高-低爆速圆板炸药串联爆轰引起平面爆轰波的变凸现象

为分析高-低爆速圆板炸药于空中串联爆轰时平面爆轰波在传播过程中演变成凸面波的现象,分别对平面爆轰波阵面后爆轰产物状态参数的分布、有效药量与柱面装药几何尺寸的关系、爆轰产物的状态方程及强爆轰关系式进行了讨论。并以100 mm50 mm的TNT与RC炸药串联爆轰为例,描述了平面爆轰波演变为凸面爆轰波的过程,预估了爆轰波的平面范围和波形差。预估结果与实验结果基本符合。     

基于PDV的JOB-9003炸药爆轰反应区测量

炸药的反应区数据对爆轰过程的精密建模具有重要意义，为了得到JOB-9003炸药的反应区信息，采用光子多普勒测速仪（PDV）对JOB-9003炸药的爆轰反应区进行了实验研究。实验中利用火炮发射高速蓝宝石飞片冲击起爆被测炸药，在炸药后表面安装镀膜氟化锂（LiF）窗口测量炸药一维稳态爆轰时的界面粒子速度，测试过程的时间分辨率小于1 ns，测速相对不确定度小于2%。通过读取界面粒子速度时程曲线的拐点来确定CJ点，根据阻抗匹配公式计算炸药的CJ压力。研究结果表明，JOB-9003炸药界面粒子速度时程曲线上存在较为明显的拐点，JOB-9003炸药的化学反应时间为（11±2）ns，对应的化学反应区宽度为（0.075±0.014）mm，JOB-9003炸药的CJ爆压为（35.6±0.9）GPa，冯诺依曼（Von Neumann）峰处的压力为（47.9±1.2）GPa。     

高能炸药爆轰波反应区流场的拉格朗日分析方法

给出了一种简单的、对高能炸药爆轰反应区流场进行拉格朗日分析的方法。若已知未反应炸药和反应产物的状态方程，采用适当假设，我们可以在不知道反应速率函数的情况下得到爆轰反应区中的关系ｐ（）和ｕ（）等。根据这些关系及爆轰反应区中拉氏量计的实验结果ｐ（ｔ）［或ｕ（ｔ）］，通过插值或数据拟合可以得到爆轰反应区中的反应流场。我们将此方法应用于ＰＢＸ－９４０４炸药，并得到其爆轰反应区中的反应流场。     

快速热点火熔奥梯铝炸药燃烧转爆轰实验研究

以熔铸型含铝混合炸药熔奥梯铝为对象，研究铸装含铝混合炸药快速热点火后的燃烧转爆轰特性。建立了快速热点火燃烧转爆轰实验平台，由实验装置（加热装置、约束钢管、炸药）、压力测试系统、光纤测速系统组成；加热装置加热15 mm厚45钢钢板，峰值温度大于1 100 ℃，温升速率为85～95 ℃/s。开展了快速热点火带壳熔奥梯铝炸药燃烧转爆轰实验，由加热装置加热约束钢管内熔奥梯铝炸药，炸药化学反应阵面压力和传播速度分别由压电性高压压力传感器和光纤探针测定；实测阵面压力约1 GPa，传播速度最大约2 600 m/s。由光纤数据获得炸药化学反应阵面传播轨迹，通过特征线方法获得冲击形成点，半定量给出冲击形成距离大于850 mm；并比较了管体破片质量实测值与炸药完全爆轰时破片平均质量计算值，实测值远小于计算值。综合实测化学反应阵面传播速度和压力、冲击形成距离分析、破片质量比较，可确定熔奥梯铝炸药没有发生完全爆轰，其化学反应状态为爆燃。另外，采用Adams和Pack模型、CJ燃烧模型，都能够半定量的预估冲击形成距离和燃烧波后压力，为实验设计提供依据，但CJ燃烧模型的计算结果更接近于实测值。     

凝聚炸药非理想爆轰的数值模拟

本文对凝聚炸药非理想爆轰的数值模拟进行了系统介绍。对敏感、钝感炸药的理想与非理想爆轰的数值模拟方法、宏观反应速率方法及近年发展起来的ＤＳＤ（ＤｅｔｏｎａｔｉｏｎＳｈｏｃｋＤｙｎｔｉｍｉｃｓ）方法和波阵面追踪法,以及对这些方法的适应能力、存在的主要问题进行了分析与讨论。      

