两种混合单元混合机理的数值模拟

为了研究SV型和SX型混合单元在全静态乳化器的混合机理,使用群体平衡模型对乳化器内部流场进行模拟分析。结果表明,SV型与SX型混合单元的混合机理是油相与水相材料通过混合单元时其空间流动方向改变,在流场内形成大量的漩涡,从而达到乳化的目的;通过比较流体在经过SV型和SX型混合单元后的水相索特平均直径(d_(32)),得出SV型混合单元的乳化效果更强,但同时消耗更多的能量,压降更大。     

Meso-structure construction and effective modulus simulation of PBXs

ABSTRACT

The polymer-bonded explosive (PBX) is a kind of multi-phase composite consisting of the polymeric binder and embedded energetic particles, in which the particle volume fraction (PVF) is often higher than 90%. In the present work, by using the Voronoi-polygon generation method along with the concept of gradation to generate Voronoi particles with given gradation, and with further operations including modification, shrinking, smoothing, etc. to the particles, a new meso-structure construction method for PBXs is proposed. The constructed meso-structures possess good gradation relationship and have high PVFs (94.99% in maximum) simultaneously. The strict periodicity on the boundaries of the meso-structure can also be achieved. To verify the constructed PBX meso-structures, the numerical manifold method (NMM) is used to simulate the effective modulus of the constructed meso-structures by considering different influencing factors such as the size of meso-structure, PVF, gradation, and initial defects, etc. The simulation results are analyzed qualitatively, and the causes of differences between the simulation results and available experimental results or other numerical results are discussed. The validity of the proposed method for the construction of PBX meso-structures is verified. This work also provides foundations for the further numerical studies of the mechanical and thermal behaviors of PBXs at the mesoscale.     

How hydrogen-storage material affects the decomposition of nitramine explosive: CPMD investigations of LAB-doped CL20

As the most popular high-energy explosives, 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazatetracyclo [5.5.0.0.0] dodecane (Simplified as HNIW or CL20) attracts many attentions for improving its detonation appearance in the application. Here we introduce hydrogen-storage compounds into explosives to estimate the possible improved detonation performances by Car-Parrinello molecular dynamics (CPMD) simulation, where we construct lithium amidoborane (LAB) doped CL20 as the initial structure. Almost all the interactions between hydrogen and CL20 appear exothermic properties, which indicate LAB increases the enthalpies of detonation. The results suggest explosive mixed with hydrogen-storage material is possibly a new field of energetic compound.     

A Colorimetric Artificial Olfactory System for Airborne Improvised Explosive Identification

The detection of ultralow or nonvolatile target analytes remains a significant challenge for artificial olfactory systems even after decades of development, which severely limits their widespread application. To overcome this challenge, an artificial olfactory system based on a colorimetric hydrogel array is constructed for the first time as a universal representative. As an effective extension of conventional artificial olfactory systems that integrates the merits of its predecessors, the proposed system accurately mimics olfactory mucosa and specific odorant binding proteins using hydrogels endowed with specific colorimetric reagents for the detection of hypochlorite, chlorate, perchlorate, urea, and nitrate. Therefore, the proposed system is capable of detecting and discriminating between these five airborne improvised explosive microparticulates with a detection limit as low as 39.4 pg. Additionally, the system demonstrates good reusability over ten cycles, rapid response time of ≈0.2 s, and excellent discrimination properties, despite significant variation. This proof-of-concept study on colorimetric artificial olfactory systems yields a novel strategy for the direct and discriminative detection of nonvolatile airborne microparticulates.     

Evaluation of small-scale combustion of an insensitive high explosive formulation containing 3-nitro-1,2,4-triazol-5-one (NTO), 2,4-dinitroanisole (DNAN), and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX)

