Experimental and numerical investigations of flame acceleration after passing through a perforated plate in a confined space

Essentially, the engine knock or the super-knock is always accompanied by the interactions between the turbulent flame and the shock wave, with rapid chemical energy release. Thus, it is of great significance to investigate the interactions between the turbulent flame and shock waves which is the key to reveal the mechanism of the knock or super-knock. And the flame acceleration inducing pressure waves is the basic premise for the study of flame-shock interactions. Based on a self-designed constant volume chamber and 3-dimensional numerical simulation by Converge, the mechanism and impact factors of the flame acceleration after passing through the perforated plate are investigated. In addition, the influence of the initial pressure on the combustion phenomenon is discussed. According to the flame morphology and the flame tip velocity, the evolution of the flame acceleration is divided into three stages, which are the laminar flame stage, the jet flame stage and the turbulent flame stage. The flow field results show that there exists a strong jet flow at the perforated plate before the flame reaches, which drives the flame acceleration. However, after the flame passes through the perforated plate, the flow velocity downstream of the flame front decreases as it departs from the flame, which means the flow is driven by the flame. In addition, it is found that the turbulent flame velocity, pressure and pressure oscillation increase with the increase of the initial pressure.