塑料粘结TATB炸药散心爆轰波相对强度的发展

设计了几何相似的三种尺寸的半球形塑料粘结ＴＡＴＢ炸药系统。进行了驱动铜飞层和冲击有机玻璃靶的模比（或相似）实验及二维数值模拟计算，揭示了这种炸药系统散心爆轰波相对强度增长的行为。结果表明：在小尺寸情况下，炸药的爆轰性能明显偏离比例律（ｓｃａｌｉｎｇ ｌａｗ），但偏离并不很大；对于工程应用爆轰装置的精细计算，若采用不考虑化学反应的爆轰产物经验状态方程，需要用不同的状态方程参数描述不同尺寸炸药系统的行     

一类爆轰合成用乳化炸药的爆轰反应特征

结合热分解特性、爆轰产物状态及数值计算探讨所制备的含Fe、Mn(Zn)元素乳化炸药的爆轰反 应特征。对该系列乳化炸药及其爆轰产物分别进行DSC和DTG实验、XRD检测和TEM 表征,通过比较不 同类型炸药及其爆轰产物的热分解特征、爆轰产物的成分和形貌、晶型畸变度等研究该类炸药爆轰反应特征; 并通过数值计算研究和佐证了不同温度和压强状态下,爆轰固体产物可能存在状态。结果表明:硝酸铵有利 于炸药爆轰时形成相对比较均匀和平稳的爆轰反应结构,而这种结构有利于可重复性合成比较单一和均匀 的爆轰产物。高密度炸药的爆轰产物比低密度炸药的相对纯净。低密度炸药不完全爆轰,导致了爆轰产物杂 质较多;数值计算结果表明,爆轰固体产物分布相图可以辅助分析爆轰固体产物可能存在状态及Mn(Zn)的 爆轰合成机制。     

射弹撞击带盖炸药引发爆轰的机制

进行了钢射弹引爆带厚盖板的Ｔ／Ｒ（４／６）炸药的实验，观测了炸药中引发的爆轰波阵面波形。有两种结构的盖板：一种是整体钢盖板，另一种是预制塞钢盖板。在略大于引爆阈值的撞击条件下，覆盖整体盖板的炸药中出现凸面爆轰波，而在覆盖预制塞盖板的炸药中出现Ｗ形爆轰波。这一现象表明，冲击效应是前者引发爆轰的主控机制，而宏观剪切效应是后者引发爆轰的主控机制。按冲击引爆和剪切引爆机制分别进行了射弹引爆带整体盖板和预制     

CL-20混合炸药的爆轰波结构

基于爆轰数值模拟计算,分析了CL-20混合炸药爆轰反应的特征,设计了炸药与窗口的界面粒子速度测量实验装置;采用激光干涉法,测量了C-1炸药(CL-20/粘合剂/94/6)与窗口的界面粒子速度; 运用先求导、再分段拟合的方法,对界面粒子速度随时间的变化曲线进行了数据处理,确定了炸药爆轰CJ点对应的时间位置;根据CJ点对应的粒子速度,计算获得了炸药的爆轰反应区宽度和CJ爆轰压力。结果显示:密度为1.943 g/cm3的C-1炸药的爆轰反应时间为38 ns,CJ压力为34.2 GPa。     

不同铝粉尺寸含铝炸药加速金属能力的研究

对铝粉直径从几十纳米到几十微米的几种含铝炸药,进行了小尺寸装药条件下炸药加速金属平板实验,用激光速度干涉仪测量了金属平板自由面速度,比较了几种炸药对不同厚度金属平板的加速时间和加速能力。分析了铝粉在炸药爆轰中的反应情况。在小尺寸装药下,铝粉加入炸药和铝粉尺寸大小对炸药爆轰性能有明显影响。纳米铝粉使炸药作功能力有较大提高。含铝炸药爆轰中,铝主要在爆轰后期与爆轰产物反应。     

Study of detonation initiation in hydrogen/air flow

While extensive studies have been conducted concerning the formation of detonation waves in various combustible gaseous mixtures under static conditions since the 1950s, there is very little experimental work on simple flowing systems. In this study, experiments on the deflagration to detonation transition (DDT) of a hydrogen–air flow system were carried out to see the effects of tube diameter, equivalence ratio, and flow types in a premixed and non-premixed flow. Tube diameters used were 25, 50, and 100 mm. The premixed experiments show that the larger tube diameter provides a wider range in run-up distance, reduction of L _DDT/D (ratio of the run-up distance, L _DDT to tube diameter), and expansion of the detonable concentration limit by spreading the cell width. The result of the non-premixed experiments show that similar values of the run-up distance to the premixed experiments are obtained at an equivalence ratio of about 1.0, however, fluctuations of DDT occur near the DDT concentration limit. Under laminar flow conditions at a Reynolds number of less than 2,300, the difference between the two systems could not be observed. However, when the Reynolds number increases towards turbulent conditions, the DDT run-up distance decreases compared to that of static flow conditions. This paper is based on work that was presented at the 21st International Colloquium on the Dynamics of Explosions and Reactive Systems, Poitiers, France, July 23–27, 2007.     

