Experimental Study for Effects of Fluidic Obstacles on Detonation Initiation Performance

To investigate the impact of the fluidic obstacles on the deflagration to detonation transition (DDT) process, experiments were conducted in a 6mm square tube, using ethylene and 40% oxygen enriched air as fuel and oxidant, respectively. The detonation performance of the tube with fluidic obstacles was compared with that of the smooth tube, and the method of accelerating detonation using hot fluidic obstacles was first proposed. The results show that fluidic obstacles can effectively accelerate detonation initiation at proper jet diameter. For the 6mm square tube, injecting 1mm diameter non-reacting/hot gas fluidic obstacle can both remarkably accelerate detonation initiation, shortening 15% and 24% DDT distance, respectively. However, the 2mm diameter hot fluidic obstacle almost has no positive effect, even the 2mm non-reacting fluidic obstacles impedes the flame propagation. Therefore, the hot fluidic obstacles enhance detonation better than the conventional non-reacting fluidic obstacles at the same jet diameter.