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中文核心期刊

开放空间H2/CH4/空气爆炸实验与数值模拟研究

EXPERIMENTAL AND NUMERICAL STUDIES OF H2/CH4/AIR EXPLOSION IN OPEN SPACE

  • 摘要: 近年来氢的使用范围逐渐发展到各个领域, 含氢多元混合物气体在工业生产及生活燃料中被普遍使用. 为了保障含氢气体在生产、运输、使用等各个环节的安全性, 构建了开放空间混合气体爆炸测试实验系统, 研究了H2/CH4/空气混合气体爆炸压力及火焰传播特性, 给出了不同氢摩尔分数(100%, 75%, 66.67%, 50%, 33.33%)、混合气体当量比(0.8, 1.0, 1.1, 1.2, 1.4)、可燃云团尺寸(1 m3, 4 m3, 8 m3)及障碍物约束等因素对混合气体爆炸压力及火焰的影响规律. 基于经典TNT当量法, 建立了考虑混合气体组分比及可燃云团尺寸的最大爆炸超压预测模型, 修正了爆炸火焰传播半径理论模型. 结合高精度数值模拟技术揭示了加气站内建筑结构对混合气体爆炸的影响. 研究表明, 氢气的加入能够明显增强气体爆炸强度, 最大爆炸超压、火焰传播速度均随氢摩尔分数的增加而增大, 随当量比的增大先增大后减小, 当量比为1.1~1.2时最大; 通过对大尺度混合气体爆炸数值仿真与分析发现, 加气站内不同建构筑物条件下爆炸火焰传播距离、传播速度、最大爆炸超压等关键参数明显不同, 顶部和背部同时约束时, 爆炸伤害范围及事故后果最严重, 因此在划定加气站安全距离时, 应充分考虑不同建筑结构的影响.

     

    Abstract: In recent years, the use of hydrogen involves many fields. Multi-component mixture gas containing hydrogen is widely used in industrial production and domestic fuels. To ensure the safety of hydrogen containing gas in every links, e.g., production, transportation, and use, an outdoor open space mixed gas explosion test system is built. Five cases of hydrogen mole fraction (100%, 75%, 66.67%, 50%, 33.33%), five cases of equivalence ratio of mixed gas (0.8, 1.0, 1.1, 1.2, 1.4), three cases of initial volume of mixed gas (1 m3, 4 m3, 8 m3) and three kinds of constraints are adopted to study their effects on the mixed gas explosion pressure and flame. An explosion pressure prediction model considering the component ratio of the mixture and the initial volume of mixed gas is established based on the classical TNT equivalent method, and the theoretical model of explosion flame propagation radius is further modified by adding the effect of hydrogen mole fraction on the mixed gas explosion. Finally, the influence of building structure on explosion of H2/CH4/air mixtures is illustrated by experiments and large-scale high-resolution simulation. The results show that the addition of hydrogen can significantly enhance the gas explosion intensity. The maximum explosion pressure and flame propagation velocity increase with the hydrogen mole fraction, and first increases and then decreases with the increase of equivalence ratio, where the value increase to its peak value when the equivalence ratio is 1.1-1.2. At the same time, the hydrogen mole fraction and the initial volume of mixed gas seriously affect the accuracy of TNT equivalent method in predicting gas explosion pressure. The key parameters, e.g. explosion flame propagation distance, flame velocity and maximum explosion pressure, are obviously different under different construction conditions in the gas filling station. When the top and back side are restrained at the same time, the scope of explosion injury and consequences of an accident are the most serious. Thus, the influence of different building structures should be fully considered when delineating the safety distance of the gas station.

     

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