A series of experiments were conducted to study the pressure and combustion characteristics of the high-pressure hydrogen during the occurrence of spontaneous ignition and the conversion from spontaneous ignition to a jet fire and explosion. Different initial conditions including release pressure (4–10 MPa), tube diameter (10/15 mm), and tube length (0.3/0.7/1.2/1.7/2.2/3 m) were tested. The variation of the pressure and flame signal inside and outside of the tube and the development of the jet flame were recorded. The experimental results revealed that the minimum ignition pressure required for self-ignition of hydrogen at different tube diameters decreased first and then increased with the extension of tubes. The minimum ignition pressure for tubes diameters of 10 mm and 15 mm is no more than 4 MPa and the length of the tubes is L = 1.7 m. The minimum release pressure required for spontaneous ignition of a tube D = 15 mm is always lower than that of a tube D = 10 mm at the same tube length. When the spontaneous ignition occurred, it did not absolutely trigger the jet fire. The transition from spontaneous ignition to a jet fire must go through the specific stages.

进行了一系列实验，研究了自燃过程中高压氢气的压力和燃烧特性，以及自燃到喷射火和爆炸的转化过程。测试了不同的初始条件，包括释放压力（4-10 MPa），管子直径（10/15 mm）和管子长度（0.3 / 0.7 / 1.2 / 1.7 / 2.2 / 3 m）。记录管内外压力和火焰信号的变化以及喷射火焰的发展。实验结果表明，在不同管径下，氢气自燃所需的最小点火压力先随管的延伸而减小，然后增大。直径为10 mm和15 mm的管的最小着火压力不超过4 MPa，管的长度为L = 1.7 m。在相同的管长下，自燃管D = 15 mm所需的最小释放压力始终低于管D = 10 mm。当发生自燃时，它并没有绝对触发喷射火。从自燃到喷射火的过渡必须经过特定阶段。