A numerical study on the impact of chemical modeling on simulating methane-air detonations

Abstract

This article presents a study concerning the influence of chemical kinetic models on the generation and evolution of methane-air planar detonations. The open source solver rhoCentralRfFoam is applied to perform all numerical simulations. Four chemical kinetic models are considered. Two of them are highly simplified (with, at most, one global chemical reaction and two simple steps), while the other two involve 19 and 53 species, with 57 and 325 chemical reactions, respectively. Insights are provided into methane-air planar detonation waves and the development conditions under which they may or may not become self-sustained. Numerical results showed that regardless of how much time the detonation remains overdriven, without the adequate support it shall always decay to a Chapman-Jouguet (CJ) steady-state value. However, the CJ state may not stand on its own and may continue to decay until the reacting zone decouples from the leading blast. This sort of detonation failure is described and discussed.