Abstract: A rotating detonation engine includes an annulus having a first wall, a second wall, and a volume having a detonation region in which a mixture of an oxidizer and a fuel detonate in a rotating fashion to create a pressure wave and detonation exhaust, the volume defining a downstream outlet through which detonation exhaust flows. The engine further includes an oxidizer outlet to output oxidizer and a fuel outlet to output fuel into the volume. The engine further includes an obstacle positioned in the volume and extending for an obstacle distance between the first wall and the second wall that is at least twenty five percent of an annulus distance from the first wall to the second wall, the obstacle designed to reflect the pressure wave such that a reflection of the pressure wave travels downstream and reduces an amount of the detonation exhaust that travels upstream.

Abstract: A rotating detonation engine includes an annulus that defines a volume having a detonation region which is configured for a mixture of an oxidizer and a fuel to detonate in a rotating fashion, the volume defining a downstream outlet through which detonation exhaust flows. The rotating detonation engine further includes an oxidizer outlet configured to output the oxidizer into the volume. The rotating detonation engine further includes a fuel outlet configured to output the fuel into the volume such that the oxidizer and the fuel are initially insufficiently mixed to facilitate combustion. The rotating detonation engine further includes an obstacle positioned upstream from the detonation region and configured to mix the fuel and the oxidizer that are directed upstream in response to a passing detonation.

Abstract: A rotating detonation engine includes an annulus that defines a volume in which a mixture of an oxidizer and a fuel detonate in a rotating fashion, the volume defining a downstream outlet through which detonation exhaust flows. The rotating detonation engine further includes a wave arrestor positioned upstream from a location of detonation and configured to reduce a magnitude of a pressure wave traveling upstream from the location of detonation.