HNIW/HTPB传爆药的制备及性能研究

以HNIW为高能填料,以HTPB为粘结剂,采用真空浇注法制备了HNIW/HTPB传爆药。为研究HNIW基浇注型传爆药的爆炸特性,通过实验制备了HNIW/HTPB传爆药,并对其撞击感度、临界直径和爆速等性能进行了分析研究。结果表明,HNIW/HTPB传爆药对撞击作用较钝感,当HTPB的含量为12%时,其特性落高h50为51.68cm,临界直径小于0.6mm,它的实测爆速为8248m/s,接近其理论爆速8320m/s,且HNIW/HTPB传爆药各组分之间具有良好的相容性,因此该传爆药具有良好的安全性能和传爆性能,适合于微尺寸装药,从而具有广阔的应用前景。     

椰壳基活性炭吸附高氯酸盐污染物的研究

为确定高氯酸盐污染物椰壳基活性炭吸附的最佳工艺参数,以高氯酸铵模拟废水为处理对象,通过L25(5)4正交试验考察活性炭投加量、温度、pH值、高氯酸盐初始浓度等参数对活性炭吸附率的影响规律。结果表明,ClO4-的去除率随着活性炭投加量的增加、ClO4-初始浓度的增大而增大,在偏中性的环境中具有较高的去除率,高温不利于活性炭的吸附反应。最佳工艺参数:活性炭投加量为0.4 g/L,pH为中性,温度为25℃,高氯酸盐初始质量浓度为2 mg/L。在最佳工艺参数条件下对ClO4-的吸附率为74.87%。     

C6H12N4+Mg+KClO4+SrSO4系统的振荡控制和安全分析

从实验和数值分析两方面研究了C6Hl2N 4+Mg+KClO4+SrSO4反应系统的振荡燃烧现象,并对反应机理进行了深层次的分析.结果表明,振荡燃烧是由化学动力学的非线性反馈引起的,即:反应系统中镁的三相与氧气的相互竞争反应造成系统的非线性化学振荡燃烧.氧化剂和可燃剂的比值,以及频率调节剂等吸热物质可调节气相镁的生成速率,能有效地控制药剂的振荡频率.选取适当的控制参数,可以使反应按照预定的、安全的过程进行,避免爆燃的产生.本文的研究结果对化工、军事等领域的安全控制具有重要意义.     

MATLAB在垃圾填埋气体运移数值可视化中的应用

本文基于MATLAB环境对垃圾填埋场的填埋气体运移的非线性耦合模型进行了数值可视化研究,对填埋气体在填埋场中的压力分布进行了模拟计算.结果表明,填埋气体的压力随垃圾填埋深度的增加而增大,随着填埋时间的增加,气体压力变化加快,气体压力消散程度增大.对垃圾填埋气体运移进行数值模拟不仅可为垃圾气体释放所造成的环境灾害进行评价,同时也可为填埋场气体安全控制系统的工程设计提供科学依据.     

含瓦斯煤岩突出过程数值模拟

含瓦斯煤岩突出是煤炭开采过程中一种复杂的工程诱发灾害。根据煤岩体变形与瓦斯渗流的基本理论 ,考虑煤岩介质材料力学性质的非均匀性特点以及煤岩介质变形破裂过程中透气性的非线性变化特性 ,建立了含瓦斯煤岩突出过程固气耦合作用的RFPA2D Flow模型。利用该模型对石门掘进诱发的含瓦斯煤岩突出进行了初步的数值模拟 ,模拟结果再现了煤岩介质在瓦斯压力、地应力和煤岩力学性质等因素综合作用下由裂纹萌生、扩展、相互作用、贯通直至失稳抛出的突出全过程 ,揭示了采动影响下煤岩介质渐进破坏诱致突变的非线性本质 ,包括含瓦斯煤岩破裂过程中应力场的演化 ,为含瓦斯煤岩突出机理研究提供一套全新的数值试验分析工具。     

Experiments and numerical simulation on methane flame quenching by water mist

The study of extinguishment using water mist has been motivated due to the phase-out of the use of halens and the search for alternative means that preserve all of the benefits of a clean total flooding agent without adverse environmental impact. With the numerical simulation, we analyzed a gas–liquid two-phase problem including water (liquid), air and methane (gas) using Eulerian equations for the liquid phase and the full Navier–Stokes equations for the gas phase. Gaseous mass, momentum and energy equations are integrated simultaneously by a Harten–Yee explicit non-MUSCL modified-flux type TVD scheme for the convective terms and a central difference scheme for the viscous terms. Liquid phase conservation equations are solved with an application of a flux-vector-splitting scheme. In the experiments in an open room (500×500×500 mm) we observed an interaction of the diffusion flame with the water mists. The results show remarkable flame quenching and a good agreement between the numerical and experimental results.     

