受限空间瓦斯爆炸过程中火焰精细结构特性的研究
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摘要
矿井瓦斯爆炸是煤炭生产过程中发生最频繁的事故灾害,如何预防和控制瓦斯爆炸事故是目前煤矿安全生产工作的主要问题,故对瓦斯爆炸过程中火焰结构及相关参数进行深入研究具有非常重要的意义。论文采用实验研究、数值模拟和理论分析相结合的方法研究了管道中瓦斯爆炸过程中火焰传播的精细结构特性。
采用自行设计的尺寸为50cm×8cm×8cm的方形实验管道,结合高速摄像纹影系统、离子探针和微细热电偶等测试系统,探测了浓度为9.5%的甲烷-空气预混气体火焰在管道内传播过程中的动态变化过程及精细结构特性。高速摄像纹影系统清晰捕捉了瓦斯爆炸过程火焰结构的变化特征以及‘'tulip"火焰形成的全过程。火焰结构图片和所探测物理参数相结合,分析了火焰前进过程中流场附近温度、压力上升速率等相关参数的变化特征,从而揭示了管道中预混气体火焰传播特性和精细结构特性。研究结果表明：预混火焰在管道中传播过程中,火焰结构变化会经历“平滑-中心内凹-失稳”的过程,这是火焰不稳定的表现。火焰传播过程中由于压力波与反射波的共同作用,传播速度出现先加速后减速的变化过程,而"tulip"火焰形成于火焰传播速度迅速降低的区域里,且减速阶段的加速度接近最大值,火焰结构变化伴随着层流与湍流的转化,且火焰厚度会发生变化。
同时借助数值模拟平台,建立与实验条件相近的数学模型和物理模型,对管道内甲烷-空气预混气体火焰的传播过程进行了数值模拟,得到了管道内爆炸反应过程中影响火焰精细结构的相关参数(温度、压力、燃烧率、速度等)的变化过程。实验与数值模拟结果比对分析,验证了实验的合理性。
最后分析了浓度、管道长径比、管道泄压口比率和障碍物等条件对火焰前沿流场附近相关参数的影响。本课题的研究成果可为进一步预防和控制瓦斯爆炸事故的发生提供借鉴,同时,对于研究如何有效地防止工业管道中可燃气体爆炸事故、保证气体能源动力的安全,在研究方法上具有指导意义。
The accidents of gas explosion occurred most frequently in the production process of coal mine, so how to prevent and control gas explosion for the safety of coal mine is the main problem. Therefore, it's necessary to study the gas explosion process and related parameters of the flame structure. In this paper, the structure characteristics of flame propagation were studied by experiments, numerical simulation and analysis methods.
The experimental system was built up to detect the microstructure of flame and the flame propagation of 9.5 percent methane-air mixtures in pipes, which was consisted of 50cm x 8cm x 8cm square pipe, the high-speed video, the ion current and the thermocouple el. With the help of high-speed video, the characteristics of gas explosion process and the structure change of "tulip" flame formation was successfully and clearly captured. The picture of flame structure combined with the physical parameters was used to analysis on the changes of temperature, the rising rate of pressure and other related parameters' variations in the pipeline, which revealed the characteristics of premixed fine structure and the flame propagation. The research also showed that in the process of flame propagation in pipes, the flame structure sometimes experienced "smooth-center concave-instability" process, which showed the unstable of flame. During the process of flame propagation, the speed of flame traveled faster at first and then slowed down, which due to the pressure wave reflection, and "tulip" flame was formed not only in the rapid decrease speed of the region, but also the acceleration of the deceleration phase was near to maximum. The flame structure changes accomplished with turbulent flow, and the thickness of the flame also changed.
The mathematical model and similar physical model of pipe was established to study the numerical simulation of the flame propagation with premixed methane-air. Then the related parameters such as temperature, pressure, rate of speed, etc. was obtained during the burning process. Experiment and numerical simulation results revealed the rational of the experiment.
Finally the numerical simulation method was used to analyze the related parameters near the flow field of flame when the concentration, pipe length-diameter ratio, pipe pressure ratio and the obstacles changed especially. The results of this topic research could not only be further used to prevent and control gas explosion accidents, but also significant for the study of how to prevent flammable pipeline effectively and safety in gas explosion accidents.