DDT in methane-air mixtures

Experimental results from a study on the critical condition for deflagration-to-detonation transition (DDT) in methane-air mixtures are presented. Experiments were carried out at 293 K and 1 atm using methane-air mixtures with methane concentrations ranging from 5.5 to 17% vol. The tests were performed in detonation tubes with inner-diameters of 174 mm and 520 mm. Detonation cell widths l\lambda were determined in the tests for a range of methane concentrations. The results of DDT tests indicate that for a tube cross-sectional area blockage ratio (BR) of 0.3 the critical condition for DDT can be characterized by the d/l = 1d/\lambda = 1 criterion. However, for a BR = 0.6 the critical value d/ld/\lambda was significantly higher. The data also show that the critical condition for DDT can be described by L/l = 7L/\lambda = 7, where L is the characteristic length-scale of the channel volume between orifice plates. This length-scale is defined by a grouping of the orifice plate dimensions (inner and outer-diameter) and plate spacing.     

大型水平爆轰管中悬浮铝粉爆炸过程的实验研究

铝粉的燃烧与爆轰性能是粉尘爆炸领域研究的热点.利用长29.6m,内径199mm,配有40套喷粉扬尘系统的水平爆轰管,在40J电火花点火条件下,实现了悬浮铝粉-空气混和物火焰加速、爆燃、爆轰及其转捩过程,测得了爆炸波传播过程中的压力信号,并且观察到了爆轰波的稳定传播现象.实验结果表明,当铝粉浓度为300 g/m3时,在距离点火端10.15m(长径比L/D=51)处发生了DDT,测得的爆轰波传播过程中管内的最大爆速为1840m/s,最大峰值超压为10.5MPa.铝粉尘爆炸波在爆轰管内的传播过程可分为爆燃段、爆燃转爆轰(DDT)、爆轰增强以及稳态爆轰四个阶段.     

DDT and detonation waves in dust-air mixtures

This paper summarizes the studies of DDT and stable detonation waves in dust-air mixtures at the Stosswellenlabor of RWTH Aachen. The DDT process and propagation mechanism for stable heterogeneous dust detonations in air are essentially the same as in the oxygen environment studied previously. The dust DDT process in tubes is composed of a reaction compression stage followed by a reaction shock stage as the pre-detonation process. The transverse waves that couple the shock wave and the chemical energy release are responsible for the propagation of a stable dust-air detonation. However, the transverse wave spacing of dust-air mixtures is much larger. Therefore, DDT and propagation of a stable detonation in most industrial and agricultural, combustible dust-air mixtures require a tube that has a large diameter between 0.1 m and 1 m and a sufficient length-diameter ratio beyond 100, when an appropriately strong initiation energy is used. Two dust detonation tubes, 0.14 m and 0.3 m in diameter, were used for observation of the above-mentioned results in cornstarch, anthraquinone and aluminum dust suspended in air. Smoked-foil technique was also used to measure the cellular structure of dust detonations in the 0.3 m detonation tube. Received 11 February 2000 / Accepted 1 August 2000     

Studies of DDT enhancement approaches for kerosene-fueled small-scale pulse detonation engines applications

Two-phase small-scale pulse detonation engine (SPDE) offers a competitive alternative for small-scale propulsion systems from a high cycle efficiency and structural simplicity standpoint. SPDE models are designed with the aero-valve, and three different cases of obstacle combinations are used as deflagration-to-detonation transition (DDT) devices. The inner diameters of detonation tubes are 29?mm, and the lengths of three SPDEs are 995, 1,100, and 1,175?mm. Using kerosene-air as the fuel-oxidizer, a series of high-frequency detonation tests is conducted to seek efficient DDT enhancement approaches that reduce DDT distance and time and increase the frequency of kerosene-fueled SPDE. The results show that the fully developed detonation wave can be achieved at a distance of 3.4 times the minimum characteristic distance for gaseous detonation formation from the igniter and that the SPDE can steadily operate at a maximal frequency of 62.5?Hz. By adopting these DDT enhancement approaches, the detonability of kerosene is significantly improved. In addition, experiments are performed to study the effects of firing frequencies on detonation transitions. The results clearly indicate that the values of detonation wave pressures and velocities, the degree of overdriven wave, the ignition delay times, and detonation initiation times vary with frequencies. In terms of the performance, the optimal frequencies of three SPDE models are 20, 42.5, and 50?Hz, respectively.     

