负压环境对炸药爆炸冲击波影响的实验研究

为了研究负压环境对炸药爆炸冲击波的影响,在自制可调真空度爆炸容器中进行负压爆炸实验,采用PCB压力传感器测量罐体轴线固定位置点的冲击波超压,分析了在0、-20、-40、-60、-80、-90、-99kPa等不同负压环境下罐体内测点爆炸冲击波反射超压时程曲线。结果表明,爆炸环境负压降低,测点一次、二次冲击波峰值超压随之降低,在-40kPa和-99kPa负压环境下超压降低显著;爆炸冲击波速度大小与传播介质密度相关,即环境负压越低,气体越稀薄,冲击波传播速度越快;爆炸冲击波速度随环境负压降低而升高,与超压降低强度无相关性;负压环境不改变容器内实验雷管爆炸的气体产物生成量;在近似真空环境中,爆炸冲击波主要以爆轰产物为传播介质,冲击波速度提高受限于爆轰产物运动速度,强度弱,衰减迅速。     

负压条件下球形爆炸容器内乳化炸药冲击波参数研究

为了探究负压条件下乳化炸药冲击波参数,在4m直径可调真空度球形爆炸容器内,开展不同负压和不同药量条件下的乳化炸药内爆实验,获得冲击波的超压时程曲线,重新拟合了乳化炸药在不同负压环境下的峰值超压公式和正压冲量公式。结果表明,乳化炸药质量每减少50g,峰值超压平均下降27%;环境压力每降低20kPa,峰值超压平均下降8.66%;乳化炸药在不同负压环境下的正压冲量约为单质炸药的81.3%;负压条件下的乳化炸药峰值超压和正压冲量实验值与传统经验公式相比误差均大于10%,而基于常压实验值拟合的公式与不同工况下的实验值误差均小于4%,能够精确预测不同负压环境下乳化炸药的冲击波参数。     

炸药爆轰参数与空中爆炸冲击波超压的关系

为研究炸药爆轰参数与空中爆炸冲击波超压之间的关系,设计了不同铝含量的RDX/Al、HMX/Al混合炸药,并进行了空中爆炸试验。根据爆炸相似理论,用相同条件下实测TNT超压数据,计算了冲击波超压的TNT当量。采用不同方法计算了炸药的爆轰参数。结果表明,炸药空中爆炸冲击波超压与爆热、爆容和爆速乘积TNT当量的1/3次方满足线性关系,且回归线在y轴上的截距为0,斜率与炸药的类型有关。对于TNT,斜率为1;对于RDX/Al混合炸药,斜率为1.053(R2=0.9996);对HMX/Al混合炸药,斜率为1.073(R2=0.9995),表明炸药的爆热、爆速和爆容对空中爆炸冲击波超压的影响相同。     

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.     

RDX基含铝炸药水中爆炸近场冲击波特性

通过水中爆炸试验,得到了RDX基含铝炸药在不同比例距离((-R))处的水中冲击波峰值压力、冲量和冲击波能.结果表明,在测试范围内,(-R)＜1.5 m/kg1/3,Al的质量分数为10%～20%时,冲击波峰值压力基本不变;(-R)≥1.5 m/kg1/3时,Al的质量分数为0～30%时,冲击波峰值压力基本不变.测试范围内,Al的质量分数为20%～30%时,冲量基本不变;Al的质量分数小于20%,冲量随Al含量的增加不断增大.(-R)＜1.0 m/kg1/3时,冲击波能随比例距离的增加而不断衰减;(-R)≥1.0 m/kg1/3时,冲击波能随比例距离的增加基本保持不变.(-R)=0.79 m/kg1/3(药柱18倍半径处)时,冲击波能量利用率只有25%左右,初始冲击波能损失了近1/2～3/5.     

