Experimental investigation on shock wave propagation and self-ignition of pressurized hydrogen in different three-way tubes

This paper experimental investigated the shock wave propagation characteristics and self-ignition produced by the high-pressure hydrogen release in the three-way tubes. Two Y-shaped tubes (60°, 120°) and one T-shaped tube (180°) were used in the experiments and the initial release pressure was 3–8 MPa. The pressure and photoelectric signals in tubes were recorded by the sensor. The results showed that the intensity of shock wave was enhanced or attenuated during the entire releasing process, but the dominant effect was distinct under different conditions and the two effects synergistically affected the occurrence possibility of self-ignition. The critical release pressure for self-ignition in the three-way tubes decreased with the increasing of the bifurcation angle, and the most difficult to occur the self-ignition was the 60° Y-tube in this study. In addition, quenching occurred in the 60° Y-tube when the initial release pressure was 6 MPa, because the temperature of the mixture dropped by the expansion effect. Furthermore, the intensity of the reflected shock wave was not strong enough to promote hydrogen rekindled. This experimental results have reference value for the safety of high-pressure hydrogen production, storage and transportation, and are helpful to understand the influence of bifurcation structure on self-ignition in energy application.