氢能的低成本高效远距离输送是限制氢能规模化应用的技术瓶颈之一。将氢气按一定比例混入天然气后利用现有的天然气管网输送掺氢天然气是目前实现氢气远距离输送的有效技术方案。然而，高压掺氢天然气泄漏自燃成为了威胁这一技术方案稳定实施的安全问题之一。为此，本文利用理论计算和数值模拟相结合的方法对高压掺氢天然气泄漏自燃过程进行了研究。

首先，基于扩散点火理论和激波管流动理论，对高压掺氢天然气泄漏后激波作用区域关键参数的理论计算公式进行分析，建立了高压掺氢天然气泄漏激波流场特性计算模型，并根据相关实验数据进行验证。基于CFD模拟，研究了不同工况下激波传播特性。结果表明：掺氢比例越大，泄放压力越高以及管道内径越小，均会使激波作用压力越大，激波平均传播速度越大，半球形激波、马赫盘、桶形激波等典型结构形成的更快；管道长度的改变对激波的传播特性影响较小，且激波平均传播速度的最大值存在极限，约为1300 m/s；另外，管道内突缩结构会因为多维激波的共同作用使激波强度增大，突扩结构会使激波在下游传播过程中结构更加分散。

其次，研究了掺氢比例、泄放压力、管道内部结构（内径、长度、横截面）对高压掺氢天然气泄漏到泄放管道内自燃特性的影响。掺氢比例越大、泄放压力越高，越有利于自燃的发生，且初始自燃着火越易在靠近爆破片位置发生。研究发现：当泄放压力为25 MPa时，掺氢比例为0%的纯甲烷气体在管内未发生自燃现象，当掺氢比例从5%到30%时，发生自燃着火的温度从1130 K降低至1087 K，发生自燃着火的时间从157 μs缩短至110 μs，发生自燃着火的距离从134mm缩减到100mm（距离爆破片）。当泄放压力为13 MPa时，掺氢比例为20%的掺氢天然气也未在管道内发生自燃现象，泄放压力从19 MPa到40 MPa，发生自燃着火的时间从194 μs缩短至61 μs，发生自燃着火的距离从166mm缩减到60mm（距离爆破片）。在同等条件下，较小的管道内径有利于自燃的发生，较大的管道内径为高压掺氢天然气射流在管道内的膨胀提供更大的空间，因此自燃不易发生。随着管道长度的增加，掺氢天然气-空气混合物在管内的停留时间也越长，则更有利于自燃的发生。另外，还发现泄放管道内部结构的改变对自燃现象的影响是不确定的，当管道横截面减小时（突缩结构），更容易发生自燃；横截面增大时（突扩结构），自燃的可能性较小。因此，可通过降低掺氢比例、减小泄放压力、增大管道内径、缩短管道长度以及避免管道结构的改变进行降低自燃的发生。

最后，对管道外激波传播特性和自燃火焰的传播特性进行分析。发现掺氢比例越大，泄放压力越高，对管壁产生激波作用的压力最大值越高，自燃火焰燃烧的时间更久；管道外障碍物的存在会增加开放空间内反射激波的形成，因此自燃火焰的传播持续时间更长，且障碍物的形状对激波强度和燃烧特性的影响较大。可通过控制管道内自燃的发生以及避免管外障碍物的存在降低管外的火焰传播。研究成果可为掺氢天然气的安全应用提供理论基础。

The low-cost and efficient long-distance transportation of hydrogen energy is one of the technical bottlenecks limiting the large-scale application of hydrogen energy. It is an effective technical scheme to realize the long-distance transportation of hydrogen by mixing hydrogen into natural gas in a certain proportion and using the existing natural gas pipeline network to transport hydrogen-doped natural gas. However, the spontaneous combustion of high-pressure hydrogen-doped natural gas leakage has become one of the security issues that threaten the stable implementation of this technical solution. Therefore, this paper studies the leakage and spontaneous combustion process of high-pressure hydrogen-doped natural gas by combining theoretical calculation and numerical simulation.