炸药水下爆炸冲击波参数的修正

根据有限水域中TNT、钝化RDX的测试结果,结合所采用传感器的特点．得出了一种修正冲击波参数(峰压、比冲能)的方法。结果表明,修正后的峰压与计算值接近,TNT、钝化RDX的比冲能分别占其总能量的46％、44％左右,并使测试总能量占其爆热值的95％以上。     

自制炸药的冲击波超压测试及TNT当量估算

为评估典型自制炸药的威力,采用无线存储测试仪测量了一定质量的雷药、三过氧化三丙酮(TATP)、六亚甲基三过氧化二胺(HMTD)、高氯酸钾/铝及硝酸铵/铝5种自制炸药爆炸后不同距离处的冲击波超压及衰减规律。运用非线性显式动力学软件AUTODYN建立了TNT炸药-土壤-空气域有限元模型,用流固耦合算法计算了不同质量TNT的超压场,获得了距离爆心38、58和78cm处TNT炸药质量-超压曲线,依据该曲线计算了自制炸药的TNT当量。结果表明,TATP、HMTD的TNT当量系数计算结果与文献值基本一致,相对误差在2%以内。     

TNT、PBX和Hexel空中爆炸冲击波参数的实验研究

利用空中爆炸测试系统,对相同质量不同密度不同装药的TNT、PBX和Hexel进行了空中爆炸参数测试。比较了3种炸药在相同测点处的冲击波峰值超压和冲量的大小。研究了冲击波峰值超压和冲量与比例距离的关系。结果显示,TNT的冲击波峰值超压和冲量明显低于PBX和Hexel;在比例距离（1．8～4．9）m／kg^1/3。范围内,Hexel的冲击波峰值超压和冲量高于PBX。当比例距离为6．1m／kg^1/3时,Hexel的冲击波峰值超压和冲量与PBX相当。     

水下爆炸冲击波传播的近似计算

水下爆炸冲击波传播计算由能流密度一时间曲线经验表达式化简。用简单数值积分法解由拉格朗日形式流体动力学方程、Hugoniot方程和能流密度一时间关系式组成的偏微分方程组,不同距离处的冲击波峰值由单点初始数据计算。结果表明,由近似计算方法所得结果与实测数据和相似律结果一致。适当选取起算参数,在5倍装药半径以外的爆炸远场范围计算精度良好。5倍装药半径以内的爆炸近场,冲击波未充分形成,计算方法失效。计算了几种含铝炸药的冲击波传播,表明冲击波能显著影响冲击波传播特性,冲击波能有利于抑制超压衰减。     

炸药空中与水中爆炸冲击波超压的换算关系

通过经验公式分析及模拟实验研究,对炸药装药空中与水中爆炸产生的冲击波超压换算关系进行了研究.结果表明,当比例距离r=R/W1/3的取值范围在1.5～2.5时,炸药装药空中与水中爆炸冲击波超压有定量的换算关系,并拟合出确定的换算公式.通过理论和经验数据分析,得出其他装药水中冲击波超压TNT当量的换算方法,冲击波参数TNT当量应根据炸药水中爆炸的冲击波能进行换算.通过对比证明,根据冲击波参数TNT当量修正后的经验公式计算结果精度可以满足工程设计使用.     

纳米吸波材料在人体防护中的现状及发展方向

电磁辐射对人类健康及其生活环境造成极大威胁 ,回顾了人体防护服的发展 ,就纳米吸波材料的吸波机理、与纤维或织物的结合等进行探讨 ,并对其发展前景给出了一些设想     

Influence of Blast Wave on Hard Structure

In this paper the pressure-time histories of bursting gas vessels in closed rooms are investigated and discussed on the basis of TNT-nomograms. Experimental data of TNT-charges from 0.1 kg to 1.5 kg were measured on various points in a closed room. To describe the results a simplified linear wave model was applied and a good agreement with the experimental data observed. Similar experiments with bursting gas storage vessel were performed and compared with the TNT-results. A TNT-blast equivalent was defined and established. In addition a computer code was created. By use of the input data, which are energy content of the vessel, geometry of the room and other physical parameters, pressure-time histories are calculated. These can be directly used for predicting the loading factors of hard structures.     

浅谈噪声测量方法及对人体的危害

影响人体的噪声有很多类,而且对人体的危害非常大,文章只对工业企业厂界噪声的测量方法和它对人体的一些危害进行阐述。     

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 %.     

