Experimental investigation on spontaneous combustion of high-pressure hydrogen leakage to form jet fire

In this paper, to investigate the variation of the critical initial release pressure with the pipeline length in high-pressure hydrogen leakage that leads to spontaneous combustion and the transition process from spontaneous combustion flame inside the tube to the jet flame outside the tube, we conducted experiments using a pressure gauge, a photoelectric and high-speed camera, etc. Our results showed that, at the same pipeline length and under a low initial release pressure, hydrogen is not apt to spontaneous combustion. The minimum initial release pressure of hydrogen spontaneous combustion decreases slowly and then increases rapidly with as the pipe length increases. At the same pipeline length, the greater the initial release pressure, the faster the shock wave propagation, and the closer the hydrogen self-ignition position inside the pipe to the rupture disc. It is found that the flame combustion is intensified after the airflow passed through the Mach disk. With the increase of time, the flame length increases first and then decreases gradually, the average propagation speed of the jet flame tip decreases gradually. The flame width increases first and then decreases rapidly to a stable value. © 2019, Editorial Staff of EXPLOSION AND SHOCK WAVES. All right reserved.