Firstly, based on the diffusion ignition theory and the shock tube flow theory, the theoretical calculation formulas of the key parameters of the shock wave region after the leakage of high-pressure hydrogen-doped natural gas are analyzed. The calculation model of the shock wave flow field characteristics of high-pressure hydrogen-doped natural gas leakage is established and verified according to the relevant experimental data. Based on CFD simulation, the propagation characteristics of shock wave under different working conditions are studied. The results show that the larger the hydrogen blending ratio, the higher the discharge pressure and the smaller the inner diameter of the pipeline, the greater the pressure of shock wave, the greater the average propagation velocity of shock wave, and the faster the formation of typical structural forms such as hemispherical shock wave, Mach disk and barrel shock wave. The change of the pipe length has little effect on the propagation characteristics of the shock wave, and the maximum value of the average propagation velocity of the shock wave has a limit of about 1300 m/s. In addition, the sudden contraction part in the pipeline will increase the strength of the shock wave due to the combined action of the multi-dimensional shock wave structure, and the sudden expansion part will make the shock wave structure more dispersed in the downstream propagation process.

Secondly, the effects of hydrogen blending ratio, discharge pressure and pipeline internal structure (inner diameter, length, cross section) on the spontaneous combustion characteristics of high-pressure hydrogen-doped natural gas leaking into the discharge pipeline were studied. The greater the hydrogen blending ratio and the higher the discharge pressure, the more conducive to the occurrence of spontaneous combustion, and the initial spontaneous combustion ignition is more likely to occur near the position of the bursting disc. It was found that when the discharge pressure was 25 MPa, the pure methane gas with a hydrogen blending ratio of 0 % did not spontaneously ignite in the tube. When the hydrogen blending ratio was from 5% to 30%, the temperature of spontaneous ignition decreased from 1130 K to 1087 K, the time of spontaneous ignition was shortened from 157 μs to 110 μs, and the distance of spontaneous ignition was reduced from 134 mm to 100 mm (from the bursting disc). When the discharge pressure is 13 MPa, the hydrogen-doped natural gas with a hydrogen blending ratio of 20% does not spontaneous combustion in the pipeline. When the discharge pressure is from 19 MPa to 40 MPa, the time of spontaneous combustion is shortened from 194 μs to 61 μs, and the distance of spontaneous combustion is reduced from 166 mm to 60 mm (from the bursting disc). Under the same conditions, the smaller pipe diameter is conducive to the occurrence of spontaneous combustion, and the larger pipe diameter provides more space for the expansion of high-pressure hydrogen-doped natural gas jet in the pipeline, and spontaneous combustion is not easy to occur. With the increase of pipeline length, the residence time of hydrogenated natural gas-air mixture in the pipeline is longer, which is more conducive to the occurrence of spontaneous combustion. In addition, it is also found that the influence of the change of the internal structure of the discharge pipeline on the spontaneous combustion phenomenon is uncertain. When the cross section of the pipeline is reduced (sudden contraction structure), spontaneous combustion is more likely to occur; when the cross section increases (sudden expansion structure), the possibility of spontaneous combustion is small. Therefore, the occurrence of spontaneous combustion can be reduced by decreasing the proportion of hydrogen doping, reducing the release pressure, increasing the inner diameter of the pipeline, shortening the length of the pipeline and avoiding changes in the structure of the pipeline.

Finally, the propagation characteristics of shock wave and spontaneous combustion flame outside the pipeline are analyzed. It is found that the higher the hydrogen blending ratio, the higher the discharge pressure, the faster the formation of typical structural forms such as hemispherical shock wave, Mach disk and barrel shock wave, the higher the maximum pressure of shock wave on the tube wall, and the longer the time of spontaneous combustion flame combustion; the existence of obstacles outside the pipe will increase the formation of reflected shock waves in the open space, so the propagation duration of the spontaneous combustion flame is longer, and the shape of the obstacle has a great influence on the shock wave intensity and combustion characteristics. The flame propagation outside the pipe can be reduced by controlling the occurrence of spontaneous combustion inside the pipe and by avoiding the presence of obstacles outside the pipe. The research results can provide a theoretical basis for the safe application of hydrogen-doped natural gas.

[1]杨勇平. 氢能，现代能源体系新密码[EB/OL]. 国家能源局, 2022-05-07.

[2]沈晓波, 章雪凝, 刘海峰. 高压氢气泄漏相关安全问题研究与进展[J]. 化工学报, 2021, 72(3): 1217-1229.

