近年来，燃气爆炸事故时有发生，造成严重的人员伤亡和财产损失，影响人们的安全感和幸福感，阻碍社会经济的发展。其中，按照燃气气源分类，LPG（液化石油气）爆炸事故的占比最高。因此，为了有效防控LPG的爆炸，本文研究了LPG的爆燃特性，通过可视管道气体与粉尘爆炸综合实验系统，结合高速摄影机和PIV粒子图像测试系统获得了LPG在不同成分配比、不同当量比以及不同障碍物阻塞率条件下的爆炸压力、火焰传播图像和流场，通过理论分析，得到如下主要结论：

      火焰传播速度随着时间的变化呈现先增大后减小的变化趋势，当“郁金香形”火焰出现时，火焰传播速度达到最小值。LPG中的C₃H₈占比越大，火焰传播速度越快。当量比越接近1.0，火焰充满整个管道所用的时间越短，火焰锋面受到反弹冲击波的影响较大，“郁金香形”火焰结构被破坏，火焰锋面出现明显的褶皱。在管道中布置障碍物，火焰传播速度随着时间的变化呈现先增大后减小，然后骤增，最后振荡变化的趋势。火焰越过障碍物之前，冲击波遇到障碍物出现反弹，火焰结构出现“平面形”，火焰越过障碍物时，火焰传播速度骤增。

      LPG的气体成分配比对最大爆炸压力的影响不大，但对最大爆炸压力上升速率、达到最大爆炸压力时间和达到最大爆炸压力上升速率时间的影响明显，最大爆炸压力上升速率随着C₃H₈占比的增大而逐渐增大，而达到最大爆炸压力时间、达到最大爆炸压力上升速率时间随着C₃H₈占比的增大而逐渐减小。在同一种成分配比条件下，最大爆炸压力和最大爆炸压力上升速率随着当量比的增大呈现出先增大后减小的变化趋势。随着障碍物阻塞率的增大，最大爆炸压力逐渐增大，而达到最大爆炸压力时间逐渐减小。

      LPG中的C₃H₈占比越大，流场分布越均匀，但是，整体上来看，气体成分配比对流场的影响不大；LPG当量比的变化对流场的影响明显，当量比越接近1.0，局部出现高涡量区域的面积越大；管道中障碍物的存在能够明显改变爆炸流场的结构，随着障碍物阻塞率的逐渐增大，涡旋结构的数量增多。火焰结构、火焰传播、爆炸压力与流场之间存在高耦合性，流场中高涡量区域的面积越大，火焰传播速度越快，爆炸压力越大。

      本文研究的成果以期达到强化对LPG爆燃特性的认识和丰富、完善气体爆炸理论的目的，为LPG的爆炸防控提供理论参考。

        In recent years, gas explosions have occurred from time to time, causing serious casualties and property damage, affecting people's sense of security and well-being, and hindering socio-economic development. Among them, according to the classification of gas sources, LPG (liquefied petroleum gas) has the highest percentage of explosive accidents. Therefore, to effectively prevent and control the explosion of LPG, this paper studied the deflagration characteristics of LPG, through the visual pipeline gas and dust explosion integrated experimental system, combined with a high-speed camera and PIV particle image test system to obtain the explosion pressure, flame propagation images and flow field of LPG in different composition ratios, different equivalence ratios, and different obstacle blockage rate conditions. Through theoretical analysis, the main conclusions are as follows:

        The flame propagation speed showed a trend of increasing first and then decreasing with time, and the flame propagation speed was the smallest at the moment of "tulip" flame appearance. The larger the proportion of C₃H₈ in LPG, the faster the flame propagation speed. The closer the equivalent ratio was to 1.0, the shorter the time it took for the flame to fill the whole pipe, the more the flame front was affected by the bouncing shock wave, the more the "tulip" flame structure was destroyed, and the flame front appeared obvious folds. In the pipeline arrangement of obstacles, flame propagation speed with the change of time appeared first increased and then decreased, and then increased abruptly, and finally oscillating changed in the trend. Before the flame crossed the obstacle, the shock wave bounced off the obstacle and the flame structure appeared "flat", and when the flame crossed the obstacle, the flame propagation speed increased sharply.