Detonability of simple and representative components of pyrolysis products of kerosene: pulsed detonation engine application

The use of liquid fuels such as kerosene is of interest for the Pulse Detonation Engine (PDE). In this context, a representative gaseous mixture of the lighter products resulting from the decomposition of a kerosene of type JP-10 was studied. The detonability limits of simple components (hydrogen, ethylene, propylene) and mixtures of these components were tested in a 50 mm diameter and 2.5 m long detonation tube. This dimension is compatible with the applications of the aircraft industry and more particularly the PDE. The influences of the nitrogen dilution, geometry of the DDT device (Schelkin spiral), ignition energy and initial pressure were investigated. This paper was based on work that was presented at the 19th International Colloquium on the Dynamics of Explosions and Reactive Systems, Hakone, Japan, July 27 - August 1, 2003. Communicated by J.E. Shepherd     

Comparison of critical conditions for DDT in regular and irregular cellular detonation systems

Abstract. The results of an experimental study of DDT in mixtures with regular and irregular detonation cellular structures are presented. Experiments were carried out in a tube 174 mm i. d. with obstacles (blockage ratios were 0.1, 0.3, and 0.6). Mixtures used were hydrogen–air and stoichiometric hydrogen–oxygen diluted with , Ar, and He. The critical conditions for DDT are shown to depend on the regularity of the cellular structure of test mixtures. The critical values of the cell sizes in Ar- and He-diluted mixtures are shown to be significantly smaller than those in -diluted mixtures. This means that systems with a highly regular detonation cellular structure have far less capacity for undergoing DDT compared to irregular ones with the same values of detonation cell sizes. Received 18 November 1999 / Accepted 15 May 2000     

A study on jet initiation of detonation using multiple tubes

A detonator consisting of a dense bundle of small-diameter tubes (4.4–19 mm) is tested experimentally using stoichiometric mixtures of hydrogen–oxygen and hydrogen–air. Tests are conducted in a 5,200-mm long detonation tube fitted with a schlieren photograph section and smoked foil to record the deflagration to detonation (DDT) transition. It is confirmed that the flame jet emanating from the tube assembly causes detonation initiation immediately downstream of the detonator, with little dependence on the size of the detonation tube. For the fuel–air mixture, the insertion of Shchelkin spirals into each of the smaller tubes enhances the development of the turbulent flame jet, leading to a shorter DDT distance. Multi-point spark ignition is also shown to provide a further reduction in the DDT distance compared to single-point ignition. PACS 47.40.-x; 47.40.Nm; 47.70.Fw; 82.40.-g; 82.40.Fp     

Combustion in a horizontal channel partially filled with a porous media

Experiments were carried out to investigate the combustion propagation phenomenon in a horizontal channel partially filled with ceramic-oxide spherical beads. A 1.22 m long, 43 mm nominally thick layer of spherical beads is located at the ignition end of a 2.44 m long, 76 mm square channel. Tests were performed with 6.4 and 12.7 mm diameter beads. A flame is ignited at the bead end wall by an automotive spark ignition system. Flame propagation and pressure measurements are obtained via ionization probes and piezoelectric pressure transducers mounted on the top and bottom surfaces of the channel. High-speed schlieren video was used to visualize the structure of the explosion front. Experiments were performed with a 31% nitrogen diluted stoichiometric methane–oxygen mixture at room temperature and at an initial pressure in the range of 15–50 kPa. For initial pressures of 15 and 20 kPa the flame accelerates to a velocity close to the speed of sound in the combustion products. For initial pressure of 30 kPa and higher DDT occurs in the gap above the bead layer. An explosion front propagating at a velocity just under the CJ detonation velocity is detected in the bead layer even though the bead layer pore size is much smaller than the detonation cell size. It is demonstrated that flame propagation within the bead layer is the driving force behind the very rapid flame acceleration observed, however the DDT event occurring in the gap above the bead layer is not affected by the bead layer porosity. Schlieren video indicates that the structure of the explosion front varies across the channel height and with propagation distance down the channel.     

模型复合推进剂燃烧转爆轰研究

本文较详细地研究了模型推进剂(AP/wax,AP/A1/wax,AP/RDX/A1/wax)由燃烧转爆轰(DDT)的过程。分析了装药密度和铝粉含量对装药DDT的影响。结果表明:模型推进剂当其配比接近零氧平衡时较易产生DDT;含与不含铝粉的AP/粘合剂系复合推进剂药柱以及硝胺含量为20％的AP/硝胺炸药/A1粘合剂系复合推进剂药柱都不可能产生DDT。