[3]刘翠伟, 裴业斌, 韩辉, 等. 氢能产业链及储运技术研究现状与发展趋势[J]. 油气储运, 2022, 41(5): 498-514.

[4]Zhou S Y, Luo Z M, Wang T, et al. Research progress on the self-ignition of high- pressure hydrogen discharge: A review[J]. 2022, 47(15): 9460-9476.

[5]廖倩玉, 陈志光. 天然气管道掺氢输送安全问题研究现状[J]. 城市燃气, 2021(4): 19-26.

[6]任若轩, 游双矫, 朱新宇, 等. 天然气掺氢输送技术发展现状及前景[J]. 油气与新能源, 2021, 33(4): 26-32.

[7]Lynch F E, Marmaro R W. Special purpose blends of hydrogen and natural gas: USA, 5139002[P]. 1992−08−18.

[8]周承商, 黄通文, 刘煌, 等. 混氢天然气输氢技术研究进展[J]. 中南大学学报(自然科学版), 2021, 52(1): 31-43.

[9]赵永志, 张鑫, 郑津洋, 等. 掺氢天然气管道输送安全技术[J]. 化工机械, 2016, 43(1): 1-7.

[10]李敬法, 苏越, 张衡, 等. 掺氢天然气管道输送研究进展[J]. 天然气工业, 2021, 41(4): 137-152.

[11]蒋敏华, 肖平, 刘入维, 等. 氢能在我国未来能源系统中的角色定位及“再电气化”路径初探[J]. 热力发电, 2020, 49(1): 1-9.

[12]周理. 高压氢气泄漏自燃现象的模拟[D]. 重庆: 重庆大学, 2014.

[13]Li Y C, Bi M S, Zhang S L, et al. Dynamic couplings of hydrogen/air flame morphology and explosion pressure evolution in the spherical chamber[J]. International Journal of Hydrogen Energy, 2018, 43(4): 2503-2513.

[14]肖华华, 孙金华. 高压氢气泄漏自燃研究现状及展望[J]. 安全与环境学报, 2009, 9(04): 125-129.

[15]汤文辉. 冲击波物理[M]. 北京: 科学出版社, 2011.

[16]谭迎新, 薄涛. 激波诱导下煤粉的爆炸压力测试[J]. 中国安全科学学报, 2009, 19(7): 74-77.

[17]余明高, 赵万里, 游浩. 高压瓦斯泄放自燃实验研究[J]. 煤炭学报, 2011, 36(6): 959-963.

[18]游浩, 余明高, 刘欣华, 等. 激波诱导预混瓦斯燃烧的数值模拟[J]. 煤炭学报, 2012, 37(9): 1553-1558.

[19]任鹏. 激波诱导瓦斯气体燃烧的实验研究[D]. 河南理工大学, 2012.

[20]杨基明, 李祝飞, 朱雨建, 等. 激波的传播与干扰[J]. 力学进展, 2016, 46: 541-587.

[21]李雪芳, 王俞杰, 罗峰, 等. 欠膨胀氢气射流激波结构数值模拟研究[J]. 工程热物理学报, 2018, 39(4): 880-886.

[22]Pan X H, Wang Q Y, Yan W Y, et al. Experimental study on pressure dynamics and self-ignition of pressurized hydrogen flowing into the L-shaped tubes[J]. International Journal of Hydrogen Energy, 2020, 45(7): 5028-5038.

[23]Jiang Y M, Pan X H, Zhang T, et al. Shock waves, overpressure, and spontaneous ignition of pressurized hydrogen in T-shaped tubes[J]. Process Safety and Environmental Protection, 2023, 172: 535-545.

[24]Jia T M, Li G X, Yu Y S, et al. Propagation characteristics of induced shock waves generated by diesel spray under ultra-high injection pressure[J]. Fuel, 2016, 180: 521-528.

[25]贾涛鸣. 超高喷射压力下燃油射流雾化特性及诱导激波演变规律的试验研究[D]. 北京交通大学, 2018.

[26]Li P, Duan Q L, Jin K Q, et al. Experimental study on shock waves, spontaneous ignition, and flame propagation produced by pressurized hydrogen release through tubes with varying obstacle location[J]. Fuel, 2021, 290: 120093.

[27]Li P, Duan Q L, Gong L, et al. Effects of obstacles inside the tube on the shock wave propagation and spontaneous ignition of high-pressure hydrogen[J]. Fuel, 2019, 236: 1586-1594.