        The gas composition ratio of LPG had little effect on the maximum explosion pressure but had a significant effect on the maximum explosion pressure rise rate, the time to reach the maximum explosion pressure, and the time to reach the maximum explosion pressure rise rate. The maximum explosion pressure rise rate gradually increased with the increase in the proportion of C₃H₈, while the time to reach the maximum explosion pressure, the time to reach the maximum explosion pressure rise rate decreased with the increase of C₃H₈ proportion. In the same proportional ratio conditions, the maximum explosion pressure and the maximum explosion pressure rise rate increased first and then decreased with the increase of the equivalence ratio. As the obstruction rate increased, the maximum explosion pressure gradually increased, and the time to reach the maximum explosion pressure gradually decreased.

        The larger the proportion of C₃H₈ in LPG, the more uniform the flow field distribution, but, overall, the gas composition ratio had little effect on the flow field. The variation of the LPG equivalent ratio had a significant effect on the flow field, the closer the equivalent ratio was to 1.0, the larger the area of localized high vorticity region appeared. The obstacle could significantly change the structure of the explosive flow field, and the number of vortex structures increased as the obstruction rate of the obstacle increased. There was a high coupling between flame structure, flame propagation, explosion pressure, and flow field. The larger the area of the high vortex region in the flow field, the faster the flame propagation and the higher the explosion pressure.

        The results of this study are intended to achieve the purpose of strengthening the understanding of the deflagration characteristics of LPG and enriching and improving the theory of gas explosion and providing a theoretical reference for the explosion prevention and control of LPG.

[1]彭澎,程诗奋,陈闪闪,等.全球液化石油气运输网络贸易社区特征及其演化分析[J].自然资源学报, 2020, 35(11):2687-2695.

[2]田春荣.中国液化石油气生产与进出口现状及展望[J].天然气工业, 2010, 30(10):95-99.

[3]孙嘉远.某60万吨液化石油气储配库泄漏风险评价及预警系统的开发[D].大庆:东北石油大学, 2021.

[4]许贵贤.液化石油气储罐事故后果分析[J].华北科技学院学报, 2016, 13(6):101-105.

[5]孙宝平,张海英,吕淑然,等.LPG罐车泄漏爆炸事故验证及影响因素数值模拟[J].北京理工大学学报, 2021, 41(02):137-142.

[6]Jia Q, Fu G, Xie X, et al. LPG leakage and explosion accident analysis based on a new SAA method[J]. Journal of Loss Prevention in the Process Industries, 2021, 71(5):104467. DOI:10.1016/j.jlp.2021.104467.

[7]李孝斌.矿井瓦斯爆炸感应期内反应动力学分析及光学特征研究[D].西安:西安科技大学, 2010.

[8]李艳丽.丙酮存在环境7-ACA粉体燃爆特性及抑爆研究[D].石家庄:河北科技大学, 2016.

[9]Zhang J, Sun Z, Zheng Y, et al. Coupling effects of foam ceramics on the flame and shock wave of gas explosion[J]. Safety Science, 2012, 50(4):797-800.

[10]郑凯.管道中氢气/甲烷混合燃料爆燃预混火焰传播特征研究[D].重庆:重庆大学, 2017.

[11]Zhang, Q, Ma Q. Dynamic pressure induced by a methane-air explosion in a coal mine[J]. Transactions of The Institution of Chemical Engineers. Process Safety and Environmental Protection, 2015, 93:233-239.

[12]Jiang B, Lin B, Shi S, et al. Theoretical Analysis on the Attenuation Characteristics of Strong Shock Wave of Gas Explosion - ScienceDirect[J]. Procedia Engineering, 2011, 24:422-425.

[13]Jia Z, Ye Q, Liu W, et al. Numerical Simulation on Shock Failure Characteristics of Pipe Surface with Different Radii under Gas Explosion[J]. Procedia Engineering, 2018, 211:288-296.