采用自行设计的尺寸为50cm×8cm×8cm的方形实验管道,结合高速摄像纹影系统、离子探针和微细热电偶等测试系统,探测了浓度为9.5%的甲烷-空气预混气体火焰在管道内传播过程中的动态变化过程及精细结构特性。高速摄像纹影系统清晰捕捉了瓦斯爆炸过程火焰结构的变化特征以及‘'tulip"火焰形成的全过程。火焰结构图片和所探测物理参数相结合,分析了火焰前进过程中流场附近温度、压力上升速率等相关参数的变化特征,从而揭示了管道中预混气体火焰传播特性和精细结构特性。研究结果表明：预混火焰在管道中传播过程中,火焰结构变化会经历“平滑-中心内凹-失稳”的过程,这是火焰不稳定的表现。火焰传播过程中由于压力波与反射波的共同作用,传播速度出现先加速后减速的变化过程,而"tulip"火焰形成于火焰传播速度迅速降低的区域里,且减速阶段的加速度接近最大值,火焰结构变化伴随着层流与湍流的转化,且火焰厚度会发生变化。
同时借助数值模拟平台,建立与实验条件相近的数学模型和物理模型,对管道内甲烷-空气预混气体火焰的传播过程进行了数值模拟,得到了管道内爆炸反应过程中影响火焰精细结构的相关参数(温度、压力、燃烧率、速度等)的变化过程。实验与数值模拟结果比对分析,验证了实验的合理性。
最后分析了浓度、管道长径比、管道泄压口比率和障碍物等条件对火焰前沿流场附近相关参数的影响。本课题的研究成果可为进一步预防和控制瓦斯爆炸事故的发生提供借鉴,同时,对于研究如何有效地防止工业管道中可燃气体爆炸事故、保证气体能源动力的安全,在研究方法上具有指导意义。
The accidents of gas explosion occurred most frequently in the production process of coal mine, so how to prevent and control gas explosion for the safety of coal mine is the main problem. Therefore, it's necessary to study the gas explosion process and related parameters of the flame structure. In this paper, the structure characteristics of flame propagation were studied by experiments, numerical simulation and analysis methods.
The experimental system was built up to detect the microstructure of flame and the flame propagation of 9.5 percent methane-air mixtures in pipes, which was consisted of 50cm x 8cm x 8cm square pipe, the high-speed video, the ion current and the thermocouple el. With the help of high-speed video, the characteristics of gas explosion process and the structure change of "tulip" flame formation was successfully and clearly captured. The picture of flame structure combined with the physical parameters was used to analysis on the changes of temperature, the rising rate of pressure and other related parameters' variations in the pipeline, which revealed the characteristics of premixed fine structure and the flame propagation. The research also showed that in the process of flame propagation in pipes, the flame structure sometimes experienced "smooth-center concave-instability" process, which showed the unstable of flame. During the process of flame propagation, the speed of flame traveled faster at first and then slowed down, which due to the pressure wave reflection, and "tulip" flame was formed not only in the rapid decrease speed of the region, but also the acceleration of the deceleration phase was near to maximum. The flame structure changes accomplished with turbulent flow, and the thickness of the flame also changed.
The mathematical model and similar physical model of pipe was established to study the numerical simulation of the flame propagation with premixed methane-air. Then the related parameters such as temperature, pressure, rate of speed, etc. was obtained during the burning process. Experiment and numerical simulation results revealed the rational of the experiment.
Finally the numerical simulation method was used to analyze the related parameters near the flow field of flame when the concentration, pipe length-diameter ratio, pipe pressure ratio and the obstacles changed especially. The results of this topic research could not only be further used to prevent and control gas explosion accidents, but also significant for the study of how to prevent flammable pipeline effectively and safety in gas explosion accidents.
引文
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[32]王宝瑞,雷宇,张孝谦.甲烷-空气湍流预混V形火焰特性的数值模拟[J].工程热物理学报,2004,(25)：229-232
[33]胡学义.煤矿瓦斯爆炸事故数值模拟分析[J].爆破,2003,(20)：3-5.
[34]杨宏伟,范宝春,李宏志.障碍物导致火焰变形的数值模拟[J].流体力学实验与测量,2002,16(2)：47-51.
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[2]赵宁.中国煤矿引发的法律问题思考[D].兰州：兰州大学,2009.
[3]崔兆华.2001-2008年我国煤矿瓦斯爆炸事故统计及原因分析[J].科技情报开发及经济,2009,19(21)：139-140.
[4]柳晓莉,郭立稳,张志业.2005年1月-2009年6月煤矿死亡事故统计分析[J].河北理工大学学报,2010,32(2)：12-15.
[5]张奇,白春华,梁慧敏.燃烧与爆炸基础[M].北京：北京理工大学出版社,2007：56-60.
