Coupling of detonation structure and upstream inhomogeneities in a rotating detonation engine

Rotating detonation rocket engines (RDREs) exhibit significant inhomogeneities in reactant composition upstream of their azimuthally-propagating detonation waves. These inhomogeneities impact performance characteristics of the combustor, as well as complicate the modeling of these systems. This work presents an analysis of a large-eddy simulation of a laboratory-scale RDRE, which resolves many of the inhomogeneities associated with scalar mixing and turbulent combustion. Lagrangian tracer particles are used as an analytical tool to track Eulerian state data, enabling extraction of detonation properties. Using this method, we show that the significant preburning present in this combustor is correlated with lower pressure ratios across the detonation front, consistent with prior results. Furthermore, we show that the detonation wave is distorted by these inhomogeneities into a non-planar shape. This distortion is indicative of pronounced detonation speed variations across the wave front, which is caused by upstream inhomogeneities and leads to the variation in pressure ratio. Finally, the detonation induces recirculation zones, which transport combustion products to the base of the combustor, thereby coupling to the upstream inhomogeneity of the next passing wave.