ABSTRACT

Energetic materials are often disposed by open-burning or open-detonation as it is a cost-effective and efficient means of destroying explosive material, and often minimizes the need to transport hazardous explosives to treatment facilities. This practice is often scrutinized for the negative environmental impact of the odorous and unsightly toxic gaseous emissions as well as the resulting deposition residues, which often contain unburned energetic materials. With the increasing use of Insensitive High Explosive compositions in munitions, it is essential that the potential environmental impact of their disposal is assessed before their extensive use to prevent the kind of contamination incidents experienced with legacy explosives. Therefore, the aim of this work was to develop a controlled laboratory experiment to identify the gaseous emissions and the energetic material residues that are generated through the combustion of the IHE components 3-nitro-1,2,4-triazol-5-one (NTO), 2,4-dinitroanisole (DNAN), and 1,3,5-trinitroperhydro-1,3,5-triazine (RDX). A sealed vial containing small (mg) quantities of energetic material was heated until the energetic material combusted. Gas chromatography/mass spectrometry (GCMS) was used to calculate the oxygen consumption and to identify the gases that were generated. The solid residues were analyzed by high-performance liquid chromatography (HPLC) to quantify unburned energetic material. Results showed that DNAN was the most resistant to burning, thus leaving significant quantities of unreacted starting material in the vial. An interesting observation for the IHE formulation was that DNAN also inhibited the combustion of NTO and RDX. The gases emitted during the open burning of IHE components and mixtures included CO, CO₂, and N₂O as expected, but the proportions differed when the components and mixture were compared, reflecting the influence of DNAN on the burning behavior. From our data, we concluded that open-burning DNAN-based formulations is an environmentally unfavorable waste-management practice for the disposal of IHEs mainly due to generation of solid residues as well as unburnt DNAN.     

复合敏化乳化炸药爆速研究

通过对大量测试数据的整理和分析讨论,得出玻璃微球与气泡复合敏化的乳化炸药爆速与炸药密度、敏化剂含量等因素的关系。由显著性分析可知,复合敏化剂中的任何一种组分都对乳化炸药的爆速有显著影响。     

12路无起爆药非电传爆系统设计研究

为了提高非电传爆系统的安全性,设计了一种全系统无起爆药结构的12路无起爆药非电传爆系统,对无起爆药起爆装置、无起爆药传爆组件、无起爆药输出部件进行了结构、装药设计。通过输入端传爆性能试验、输出端传爆性能试验及作用时间试验,验证了12路无起爆药非电传爆系统结构设计合理,可大幅提高安全性及抗电磁环境能力。     

RuO2-IrO2-SnO2／Ti电极电催化氧化降解苯酚废水

针对火炸药废水中所含苯酚类污染物排放量大、难降解的问题,以RuO_2-IrO_2-SnO_2/Ti为阳极、Ti为阴极,氯化钠为电解质,采用电催化氧化法对模拟含苯酚火炸药废水进行了研究。考察了氯化钠浓度、电流密度、pH值、苯酚废水初始浓度对苯酚去除率等的影响。在苯酚去除率最佳的条件下研究了总有机碳(TOC)、化学需氧量(COD)去除率随时间的变化。采用高效液相色谱法推测了降解苯酚的中间产物及过程。结果表明,在氯化钠浓度为13 g·L~(-1),电流密度为30 mA·cm~(-2),pH值为5,苯酚废水初始浓度为500 mg·L~(-1)的条件下,反应60 min,苯酚去除率可达99.85%。在苯酚去除率最佳的条件下,反应100 min,TOC和COD的去除率分别可达53.55%、59.37%。该电极易于催化ClO~-、·OH等活性基团与苯环发生亲电加成反应生成芳香族化合物,并迅速将其氧化降解为脂肪族化合物及CO_2和H_2O。     

不同升温速率热作用下PBX-2炸药的响应规律

采用不同升温速率3,5,10,25,105℃.min-1分别对PBX-2炸药进行了烤燃试验,试验中用热电偶分别测试样品半径处和中心处的温度变化过程,通过冲击波超压测量分析了样品的反应程度,根据热分析和烤燃试验结果宏观上分析了PBX-2炸药在热作用下的响应规律。试验结果初步表明:热作用试验中PBX-2炸药随着升温速率升高反应程度降低。采用Arrhenius模型对PBX-2炸药在热作用下响应进行了数值模拟,模拟的炸药温度变化结果与试验测试结果基本一致。     

含孔炸药的孔边应力分析

为研究应力分布规律指导含孔炸药的贮存,应用ANSYS软件对不同放置方式下的含孔炸药进行了建模,采用数值仿真方法获得了不同质量含孔炸药的孔边应力分布规律;结果表明：不同放置方式下炸药孔周边应力分布规律存在较大差别,炸药自身重力对孔周边应力分布有较大影响。