Numerical study on the spontaneous-ignition features of high-pressure hydrogen released through a tube with burst conditions

Inhibition Mechanism of CH4 Addition on the Pressurized Hydrogen Spontaneous Ignition

“…Thus, the numerical simulation is seen as the alternative that can provide a more detailed information. In addition to the analysis of parameters similar to those used in the experimental studies, many numerical simulations emphasized the importance of the membrane rupture process and the expansion and entrainment flow structure near the tube exit. − These numerical studies revealed that the sharp shock waves, the short mixing time scale, and the strong enough partially premixed flames developed in the fuel-leaking tube are the three essential elements for the successful establishment of the turbulent diffusion flames on the exit lip of the tube.…”

“…14. Sensitivity of key elementary reactions on the constant pressure ignition delay time of the H 2 /CH 4 /air mixture under various CH 4 blending levels.…”

Kinetic Analysis on Spontaneous Combustion of Pressurized Hydrogen in Tubes

“…Many investigations on high-pressure hydrogen-release process have been carried out, which were mostly based on the length of a downstream tube after hydrogen breaking through a diaphragm. In some early research works, the influence of tube length − and release pressure , on spontaneous ignition was usually studied by analyzing the characteristics of the in-tube flow and out-of-tube jet flame. − With the development of the measurement technology and the improvement of computing power, the focus of research has gradually shifted from phenomenon to essence. − Several important experimental works ,, were conducted, and these results revealed that release pressure and downstream pipe diameter have a very important influence on spontaneous combustion. Kim et al visually tracked the formation and propagation of flame in the pipeline by taking shadowgraph and direct photograph through windows of the tube, which can accurately determine the ignition position and flame propagation.…”

“…In addition, lots of numerical investigations have been conducted to understand in depth the ignition process of high-pressure hydrogen release via the length of the pipe. Through the numerical simulation, Wen and Lee have studied the possibility of hydrogen spontaneous ignition, and both mentioned that the release pressure and pipe diameter directly affect the flow characteristics in the pipe, which is closely related to the fire phenomenon.…”

“…However, the deep understanding on spontaneous ignition mechanism is still lacking universality because experimental results were largely dependent on the various experimental facilities and limited by measuring instruments, while numerical results were limited by computation ability. For instance, some works that have a good performance in numerical simulation were limited to two-dimensional simulations. , …”