Predicting Maximum Attainable Detonation Velocity of CHNOF and Aluminized Explosives

This paper describes a simple method to predict the detonation velocity of pure and mixed CHNOF explosives as well as aluminized explosives at their maximum nominal density as one of the most important detonation properties. The new correlation uses the contribution of some structural parameters to apply for a wide range of ideal and non‐ideal explosives. Aluminized explosives have non‐ideal behavior and the Chapman Jouguet detonation velocities significantly differ from those expected from existing thermodynamic computer codes for equilibrium and steady state calculations. With the presented method, there is no need to use any assumed detonation products, heat of formation and experimental data. Detonation velocities at maximum nominal density of explosives predicted by this procedure show good agreement with respect to experimental values. They are more reliable compared to the calculated results of well‐known empirical methods and computed outputs using BKWS equation of state for CHNOF and aluminized explosives.     

Predicting the Detonation Velocity of CHNO Explosives by a Simple Method

A simplified method is shown, based on a semi‐empirical procedure, to estimate the detonation velocities of CHNO explosives at various loading densities. It is assumed that the product composition consists almost of CO, CO₂, H₂O and N₂ for oxygen‐rich explosives. In addition solid carbon and H₂ are also counted for an oxygen‐lean explosive. The approximate detonation temperature, as a second needed parameter, can be calculated from the total heat capacity of the detonation products and the heat of formation of the explosive by PM3 procedure. The detonation velocities of some well‐known CHNO explosives, calculated by the simple procedure, fit well with measured detonation velocities and the results from the well‐established BKW‐EOS computer code.     

工业炸药的爆轰性能研究

用有机玻璃法测定了岩石膨化、煤矿膨化、铵梯以及乳化炸药的爆速和爆压，同时用VLWR爆轰程序对岩11石膨化硝铵和铵梯炸药的爆轰参数及C—J产物的平衡组成进行了计算。结果表明，工业炸药具有低爆速和低爆压的非理想爆轰特征，而理论计算值和实验值比较接近，获得了较好的结果。     

含铝炸药圆筒试验及爆轰产物JWL状态方程研究

为分析含铝炸药在强约束条件下的爆轰性能,对含铝炸药进行了50mm圆筒试验。使用了电探讨测量炸药爆速,用高速相机记录圆筒膨胀过程,使要用了计算机图像技术对高速摄影照片进行分析处理,通过对圆筒试验二维爆轰数值模拟,标定了含铝炸药爆轰产物JWL状态方程参数。     

Effect of Al/O Ratio on the Detonation Performance and Underwater Explosion of HMX‐based Aluminized Explosives

The performance of detonation and underwater explosion (UNDEX) of a six‐formula HMX‐based aluminized explosive was examined by detonation and UNDEX experiments. The detonation pressures, detonation velocities, and detonation heat of HMX‐based aluminized explosive were measured. The reliability between the experimental results and those calculated by an empirical formula and the KHT code was verfied. UNDEX experiments were carried out on the propagation of a shock wave and a bubble pulse of a 1 kg cylindrical HMX‐based aluminized explosive underwater at a depth of 4.7 m. Based on the experimental results of the shock wave, the coefficients of similarity law equation for the peak pressure and attenuation time constant of shock wave were in acceptable agreement. The bubble motion during UNDEX was simulated using MSC.DYTRAN software, and the radius time curves of bubbles were determined. The effect of the aluminum/oxygen ratio on the performance of the detonation and UNDEX for an HMX‐based aluminized explosive was discussed.     

铝粉粒度和形状对含铝炸药性能的影响

应用含铝炸药的二次反应论和惰性热稀释理论解释了铝粉形状和粒度对炸药爆炸性能的影响机理，其根本原因是由于铝粉比表面积不同造成的。提出了含铝炸药性能的一种优化方向。     

Acceleration Ability and Heat of Explosive Decomposition of Aluminized Explosives

This paper studies the effect of aluminum particle size on the acceleration ability and heat of explosive decomposition of aluminized compositions containing HMX, nitroguanidine, and bis (2,2,2trinitroethyl) nitramine. The addition of Al increases the acceleration ability of the HEs. The replacement of Al with micronsize particles by an ultrafine powder with a particle size of 0.1 m does not lead to an additional increase in the acceleration ability. The effect of Al on the heat of explosive decomposition of the examined compositions is investigated.     

