企业战略论文惰性气体对管道内预混火焰淬熄的研究.doc

惰性气体对管道内预混火焰淬熄的研究 【论文标题】 惰性气体对管道内预混火焰淬熄的研究 【英文标题】 the research on premixed flames quenching of inert gas in duct【中文摘要】 针对惰性气体结合丝网等微通道结构使管道内火焰淬熄的研究还鲜见报道,关于高速可燃气体爆燃火焰中加入惰性气体在阻火结构中强制熄灭的研究既具有重要的学术意义,也具有非常重要的社会经济意义。本文通过实验和数值模拟的方法,研究惰性气体对火焰在微通道阻火结构中淬熄的影响规律,旨在为可燃气体燃烧爆炸的防治以及阻火器的设计应用提供理论和实验依据。本文主要工作如下:(1)本文首先通过改进试验装置,实现了惰性气体变浓度充入抑爆管路中,以多层丝网为抑爆结构,n2为熄爆剂,考察不同惰性气体浓度下多层丝网结构淬熄管道内高速c2h2/n2/o2预混火焰的规律,获得了淬熄速度和淬熄压力与惰性气体浓度、丝网几何参数的关系。进而研究惰性气体对预混火焰淬熄的影响。引入熄爆参数来反映丝网抑制火焰和爆炸压力的效果。实验结果发现,随着加入n2浓度增加,丝网结构能够淬熄的火焰压力和传播速度越大,丝网结构能够淬熄熄爆参数更大的预混火焰,即惰性气体浓度越大,丝网淬熄性能越好。(2)建立丝网结构淬熄高速火焰的数学模型,模拟c2h2/o2/inert gas在丝网内的淬熄过程,考察了惰性气体对预混火焰淬熄性能的影响,并将模拟结果与实验数据对比,验证模型的正确性。通过数值模拟考察了c2h2/o2/inert gas预混火焰在丝网中的淬熄情况,结果表明,预混火焰在丝网结构中的淬熄层数随着惰性气体浓度的增大呈减小的趋势,表明惰性气体的加入促进了火焰的淬熄。当惰性气体浓度增加到一定程度时淬熄长度基本不再变化,将继续增加惰性气体浓度而淬熄长度变化小于1mm的最小浓度值定义为惰性气体的最佳淬熄浓度。数值计算得出在丝网内惰性气体对不同活性可燃气体火焰的最佳淬熄浓度值分别为:乙炔,体积比4:1;丙烷,体积比3:1;甲烷,体积比4:1。同时比较了c2h2/o2/inert gas火焰在圆管和平板狭缝中淬熄规律,得到与丝网相同的规律。因此可以认为,惰性气体浓度对火焰淬熄的影响与微通道结构无关。(3)分析研究了惰性气体淬熄火焰的机理。对可燃气体在纯氧和惰性气体中的燃烧进行对比表明,由于惰性气体的加入,使可燃气体和氧被稀释,浓度降低,进而减小了反应速率,使燃烧释放热减少,在壁面散热条件不变的条件下,加速了火焰的熄灭。(4)比较火焰在丝网、圆管、平板狭缝微通道阻火结构中的模拟结果可知,相同情况下,he对阻火结构淬熄火焰的能力提高最强,ar次之,n2的淬熄能力最弱。 还原【英文摘要】 the research on premixed flame suppression in tubes with muti-wire meshes and inert gases are rarely reported.the research on hight speed flames quenching in suppresing structure with inert gases is not only important to academia but also to the society.to investigate the rule of the flames quenching in narrow channels with inert gases,the, quenching condition of premixed flames in muti-wire meshes with inert gases are researched experimentally and then simulated numerically in this paper.the main work and conclusions in this paper are as follows:(1) the experiment structure is improved to let the inert gases fill in the tube of various concentration,relalize the research on the quenching speed of c2h2/o2/inert gas premixed flame.acquire the relationship between the quenching speed and pressure and the the inert gases concentration and the wire mesh parameters.a concept,suppression parameter,was introduced to indicate the effects of suppressing explosion pressure and flame speed for a multilayer mesh.the experiment results reveal that the wire mesh can quenching the flame which has the larger speed and pressure with the higher inert gas concentration.it is that the mesh has better ability in quenching flame with higher inert gases concentration.