Hydrogen explosion characteristics by changing obstacle position and blockage ratio.

Combining experimental research and numerical simulation, this paper studies the effects of obstacle position and blockage ratio on hydrogen flame evolution and explosion characteristic. The mechanism of obstacle-induced turbulence on the hydrogen flame acceleration is revealed. The results show that in a double obstacle tube, When the obstacle spacing is larger, the turbulent combustion intensity and pressure rise rate is relatively higher, and the pressure oscillation is enhanced. The sufficient turbulent combustion promotes the formation of stronger vortex motion at the downstream obstacle. As the blockage ratio increases, the turbulent combustion intensity, flame front speed, and pressure rise rate increases significantly. While obstacles with a high blockage ratio have a blocking effect on the pressure, slightly weakening the pressure oscillation. As the blockage ratio increases, the jet speed at the obstacle increases, the scale and speed of vortex increase, and the vorticity magnitude of unburned and burned area increases. • Effects of obstacle position and blockage ratio on hydrogen explosion are investigated. • A numerical model is developed to analyze the flame evolution and pressure dynamic. • Mechanism of obstacle-induced turbulence on the hydrogen flame acceleration is revealed. [ABSTRACT FROM AUTHOR]