Numerical Investigations on Unsteady Detonation Flame Dynamics in a Rotating Detonation Engine

Using the high-fidelity large-eddy simulation (LES) techniques, this study conducts a quantitative investigation on unsteady dynamics of correlated injector flow and detonation flame physics in a methane and oxygen rotating detonation engine (RDE). This research was designed to examine the interaction between co-rotating detonation waves (DW) and shock-waves (SW) formed in the tested rig. The observed flow field exhibits strong unsteadiness due to high-speed injector flow, high temperature heat release rate and wave-to-wave interaction. In the tested RDE configuration, a pair of co-rotating DW was found to form and generate another pair of counter-rotating (CR) shock-waves, which is weaker compression wave sustained through their pressure-relaxation dynamics behind the detonation front and injector feedback. This also alters injector discharge characteristics, impacting propellant fuel and air supply into the combustion chamber. Successive passage of these waves near the injector exits drives oscillatory flow, cyclic mass-flow reduction, and transient transitions between subsonic and supersonic flow regimes within the injector nozzles. These findings provide unexplored insights into wave-driven injection dynamics and mechanisms of sustained DW-SW dynamics.