Transition to detonation in a hydrogen-air mixtures due to shock wave focusing in the 90-deg corner

卷:48

Article

关键词: FLAME ACCELERATION;    SELF-IGNITION;    INITIATION;    REFLECTION;    DDT;    DEFLAGRATION;    RELEASE;    GAS;   

DOI  :  10.1016/j.ijhydene.2022.12.240

来源: SCIE

【 摘 要 】

This work presents experimental observation of the ignition modes due to shock wave focusing in a 90 -deg corner in a mixture of 20%-55% H2 in air with the main purpose of recognizing critical conditions for transition to detonation. The results showed three ignition modes, first 'weak' ignition followed by deflagration with ignition delay time higher than-1 ms, second 'strong' with instantaneous transition to detonation, and third with deflagrative ignition and delayed transition to detonation. The transition was observed only when specific shock wave velocity was reached. The transition velocity for stoichiometric mixture was approx. 715 m/s corresponding to M = 1.75 and 71% of speed of sound in products. For leaner or richer mixtures, the transition velocity increased approaching the speed of sound in products at approx. 18% and 58% H2. (c) 2022 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

【 授权许可】

Free