炸药爆轰的连续介质本构模型和数值计算方法

假定炸药和爆轰产物处于局部热力学平衡状态, 即它们的压力和温度相同, 利用热力学基本关系建立炸药爆轰过程的连续介质本构模型的一般理论框架. 在此框架下, 炸药爆轰本构模型由一组常微分方程构成, 包括炸药和爆轰产物的状态方程、简单混合法则、化学反应速率方程和能量守恒方程, 易于由成熟的计算方法如梯形法等进行求解. 一组广义Maxwell型非线性固体本构形式的微分方程描述了压力和温度随时间的演化速率与应变率和化学反应速率的关系, 借助简单混合物理论, 其中的系数由炸药和爆轰产物的材料参数确定. 未反应的炸药和爆轰产物采用JWL状态方程, 化学反应率方程采用Lee-Tarver点火-燃烧二项式模型, 模拟PBX-9404炸药的一维冲击波起爆过程和爆轰波传播过程. 计算结果表明了本文给出的本构模型和相应计算方法的有效性. 关键词： 炸药爆轰 本构模型 化学反应率方程 数值模拟     

The influence of multi-layer confinement on detonation propagation in condensed-phase explosives

We examine, via multi-material simulation in a two-dimensional planar geometry, the effects on steady detonation propagation of the presence of a low-density intermediate layer between a condensed-phase high explosive (HE) and a high-density metallic confiner of finite thickness. Such elastomer intermediate layers are often added to eliminate air-gaps and the associated jetting effects that can arise due to machining imprecisions, or to prevent HE cracking due to environmental changes. Without an intermediate layer, the flow structure of a steady detonation/metal confiner interaction is well understood. In particular, there is no reflected wave passed into the HE due to the metal confinement. With the elastomer layer present, we find that, as the intermediate layer width increases, a complex wave interaction and communication path develops between the HE, intermediate, and metal layers. For thin intermediate layers, a shock-driven subsonic flow develops in the intermediate layer, passing information from the metal layer to the HE, with the detonation speed decreasing as the intermediate layer width increases. For wider intermediate layers, a Mach stem configuration develops in the intermediate layer, forcing a shock to be reflected into the HE. Simultaneously, a localized Prandtl-Meyer fan emerges from the intersection of the detonation shock with the HE-intermediate layer material interface. These HE structures are shown to have a substantial effect on the structure of the detonation driving zone. The Prandtl-Meyer fan becomes the dominant structure for critically large intermediate layer widths, wherein the presence of the metal layer does not affect the detonation propagation. We examine the detonation propagation speed and reaction and driving zone structure as a function of varying intermediate layer width. Two confinement metals are examined, along with two high explosive and three metal layer widths.     

Detonation of explosive Proppant: RDX-containing water-saturated sand

The results of experimental investigations and thermodynamic calculations of the detonation of explosive proppant, an RDX-containing water-saturating sand, are reported. The material studied is of interest for use as an explosive additive to propping material injected into hydraulic fractures of oil-bearing beds. The tests were conducted in duralumin casings with cylindrical or planar inner channels. The dependences of the detonation velocity on the RDX content in the mixture in the range of 14 to 74 wt %, RDX and sand particle size, and initial temperature are examined. The critical detonation diameter of the charge decreases with increasing content RDX in the mixture, being only several millimeters at RDX contents of 30 wt % and above. Polydisperse RDX provides a high detonability of such mixtures; use of narrow particle size RDX fractions, especially coarse (0.4–0.7 mm), significantly increases the critical detonation diameter. As the initial temperature of the mixture is increased from 20 to 90°C, the critical detonation width decreases severalfold. The detonation of mixtures in a convergent planar channel occurs at a constant rate, which differs little from the detonation velocity measured in a cylindrical channel. Reaching the place where the opening of the channel is less than the critical width, detonation fails abruptly. Thermodynamic calculations of the detonation characteristics of the explosive proppant are performed using the BKWS equation of state under the assumption that the sand component behaves as an inert additive, being in mechanical equilibrium with the detonation products of the RDX-water mixture. A satisfactory agreement with the experimental data on the detonation velocity and its dependence on the RDX content is demonstrated. This makes it possible to conclude that RDX mixed with water-saturated sand detonates within a narrow reaction zone without significant convective heat transfer to the inert additive.     