[28]Jin K Y, Yang S N, Gong L, et al. Numerical study on the spontaneous ignition of pressurized hydrogen during its sudden release into the tube with varying lengths and diameters[J]. Journal of Loss Prevention in the Process Industries, 2021, 72: 104592.

[29]Astbury G, Hawksworth S. Spontaneous ignition of hydrogen leaks: a review of postulated mechanisms[J]. International Journal of Hydrogen Energy, 2007, 32: 2178-2185．

[30]Merilo E, Groethe M, Adamo R, et al. Self-ignition of hydrogen releases through electrostatic discharge induced by entrained particulates[J]. International Journal of Hydrogen Energy, 2012, 37: 17561-17570.

[31]Imamura T, Mogi T, Wada Y. Control of the ignition possibility of hydrogen by electrostatic discharge at a ventilation duct outlet[J]. International Journal of Hydrogen Energy, 2009, 34: 2815-2823.

[32]Wolanski P, Wojcicki S. Investigation into the mechanism of the diffusion ignition of a Combustible gas flowing into an oxidizing atmosphere[J]. Proceedings of the Combustion Institute, 1972(14): 1217-1223.

[33]Li J, Myoung N, Kwon J, et al. A theoretical analysis of temperature rise of hydrogen in high-pressure storage cylinder during fast filling process[J]. Advances in Mechanical Engineering, 2020, 12(12): 1-10.

[34]Ungut A, James H. Autoignition of gaseous fuel-air mixtures near a hot surface[C]. Hazards XVI: Analysing the Past, Planning the Future. 2001: 487-501.

[35]Xu B P, HIMA L EL, Wen J X, et al. Numerical study on the spontaneous ignition of pressurized hydrogen release through a tube into air[J]. Journal of loss prevention in the process industries, 2008, 21(2): 205-213.

[36]汪志雷, 潘旭海, 蒋军成. 高压氢气泄漏自燃研究进展[J]. 南京工业大学学报(自然科学版), 2019, 41(5): 656-663.

[37]周魁斌, 刘娇艳, 蒋军成. 高压可燃气体泄漏动力学过程与喷射火热灾害分析[J]. 化工学报, 2018, 69(4): 1276-1287.

[38]董刚, 唐维维, 杜春, 等. 高压管道天然气泄漏扩散过程的数值模拟[J]. 中国安全生产科学技术, 2009, 5(06): 11-15.

[39]胡夏琦. 含硫化氢高压天然气管道泄漏的数值模拟[D]. 山东: 中国石油大学(华东), 2006.

[40]Wang Z L, Pan X H, Jiang Y M, et al. Experiment study on the pressure and flame characteristics induced by high-pressure hydrogen spontaneous ignition[J]. International Journal of Hydrogen Energy, 2020, 45(35): 18042-18056.

[41]Wang Z L, Pan X H, Wang Q Y, et al. Experimental study on spontaneous ignition and flame propagation of high-pressure hydrogen release through tubes[J]. International Journal of Hydrogen Energy, 2019, 44(40): 22584-22597.

[42]Rudy W, Teodorczyk A, Wen J. Self-ignition of hydrogen- nitrogen mixtures during high-pressure release into air [J]. International Journal of Hydrogen Energy, 2017, 42(11): 7340-7352.

[43]Wen J X, Xu B P, Tam V H Y. Numerical study on spontaneous ignition of pressurized hydrogen release through a length of tube [J].Combustion and Flame, 2009, 156(11): 2173-2189．

[44]余明高, 任鹏, 游浩, 等. 基于不同直径的高压管道瓦斯泄放自燃实验研究[J]. 中国矿业大学学报, 2012 ,41(2): 194-199.

[45]Gong L, Duan Q L, Jiang L, et al. Experimental study on flow characteristics and spontaneous ignition produced by pressurized hydrogen release through an Omega-shaped tube into atmosphere[J]. Fuel, 2016, 184: 770-779.

[46]Gong L, Jin K Y, Yang S N, et al. Numerical study on the mechanism of spontaneous ignition of high-pressure hydrogen in the L-shaped tube[J]. International journal of hydrogen energy, 2020, 45(56): 32730-32742.