A comparative study of the effect of clay binders on iron oxide sorbent in the high-temperature removal of hydrogen sulfide

The purpose of this study is to investigate the effect of clay binder, an important additive, on the performance of iron oxide sorbent in high temperature coal gas desulfurization. The four clay binders chosen for the study were kaolinite, diatomite, bentonite and brick clay. The sulfidation–regeneration cycles were conducted in a fixed-bed reactor. XRD, DTA and FTIR, together with texture characterizing techniques, such as mercury porosimetry and nitrogen adsorption, were adopted to characterize the sorbents and raw materials. The results obtained show that sorbents prepared from various clay binders exhibit different breakthrough behaviors. In addition, a correlation between pore volume and sulfur capacity reveals that sorbents with a greater number of pores larger than 200 nm (diameter), exhibit higher sulfur capacity. The reason for this is that a greater number of large pores can improve diffusion and provide a larger space for relieving heat impact. However, too many large pores may result in weak strength and very low bulk density, thus a balance between large pores and the density must be achieved. This study also reveals that clay binder can contribute to the modification of a sorbent's texture as gas is released when the mineral structure changes during calcination. In addition, a clay mineral with an active interlayer has been shown to be beneficial in improving the dispersion of active components in the sorbent, because of the existence of an interaction between the mineral and red mud.     

粉煤灰-煤矸石基胶结充填材料制备与性能研究

为了解决我国煤矿采空区地表沉陷以及"三下"压煤资源浪费的问题,提出以粉煤灰-水泥熟料-脱硫石膏复合胶凝材料为胶结材,原状粉煤灰为细骨料,破碎后的煤矸石为粗骨料制备新型煤矿开采胶结充填材料。依据正交试验结果和各因素影响规律趋势图,确定充填材料的优化配合比。研究结果表明,适当增大水泥熟料掺量可缩短材料初凝时间,减小水胶比能使材料强度显著提高,而材料坍落度可通过选取适宜的浆体中的固体质量分数和灰矸比来有效调节,当胶凝材料中水泥含量为15%,脱硫石膏含量为8%,水胶比为2,灰矸比为2∶3,浆体中的固体质量分数为70%时,充填材料性能可达到最佳。通过试验优选材料各项参数,工业废弃物可以用来制备高质量的胶结充填材料。     

约束空间可燃气体燃烧爆轰特性的数值研究

在可燃气体的输送、贮存、加工和使用过程中,容易发生可燃气体的燃烧和爆炸事故。文中基于有限体积方法,采用五阶WENO格式进行左右状态量的重构后,利用ROE格式进行空间离散,自行开发程序对甲烷氧气的气相爆轰波传播过程进行了数值研究。计算结果表明:在CH4质量分数为10%的混合气体中,高温高压气团可诱导气相发生爆轰,爆轰波以2133.3 m/s的速度传播。在带有障碍物的约束空间内,文中分析了障碍物不同高度、不同间距条件下爆轰波传播时波的绕射、马赫反射等现象,给出障碍物表面压力随时间变化历程和冲量值,揭示波与障碍物的相互作用机理以及由此引发流场的变化规律,为有效地控制可燃气体的燃烧速率、防治爆炸灾害的发生提供理论依据。     

无机包覆聚苯乙烯泡沫板烟气产生规律研究

聚苯乙烯泡沫板在建筑节能中具有重要应用,其阻燃防火性能影响建筑火灾安全。应用UL-94垂直燃烧性能测试方法研究无机包覆聚苯乙烯泡沫板在垂直状态下的燃烧情况,结果表明包覆后的聚苯乙烯试样的等级可达到V-1以上;应用烟密度仪和气体分析仪研究无机包覆聚苯乙烯泡沫板燃烧烟气产生规律,结果表明MgSO_4/MgO、α-石膏、无机黏结剂、无机粘结剂/膨润土均对聚苯乙烯泡沫起到阻燃效果,并对烟气产生抑制作用,抑烟能力由大到小为MgSO_4/MgO,α-石膏、无机黏结剂/膨润土、无机黏结剂。同时能不同程度地影响聚苯乙烯泡沫燃烧时产生CO_2、CO有毒有害气体的体积分数,其中CO_2的最大体积分数分别为2.09%、1.79%、1.52%、1.62%;CO的最大体积分数分别为434×10~(-6)、340×10~(-6)、358×10~(-6)、369×10~(-6),从数据分析可知,4种无机包覆聚苯板中,无机黏结剂在4种包覆剂中对CO_2生成的影响效果更佳,α-石膏在4种包覆剂中对CO生成的影响效果更佳。     

