Pressure Distribution and Performance Impacts of Aerospike Nozzles on Rotating Detonation Engines

Rotating detonation engines RDEs have the potential to further increase the performance of air-breathing propulsion devices and are currently being explored as an option for missions with wide altitude and flight Mach number ranges. Aerospike nozzles lend themselves well to this type of application because they possess altitude-compensating characteristics. However, the effects of the unsteady nozzle inlet dynamics associated with RDEs on aerospike nozzle performance have not been fully determined. Consequently, aerospike nozzle design has not yet been optimized for RDE applications. A contoured aerospike nozzle was designed for implementation on a RDE to examine the effect of ideal aerospike profiles on RDE performance. Currently, no nozzle design technique accounts for transient throat conditions inherent in RDE operation. Therefore, the nozzle contour was designed using a traditional, steady-state design methodology at both on- and off-design conditions anticipated throughout the combustion cycle. Steady-state, non-reacting computational fluid dynamics CFD simulations were performed on various nozzle geometries over multiple pressure ratios to investigate the flow field structure along the nozzle contour and justify design tradeoffs. Future work is needed to implement this nozzle design to investigate the effect of RDE-specific flow fields on nozzle performance.