Influence of Obstacles on the Vented Hydrogen Deflagration in an Explosion Tube.

The experiments and simulations of vented hydrogen-air mixture explosions in the tube are investigated with the influence of the obstacle. The internal pressure curves of different hydrogen concentrations are analyzed in the presence of an obstacle. The internal overpressure has two obvious overpressure peaks without an obstacle. As the obstacles are placed in the tube, the maximum internal pressure is markedly elevated. Two maximum overpressures of the 16 cm obstacle and 9 cm obstacle are just same, the internal pressure curve has multiple overpressure peaks in the presence of the 16 cm obstacle. The presence of obstacles has influenced the duration of the vented hydrogen-air mixtures. In the presence of obstacles, the location changes of the flame propagation location have marked sudden decreases. The sudden decrease corresponds to a secondary increase of flame propagation. The maximum flame length with presence of 16 cm obstacle is the longest. Simulated results show that the area of the flame notably increased with the effect of the obstacle. As the burning mixture approached the obstacle, the flame was stretched of the shape, and the integral structure was segmented into two flame fronts. It can be found that the presence of the obstacle will speed up flame propagation.