Methane-air Detonations in 2D and 3D Channels with Complex Chemistry*

Formation of gaseous methane detonations is a major safety concern in a wide range of industrial settings and mining operations. Prevention of such industrial accidents requires a thorough understanding of detonation properties in such mixtures, in particular in the context of the mechanisms of detonation formation and propagation at near-limit conditions. In this work, we carry out a systematic numerical investigation of methane-air detonations propagating in 2D and 3D channels using realistic boundary conditions, complete molecular transport, and complex chemistry. A fully compressible block-based adaptive mesh refinement code Athena-RFX++ is employed to achieve high numerical resolution. We present the overall detonation structure and dynamics in methane-air mixtures with the primary focus on the following questions: a) How does detonation structure differ between 2D and 3D? b) How well can modern physico-chemical models represent methane-air detonation properties both on large (cell structure) and small (triple-point collision) scales? c) What are the propagation limits (as a function of channel size and equivalence ratio) in 2D and 3D channels? Finally, comparison with existing experimental data on methane-air detonations is discussed.