Theoretical prediction of hydrogen cloud explosion overpressure considering self-accelerating flame propagation
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摘要: 通过揭示当量比对氢气云爆炸火焰形态、火焰半径和爆炸超压峰值的影响规律，本文拟建立耦合火焰自加速传播的氢气云爆炸超压预测模型。结果表明：氢气云爆炸火焰传播速度由大至小对应的当量比依次是Φ=2.0、Φ=1.0和Φ=0.8。Le＜1.0和Le＞1.0的氢气云爆炸火焰表面均出现胞格结构，胞格结构的出现必然会增加火焰燃烧表面积，进而出现“火焰自加速”现象。对于特定的当量比，随着压力监测点和点火位置间距的增加，爆炸超压峰值的正值和负值绝对值均单调减小；对于特定的压力监测点，爆炸超压峰值的正值和负值绝对值随当量比的关系存在些许差异；不同当量比和监测点位置的爆炸超压峰值的负值绝对值大都高于正值。耦合火焰自加速传播的氢气云爆炸超压预测模型可成功预测不同压力监测点薄膜破裂前氢气云爆炸超压的发展过程。Abstract: On the basis of revealing the effects of equivalence ratio on flame morphology, radius and maximum explosion overpressure, this work was aimed at establishing a theoretical model to predict hydrogen cloud explosion overpressure by considering self-accelerating flame propagation. The results indicated that the decreasing order of flame propagation velocity is Φ=2.0, Φ=1.0 and Φ=0.8. For Le＜1.0 and Le＞1.0, the cellular structures could be formed on the flame surface, which would increase flame surface area and result in self-accelerating flame propagation. When the equivalence ratio was fixed, the positive maximum explosion overpressure and absolute value of negative maximum explosion overpressure continue to decrease as the distance between pressure senor and ignition source increases. As the equivalence ratio changes, there are some differences for positive maximum explosion overpressure and absolute value of negative maximum explosion overpressure at the fixed distance. The absolute value of negative maximum explosion overpressure was relatively higher than positive maximum explosion overpressure. Before rupture of thin film, the explosion overpressure evolution at various monitoring points could be reproduced using the theoretical model considering self-accelerating flame propagation.
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图 2 氢气云爆炸典型超压曲线（Φ=2.0）
Figure 2. Typical curves of hydrogen cloud explosion overpressure (Φ=2.0)
图 3 当量比对氢气云爆炸火焰形态的影响规律
Figure 3. Effects of equivalence ratio on flame morphology of hydrogen cloud explosion
图 4 Le＜1.0和Le＞1.0的氢气云爆炸火焰自加速传播特征
Figure 4. Self-accelerating flame propagation of hydrogen cloud explosion of Le＜1.0 and Le＞1.0
图 5 当量比对热膨胀比和火焰厚度的影响
Figure 5. Effects of equivalence ratio on thermal expansion ratio and flame thickness
图 6 当量比对氢气云爆炸超压峰值（正值和负值）的影响规律
Figure 6. Effects of equivalence ratio on maximum explosion overpressure (positive and negative value)
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