铝含量对RDX基含铝炸药爆压和爆速的影响

利用锰铜压力传感器和测时仪测量了不同铝含量的RDX基含铝炸药的爆压和爆速。拟合出爆压、爆速与铝含量的关系式,分析了铝含量对RDX基含铝炸药爆压、爆速的影响因素。结果表明,随着铝含量的增加,RDX基含铝炸药的爆压和爆速呈线性减小。计算了铝粉的质量分数在0~40%时所对应的PC-J=A(x)0ρD2中的A(x)值,拟合出A(x)值与铝含量的关系式,得到RDX基含铝炸药爆压与爆速之间的关系式。     

Mechanical Sensitivity and Detonation Parameters of Aluminized Explosives

Experiments were performed to study the effect of the species particle size and structure of aluminized mixture samples on the sensitivity and detonation parameters of HMX, nitroguanidine, bis(2,2,2trinitroethyl)nitramine, and their mixtures with an Al powder with a mean particle size of 0.1 – 150 m. The addition of ultrafine Al to HMX and bis (2,2,2trinitroethyl)nitramine substantially increases the sensitivity to mechanical effects and decreases the detonation velocity. In compositions with nitroguanidine, the detonation velocity practically does not vary. For nitroguanidine, the width of the chemicalreaction zone and Chapman–Jouguet parameters were determined by recording the detonationpressure profiles. The pressure profiles for bis(2,2,2trinitroethyl)nitramine show that detonation decomposition can occur in two stages. A twopeak detonationwave structure was detected for mixtures of HMX with Al. Temperature measurements indicate that Al interacts with detonation products in the immediate proximity to the front. The highest temperature was recorded for compositions containing ultrafine aluminum and an aluminum dust.     

低爆速爆炸焊接炸药的配方设计

低爆速爆炸焊接炸药以2号抗水岩石硝铵炸药为主体，配以相应的消焰剂和密度调节剂，以适应双金属爆炸复合焊接的要求,研究表明，改变消焰剂和密度调节剂含量，可以得到不同的低爆速焊接炸药，该炸药具有优良的安全性能和可靠的爆炸性能。     

Highly Thermal Stable TATB‐based Aluminized Explosives Realizing Optimized Balance between Thermal Stability and Detonation Performance

In this work, a series of TATB‐based aluminized explosives were formulated from 1, 3, 5‐triamino‐2, 4, 6‐trinitrobenzene (TATB), aluminum powders and polymeric binders. The thermal stability, heat of detonation, detonation velocity and pressure of the TATB based aluminized (TATB/Al) explosives were systematically investigated by cook‐off, constant temperature calorimeter, electrometric method and manganin piezo resistance gauge, respectively. The selected PBX‐3 (70 wt% TATB/25 wt% Al/5 wt% fluorine resin) achieved optimized balance between thermal stability and detonation performance, with the thermal runaway temperature around 583 K. The thermal ignition of TATB‐based aluminized explosive occurred at the edge of the cylinder according to the experimental and numerical simulations. Moreover, the critical thermal runaway temperature for PBX‐3 was calculated based on the Semenov's thermal explosion theory and the thermal decomposition kinetic parameters of the explosive, which was consistent with the experimental value.     

Computational Studies on the Molecular Stability and Detonation Performance of Nitraminebenzene Derivatives as Novel High-Energy Materials

In this article the detonation performance and stability of the benzene derivatives were studied theoretically to facilitate further developments of energetic materials. The gas-phase heats of formation were calculated based on the isodesmic reaction. The solid-phase heats of formation and heats of sublimation were estimated in the framework of the Politzer approach. Molecular stability was calculated by bond dissociation energies and characteristic height. Detonation velocity and pressure were obtained according to Kamlet-Jacobs equations. The results show that all compounds have positive heats of formation, and compounds D1, D2, D3, E, and F have high detonation performance. In addition, the breaking of N?N bond may be initial step in initiation process. Furthermore, theoretical result suggestions that the most of derivatives have good thermal stability. These calculations could provide basic information that may prove useful for the molecular design of novel high-energy density materials.     

Titania Nanocrystalline Prepared by Detonation Method and Calculation of Detonation Parameters

As a promising method for synthesizing nanosized materials, detonation method was used to prepare TiO₂ nanoparticles. A new method for predicting the Chapman‐Jouguet (C‐J) detonation parameters of C_aH_bO_cN_dTi_e explosives, such as detonation heat, detonation temperature, and detonation pressure, was introduced according to the approximate reaction equations of detonation. The coefficient of oxygen balance of explosive was also calculated according to the specific detonation synthesis experiment. The calculation method was more useful in predicting the formation processes of detonation products and optimizing the experimental procedure. It could also support theory foundation for further experiments to some extent.     

Detonation Performance of TATP/AN‐Based Explosives

The detonation velocity and performance were determined for four mixtures of triacetone triperoxide (3,3,6,6,9,9‐hexamethyl‐1,2,4,5,7,8‐hexoxonane, TATP), ammonium nitrate (AN) and water (W) by cylinder expansion tests. The composition of these mixtures varied in the following ranges: 21–31% TATP, 37–54% AN and 19–32% W. The obtained results were compared with those of powdery 2,4,6‐trinitrotoluene (TNT), AN‐fuel oil explosive (ANFO) and emulsion explosive. It was found that the tested TATP/AN/W mixtures represent typical non‐ideal explosives with relatively low critical diameter and with high sensitivity to initiation despite the high content of water due to the presence of the primary explosive (TATP). The detonation velocity is comparable to that of powdery TNT (at similar density). However, the acceleration ability is significantly lower than that of powdery TNT.     