[14]Cheng W, Zhao Y, Addai E. Investigation on propagation mechanism of large scale mine gas explosions[J]. Journal of Loss Prevention in the Process Industries, 2017, 49:342-347.

[15]王涛.管道内甲烷爆炸特性及CO2抑爆的实验与数值模拟研究[D].西安:西安科技大学, 2014.

[16]Mitu M, Giurcan V, Razus D, et al. Propagation indices of methane-air explosions in closed vessels[J]. Journal of Loss Prevention in the Process Industries, 2017, 47:110-119.

[17]钟伟.管内液化石油气爆燃传播规律的实验研究[D].哈尔滨:哈尔滨工程大学, 2012.

[18]邵辉,段国宁,邵峰.液化石油气点火能试验及爆炸火焰传播分析[J]. 中国安全科学学报, 2011, 21(8):54.

[19]刘金彪.可燃气体混合均匀性对其爆炸特性的影响研究[D].太原:中北大学, 2018.

[20]李哲,陈先锋,孙玮康.浓度梯度对甲烷-空气混合气体爆炸特性参数的影响[J].振动与冲击, 2021, 40(11):26-32.

[21]Kundu S, Zanganeh J, D Eschebach, et al. Explosion characteristics of methane-air mixtures in a spherical vessel connected with a duct[J]. Process Safety and Environmental Protection, 2017, 111:85-93.

[22]Li F, Li G, Sun Z. Explosion Behaviour of 30% Hydrogen/70% Methane-Blended Fuels in a Weak Turbulent Environment[J]. Energies, 2017, 10(7). DOI: 10.3390/en10070915.

[23]Kundu S, Zanganeh J, Eschebach D, et al. Confined explosion of methane-air mixtures under turbulence[J]. Fuel, 2018, 220(15):471-480.

[24]吴志远,胡双启.点火能对液化石油气爆炸压力影响的试验研究[J].安全与环境学报, 2008, 08(5):138-141.

[25]李润之,黄子超,司荣军.环境温度对瓦斯爆炸压力及压力上升速率的影响[J].爆炸与冲击, 2013, 33(04):415-419.

[26]Huang L, Li Z, Wang Y, et al. Experimental assessment on the explosion pressure of CH4-Air mixtures at flammability limits under high pressure and temperature conditions[J]. Fuel, 299. DOI: 10.1016/J.FUEL.2021.120868.

[27]Cui G, Wang S, Liu J, et al. Explosion characteristics of a methane/air mixture at low initial temperatures[J]. Fuel, 2018, 234(15):886-893.

[28]Wang S, Wu D, Guo H, et al. Effects of concentration, temperature, ignition energy and relative humidity on the overpressure transients of fuel-air explosion in a medium-scale fuel tank[J]. Fuel, 2020, 259(1):116265. DOI:10.1016/j.fuel.2019.116265.

[29]Razus D, Brinzea V, Mitu M. Inerting effect of the combustion products on the confined deflagration of liquefied petroleum gas–air mixtures [J]. Journal of Loss Prevention in the Process Industries, 2009, 22(4):463-468.

[30]Yao J, Zhang C, Liu W, et al. The explosion characteristics of diethyl ether-Al mixtures under different ambient conditions[J]. Combustion and Flame, 2021, 227:162-171.

[31]张增亮,王昕,王昊平.带孔障碍物对管道中可燃气体爆炸特性的影响[J].化工学报, 2019, 70(11):4497-4503.

[32]Li H, Guo J, Tang Z, et al. Effects of ignition, obstacle, and side vent locations on vented hydrogen–air explosions in an obstructed duct[J]. International Journal of Hydrogen Energy, 2019, 44(36):20598-20605.

[33]Wang L, Ma H, Shen Z, et al. The influence of an orifice plate on the explosion characteristics of hydrogen-methane-air mixtures in a closed vessel[J]. Fuel, 2019, 256(15):115908. DOI:10.1016/j.fuel.2019.115908.

