Thermodynamics of a Rotating Detonation Engine

Abstract

A practical thermodynamic cycle model of a rotating detonation engine (RDE) is developed for the purpose of predicting performance and understanding flow field behavior. The cycle model is based on a heuristic analysis of a RDE numerical simulation. The model is compared to the simulation and to laboratory experiment with good results. The RDE constrains a detonation wave to rotate inside a cylindrical annulus, has no moving parts and requires a single ignition sequence. Thrust is produced continuously and at high frequency. The simplicity of the RDE offers the possibility of a practical detonation engine with efficiencies that exceed conventional Brayton cycles. A RDE numerical simulation (courtesy of the Naval Research Laboratory) is post-processed to yield the underlying thermodynamics. The time-accurate numerical simulation is averaged over many cycles. A Galilean transformation is applied to the time-averaged solution to produce a solution field in the rotating frame of reference. Streamlines are created in the transformed solution field. Velocity, pressure and temperature are extracted along the streamlines. Pressure-volume and enthalpy-entropy diagrams are plotted to expose the simulation thermodynamics.