Pressure oscillation with destructive effect of flame propagation of a stoichiometric hydrogen-air mixture in a confined space

In the present work, the formation mechanism of high-intensity combustion with high pressure oscillation and its destructive effects was studied by a newly designed constant volume combustion bomb equipped with a perforated plate. The stoichiometric H-2-air mixture was selected as the test fuel because of its high flame propagation velocity with obvious shock wave, which easily leads to a strong pressure oscillation. Two kinds of high-intensity combustion phenomena, including the continuous acceleration of the flame front and end-gas auto ignition, were obtained. The results show that the ultrafast and intense combustion would lead to a high pressure oscillation, consequently caused damage to the experimental device, such as the optical glass and perforated plate. The perforated plate vibrated back and forth in situ forced by the combustion waves. The peak pressure was up to 10.3 MPa and maximum amplitude of pressure oscillation was 4.2 MPa when the optical glass was damaged. And according to FFT analysis, the frequency of in-cylinder pressure changed because of the combustion mode transition. The present work provides an alternative method to not only grasp the destructive mechanism of knocking combustion, but also understand the destructive effect of the combustion of the hydrogen-air mixture. (C) 2017 Elsevier B.V. All rights reserved.