(2) the geometrical model of wire mesh has been formed,simulate the process of the flame quenching in the wire mesh.stimulate the premixed flame c2h2/o2/inert gas quenched in wire mesh to make out the infulence of the inert gases to the flame quenching.compare the result of the experiment and the simulation to assure the model is accurate.the simulation of c2h2/o2/inert gas premixed flame quenching in wire mesh with different inert gases concentration are studied.it is found that there is more quenching layers as the concentration of inert gases increasing,it reveals the inet gases accelerate the flame quenching.once the concentrations increase to some extent,the quenching lengths of flame in wire mesh will not change.define the minimum concentration when quenching lengths change less than 1mm as the critical concentrantion.the critical concentration to different activity flames are separately:acetylene,4:1;propane,3:1;methane,4:1.(3) analysis the mechanism of the flame quenching with inert gases.the comparation of the combustion in oxygen and the inert gases reveals that the reason for flame extinguishing easier in inert gases can be explained that premixed mixtures are diluted with the complement of inert gases,which eventually leads to the reduction of reaction rate. (4) compare the simulation results of the flame quenching in the wire mesh,duct,and the paralell paltes,helium is best to the flame quenching effect,and argon takes the second place, nitrogen is the worst. 还原【中文关键词】 火焰; 惰性气体; 丝网; 淬熄; 数值模拟; 最佳淬熄浓度 【英文关键词】 flame; inert gases; wire mesh; quenching; numerical simulation; critical quenching concentration【论文目录】 摘要 4-5 abstract 5-6 引言 9-10 1 文献综述 10-31 1.1 可燃气体的爆炸 10-17 1.1.1 可燃烧气体爆炸的基本形式 10-11 1.1.2 火焰加速机理 11-12 1.1.3 湍流火焰加速机理 12-13 1.1.4 管道可燃气体的爆炸研究 13-17 1.2 火焰淬熄研究进展 17-23 1.2.1 火焰淬熄机理 17-18 1.2.2 淬熄的实验研究 18-22 1.2.3 多层丝网结构的淬熄性能研究 22-23 1.3 阻火器 23-25 1.4 惰性气体的抑爆研究 25-27 1.5 气体爆炸数值模拟研究的现状与进展 27-29 1.5.1 计算流体动力学概述 27-28 1.5.2 cfd对气体爆炸的模拟 28-29 1.6 本论文研究内容和技术路线 29-31 1.6.1 研究内容 29-30 1.6.2 技术路线 30-31 2 实验条件 31-35 2.1 实验装置 31-32 2.2 计算预混气体各组分浓度 32-33 2.3 实验步骤 33-34 2.4 本章小结 34-35 3 惰性气体对多层丝网熄爆性能影响的实验研究 35-51 3.1 熄爆性能参数 35 3.1.1 速度参数法 35 3.1.2 压力参数法 35 3.1.3 熄爆参数法 35 3.2 速度参数法的实验结果 35-41 3.3 压力参数法的实验结果 41-46 3.4 熄爆参数法的实验结果 46-50 3.5 本章小结 50-51 4 预混火焰传播控制方程及数值方法 51-63 4.1 几何模型 51-52 4.2 基本假设及说明 52-53 4.3 数学模型 53-56 4.3.1 均相湍流燃烧的时均方程组 53-54 4.3.2 湍流模型 54-55 4.3.3 燃烧模型 55-56 4.4 数值方法 56 4.4.1 维方程的离散 56 4.4.2 压力-速度耦合 56 4.5 边界条件和初始条件 56-57 4.6 网格独立性分析 57-58 4.7 数值结果与实验结果比较 58-59 4.8 火焰在丝网中淬熄的数值模拟 59-62 4.9 本章小结 62-63 5 惰性气体在丝网中对火焰淬熄的