All Eulerian method of computing elastic response of explosively pressurised metal tube

We present an all Eulerian approach to simulate the elastic response of a metal tube loaded explosively by a gaseous detonation. The high strain rate deformation of the metal tube subjected to high explosive detonation is mathematically described by hyperbolic processes where the characteristics of existing wave motions were correlated with the local particle velocities through the speed of sound in the metal. This is a favourable case for the hydrocode which is based on a compressible gas dynamics solver and for simulating a high strain rate and dominantly plastic response of a material subject to an explosive loading. The hydrocodes fall substantially short of predicting elastic motion without the plastic flow of the confining material, for relatively minor pressure loadings due to a gaseous explosion as opposed to a high explosive detonation of a charged tube. The corresponding loading pressure due to gaseous explosion is a few orders of magnitude lower than those resulting from high explosive loadings. Utilising a hydrocode designed to handle the reactive process leading to a plastic flow of the confining materials is of great interest and a significant challenge. The new technique, based on the Eulerian framework, preserves the feature of a Lagrangian code while utilising all the benefits of an Eulerian solver that uses fixed grids with the level-sets for defining the multi-material interfaces. The hybrid particle level-set algorithm is combined with a hydrodynamic solver that adds an elasticity correction when handling the structural response while the overall scheme remained hyperbolic during the entire reactive flow. Several unseen dynamics of detonation flow associated with the elastically loaded tube of finite thickness are reported by using the present method for analysing the highly pressurised vessel.     

用TNT的{D,ρ0}实验数据对爆轰的ZND理论的检验

爆轰产物中或多或少含有固态碳 ,一相的排平物态方程被推广为两相的之后 ,以某种炸药的一条已知等熵线为参考曲线 ,就可以用来估算其各种初始装药密度下的爆轰参数 .用产物中含碳量较多的TNT的 {D ,ρ0 }实验数据与理论估算值相比较 ,可以对爆轰的ZND理论的假设进行检验 .检验的结果再一次表明 ,爆轰的ZND理论的假设是成立的 ,并且排平物态方程是恰当的爆轰产物的物态方程 .     

Explosive compositions based on the mechanoactivated metal-oxidizer mixtures

Detonation-like regimes in mechanoactivated energetic composites (MAECs) were experimentally studied. The test MAECs consisted of layers of a metal (Al, Mg) and Teflon mixed at the submicron and nano levels. The systems reacted to form solid final products. MAECs are appreciably superior to ordinary mixtures in chemical transformation rate. The burning of MAECs occurs in an explosive regime at a velocity of 300–400 m/s, with the temperature of the products being as high as 4000 K. When initiated with a HE charge, porous MAECs detonate in the steady regime. Depending on the composition and density of the samples, the detonation velocity varies from 700 to 1300 m/s, values markedly higher than the speed of sound in the initial mixture. Detonation is controlled by a hot spot mechanism, more specifically, by relay reaction propagation by jets of products.     

炸药条加载圆柱壳的数值模拟（Ⅰ）：流固耦合模拟

 对炸药条加载圆柱壳模拟X射线力学效应的试验进行了流固耦合数值模拟。首先建立了包括圆柱壳、两层缓冲橡胶、炸药条和空气在内的二维数值模型,其中,两层橡胶采用Ogden超弹性本构模型描述,炸药条及其爆轰产物采用高能炸药燃烧（High Explosive Burn）模型和JWL状态方程描述,空气采用多项式状态方程描述。然后采用多物质ALE流固耦合算法进行计算,获得了爆炸加载的物理图像、载荷传递与结构响应。结果表明,采用19条炸药条加载265 mm的圆柱壳模拟X射线余弦载荷作用,特征点应力响应基本等效;试验附加的两层橡胶对结构响应特征具有影响,在壳体质量较小和（或）刚度较低的情况下,紧密粘接会引起结构响应失真。     

镉镍蓄电池及其在大功率脉冲恒流源中的应用

 介绍了碱性镉镍蓄电池用作脉冲大电流恒流源的可行性，叙述了该类电池放电电流的规律和消除记忆效应的办法，并列出了用镉镍蓄电池组装有关恒流源样机的测试数据和实际考验结果。实验证明：在脉冲式大电流场合下，使用蓄电池作能源，可以消除常用的高功率脉冲源对市电电网的冲击，节省大量设备投资，获得具有高稳定度性能的恒流源。     

钝感炸药圆筒试验与爆轰产物JWL状态方程研究

 对以TATB为主的钝感炸药JB-9014进行了25 mm和50 mm两种装药直径的圆筒试验，测试了TU1圆筒在爆轰产物驱动下的膨胀过程R(t)关系。对圆筒试验进行了综合分析和二维数值模拟计算，综合评估了JB-9014的作功能力和圆筒试验的相似性。通过二维流体动力学数值模拟，确定得到了JB-9014炸药爆轰产物JWL状态方程参数。经对JB-9014二维平面滑移爆轰驱动试验的数值模拟检验，证明确定的JWL状态方程参数是可靠的，具有较高的精度和普适性。     

