典型炸药药柱撞击感度的试验研究

为了研究炸药成型药柱和粉状炸药撞击感度的差异,利用炸药药柱撞击感度试验装置,对5~10g量级的3种炸药药柱(TNT、Tetryl和钝化RDX)进行了撞击感度试验,分析了炸药种类、药柱高度和药柱温度对炸药药柱撞击感度的影响。结果表明,炸药药柱和粉状炸药的撞击感度趋势基本一致,但炸药药柱的撞击能(E_0)明显大于粉状炸药,对于TNT、Tetryl和钝化RDX 3种炸药,炸药药柱的撞击能与粉状炸药的临界撞击能之比(E_0/E_(50))在2.6~4.9之间;随着药柱高度由10mm增至20mm,Tetryl药柱撞击感度下限(H_0)由40cm增至105cm;药柱的温度也对炸药撞击感度有显著的影响,随着药柱温度由-40℃升至70℃,JO-8药柱撞击感度下限(H_0)由30cm升至50cm;炸药药柱的撞击感度由炸药原材料、炸药药柱的物理与化学性质等多个因素决定。     

冲击加载下分步压装装药抗过载响应特性的数值模拟与实验

为研究冲击加载下分步压装装药的响应特性,利用ANSYS/LS-DYNA软件对分步压装含铝炸药大型落锤冲击加载过程进行了数值模拟,得到不同密度分布状态药柱在冲击载荷作用下的应力分布及形变特征。探讨了径向密度差对分步压装装药撞击安全性的影响,并进行了实验验证。结果表明,与传统模压成型药柱不同,冲击加载下分步压装药柱中心区的响应应力大于边缘区,且1/2半径处的炸药微元具有较大的径向流动速率。实验验证结果与模拟结果一致。由于径向密度差的存在,冲击加载下分步压装装药内部应力分布不均,使得炸药颗粒呈现由中心向边缘流动的趋势,进而增加分步压装装药内部"热点"形成的几率。     

浇注PBX炸药药柱的动态撞击性能

将浇注型PBX-1药柱以150、240m/s速度撞击靶板,用扫描电子显微镜(SEM)技术和差示扫描量热仪(DSC)技术对撞击加载后的样品进行了分析,研究了浇注PBX炸药药柱的动态撞击性能。结果表明,在150、240m/s撞击加载条件下,PBX-1炸药不发生反应或点火;浇注炸药药柱的损伤主要表现为炸药颗粒破碎和颗粒与黏结剂的脱离。随着撞击加载速度的增大,PBX-1炸药颗粒破碎程度增大,炸药颗粒与高分子基体发生脱离现象越严重;PBX-1炸药撞击前后,热分解性能没有发生本质性的变化。     

一种工业CT定量检测炸药装药密度的方法

为了定量检测炸药的装药密度,提出了一种工业CT测量炸药装药密度的线性换算法。用蒸馏水制备已知密度的盐溶液作密度标准件,对该方法进行了验证。用该方法测量了某战斗部产品实际装药密度和某种炸药药柱的密度。结果表明,该法与排水法测量装药密度或药柱密度之间的误差为1%。认为线性换算法简单、实用,能用于检测结构简单样品的装药密度。     

国外B炸药改性技术重要进展

通过改进装药方法提高药柱质量减少装药疵病，改进炸药配方加入各种添加剂提高药柱的强度和韧性，提高药柱碎解后的点火能量、降低燃烧反应速率、降低渗油性，使Ｂ炸药的膛炸概率明显下降。     

火炸药药柱撞击感度试验装置及方法

为了提高火炸药药柱撞击感度测试的试验手段,建立了一套新的炸药药柱撞击感度测试系统,并对系统的主要技术指标进行了验证。设计了试验方法,对不同成型炸药药柱和不同尺寸的推进剂进行了撞击试验。结果表明,试验结果气体检测判定法明显好于传统的方法,药粉与药柱由于结构的不同,试验结果也不完全一致,即使相同种类的药由于尺寸不同也可能带来结果的差异。     

HTPB/AP复合推进剂装药直径对冲击波点火的影响

为研究HTPB／AP复合推进剂装药直径对冲击波点火的影响作用,用隔板实验测试了不同装药直径对冲击波点火临界燃烧厚度及峰值压力的影响。确定了最佳药柱直径,并对其点火可靠性及药柱受冲击波点火后密度变化进行测试。结果表明,药柱直径与临界燃烧隔板厚度及冲击波强度有着密切的关系。密度为1．563g／cm^3时,HTPB／AP复合推进剂的最佳冲击波点火推进剂装药直径为40mm,且冲击波点火可靠性良好,药柱受冲击波作用后,密度发生一定变化。     

加热前后PBX-2炸药的撞击响应

为了研究炸药在加热前后撞击安全性能的变化,设计了热与撞击复合加载试验系统,并对Φ50 mm×50 mmPBX-2药柱进行了试验.试验中采用热电偶测量药柱不同位置温度的变化过程,通过高速摄像照片记录了点火反应过程,用冲击波超压传感器测量了炸药的反应超压,初步获得了加热前后PBX-2炸药的撞击响应特性.结果表明,加热后的P...     