[34]谢长春.管道内甲烷爆炸火焰传播特性的实验与数值模拟研究[D].西安:西安科技大学, 2015.

[35]Huo Y, Chow W, et al. Flame propagation of premixed liquefied petroleum gas explosion in a tube[J]. Applied thermal engineering, 2017, 113:891-901.

[36]Liu Q, Zhang Y, Niu F, et al. Study on the flame propagation and gas explosion in propane/air mixtures[J]. Fuel, 2015, 140:677-684.

[37]Kim W, Mogi T, Dobashi R. Flame acceleration in unconfined hydrogen/air deflagrations using infrared photography[J]. Journal of Loss Prevention in the Process Industries, 2013, 26(6):1501-1505.

[38]Elias A, Christophe A, Joël Q, et al. Darrieus–Landau instability and Markstein numbers of premixed flames in a Hele-Shaw cell[J]. Proceedings of the Combustion Institute, 2019, 37(2):1783-1789.

[39]Fernandez-Galisteo D, Kurdyumov V, Ronney P. Analysis of premixed flame propagation between two closely-spaced parallel plates[J]. Combustion and Flame, 2018, 190:133-145.

[40]余明高,孔杰,王燕,等.不同浓度甲烷-空气预混气体爆炸特性的试验研究[J].安全与环境学报, 2014, 14(06):85-90.

[41]Li Q, Sun X, Wang X, et al. Geometric influence of perforated plate on premixed hydrogen-air flame propagation[J]. International Journal of Hydrogen Energy, 2018, 43(46):21572-21581.

[42]Cao X, Bi M, Ren J, et al. Experimental research on explosion suppression affected by ultrafine water mist containing different additives[J]. Journal of Hazardous Materials, 2019, 368:613-620.

[43]Gavrikov A, Golub V, Mikushkin A, et al. Lean hydrogen-air premixed flame with heat loss[J]. International journal of hydrogen energy, 2019, 44(36):20462-20469.

[44]Zheng L, Dou Z, Du D, et al. Study on explosion characteristics of premixed hydrogen/biogas/air mixture in a duct[J]. International journal of hydrogen energy, 2019, 44(49):27159-27173.

[45]Zheng K, Yu M, Liang Y, et al. Large eddy simulation of premixed hydrogen/methane/air flame propagation in a closed duct[J]. International Journal of Hydrogen Energy, 2018, 43(7):3871-3884.

[46]Xiao H, Houim R, Oran E. Formation and evolution of distorted tulip flames[J]. Combustion and Flame, 2015, 162(11):4084-4101.

[47]Xiao H, Duan Q, Sun J. Premixed flame propagation in hydrogen explosions[J]. Renewable and Sustainable Energy Reviews, 2018, 81:1988-2001.

[48]Huang Z, Liu Z, Chen S, et al. Numerical simulation and study on the transmission law of flame and pressure wave of pipeline gas explosion[J]. Safety Science, 2012, 50(4):806-810.

[49]Chen Y, Qian X, Zhang Q, et al. Study on the effects of initial pressure and temperature on the explosion characteristics of DME-blended LPG mixtures in an obstructed confined pipeline[J]. Fuel, 2019, 257. DOI:10.1016/j.fuel.2019.116047.

[50]Zheng K, Yu M, Zheng L, et al. Experimental study on premixed flame propagation of hydrogen/methane/air deflagration in closed ducts[J]. International Journal of Hydrogen Energy, 2016, 42(8):5426-5438.

[51]Li Y, Bi M, Gao W. Theoretical pressure prediction of confined hydrogen explosion considering flame instabilities[J]. Journal of Loss Prevention in the Process Industries, 2019, 57:320-326.

[52]余明高, 纪文涛, 温小萍, 等.交错障碍物对瓦斯爆炸影响的实验研究[J].中国矿业大学学报, 2013, 42(03):349-354.