光催化和吸收组合工艺净化丙酮气体的研究

为了获得"光催化"与"吸收"联合净化VOCs气体的最佳组合工艺,首先以泡沫陶瓷为载体,羧甲基纤维素钠为黏结剂,采用浸渍-黏结法制得TiO2/泡沫陶瓷光催化材料,然后在自制的VOCs气体净化系统中,选择水溶性的丙酮气体为代表性VOCs气体,以水为吸收剂,考察了"光催化"与"吸收"不同组合工艺对丙酮气体的净化性能,并借助GC/MS和LC/MS手段对尾气和吸收液中的产物相进行分析测定。结果表明,纳米TiO2在泡沫陶瓷上的平均负载率为3.5%,且主要集中负载于陶瓷孔隙附近。不同组合工艺对丙酮气体的净化效率由高到低依次为"光催化+吸收""吸收+光催化""吸收""光催化",其中在"光催化+吸收"最佳工艺条件(液气比为5 L/m3、停留时间为6 s、光照强度为60W)下,丙酮气体的最高去除率达93.7%以上。气相和液相产物分析结果表明,丙酮气体经"光催化"处理后会产生O3和CH3COOH中间产物,但CH3COOH的产生量很少,在以"光催化"为末端工序的尾气中难以测出,而在以"吸收"为末端工序的循环吸收液中反而能检出。在此基础上,给出了"光催化+吸收"净化工艺的反应机理方程。研究得出,"光催化+吸收"工艺组合不仅可实现丙酮气体的高效净化,而且可避免"光催化"末端工序带来的O3和CH3COOH二次污染问题。     

障碍物条件下纳米SiO2粉体抑制瓦斯爆炸特性

为了研究障碍物条件下纳米SiO_2粉体对瓦斯爆炸的抑制特性,采用自行搭建的150 mm×150 mm×500 mm可视化瓦斯爆炸试验系统,分别对不同质量浓度和粒径的纳米SiO_2粉体抑爆特性进行了试验研究。结果表明:在障碍物条件下,纳米SiO_2粉体对瓦斯爆炸具有良好的抑制效果,0.10 g/L的30 nm SiO_2粉体可使9.5%瓦斯气体的最大火焰传播速度降低35%,爆炸超压降低34%;然而,纳米SiO_2粉体并非质量浓度越大抑爆效果越好,而是存在最佳抑爆质量浓度,即随纳米SiO_2粉体质量浓度上升,其抑爆性能先增大后减小,最佳抑爆质量浓度约为0.10 g/L;此外,纳米SiO_2粉体的抑爆性能与其粒径相关,且存在最佳抑爆粒径,相同质量浓度下30 nm SiO_2粉体比15nm和50 nm SiO_2粉体的抑爆效果好。     

T型结构压力管道流固耦合模拟与试验验证

为研究T型压力管道结构内部流体非定常流动诱发的管道振动问题,采用流固耦合分析方法进行分析,借助有限元分析软件ADINA对输送气体介质的T型压力管道结构的进行了流固耦合数值模拟,得到了管内流体流动参数的变化以及管道应力分布规律,并预测了管道振动特性。同时,利用管道振动测试试验系统进行T型管道结构的振动特性进测试,得到压力管道耦合振动响应频率。结果表明:流固耦合数值计算的结果与试验结果能较好地吻合,流体介质的T型压力管道内存在明显的流固耦合效应,不考虑流固耦合作用结果与实验结果相差很大。     

A New Homogeneous Non-Equilibrium Model to Compute Vapor-Liquid Two-Phase Critical Pressure Ratios of Multicomponent Hydrocarbon Mixtures