Embedded particle size distribution and its effect on detonation in composite explosives

This paper discusses the effects of stochastically varying inert particle parameters on the long-term behaviour of detonation front propagation. The simulation model involves a series of cylindrical high explosive unit cells, each embedded with an inert spherical particle. Detonation shock dynamics theory postulates that the velocity of the shock front in the explosive fluid is related to its curvature. In our previous work, we derived a series of partial differential equations that govern the propagation of the shock front passing over the inert particles and developed a computationally efficient simulation environment to study the model over extremely long timescales. We expand upon that project by randomising several properties of the inert particles to represent experimental designs better. First, we randomise the particle diameters according to the Weibull distribution. Then we discuss stochastic particle spacing methods and their effects on the predictability of the shock wave speed. Finally, we discuss mixtures of plastic and metal particles and material inconsistency among the particles.     

钝感炸药爆轰驱动研究

 对两种典型的钝感炸药（IHE）的爆轰驱动模型进行了实验研究。一种是点爆散心波驱动，另一种是滑移爆轰驱动。并在同一条件下做了非钝感炸药（HE）的爆轰驱动实验，以比较IHE和HE驱动规律的异同。对实验模型用二维数值模拟及拟合公式进行了计算，最后给出了在本实验条件下两种炸药驱动规律差异，也对计算偏差范围作了估计。     

散心爆轰的数值模拟

本文在瞬时稳态爆轰的假定下,简要叙述了散心爆轰的不定常性质。在散心爆轰的数值模拟方法中,我们改进了人造粘性并用Cochran反应率和JWL状态方程来描述炸药的引爆过程。计了几个典型的散心爆轰问题,得到了比较满意的结果。     

High-order numerical simulation and modelling of the interaction of energetic and inert materials

We present an integrated algorithm on a Eulerian grid, for multimaterial simulations of energetic and inert materials modelled by non-ideal equations of state. We employ high-resolution shock capturing numerical algorithms for each material inside its domain and use an overlap domain method across the interface, maintained by a recently developed, hybrid, level-set algorithm. For applications to condensed explosives we implement a non-ideal, wide-ranging equation of state and reaction rate law. For inert materials, like plastic, metal, water, etc., we implement a (linear in the pressure) Mie–Grüneisen, (U _p ?U _s ), equation of state. We present a series of verifications of the integrated multimaterial code and show validations against experiment. We show examples of simulations of various experiments associated with real or planned experiments, some of which contain energetic materials (specifically the condensed explosives PBX-9502 and PBX-9501).     

爆轰产物JWL状态方程应用研究

 通过对凝聚态炸药爆轰产物JWL状态方程的研究,提出了一种确定JWL状态方程参数的γ拟合法,即利用γ律状态方程来拟合JWL状态方程参数。这种新方法不需进行圆筒试验,与现有方法比较,具有经济、安全、方便、准确的特点。利用这种方法拟合确定了4种常用炸药TNT、C-4、PETN、HMX的JWL状态方程参数,通过与圆筒试验法得出的JWL状态方程p-V曲线进行对比,证明γ拟合法具有较高的精度,完全可以满足计算爆炸力学的应用。     

固体炸药爆轰的一种考虑热学非平衡的反应流动模型

基于固体炸药爆轰过程中化学反应混合区内的固相反应物与气相生成物处于力学平衡状态及热学非平衡状态的事实,提出一种考虑热学非平衡效应的反应流动模型来描述固体炸药的爆轰流动现象.该爆轰流动模型的主要特点是,在反应混合物Euler方程和固相反应物质量守恒方程的基础上,通过附加一套关于固相反应物的组分物理量的流动控制方程来表达固相反应物与气相生成物之间的热学非平衡效应.根据反应混合区内固相反应物与气相生成物这两种化学组分保持各自内能守恒的混合规则,并借助它们具有压力相等的性质以及满足体积分数总和为1的条件,推导获得的附加方程有：固相反应物的内能演化方程、体积分数演化方程及反应混合物的压力演化方程.这样,建立的爆轰模型包括：反应混合物的质量守恒方程、动量守恒方程、总能量守恒方程、压力演化方程,以及固相反应物的质量守恒方程、内能演化方程、体积分数演化方程.对所获得的爆轰模型方程组采用一个时空二阶精度的有限体积法进行数值求解,典型爆轰问题算例结果表明本文提出的固体炸药爆轰模型是合理的.     