Thrust Performance of an Ideal Pulse Detonation Engine

Quasisteady and twodimensional unsteady formulations of the problem on the operation cycle of a pulse detonation engine are derived. A formula for the specific impulse is obtained, and the thrust performance of the engine is calculated. It is found that the thrust performance of this engine for flight Mach numbers M [0; 3.6] and compression ratios p ₂/p ₁ [1; 80] are always higher than those of the ramjet and onespool turbojet. As the compression ratio increases, the advantage of the pulse detonation engine becomes less noticeable.     

TATB基含铝炸药作功能力的试验研究

为评价TATB基含铝炸药的作功能力,通过ANSYS-LSDYNS软件,采用Lee-Tarver点火增长三项式模型模拟含铝炸药的圆筒试验,获得了含铝炸药的JWL状态方程及反应速率参数。利用激光位移干涉仪研究了不同铝粉尺寸的含铝炸药加速铜飞片的能力,用数值计算验证了标定的圆筒试验参数。结果表明,粒径较小的铝粉能够使铜飞片获得更大的自由面速度,加速铜飞片的时间缩短,表现为粒径2μm铝粉的含铝炸药反应时间比粒径10μm铝粉的含铝炸药缩短13.6%。计算值与试验结果吻合较好,表明圆筒试验得到的爆轰产物参数是有效的。     

Review on Melt Cast Explosives

A systematic overview of melt cast explosives is given. The research on melt cast explosives over several decades can be divided into three broad areas: (i) aromatic compounds with C CH₃, N CH₃, OCH₃ C NO₂, N NO₂ and ONO₂ groups, (ii) improved synthesis of compounds, which are currently used in formulations or which have shown promise for such use and (iii) the preparation of melt cast formulations with various compositions. Exudation, high volume change from liquid to solid, super cooling, irreversible growth, fragility and unpredictable sensitivity are the disadvantages of existing melt cast formulations.     

不同直径含铝炸药的作功能力

为具体考察不同直径含铝炸药能量释放过程偏离相似律的程度,采用高速转镜扫描相机及单狭缝扫描技术对两种不同直径（50和100mm）的含铝炸药进行了圆筒试验,扫描狭缝分别距圆筒尾端200mm（直径为50mm）和300mm（直径为100mm）。试验结果表明,在几何相似膨胀位置处,直径为i00mm圆筒试验相对于直径为50mm圆筒试验的壁膨胀速度偏离量约为5％,比动能偏离量约为11％,表明两种直径含铝炸药的圆筒壁膨胀速度不符合相似律,小尺寸圆筒试验将低估大尺寸含铝炸药的作功能力。     

铝粉含量对梯铝炸药爆压和冲击波参数的影响

测试了以TNT为基不同含量含铝炸药的爆压和空中爆炸冲击波参数,通过分析铝粉对炸药爆压、空中爆炸参数和爆炸冲击波超压的影响,建立了爆压与铝氧比的关系曲线、5种TNT基含铝炸药的冲击波相似律方程和TNT/Al炸药的爆压与空中爆炸冲击波超压的关系式.结果表明,随着铝粉含量的增加,炸药的爆压呈指数衰减,近距离的冲击波超压也快速减小,但爆炸场温度和爆炸火球的直径及持续时间会增大.     

Detonation Failure Characterization of Homemade Explosives

Typically characterizing home made explosives (HMEs) requires many large scale experiments, which is prohibitive given the large number of materials in use. A small scale experiment was developed to characterize HMEs such as ammonium nitrate‐fuel oil mixtures. A microwave interferometer is applied to small scale confined transient experiments, yielding time resolved characterization of a failing detonation that is initiated with an ideal explosive booster charge. Experiments were performed with ammonium nitrate and two fuel compositions (diesel fuel and mineral oil). It was observed that the failure dynamics were influenced by factors such as the chemical composition, confiner thickness, and applied shock wave strength. Thin steel walled confiners with 0.71 mm wall thickness experienced detonation failure and decoupling of the shock wave from the reaction zone. Confiners with a wall thickness of 34.9 mm showed a decrease in propagation speed and a steady reactive wave was achieved. Varying the applied shock strength by using an attenuator showed corresponding changes in the initial overdriven reactive wave velocity in the HMEs. The distance to detonation failure was also shown to depend on the attenuator length when thin wall confinement was used. This experimental method is shown to be repeatable and can be performed with little required material (about 2 g). The data obtained could be useful to model development and validation, as well as quantifying detonability of materials.