[47]Zeng Q, Duan Q L, Li P, et al. An experimental study of the effect of 2.5% methane addition on self-ignition and flame propagation during high-pressure hydrogen release through a tube[J]. International Journal of Hydrogen Energy, 2020, 45(04): 3381-3390.

[48]Zeng Q, Duan Q L, Sun D X, et al. Experimental study of methane addition effect on shock wave propagation, self-ignition and flame development during high-pressure hydrogen sudden discharge from a tube[J]. Fuel, 2020, 277: 118217.

[49]Zeng Q, Jin K Q, Duan Q L, et al. Effects of CO addition on shock wave propagation, self-ignition, and flame development of high-pressure hydrogen release into air[J]. International Journal of Hydrogen Energy, 2022, 47(32): 14714-14724.

[50]Zeng Q, Duan Q L,Jin K Q, et al. Effects of nitrogen addition on the shock-induced ignition of high-pressure hydrogen release through a rectangular tube of 400 mm in length[J]. Fuel, 2022, 308, 122016.

[51]Duan Q, Xiao, H, Gong, L, et al. Experimental study on spontaneous ignition and subsequent flame development caused by high-pressure hydrogen release: Coupled effects of tube dimensions and burst pressure[J]. Fire safety journal: An international journal devoted to research on fire safety science and engineering, 2018, 97: 44-53.

[52]Duan Q L, Zhang F, Xiong T, et al. Experimental study of spontaneous ignition and non-premixed turbulent combustion behavior following pressurized hydrogen release through a tube with local enlargement[J]. Journal of loss prevention in the process industries, 2017, 49: 814-821.

[53]Duan Q L,Zeng Q, Jin K Q, et al. Mechanism of self-ignition and flame propagation during high-pressure hydrogen release through a rectangular tube[J]. Process Safety and Environmental Protection, 2022, 164: 283-290.

[54]Duan Q L, Xiao H H, Gong L, et al. Experimental study of shock wave propagation and its influence on the spontaneous ignition during high-pressure hydrogen release through a tube[J]. International Journal of Hydrogen Energy, 2019, 44(40): 22598-22607.

[55]李雪芳, 毕景良, 林曦鹏,等.高压氢气泄漏扩散数值模拟[J]. 工程热物理学报, 2014, 35(12): 2482-2485.

[56]Xiao J, Travis J R, Breitung W. Hydrogen release from a high pressure gaseous hydrogen reservoir in case of a small leak[J]. International Journal of Hydrogen Energy, 2011, 36(3): 2545-2554.

[57]Zhang J B, Zhang X, Huang W W, et al. Isentropic analysis and numerical investigation on high-pressure hydrogen jets with real gas effects[J]. International Journal of Hydrogen Energy, 2020, 45(39): 20256-20265.

[58]Zou Q, Tian Y, Han F. Prediction of state property during hydrogen leaks from high-pressure hydrogen storage systems[J]. International Journal of Hydrogen Energy, 2019, 44(39): 22394-22404.

[59]马子超, 吕淑然, 王春雪, 等. 高压天然气管道泄漏孔位置对喷射火的影响[J].消防科学与技术, 2017, 36(01): 13-15.

[60]苟小龙, 周理. 激波管内高压氢气泄漏自燃现象的模拟研究[J]. 太阳能学报, 2015, 36(11): 2777-2781.

[61]鲁寨军, 严利果, 肖程欢, 等. 高压CO2管道泄漏的瞬态行为数值研究[J]. 安全与环境学报, 2021, 21(2): 758-763.

[62]Lowesmith B J, Hankinson G. Large scale high pressure jet fires involving natural gas and natural gas/hydrogen mixtures[J]. Process Safety and Environmental Protection, 2012, 90(2): 108-120.

[63]Zhong C, Gou X L. Inhibition Mechanism of CH4 Addition on the Pressurized Hydrogen Spontaneous Ignition[J]. Energy & Fuels, 2021, 35(2): 1715-1726.

[64]Subani N, Amin N, Agaie B G. Leak detection of non-isothermal transient flow of hydrogen-natural gas mixture[J]. Journal of loss prevention in the process industries, 2017, 48244-48253.

[65]Wang Z L, Zhang H, Pan X H, et al. Experimental and numerical study on the high-pressure hydrogen jet and explosion induced by sudden released into the air through tubes[J]. International Journal of Hydrogen Energy, 2020, 45(7): 5086-5097.

