Scaling Effects of Increased Annular Diameter in a Rotating Detonation Rocket Engine

As scaling of rotating detonation rocket engines becomes increasingly important for transition from laboratory-scale experiments to application-based testing and flight demonstrations, scaling methodologies must be studied and tested. In this study, a 76.2~mm RDRE is scaled up to a 101.6~mm annulus, proportionally scaling the injection area such that the ratio of the annulus area to the injection area is constant. This enables similar injector response for both geometries. Additionally, as symmetric injector response has been shown to be important to RDRE operation, a new injector is designed that provides axial net-momentum balance and symmetric plenum pressures around phi=1.2. These three geometries are compared on the basis of their operability limits, system pressures, detonation wave propagation and global performance. It is shown that the scaling methodology used produces an engine that provides similar performance at equivalent total mass flux, and also demonstrates that the momentum-balanced injector with greater injection area provides the same global performance with significantly reduced plenum pressures and increased detonation wave speed.