Abstract:

An experimental study was carried out on the variation of overpressure of underexpanded hydrogen jet ignition by spontaneous ignition and electric spark ignition. We measured the explosion overpressure and flame propagation rate of spontaneous ignition and electric spark ignition under different release pressures, we also analyzed the influence mechanism of initial pressure and ignition conditions on explosion overpressure. The experimental results show that under the same release conditions, the overpressure peak of spontaneous ignition is higher, the pressure rise rate is faster, and the development process of spontaneous ignition is more stable. With the release pressure of the buffer tank increasing from 6 MPa to 9 MPa, the explosion overpressure peak outside the spontaneous ignition tube first increases and then decreases. When the release pressure is 8 MPa, the explosion overpressure caused by spontaneous ignition reaches the maximum value of 15.97 kPa, while the explosion overpressure at the ignition source of electric spark decreases from 7.23 kPa to 3.17 kPa and then increases to 4.19 kPa with the increase of the release pressure. The spark ignition flame forms an irregularly shaped ignition core at the ignition source, and the flame propagation velocity is greater than the spontaneous combustion flame development velocity. This study has reference significance for the design of hydrogenation station and the risk assessment of ignition and explosion.

Key words: explosion, hydrogen, explosion overpressure, hydrogen leakage, security

摘要：

针对自燃点火与电火花点火对欠膨胀氢气射流燃爆超压的变化规律开展实验研究，测量了自燃和电火花两种点火方式在不同释放压力下的爆炸超压与火焰传播速率，分析了初始压力和点火条件对爆炸超压的影响机制。实验结果表明：相同释放条件下，自燃点火比电火花点火引发的管外爆炸超压峰值更高，压力上升速率更快，且自燃点火的发展过程更稳定；随着缓冲罐内释放压力从6 MPa升高到9 MPa，自燃管外爆炸超压峰值先升高后降低，在释放压力为8 MPa时自燃引发的爆炸超压达到最大值15.97 kPa，而电火花点火源处的燃爆超压随释放压力的上升从7.23 kPa先降低至3.17 kPa后升高到4.19 kPa；电火花点火火焰在点火源处形成了不规则形状点火核，同时火焰传播速度大于自燃火焰发展速度。本研究对于加氢站设计和燃爆风险评估具有参考意义。

关键词: 爆炸, 氢, 燃爆超压, 氢泄漏, 安全