Abstract:
Experiments were conducted in a newly designed constant volume combustion bomb with orifice plate by varying initial conditions. Hydrogen-air mixtures were used to obtained the turbulent flame front and shock wave, as well as the processes of flame-shock interactions were tracked by high-speed schlieren photography. The effects of apertures, porosities, equivalence ratios and distance between spark and orifice plate on the flame propagation speed, the intensity of shock wave and their interactions to pressure oscillation were analyzed in detail. It was found that there formed a clear shock wave after laminar flame passing through orifice plate under certain conditions.The reflected shock wave interacted with the flame front, which causes oscillating flame propagation. On the other hand, the cylinder pressure presents a violent fluctuation. It was indicated that the interaction between flame and shock wave was the reason of pressure oscillation. This work provides a references for the study of knock in SI engines and shows a method for DDT and pulse detonation phenomena research as well.