长贮过程中发动机HTPB推进剂老化机理分析

为揭示固体推进剂在长期贮存过程中的老化机理,解剖了自然贮存19年贴壁浇注的端羟基聚丁二烯橡胶推进剂装药发动机,沿着药柱径向不同位置进行了取样,并采用扫描电镜、能量色散X射线光谱仪、红外吸收光谱、交联密度等多种手段对这些样品进行了测试分析。研究发现：贴壁浇注发动机药柱不同位置推进剂的老化程度不尽相同,越靠近非金属壳体位置,推进剂的老化程度越严重。进一步深入分析表明：除了丁羟胶中双键的氧化断链和端羟基的缩合等影响推进剂老化,铝粉氧化产生的铝离子会催化丁羟胶双键与氯气或水发生加成反应生成■双键和仲醇,而铝离子迁移和分布的不均匀会引起药柱老化的不均匀性。研究结果对推进剂配方设计和防老化措施的研究具有重要意义。     

Thermal explosion of a reactive gas mixture at constant pressure for non-uniform and uniform temperature systems

In this study, the approximate and exact solutions for the stationary-state of the solids model with neglecting reactant consumption for both non-uniform and uniform temperature systems were applied on gas ignition under a constant pressure condition. The criticality conditions for a slab, an infinite cylinder, and a sphere are determined and discussed using dimensionless temperatures under constant ambient and surface temperatures for a non-uniform temperature system. Exact solution for a Semenov model with convection heat loss was also presented. The solution of the Semenov problem for constant volume or density as a solid and constant pressure were compared. The critical parameter δ is calculated and compared with those of Frank-Kamenetskii solution values. The validation of the calculated ignition temperatures with other exact solution and experimental results were offered. The relation between critical parameters form Semenov and F.K. models solution was introduced.     

One-step synthesis of FeO(OH) nanoparticles by electric explosion of iron wire underwater

In this study,we investigated electric explosion of iron wire in distilled water with different energy input adjusted by charging voltage.The as-prepared samples were characterized by X-ray diffraction (XRD),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS),showing the presence of iron and multiple iron-based compounds oxides with contents influenced by the experimental conditions.In particular,pure FeO(OH) nanoparticles were obtained using electric explosion of iron wire with energy input of 1125 J at charging voltage of 15 kV.Analysis of discharge current and resistive voltage data indicate that the high energy input induced by strong plasma discharge at high charging voltage is a key factor to form FeO(OH).This study presents a one-step method to synthesize FeO(OH) nanoparticles using electric explosion of iron wire.     

氧气体积分数对油气爆炸特性的影响

作为燃烧和爆炸三要素之一,氧气体积分数的控制对于爆炸事故的防治具有重要意义。实验研究了氧气体积分数对汽油蒸气-空气混合物（简称油气）爆炸极限和爆炸压力的影响。结果表明：随着氧气体积分数的降低,油气爆炸下限呈一阶指数规律缓慢增大,油气爆炸上限呈线性规律迅速减小;爆炸极限范围由0.92%~3.76%缩小为1点,该爆炸极限临界点为1.22%,对应的临界氧气体积分数为11.4%;油气的最大爆炸压力和最大压力上升速率随着氧气体积分数的降低而减小,油气体积分数越大,氧气体积分数影响越显著。     

Numerical simulation of base flow with hot base bleed for two jet models

In order to improve the benefits of base bleed in base flow field, the base flow with hot base bleed for two jet models is studied. Two-dimensional axisymmetric Navier–Stokes equations are computed by using a finite volume scheme. The base flow of a cylinder afterbody with base bleed is simulated. The simulation results are validated with the experimental data, and the experimental results are well reproduced. On this basis, the base flow fields with base bleed for a circular jet model and an annulus jet model are investigated by selecting the injection temperature from 830 K to 2200 K. The results show that the base pressure of the annular jet model is higher than that of the circular jet model with the changes of the injection parameter and the injection temperature. For the circular jet model, the hot gases are concentrated in the vicinity of the base. For the annular jet model, the bleed gases flow into the shear layer directly so that the hot gases are concentrated in the shear layer. The latter temperature distribution is better for the increase of base pressure.     

Study of simple plane wave generator with an air-metal barrier

Plane wave generators (PWGs) are used to accelerate flyer plates to high velocities with their generated plane waves, which are widely used in the test of dynamic properties of materials. The traditional PWG is composed of two explosives with different detonation velocities. It is difficult to implement the related fabrication processes and control the generated waves due to its complicated structures. A simple plane wave generator is presented in this paper, which is composed of two identical cylindrical high explosive (HE) charges and an air-metal barrier. A theoretical model was established based on two different paths of the propagation of detonation waves, based on which the size of air-metal barrier was calculated for a given charge. The corresponding numerical simulations were also carried out by AUTODYN-2D^® based on the calculated results, which were used to compare with the theoretical calculations. A detonation wave with a flatness of 0.039 μs within the range of 70-percent diameter of the main charge was obtained through the simulations.     

煤化工火灾爆炸事故原因调查

煤化工作为能源战略发展深加工项目,近几年发展很快也导致火灾爆炸事故频发,造成的损失非常巨大,火灾调查工作非常繁重复杂.从煤化工火灾危险性入手,从火灾调查的组织指挥、现场调查访问、现场勘验分析、综合分析等方面详细论述了煤化工火灾爆炸事故的原因调查.     

氦原子1S, 3S, 1P, 3P态的电子关联计算

本文从二次量子化公式出发,选取广义Laguerre多项式乘以γ~lcxp(-alγ)作为单电子径向函数完全集,这里a_l是依赖于轨道角动量l的变分参数,用组态相互作用方法计算了氨原子~1S,~3S,~1P,~3P态的能量和波函数。当组态限于主量子数n≤4,计算的能量相对精度约为99.9%;当组态限于%≤6,能量相对精度约为99.99%;而Hartree Fock方法的能量相对精度约为99%,利用原子波函数计算了一些原子参数,其结果与其他作者的结果符合很好。     

Numerical investigation of the shockwave overpressure fields of multi-sources FAE explosions

Shockwaves from fuel-air explosive (FAE) cloud explosions may cause significant casualties. The ground overpressure field is usually used to evaluate the damage range of explosion shockwaves. In this paper, a finite element model of multi-sources FAE explosion is established to simulate the process of multiple shockwaves propagation and interaction. The model is verified with the experimental data of a fourfold-source FAE explosion, with the total fuel mass of 340 kg. Simulation results show that the overpressure fields of multi-sources FAE explosions are different from that of the single-source. In the case of multi-sources, the overpressure fields are influenced significantly by source scattering distance and source number. Subsequently, damage ranges of overpressure under three different levels are calculated. Within a suitable source scattering distance, the damage range of multi-sources situation is greater than that of the single-source, under the same amount of total fuel mass. This research provides a basis for personnel shockwave protection from multi-sources FAE explosion.     

弹道冲击下层合板破坏模式及抗弹性能实验研究

以舰用轻型复合装甲研究为背景,针对不同纤维增强种类(包括玻纤织物 C400、C200、SW220 和芳纶纤维织物T750)以及不同面密度层合板结构,在6.2 g刚性微曲面柱形弹弹道冲击下的防护能力展开实验研究,着重讨论了层合板结构弹道冲击下破坏模式、弹体初始侵彻速度及面密度与抗弹能力和抗弹效率之间的关系,认为不同的破坏模式体现了不同的吸能特性和纤维失效机理.