induced detonation continues to getting higher and propagating upstream, initiating the main flow. The initiated partial detonation exists with the separation shock induced combustion front, forming an “oblique shock induced combustion-partial detonation” structure in the main flow. The investigation on the influence of free stream Mach number further confirms that the boundary layer has an important influence on detonation initiation. The parametric studies also show that there exists a free stream Mach number range to initiate the partial detonation in supersonic combustible flow successfully.     

Hydrogen–oxygen flame acceleration and deflagration-to-detonation transition in three-dimensional rectangular channels with no-slip walls

Hydrogen–oxygen flame acceleration and the transition from deflagration to detonation (DDT) in channels with no-slip walls are studied using high resolution simulations of 3D reactive Navier–Stokes equations, including the effects of viscosity, thermal conduction, molecular diffusion, real equation of state and detailed (reduced) chemical reaction mechanism. The acceleration of the flame propagating from the closed end of a channel, which is a key factor for understanding of the mechanism of DDT, is thoroughly studied. The three dimensional modeling of the flame acceleration and DDT in a semi-closed rectangular channel with cross section 10 × 10 mm and length 250 mm confirms validity of the mechanism of deflagration-to-detonation transition, which was proposed earlier theoretically and verified using 2D simulations. We show that 3D model contrary to 2D models allows to understand clearly the meaning of schlieren photos obtained in experimental studies. The “numerical schlieren” and “numerical shadowgraph” obtained using 3D calculations clarify the meaning of the experimental schlieren and shadow photos and some earlier misinterpretations of experimental data.     

Detonation propagation characteristic of H2–O2–N2 mixture in tube and effect of various initial conditions on it

As for the premixed H₂–O₂–N₂ gas ignited and induced by flame in tube, this paper represents systemic researches on its detonative formation process and flow field changes under different initial conditions (pressure, temperature, component concentration). The conservational Euler equation set with chemical reaction is taken as the basic gas phase equation model and the reduced elementary chemical reaction and shock wave problem are considered available so as to establish a theoretical model of premixed H₂–O₂–N₂ combustible gas detonation process. A unity coupling TVD format with second-order accuracy is adopted to solve the gas phase equation and deduce the two-dimension Riemann invariant, and the TVD format for solution of the polycomponent convection equation with elementary chemical reaction is proposed. Meanwhile, a time splitting format is adopted to perfectly treat with the rigid problem resulted from the higher time difference value between gas phase flow characteristic time and chemical reaction characteristic time. It is shown by the calculation results that the detonation waves form certain angle with relation to the tube wall surface at the initial stage of ignition, so as to incur reflections and form reflection waves; during the propagation of the detonation waves, the reflection wave structures are propagated backwards the back of waves constantly, so the whole flow field is characterized of obvious two-dimension. Besides, the excessive pressure detonation occurs at first before formation of the stable detonation propagation process, then a stable detonation propagation process forms finally. Mixed gas detonation characteristics resulted from different calculated-initially parameters are different. The higher the initial temperature and pressure of flame is, the shorter the induction time for detonation formed due to combustion acceleration of the mixed gas is, but which nearly brings no great influence on the later propagation process of the detonation waves. The initial mixed gas component can influence the detonation characteristic of the mixed gas observably, when the quantity relative ratio is close to 1 and the mixed gas with larger reaction activity, its detonation propagation speed is rapider and the pressure after detonation waves is higher. The simulation result keeps accordant with the calculated result of the typical C–J detonation theory model.     

Salts of Tetrazolone – Synthesis and Properties of Insensitive Energetic Materials

Tetrazolone (5‐oxotetrazole, 1 ) is formed by diazotization of 5‐aminotetrazole in the presence of CuSO₄. Nitrogen‐rich salts such as guanidinium ( 2 ), 1‐aminoguanidinium ( 3 ), 1,3‐diamino‐guanidinium ( 4 ), 1,3,5‐triamino‐guanidinium ( 5 ), ammonium ( 6 ), hydrazinium ( 7 ) and the hydroxylammonium ( 8 ) salts of tetrazolone were prepared by facile deprotonation or metathesis reactions. All compounds were characterized by single‐crystal X‐ray diffraction, vibrational spectroscopy (IR and Raman), multinuclear NMR spectroscopy, elemental analysis and DSC measurements. The heats of formation of 2–8 were calculated using the atomization method based on CBS‐4M enthalpies. With these values and the experimental (X‐ray) densities several detonation parameters such as the detonation pressure, velocity, energy and temperature were computed using the EXPLO5 code (V.5.04). In addition, the sensitivities towards impact, friction and electrical discharge were tested using the BAM drop hammer and friction tester as well as a small scale electrical discharge device.     

The Role of Aluminum in the Detonation and Post‐Detonation Expansion of Selected Cast HMX‐Based Explosives

In order to improve understanding of how aluminum contributes in non‐ideal explosive mixtures, cast‐cured formulations have been analyzed in a series of cylinder tests and plate‐pushing experiments. This study describes the contribution of 15 % aluminum (median size of 3.2 μm) vs. lithium fluoride (an inert substitute for aluminum; <5 μm) in cast‐cured HMX formulations in different temporal regimes. Small cylinder tests were performed to analyze the detonation and wall velocities (1–20 μs) for these formulations. Near‐field blast effects of 58 mm diameter spherical charges were measured at 152 mm and 254 mm using steel plate acceleration. Pressure measurements at 1.52 m gave information about free‐field pressure at several milliseconds. While the observed detonation velocities for all formulations were within uncertainty, significantly higher cylinder wall velocities, plate velocities, and pressures were observed for the aluminum formulations at ≥2 μs. Additionally, hydrocode calculations were performed to determine how non‐ideal behavior affected the plate test results. Collectively, this work gives a clearer picture of how aluminum contributes to detonation on timescales from 1 μs to about 2 ms, and how the post‐detonation energy release contributes to wall velocities and blast effects. The experiments indicate that significant aluminum reactions occur after the CJ plane, and continue to contribute to expansion at late times.