[6]汪泉.管道中甲烷-空气预混气爆炸火焰的传播[D].安徽：安徽理工大学,2006.
[7]王磊.瓦斯浓度对瓦斯爆炸传播的影响研究[D].重庆：煤科总院重庆研究院,2009.
[8]Moen I O,Lee J H S. Pressure development due to turbulent flame propagation in large-scale methane-air explosions[J].Combustion and Flame,1982,47:31-52.
[9]Evans M W,Schmeer M D,Schoen L J,et al.A study of high velocity flames developed by grides in tubes.Ind Proc of 3rd symposium(International) on Combustion the Combustion Institute.Pittsburgh:1949:168-185.
[10]Phylaktou H, The acceleration of flame propagation in a tube by an obstle [J].Combustion and Flame,1991,363-379.
[11]Masri A.R,Ibrahim S.S, Experiment study of premixed flame propagation over solid obstructions [J].Exp Thermal and Fluid Science,2000,21,109-116.
[12]Oh K.H, A study on the obstacle-induced variation of the gas explosion characteristics [J].J Loss Prevention in Process Industries,2001,14,597-602.
[13]林柏泉,周世宁,张仁贵.障碍物对瓦斯爆炸过程中火焰和爆炸波的影响[J].中国矿业大学学报,1999,28(2)：104-107.
[14]何学秋,杨艺,王恩元,等.障碍物对瓦斯爆炸火焰结构及火焰传播影响的研究[J].煤炭学报,2004,29(2)：186-189.
[15]Nettleten M A. Gaseous detonations [M].London, New York:Chapman and Hall,1977.
[16]Christoph Kersten. Investigation of deflagrations and detonations in pipes and flame arresters by high speed framing [J].Journal of Loss Prevention in the Process Industries, 2004,17:43-50.
[17]袁生学,黄志澄.管内爆燃转爆轰的热力学原理[J].燃烧科学与技术,1998,4(4)：403-409.
[18]徐景德,周心权,吴兵,等.矿井瓦斯爆炸传播的尺寸效应研究[J].中国安全科学学报,2001,11(6)：36-40.
[19]叶经方,范宝春.激波与火焰相互作用过程的实验研究与数值模拟[J].南京理工大学学报,2005,29(3)：316-318.
[20]叶经方,姜孝海,董刚,等.楔形障碍物诱导火焰失稳的实验研究[J].弹道学报,2005,17(3)：13-17.
[21]Mallard and Le Chatelier,Ann [J].Mine, Paris series,1883,8:277-377.
[22]Ellis,O.C.de C. Flame movement in gaseous explosive mixtures[J].Fuel in Science and Practice,1928,7:502.
[23]梁春利,李芳.管道内可燃气体爆炸研究进展[J].化工装备技术,2006,27(2)：38-41.
[24]Guenoche, Flame propagation in tubes and in closed vessels [J].In Nonsteady Flame Propagation,1964.
[25]陈东梁,孙金华,刘义,等.甲烷／空气预混气体火焰的传播特性[J].爆炸与冲击,2008,28(5)：385-390.
[26]王从银,何学秋.瓦斯爆炸火焰厚度的实验研究[J].爆破器材,2001,30(2)：28-32.
[27]李鸿德,廖继卿,夏自柱.甲瓦斯煤尘爆炸火焰温度的测定[J].计量学报,1988,9(4)：275-279.
[28]胡铁柱.瓦斯爆炸传播规律数值模拟研究[D].北京：中国矿业大学,2008.
[29]Michele Maremonti, Numerical Simulation of gas explosions in linked vessels[J] Journal of Loss Prevention in the Process Industries,1999,12:189-194.
[30]Fairweather M et al. Studies of premixed flame propagation in explosive tubes [J]. Combustion and Flame,1996,116:504-518.
[31]林柏泉,桂晓宏.瓦斯爆炸过程中火焰厚度测定及其温度场数值模拟分析[J].实验力学,2002,17(2)：227-233
[32]王宝瑞,雷宇,张孝谦.甲烷-空气湍流预混V形火焰特性的数值模拟[J].工程热物理学报,2004,(25)：229-232
[33]胡学义.煤矿瓦斯爆炸事故数值模拟分析[J].爆破,2003,(20)：3-5.
[34]杨宏伟,范宝春,李宏志.障碍物导致火焰变形的数值模拟[J].流体力学实验与测量,2002,16(2)：47-51.
[35]赵衡阳.气体和粉尘爆炸原理[M].北京：北京理工大学出版社,1995：23-24.
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