黏结剂影响混合炸药低速撞击响应敏感性研究

为了研究黏结剂对炸药低速撞击响应的影响,采用自行研发的落锤式撞击感度装置对含不同黏结剂炸药的撞击感度进行了研究,对比了相同配比下含不同黏结剂药柱的响应敏感性,分析了不同黏结剂对炸药低速撞击响应的影响规律,研究了不同黏结剂的作用机理。结果表明,含增塑剂的黏结体系使炸药更加钝感,SA黏结剂对炸药低速撞击响应的钝感效果最好。     

钝感复合装药结构枪击试验尺寸效应的数值模拟

利用有限元软件AUTODYN对钝感复合装药药柱进行枪击感度数值模拟。结果表明,外层采用TATB钝感炸药,内层采用PBX-9404高能炸药的复合装药结构既可减小炸药的枪击感度,又能得到比单一钝感炸药高的能量输出。通过分析装药结构的尺寸效应,得到装药结构与枪击感度的对应规律。     

含废弃丁羟推进剂的凝胶炸药

为安全处理和再利用废弃固体推进剂,通过添加单基药将丁羟推进剂再利用制备了灌注式凝胶炸药.采用验证板试验及电离探针法研究了不同装药配比、推进剂颗粒尺寸及装药直径对炸药爆轰性能的影响.结果表明,丁羟推进剂难以发生爆轰,若添加适量单基药,能显著提高炸药的爆轰感度,并降低其临界直径;该凝胶炸药密度为1.6 g/cm3,直径为7...     

Numerical simulation of the influence of an axially asymmetric charge on the impact initiation capability of a rod-like jet

With the aim to improve the impact initiation capability of a rod-like jet, this paper presents the influence of an axially asymmetric shaped charge on the jet studied by means of numerical simulations. According to Held’s initiation criterion, the impact initiation capability of the jet is affected by the jet tip velocity and diameter. The detonation radius over the longitudinal axis, restricted by the charge radius over the same axis, affects the detonation wave in the charge, the force acting on the liner, and, therefore, the jet velocity and shape. Based on these laws, the structure of the axially asymmetric charge is optimized. Compared with axisymmetric jets, axially asymmetric rod-like jets possess a higher impact initiation capability.     

Energy release of mixed explosives during propagation of a nonideal detonation under conditions similar to the operation conditions of a blasthole charge

Detonation experiments were performed in a specially developed explosive device simulating a blasthole using charges of fine-grained and coarse-grained (granular) 30/70 TNT/ammonium nitrate mixtures of identical density 0.89 g/cm³ in steel shells with an inner diameter of 28 mm and a wall thickness of 3 mm at detonation velocities of 4.13 and 2.13 km/sec, respectively. Despite significant differences in detonation velocity (pressure), identical expansion of the charge shells was observed. On the other hand, numerical simulations of detonation propagation in the explosive device with the corresponding velocities ignoring the possibility of energy release behind the shock front show that the expansion of the charge shell is always greater in the case of a high-velocity regime. It is concluded that under the conditions simulating detonation propagation and the work of explosion products in a blasthole, effective additional energy release occurs behind the low-velocity (nonideal) detonation front. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 4, pp. 111–120, July–August, 2007.     

Modélisation Mathématique de la Décantation de la Boue Rouge

A good performance of the solid‐liquid unit operation is required for the economical exploitation of the Bayer process. A computational fluid dynamics (CFD) model simulating the operation of the last washing stage mud thickener of a large Canadian alumina plant is presented. The parametric study of the impact of changes in four parameters shows that the diameter of flocculated red mud particles, the feed flow rate and the radius of the feed well are critical parameters for the operation of the thickener.     

