三波点的测量与实验技术研究

为研究爆炸冲击波传播过程中三波点的轨迹和在三波点上下不同位置测量结果的区别以及与在地面测量冲击波压力的关系,采用在不同高度布放自由场压力传感器,测量了炸药爆炸的冲击波超压,试验研究了三波点的高度.在相应位置的地面放置壁面压力传感器,得到相同测量位置处地面冲击波的压力参数及在距地面一定高度爆炸的三波点轨迹.对比分析了两种测量方法的相对标准差,得到不同测量方法对测量不确定度的影响.结果表明.用自由场压力传感器在三波点上方的测量精度较后者高.     

FAE装置炸高对爆炸压力场影响的实验研究

FAE装置炸高对爆炸压力场有重要影响，本文通过相同条件下不同炸高的FAE装置进行实验，利用多通道数据采义和地面模拟目标进行空气冲击波测量和地面毁伤效率应评估，实验结果表明；FAE装置炸高对爆炸空气冲击波有重要影响，它不仅影响毁伤半径，而且还影响不同距离处的冲击波作用时间和压力峰值。     

有限空间炸药装药内爆炸威力的评估方法综述

通过分析有限空间内爆炸过程和能量释放特点以及自由场与有限空间内爆炸的能量输出特性,讨论了冲击波压力-冲量、屋顶举起位移、准静态压力和冲量-准静态压力4种内爆炸威力评估方法的适用性,提出应当使用冲击波峰值压力和冲量评估炸药爆轰释放的能量、准静态压力评估炸药内爆炸释放的总能量、屋顶举起位移和冲量-准静态压力权衡的方法评估炸药内爆炸的综合威力性能。附参考文献27篇。     

半密闭条件下爆炸场的温度与压力测量

通过测量不同铝含量炸药的爆炸场温度和压力参数,研究了在半密闭条件下,炸药爆炸场温度、压力的响应特征及规律.结果表明,设计的试验装置适合研究在半密闭条件下炸药的温度-压力性能.在半密闭条件下,超压曲线不同于自由场的超压测量曲线;理想单质炸药的压力明显高于其含铝炸药,铝含量的增加可增大爆炸压力的作用时间,并提高爆炸场温度及温度对环境的作用时间.当铝粉的质量分数为30%～41%时,爆炸温度出现温度平台,大约在1 000 ℃;在半密闭条件下,测量距离影响温度和压力的分布.     

基于Riemann问题的可压缩多介质流体数值模拟及在二维爆炸冲击波传播问题中的应用

为有效提高可压缩多介质流体数值模拟的精度和稳定性,需要准确描述界面的位置以及界面两侧介质间的相互作用。针对JWL、多项式等具有高度非线性状态方程的多种流体间的相互作用问题,提出了一种通用、高效、误差可控的Riemann问题求解方法,能有效提高物质界面上各物理量的计算精度。结合Euler坐标系下的可压缩多介质流体数值方法,建立了一套能够模拟具有高密度比、高压力比以及复杂状态方程的二维多介质流体计算体系;结合网格自适应技术,对TNT空中爆炸自由场、TNT爆炸近区冲击波反射和水下爆炸等问题进行了数值模拟,并与实测结果进行了对比。结果表明,数值计算的爆炸冲击波参数与相关实测结果一致,表明该方法可用于复杂环境下爆炸冲击波传播规律的研究。     

PVDF计在水中爆炸近场压力测试中的应用

为得到炸药水中爆炸冲击波在一定近场范围内的压力剖面曲线和峰值压力随传播距离的衰减规律,采用在炸药起爆轴线上布置4个PVDF计测量冲击波压力以及在相同实验情况下对炸药轴线上冲击波轨迹进行高速扫描的方法,研究了PVDF计测试近场压力的可行性.结果表明,PVDF计可以用于水中爆炸近场冲击波压力的测量,在量程允许范围内,能得到较准确的冲击波压力峰值;在冲击波强度小于4GPa的情况下,得到了冲击波的压力衰减历程,获得近场压力剖面曲线,对评估舰船抗爆性能具有重要意义.     

爆炸冲击波对人体损伤与防护分析

为研究爆炸冲击波对人的损伤与防护问题,分析了爆炸防护人员损伤的阈值问题,并以"Jose Henrych"经验式为计算模型,探讨了标准TNT炸药在不同当量条件下、在空气自由场中点爆炸时冲击波的变化规律.在此基础上得出了不同装药量时的鼓膜损伤和不同死亡率下的安全距离,经验证,所得结果是准确、可行的.     

