Numerical study on the effects of the obstacle shapes on the spontaneous ignition of high-pressure hydrogen in a tube.

It is necessary to investigate the impact of different obstacle shapes on high-pressure hydrogen spontaneous ignition due to the role obstacles play in promoting its generation. This paper first carried out model validation and found that the simulation could accurately reproduce the position and time of the initial flame detection, flame evolution, and pressure in the triangular-shaped obstacle tube as observed in the experiments. Subsequently, simulations were employed to explore the impact of three different obstacle shapes (triangular-shaped, arc-shaped, and square-shaped) on spontaneous ignition with the tube. The variation in obstacle shapes affects the initial flame detection position and the length of the flame, while it has minimal impact on the spontaneous ignition time. The square-shaped obstacles result in the closest initial flame detection position point to the burst disk and the longest flame in the tube, followed by the arc-shaped obstacles, and finally the triangular-shaped obstacles. • The effects of the obstacle shapes were numerically studied on the spontaneous ignition of high-pressure hydrogen. • The four aspects of the simulation results were compared and verified with the experimental data. • The distribution of the flammable mixture was investigated inside each obstructed tube. • The evolution of hydrogen molar fraction was investigated in the axial and radial directions. [ABSTRACT FROM AUTHOR]