[53]Li G, Wu J, Wang S, et al. Effects of gas concentration and obstacle location on overpressure and flame propagation characteristics of hydrocarbon fuel-air explosion in a semi-confined pipe - ScienceDirect[J]. Fuel, 285, 119268. DOI:10.1016/j.fuel.2020.119268.

[54]Gao K, Li S, Liu Y, et al. Effect of flexible obstacles on gas explosion characteristic in underground coal mine[J]. Process Safety and Environmental Protection, 2021, 149:362-369.

[55]Huang, Chen X, Liu L, et al. The influence of opening shape of obstacles on explosion characteristics of premixed methane-air with concentration gradients[J]. Process Safety and Environmental Protection, 2021, 150:305-313.

[56]Wan S, Yu M, Zheng K, et al. Influence of obstacle blockage on methane/air explosion characteristics affected by side venting in a duct[J]. Journal of Loss Prevention in the Process Industries, 2018, 54:281-288.

[57]Yu M, Zheng K, Chu T. Gas explosion flame propagation over various hollow-square obstacles[J]. Journal of Natural Gas Science and Engineering, 2016:221-227.

[58]Qin Y, Chen X. Flame propagation of premixed hydrogen-air explosion in a closed duct with obstacles[J]. International Journal of Hydrogen Energy, 2021, 46( 2):2684-2701.

[59]Li R, Luo Z, Cheng F, et al. A comparative investigation of premixed flame propagating of combustible gases-methane mixtures across an obstructed closed tube[J]. Fuel, 2021, 289. 119766. DOI:10.1016/j.fuel.2020.119766.

[60]Sarli V D, Benedetto A D, Russo G. Large Eddy Simulation of transient premixed flame–vortex interactions in gas explosions[J]. Chemical Engineering Science, 2012, 71:539-551.

[61]肖华华. 管道中氢-空气预混火焰传播动力学实验与数值模拟研究[D].合肥:中国科学技术大学, 2013.

[62]Sarli V, Benedetto A, Long E, et al. Time-Resolved Particle Image Velocimetry of dynamic interactions between hydrogen-enriched methane/air premixed flames and toroidal vortex structures[J]. International Journal of Hydrogen Energy, 2012, 37(21):16201-16213.

[63]Rao C, Zhang Y, Cao W, et al. Experimental and numerical studies of premixed methane-hydrogen/air mixtures flame propagation in closed duct[J]. The Canadian Journal of Chemical Engineering, 2018, 96(12): 2684-2689.

[64]Xiao H, Makarov D, Sun J, et al. Experimental and numerical investigation of premixed flame propagation with distorted tulip shape in a closed duct[J]. Combustion and Flame, 2012, 159(4):1523-1538.

[65]温小萍.瓦斯湍流爆燃火焰特性与多孔介质淬熄抑爆机理研究[D].大连:大连理工大学, 2014.

[66]徐维. 贫燃预混旋流燃烧大涡模拟及模型对比分析[D].大连:大连理工大学, 2019.

[67]Guo S, Wang J, Zhang W, et al. Investigation on bluff-body and swirl stabilized flames near lean blowoff with PIV/PLIF measurements and LES modelling[J]. Applied Thermal Engineering, 2019, 160:114021. DOI:10.1016/j.applthermaleng.2019.114021.

[68]Boushaki T, Merlo N, Persis S D, et al. Experimental investigation of CH4-air-O2 turbulent swirling flames by Stereo-PIV[J]. Experimental Thermal and Fluid Science, 2019, 106:87-99.

[69]Fujisawa N, Iwasaki K, Fujisawac Ki, et al. Flow visualization study of a diffusion flame under acoustic excitation[J]. Fuel, 2019, 251: 506-513.

[70]Chen L, Wang Q, Zhang Y. Flow characterisation of diffusion flame under non-resonant acoustic excitation[J]. Experimental Thermal and Fluid Science, 2013, 45:227-233.