甲烷爆炸对建筑物内外压力场分布的影响

天然气泄漏导致的预混爆炸，会严重威胁周围人员的生命及财产安全，因此掌握气体预混爆炸在建筑物周围产生压力场的分布至关重要。基于Fluent软件，建立了适用于甲烷无约束爆炸超压的计算模型，并通过实验数据对其修正，结果表明：在化学计量浓度下参与燃烧爆炸的预混气体体积约为总体积的1/3，即当量体积。在此基础上建立了适用于甲烷约束爆炸的仿真模型，分析了建筑物高度和宽度对建筑周围压力场的影响，并进一步研究了气体爆炸对建筑物内部压力场分布的影响。结果表明，在建筑物不失效前提下，背对爆炸源一侧中上部为较安全区域，在紧急爆炸事故中，盲目的向下逃生，反而容易受到爆炸超压的强烈冲击。     

Al/PTFE与炸药组合装药的爆炸释能特性

为探究Al/PTFE活性材料与高能炸药组合装药的爆炸释能特性，制备了3种包含不同组分和质量的Al/PTFE活性材料的组合装药样品，并进行了爆炸试验，测量了不同距离处的自由场入射冲击波超压，拍摄了活性材料抛撒、反应、火球扩展等过程的图像，通过与裸装药静爆试验进行对比，分析了活性材料的反应特性及对冲击波超压参量的增益机理。结果表明，活性材料抛撒过程中经历了自身反应、与爆轰产物的无氧反应以及铝粉等与空气的有氧反应，相比于裸装药，二次反应增大了爆炸火球半径并大幅延长了火光持续时间，在中远场范围内有效增强了冲击波，2.5m测点处冲击波超压和比冲量最大分别达到了裸装药的1.8倍和1.5倍，且铝粉浓度越高，增益比例相对越强，但随着传播距离增大，铝粉稀释，差异逐渐缩小；通过选用合适组分比例和质量的Al/PTFE活性材料，有益于弥补近场材料破碎和抛撒造成的冲击波能量损失，同时后燃反应为中远场提供能量补充，有望实现爆炸释能整体增益。     

壳体厚度和爆炸深度对水下爆炸冲击波的影响

根据Cole水下爆炸冲击波经验公式和C-J爆轰理论,用AUTODYN软件对带壳小药量装药水下爆炸进行数值模拟,计算了不同壳体厚度的TNT水下爆炸冲击波压力峰值,得到带壳装药水下爆炸冲击波峰值压力的拟合公式,分析了冲击波随装药壳厚与半径比以及爆炸深度的变化规律.结果表明,带壳装药水下爆炸的冲击波峰值压力随壳厚与装药半径比...     

GI-920炸药爆轰波阵面的光纤探针测量

利用熔石英在冲击作用下的发光特性开发了一种测量冲击到达时间的光纤探针技术。当爆轰波阵面到达光纤探针端面时会产生一个瞬时光信号,经光纤传输到光电探测器,变换为电信号,再由示波器记录,通过判读就可以知道冲击波或飞片到达光纤探针的时刻。采用芯径0．3mm的石英光纤探针阵列对一点起爆的爆压为10GPa的GI-920炸药的爆轰波阵面进行了测量,测量到3条不同直径上的波形,并利用所测数据绘出爆轰波阵面的三维形状图。结果表明,随着测试半径增大,爆轰到达时间分散性明显增加,爆轰波阵面的倾角也增大。实验所得信号的上升时间均小于4ns,说明光纤探针技术为炸药爆轰时间参数的测量提供了一种新的高精度的测试手段。     

应用二维黏性CE/SE方法模拟挡波墙对爆炸流场的影响

应用高精度的二维黏性CE/SE方法模拟爆点周围有挡波墙的爆炸流场,分析了挡波墙与冲击波相互作用的规律,得到了能够反映波系结构变化的压力等值线图.数值计算结果显示了冲击波遇挡波墙发生反射、绕流等现象;通过与无挡波墙时的爆炸流场对比,分析了挡波墙的削波作用;同时考察了挡波墙的高度、厚度对远场压力的影响.数值计算结果对于爆炸流场的防护具有理论指导意义.     

Theoretical Prediction of Pressure and Temperature of an Aluminized High Explosive in Underwater Explosion

The blast wave propagation in underwater explosion was studied. The shock propagation in water medium was different from that in air. The blast effect in water lasted longer and offered resistance to the expansion of hot gases and release of energy. A theoretical analysis of the expansion of blast wave in water was carried out and numerical results for pressures and temperatures were obtained as functions of distance and time by analytically solving the governing equations. The initial peak pressures of blast waves, which were required for theoretical analysis were calculated using the blast wave theory. Underwater blasts with different weights (0.045, 0.5, and 1.0 kg) of the aluminized high explosive HBX‐3 were conducted to record pressure as a function of distance and time from the blast point. Theoretical results were compared with experimental data and empirical data for HBX‐3 from literature. Since the measurement of pressure and temperature at close proximity of point of detonation is difficult, theoretical modeling of underwater blast is of significant importance.     