钝感高能炸药爆轰产物JWL状态方程再研究

对钝感高能炸药JB-9014的爆轰产物JWL状态方程进行了深入研究。利用改进的圆筒试验技术,得到了筒壁膨胀的质点速度、位移和加速度的实验结果;通过解析分析和曲线拟合相结合的方法,确定了爆轰产物JWL状态方程参数;采用ANSYS/LS-DYNA3D程序进行了数值模拟,并与实验结果进行了对比和分析,验证了状态方程参数的适用性。     

180°圆弧形钝感炸药的爆轰波传播

 采用贴体坐标下与Level Set方法相结合的爆轰冲击波动力学（DSD）计算方法,研究了180°圆弧形钝感炸药中非理想爆轰波的传播过程。通过数值模拟计算和实验测量的对比分析,得到了180°圆弧形炸药中爆轰波传播的一些规律：圆弧形钝感炸药可以实现定常爆轰,即在极坐标中整个爆轰波以固定角速度转动。这种定常阵面的形状和角速度与圆弧的外半径无关,定常体系依赖于圆弧形炸药的内半径和覆盖圆弧的外壳物质。对描述圆弧形炸药中爆轰波传播规律的经验公式进行了研究,结果表明这些经验公式能够准确描述爆轰波速度的变化,在实验测量和预估方面具有一定的参考价值。     

利用单色谱仪研究炸药粉快速反应产物发射谱

利用作者研制的快速反应（爆轰）光谱探测技术研究了五种常用猛炸药快速反应最终产物光谱。研究表明，随着炸药负氧平衡值的影响，最终产物Ｈ２Ｏ的含量也增加，同样随着炸药中碳含量的增加ＣＯ２量增加，固体Ｃ２也明显增多，它能为爆轰产物合成金刚石选用主炸药提供有参考价值的数据，实验值与ＢＫＷ方程计算进行了比较，其趋势是一致的，为微观研究炸药粉快速反应提供了一个较简便而行之有效的方法。     

Peel-off case failure in thermal explosions observed by the deflagration cylinder test

We have discovered a previously unidentified thermal explosion mode using the Los Alamos deflagration cylinder test (DFCT). The DFCT is a “pipe bomb”-style test similar to the detonation cylinder test (DTCT), which has been used for many years to calibrate detonation product equations of state. The shot is heated in an oven to a uniform test temperature. The pre-heated high explosive (HE) is triggered by a hot wire initiator on one end. The tube is back-illuminated by a bright light source, and its combustion-driven deformation and subsequent break-up are observed by a high-speed framing camera. Like the DTCT, the DFCT tube wall motion provides the primary diagnostic. A variety of reactive responses are possible, including quasi-steady deflagration and deflagration-to-detonation transition. This paper focuses on the behavior of the HMX-based explosive PBX 9501 at 155 °C. Under this condition burning appeared to occur only at the HE/tube interface, causing the tube to peel away from the HE core. Peel-off propagated as a wave that traveled along the tube at 500 m/s. This failure mode resulted in vigorous case venting, but the response was otherwise benign. We derive a steady peel-off-wave model that reproduces the essential observed features for realistic PBX 9501 parameter values.     

Detonation performance of the CL-20-based explosive LX-19

The generation of constitutive detonation performance model components for high explosives (HEs) invariably involves reference to experiment, as reliable first-principles determinations of these models are beyond our current capability. Whatever its form or complexity, the detonation performance model must be able to accurately capture the detonation wave timing and the energy release that it triggers upon arrival. Specifically, the HE products equation-of-state (EOS), which largely determines the detonating HE’s ability to do useful work on its surroundings, is typically inferred from cylinder expansion tests where metal-confined HE cylinders are detonated and the ensuing outer confiner wall-expansion trajectory is recorded. Expensive, iterative comparisons to multimaterial hydrodynamic (or “hydrocode”) simulations of these experiments are then used to constrain the parameters of the chosen EOS form. Here, we report on new detonation performance experiments produced for the highly-ideal, plastic-bonded explosive and CL-20-based LX-19 which are used to produce a new sub-scale detonation performance model for the explosive. This includes new products EOS and a new Detonation Shock Dynamics front propagation law. We also confirm the capability of two new, non-hydrocode-based products EOS generation techniques to accelerate the HE model parameterization process. This latter development is particularly significant for detonation performance modeling of new HE formulations.