The critical pressure ratio (η_c) is an essential parameter for computing the vapor-liquid two-phase critical pressure and mass flow rate of multicomponent hydrocarbon mixtures flowing through valves and leakage orifices. The Homogeneous Non-Equilibrium Diener-Schmidt (HNE-DS) model widely used to calculate η_c assumes that the fluid's volume linearly changes with the pressure (using the Clausius-Clapeyron equation), which is not suitable for multicomponent gas mixtures. In this paper, a new Homogeneous Non-Equilibrium (new-HNE) model is proposed to calculate η_c of gas mixtures. Firstly, a new critical flow compressibility factor (ω_c) is developed from its thermodynamic definition and the Peng-Robinson equation of state (EOS), overcoming the inherent limitations of the Clausius-Clapeyron equation. Then, η_c is correlated to the newly derived ω_c by fitting experimental data at various pressures and gas mass fractions of both single-component and multicomponent gas mixtures, yielding the new HNE-DS model. Results show that, for the water-steam and air-water two-phase flow, the average relative deviations (ARD) between the calculated critical pressure ratios and experimental values are equal to 2.8% and 4.93%, respectively, which represents a significant improvement in comparison with the original HNE-DS model. Moreover, this new model is extended to the applications of Liquefied natural gas (LNG)/liquefied petroleum gas (LPG) fluids, and will further contribute to the calculation of the leakage mass flow rate of fluid flowing through the orifices/valves.     

管道结构对氢/空预混气体爆炸特性影响研究

为研究管道结构对氢-空预混气体爆炸特性影响,采用实验与数值模拟相结合的方法,分析不同管道结构内氢-空预混气体燃爆时火焰传播进程、爆炸压力、湍流动能变化及流场分布.结果表明:90°弯管对氢-空预混气体爆炸强度增强作用明显高于T型分岔管和直管.火焰阵面在结构突变处褶皱变形较明显,并出现大尺度强湍流和涡团,气团脉动速度与湍流...     

细雾水与火焰的相互作用

本文分析了细雾水滴与浮升火焰羽流的相互作用,推导出雾滴在火场下降过程中的运动方程,、汽化速率方程和热量衡算方程。采用龙格－库塔差分方法,数值求解所得到的有关方程。     

水雾作用下气体爆炸火焰传播的实验研究

利用自行设计的全程透明的火焰加速管和水喷雾系统，对不同水雾条件下的气体火焰传播现象进行了实验研究。运用光电传感器与数字摄像技术分析了不同浓度的甲烷在不同水雾条件下的火焰传播速度、火焰阵面轨迹以及火焰结构特性，并通过对传播火焰反应区温度的测量，探讨了水雾抑制气体爆炸火焰传播的内在机理及所需的条件。实验结果表明：由于水雾作用于火焰反应区，降低了火焰反应区内的温度和气体燃烧速度，延长火焰阵面的预热区，减缓火焰阵面传热与传质的进行，从而使传播火焰得以抑制。水雾对气体爆炸火焰传播的抑制效果与水雾流量速度、雾区浓度以及火焰到达水雾区的火焰传播速度有关。     

Numerical study on the initial expansion of two-phase cloud from an instantaneous release

In industries some dangerous liquefied gases may accidentally release and it may form a flammable or toxic mixture after mixing with air. One tool that is being developed in industry for two-phase cloud dispersion modeling is computational fluid dynamics (CFD). In this paper, the dispersion processes of different dangerous materials including liquefied chlorine, liquefied ammonia and liquefied petroleum gas were simulated in the same condition to analyze the characteristics of the initial expansion processes by CFD tool. The heat and mass transfer between droplets and the vapor after an instantaneous release event was calculated by using the Eulerian–Lagrangian method. The results from a number of 3-D CFD based studies were compared with the available small-scale experimental results. The results show that the present model and numerical simulation are reliable.     

Evaluation of gas release rate through holes in pipelines

A mathematical model of an accidental gas release in a long transmission pipeline is presented in terms of computational fluid mechanics. It was found that the hole model is suitable for the release of gas through a small hole, while the pipe model is suitable for the gas release through a hole corresponding to the complete breaking of the pipe. In this paper, a new model was proposed for a hole that lies between both these situations. The results of the example show that when the initial inside pressure is higher than 1.5 MPA, the mass of gas released during the sonic flow is more than 90% of the total mass of gas released. The average release rate of the total release process could be substituted by the average release rate of the sonic flow, or by 30% of the initial release rate. This approximation would become more accurate with the increase in the initial inside pressure.