Recording the Position of a Blast‐Wave Front in Air

This paper describes a simple method of determining the trajectories of blast waves in the near field of explosions of condensed explosives. The method is based on the experimental finding of the occurrence of an electric potential across the core of an antenna through which the front of a blast or a shock wave passes.     

Development of a Structure for Blast Wave Mitigation

The internal structure of a blast containment container has been developed and examined by experiments involving the explosion of a high explosive. A steel pipe was selected as an effective structure for blast mitigation, because it dramatically reduces the blast wave in the radial direction near the explosion source. To also reduce the blast wave in the axial direction, two types of model structures consisting of a steel pipe as the main part were examined by both high‐speed photography and pressure measurements of the blast waves. A 0.34‐scale internal structure was constructed by combining these structures. To induce a powerful mitigation effect, the internal structure was filled with a shock‐absorbing material. The peak pressures of C4 explosions in free air were obtained on the basis of the published blast wave data for TNT explosions in free air using an equivalent weight of 1.37. The peak pressures of the blast waves from the structures for all cases were compared with the blast wave data for C4 explosions in free air to estimate the blast mitigation effect. As a result it was estimated that the internal structure not only eliminates the blast pressure in the radial direction but also reduces the blast wave in the axial direction by 36 %. By combining the effects of the internal structure and the shock‐absorbing material, the structure can reduce the peak pressure by 75 %.     

On the Use of Composite Charges to Determine Insensitive Explosive Material Properties at the Laboratory Scale

Laboratory‐scale air‐blast experiments an gram‐range composite explosive charges are presented. The composite charges consist of a spherical booster charge surrounded by a concentric, spherical “candidate material” shell charge. By way of composite charge explosive characterization, the candidate explosive material is able to be characterized through the “removal” of the known booster effects. Using peak shock wave pressures, a method is developed to remove the booster effects from the composite charge’s signature to yield the sole effects of the candidate explosive material, permitting its characterization. Air‐blast explosive tests are conducted using digital high‐speed shadowgraph visualization to measure the resulting shock wave radial position as a function of time. Booster and composite charge data are converted to Mach number versus shock wave radius profiles and subsequently to peak shock wave pressure versus shock wave radius profiles for characterization of the shell material. Explosives tested include: PETN, RDX, HMX, and Alliant Bullseye® SP.     

Performance of Unconfined Detonable Fuel Aerosols of Different Height to Diameter Ratios

Unconfined fuel aerosols known as fuel air explosives (FAE) are detonable in nature over a wide range of fuel concentrations in air. The fuel aerosols are formed by dispersing the fuel in air by explosive means and detonated using a suitable initiator charge leading to the generation of a high impulse blast. For weapon applications, the designers aim for higher lethal area for damaging soft targets. Theoretical estimations have shown that aerosols of lower height to diameter ratio (H/D) produce higher blast pressures at longer distances, thereby enhancing lethal area. However, there is no experimental data available in the open literature to validate the theoretical findings. In this study two approaches were followed to generate detonable aerosols of different H/D, viz.; use of different burster charge loadings for a given fuel container known as canister and fuel quantity and use of different size canisters for the same fuel quantity and burster charge loading. The aerosols formed by a given size of canister and 4.2 kg propylene oxide with different burster charge loadings having similar H/D values and blast performance. In the second approach, a canister with lower H/D containing 18.5 kg propylene oxide generated aerosols of lower H/D and higher blast performance at longer distances as compared to that of a canister with higher H/D with the same fuel quantity. The better canister fragmentation and fuel dispersion observed for the canister of lower H/D has been attributed to the better utilization of burster charge energy as evident from theoretical estimation of the time period for completion of the burster charge detonation and shock wave travel to canister wall. The experimentally observed initial velocity of fuel dispersion was found to be in well agreement with the theoretically estimated values. The results indicate tailorability of blast performance for a given quantity of fuel by choosing the canister H/D.     

爆炸冲击波绕过墙体的数值模拟研究

利用ALE算法和炸药爆轰产物的JWL状态方程对爆炸冲击波绕过墙体的环流现象进行了数值模拟,得到了在爆炸物周围有障碍物的爆炸场初始发展和绕过墙体环流的情况,解析了空气冲击波的绕流规律。实验结果与数值模拟基本相符,反映了爆炸波绕过障碍物的详细过程。