Resuspension of Particulate Matter from Carpet Due to Human Activity

This work investigated the resuspension and subsequent translocation of particulate matter (PM) from carpeted flooring surfaces due to walking. In addition, the effect of HVAC systems and ceiling fans on mixing and/or translocation of resuspended PM was studied. Testing took place both in a residence with a well-worn, soiled carpet and in an environmental test chamber. Prescribed walking occurred with PM measurements taken at multiple sampling heights. Scanning electron microscopy (SEM) of carpet fibers was used to determine the fraction of dust available for resuspension. These data, in conjunction with resuspended mass concentrations from this study, were used to generate emission factors by particle size for walking on both new and worn carpet.

Carpet loading does not affect the emission factor, indicating that the amount of resuspended PM is directly proportional to the available PM in the carpet. While relative humidity (RH) plays an important role in resuspension from new carpets, with high RH enhancing resuspension, it has the opposite affect with old carpets, with increased RH decreasing resuspension. With the HVAC system on, translocated particles 1.2 m horizontally from the source had number concentrations of approximately 20–40% of those at the source. With a ceiling fan on, extensive mixing was noted with little difference seen in particle resuspension by height. With the ceiling fan off, there was very little mixing present and particle size varied substantially by height.     

Aerodynamic Particle Resuspension Due to Human Foot and Model Foot Motions

Human foot motions such as walking and foot tapping resuspend the particulate matter on the floor and redistribute it, increasing the particle concentration in air and affecting the indoor air quality. The objective of this article is to experimentally investigate the mechanism of particle resuspension and redistribution due to human foot motion from focusing on aerodynamic effect. In particular, we have examined generation and deformation of a vortex produced by foot motion and how it is affected by the shape of the shoe sole. The experimental methods used were particle visualizations and particle image velocimetry (PIV) measurements in air, supplemented by dye flow visualization in water. The flow visualizations with human foot tapping and stomping were performed to elucidate the particle resuspension in real situations. In the laboratory experiment, the foot was modeled as either an elongated plate or a prosthetic foot wearing a slipper, moving normal to the floor downward or upward. The particle resuspension and redistribution were associated with the wall jet between the foot and floor and the vortex dynamics. With the elongated plate foot model and the slipper, three-dimensional vortex structure strongly affected the particle redistribution and its direction.

Copyright 2013 American Association for Aerosol Research     

Theoretical and Experimental Studies on Blast Wave Propagation in Air

High pressure and temperature are produced when high explosives are detonated in open air. The heat of detonation of the explosive compound, peak pressure, and temperature of the blast wave are important blast parameters. A blast wave generated due to explosion propagates into the air medium at supersonic speed until the pressure in the blast zone is released completely. The intensity of the impact by the blast wave on any intervening solid object depends on the blast parameters and the speed of propagation of the blast wave. A theoretical analysis is carried out to predict the pressure produced in the expanding blast zone as function of distance and time by analytically solving the governing equations. The initial peak pressure and temperature of blast wave, which are required in the theoretical analysis, were calculated making use of the blast wave theory. For comparison, experiments were conducted by detonating different weights of high explosives, and pressures were recorded at various distances from the blast point. The high explosives used in the experiments were TNT (0.045, 0.5, 1, 15, and 40 kg) and Composition B (0.045, 0.5, 1, and 15 kg). The theoretical results are validated by comparison with the experimental data and empirical equations available in literature.     

Study of the Blast Wave Parameters from Small Scale Explosions

Although the science of blast overpressure is well understood there are major difficulties in obtaining accurate values for peak overpressure, positive duration, and positive impulse. These parameters are required to assess damage potential of blast overpressures. This paper describes the problems associated with such measurements and how the problems can be overcome by the use of known analytical techniques based on the modified Friedlander equation. Other methods used include curve smoothing of the pressure-time history and integration to obtain impulse values through which the curve decay parameter can be found. Several different analytical methods are compared. The experiments have been carried out on small charges (200 g and 400 g) and the results obtained analysed to assess far-field distances for such charges. This has been achieved by comparing peak overpressure values with the scaled distance.     

人体健康与饮水

水是生命代谢不可代替的物质,饮水健康已越来越受到普遍关注。时时有人对周边饮水提出疑问,因此课题组立项研究作出了概要性述评。