Impact charging of particulate materials

When a particle impacts on a wall, electrostatic charges may be generated. This is called contact/impact/frictional electrification. One question to be answered is how and what process dominate the amount of the charge. In this respect, the separating process, rather than the contacting one, is important. It is shown that the potential difference between the surfaces can increase so rapidly in the separation process that it can cause gas discharge. Once such a gas discharge takes place, the charge on each surface can relax on the path: the amount of charge after the separation is a kind of residual charge after the charge relaxation. This process has been modeled and the model is called the “charge relaxation model.” It can estimate the amount of the impact charge without any empirical parameters, although the gas discharge itself is only an assumption so far which has not been directly observed or confirmed experimentally. In the experimental aspect, an “impact charging experiment” with single particles was carried out to provide a basis for the fundamental discussions. Polymer as well as metal particles about 3 mm in diameter ones were initially used, and the results showed good agreement with the “charge relaxation model.” The sensitivity of the instrument was enhanced to allow measurements with micrometer particles. These results are also reviewed here.     

Interpretation of Volatility Tandem Differential Mobility Analyzer (V-TDMA) data for accurate vapor pressure and enthalpy measurement: Operational considerations,multiple charging,and introduction to a new analysis program (TAO)

Abstract

Significant evaporation of pure aerosols in a Volatility Tandem Differential Mobility Analyzer (V-TDMA) creates two Condensation Particle Counter (CPC) response peaks. Two hypotheses for the observed peaks have been proposed: the existence of two phases or the separation of the singly charged experimental size distribution from the remaining experimental size distributions with charges greater than 1 (charge separation). To explore this observation, we atomized pure levoglucosan aerosol and evaporated the aerosol until two peaks formed. We used an additional classifier and neutralizer to select particles from each of the two peaks and assessed the number of charges on the particles. The smaller diameter peak contained singly charged particles, and the larger diameter peak contained the remaining charges. The charge separation hypothesis alone accounts for the two-peak observations. We used a new V-TDMA model named TAO and show that charge separation should occur in other pure components as well. The TAO model was then used to display the impact of different DMA transfer functions, different inlet size distributions, and different oven residence time distributions (RTDs) on the CPC response. Large errors are possible when direct measurement of the RTD is not performed or when wide RTDs are used. We recommend use of narrow transfer functions with narrow RTDs to detect charge separation. When the singly charged CPC response is isolated (smaller diameter peak in the two peak response), accurate estimations of vapor pressure can be recovered, assuming accurate values for gas phase diffusivity, surface energy, particle density, etc. are used.

Copyright © 2020 American Association for Aerosol Research     

102枪装127弹射孔工艺在大庆油田的开发与应用

为探索在大庆油田140mm套管井上应用127射孔弹以提高射孔穿深,达到更好的射孔效果,研制出102枪装127弹射孔工艺技术。模拟井和地面试验井试验表明,该工艺解决了枪身强度、合理装药量等关键技术,使该项新工艺既实现了射孔弹最佳合理炸高和枪靶间隙以达到深穿透的目的,又防止了102枪涨大、炸裂。大庆油田近千口井现场试验表明,该技术的射孔穿深、孔径等技术指标在行业标准允许的范围内,并能有效地提高采液、采油强度。     

Experiments of Initiation of Covered,but Unconfined HE Charges under different test conditions by shaped charge jets

The initiation behavior of TNT/RDX 35/65 high explosive charges under the impact of the jet from a 44 mm diameter shaped charge with 7.8 mm/m̈s jet tip velocity, which has previously perforated a 100 mm thick barrier is reported. In these tests,

• the high explosive charge under test was divided into different sections by transverse air gaps, with the first section being in contact with the barrier, or
• the 100 mm thick barrier was sub-divided in such a way that one part of it was in contact with the high explosive charge under test, or
• various air gaps, ranging from 0.5 mm to 450 mm, were made between the acceptor charge and the barrier.

     

The Effect of Particle Morphology on Unipolar Diffusion Charging of Silver Nanowires

We investigated the effect of particle morphology on unipolar charging of nanowires. The average diameters of silver nanowires were 32, 48, and 68 nm. Particle electrical capacitance is an important parameter that determines the mean charge per particle in a continuum regime. We predicted that a nanowire has larger electrical capacitance than a sphere, and for a nanowire, the electrical capacitance increases as its diameter decreases. The mean charge per nanowire particle was calculated with the electrical capacitance obtained from theoretical analysis as a function of electrical mobility diameter. The mean charge per particle was measured for polystyrene latex particles with an electrical mobility diameter of 100–300 nm, and silver nanowires with an electrical mobility diameter of 200–400 nm. For a given electrical mobility diameter, the mean charge per particle of a nanowire in theoretical analysis and experiments was larger than that of a sphere, and it increased as the diameter of the nanowire decreased. Our results indicate that the mean charge per particle of a nanowire is dependent on particle morphology such as the diameter and the length.

Copyright 2015 American Association for Aerosol Research