[66]马青峰, 韩辉, 李玉星, 等. 受限空间掺氢天然气泄漏与燃爆特性研究综述[J]. 油气与新能源, 2023, 35(1): 117-128.

[67]钟北京, 傅维标. 甲烷火焰中氢气对着火与燃尽的影响[J]. 燃烧科学与技术, 2001(2): 194-198.

[68]魏胜. 氢气和稀释气体对甲烷/空气预混火焰稳定燃烧特性的影响规律研究[D]. 重庆大学, 2014.

[69]周静. 天然气管线掺混氢气的特性分析[D]. 辽宁石油化工大学, 2020.

[70]Hafsi Z, Elaoud S, Mishra M. A computational modelling of natural gas flow in looped network: Effect of upstream hydrogen injection on the structural integrity of gas pipelines[J]. Journal of Natural Gas Science and Engineering, 2019, 64: 107-117.

[71]Jones D R, Al-Masry W A, Dunnill C W. Hydrogen-enriched natural gas as a domestic fuel: an analysis based on flash-back and blow-off limits for domestic natural gas appliances within the UK[J]. Sustainable Energy & Fuels, 2018, 2(4): 710-723.

[72]Molnarne M, Schroeder V. Hazardous properties of hydrogen and hydrogen containing fuel gases[J]. Process Safety and Environmental Protection, 2019,130: 1-5.

[73]刘方, 杨宏伟, 韩银杉, 等. 天然气掺氢比对终端用气设备使用性能的影响[J]. 低碳化学与化工, 2023, 48(2): 174-178.

[74]Gondal I A. Hydrogen integration in power-to-gas networks[J]. International Journal of Hydrogen Energy, 2019, 44(3): 1803-1815.

[75]Wolanski P, Wojcicki S. Investigation into the mechanism of the diffusion ignition of a Combustible gas flowing into an oxidizing atmosphere[J]. Proceedings of the Combustion Institute, 1972(14): 1217-1223.

[76]王新月, 热力学与动力学基础[M]. 陕西西安: 西北工大出版社, 2004: 124.

[77]赵万里. 高压瓦斯泄放自燃实验研究[D]. 河南理工大学, 2011.

[78]章霞. 基于激波管研究NO2对甲烷、乙烷和天然气点火特性的影响[D]. 西南交通大学, 2018.

[79]陈强. 激波管流动的理论和实验技术[M], 安徽: 中国科学技术大学出版社, 1979, 31-89.

[80]何川. 流体力学[M]. 重庆: 重庆大学出版社, 2018: 228.

[81]董玉林, 李全华. 混合理想气体绝热指数γmix的计算公式推导与熵[J]. 武汉理工大学学报, 2021, 43(9): 85-87+92.

[82]方达宪, 王艳华, 王伟, 等. 流体力学[M]. 南京东南大学出版社, 2018: 258.

[83]Zhu M Y, Jin K Q, Duan Q L, et al. Numerical simulation on the spontaneous ignition of high-pressure hydrogen release through a tube at different burst pressures[J]. International Journal of Hydrogen Energy, 2022, 47(18): 10431-10440.

[84]张嘉琦. 基于FLUENT室内天然气管道泄漏扩散数值模拟[D]. 东北石油大学, 2020.

[85]Gong L, Li Z S, Jin K Y, et al. Numerical study on the mechanism of spontaneous ignition of high-pressure hydrogen during its sudden release into a tube[J]. Safety Science, 2020, 129, 104807.

[86]汪东旭, 张尊华, 梁俊杰, 等. 激波管内黏性流场流动数值模拟[J]. 武汉理工大学学报(交通科学与工程版), 2021, 45(3): 492-498.

[87]张双. 氢气和稀释气体对甲烷/空气预混层流火焰燃烧特性的影响研究[D]. 重庆大学, 2014.

[88]唐玮旻. 微细尺度下掺氢对甲烷燃烧及熄火特性影响的数值研究[D]. 重庆大学, 2015.

[89]Kaneko W, Ishii K. Effects of diaphragm rupturing conditions on self-ignition of high-pressure hydrogen[J]. International Journal of Hydrogen Energy, 2016, 41(25): 10969-10975.