[71]Wang S, Zheng J, Li L, et al. Evolution characteristics of 3D vortex structures in stratified swirling flames studied by dual-plane stereoscopic PIV[J]. Combustion and Flame, 2022, 237, 111874. DOI:10.1016/j.combustflame.2021.111874.

[72]Tanahashi M, Hirayama T, Taka S, et al. Measurement of fine scale structure in turbulence by time-resolved dual-plane stereoscopic PIV[J]. International Journal of Heat and Fluid Flow, 2008, 29(3):792-802.

[73]丁以斌.锆粉云火焰传播特性的实验研究[D].合肥:中国科学技术大学, 2010.

[74]喻健良,侯玉洁,闫兴清,等.密闭空间内聚乙烯粉尘爆炸火焰传播特性的实验研究[J].化工学报, 2019, 70(3):1227-1235.

[75]Zhang X, Yu J, Sun J, et al. Effects of turbulent intensity on nano-PMMA flame propagation behaviors[J]. Journal of Loss Prevention in the Process Industries, 2016, 44:119-124.

[76]Hosseinzadeh S, Vanierschot M, Norman F, et al. Flame propagation and flow field measurements in a Hartmann dust explosion tube[J]. Powder Technology, 2017, 323:346-356.

[77]Yu X, Yu J, Zhang X, et al. Combustion behaviors and residues characteristics in hydrogen/aluminum dust hybrid explosions[J]. Process Safety and Environmental Protection, 2020, 134:343-352.

[78]Gao W, Mogi T, Rong J, et al. Motion behaviors of the unburned particles ahead of flame front in hexadecanol dust explosion[J]. Powder Technology, 2015, 271:125-133.

[79]裴蓓,张子阳,潘荣锟,等.不同强度冲击波诱导沉积煤尘爆炸火焰传播特性[J].煤炭学报, 2021, 46(2):498-506.

[80]Xu H, Wang X, Li Y, et al. Experimental investigation of methane/coal dust explosion under influence of obstacles and ultrafine water mist[J]. Journal of Loss Prevention in the Process Industries, 2017, 49:929-937.

[81]Lee T, Sung J, Park D. Experimental investigations on the deflagration explosion characteristics of different DME–LPG mixtures[J]. Fire Safety Journal, 2012, 49:62-66.

[82]Vaagsaether K, Gaathaug A, Bjerketvedt D. PIV-measurements of reactant flow in hydrogen-air explosions[J]. International Journal of Hydrogen Energy, 2019, 44(17): 8799-8806.

[83]GB 11174-2011, 液化石油气[S].北京:中国标准出版社, 2011.

[84]Bychkov V, Akkerman V, Fru G, et al. Flame acceleration in the early stages of burning in tubes[J]. Combustion and Flame, 2007, 150(4):263-276.

[85]余明高,栾鹏鹏,郑凯,等.管道内预混合成气爆炸特性[J].化工学报, 2018, 69(10):4486-4494.

[86]Luo Z, Hao Q, Wang T. et al. Experimental study on the deflagration characteristics of methane-ethane mixtures in a closed duct[J]. Fuel, 2020,259:1-16.

[87]Sun Z, Li G. Turbulence influence on explosion characteristics of stoichiometric and rich hydrogen/air mixtures in a spherical closed vessel [J]. Energy conversion and management, 2017, 149:525-535.

[88]赵衡阳,气体和粉尘爆炸原理[M].北京:北京理工大学出版社, 1996.

[89]Alharbi A, Masri A, Ibrahim S. Turbulent premixed flames of CNG, LPG, and H2 propagating past repeated obstacles[J]. Experimental Thermal and Fluid Science, 2014, 56:2-8.

[90]王彦植.示踪粒子成像技术在燃烧流场的测量研究[D].上海:上海交通大学, 2018.

[91]桂晓宏.瓦斯爆炸过程中动态、非稳定火焰与爆炸波传播规律的研究[D].徐州:中国矿业大学, 2002.

[92]刘晓利,李鸿志,叶经方,等.障碍物对铝粉火焰加速作用的研究[J].爆炸与冲击, 1995, 15(1):11-19.