Effects of flow-field structures on the stability of rotating detonation ramjet engine

摘要

Due to less attention received by rotating detonation ramjet engine (RDRE), the three-dimensional flow-field structures and their influence on stability are less understood than rocket-mode rotating detonation engine (RDE). This paper presents three-dimensional numerical investigations on the RDRE model with a Laval inlet. The computations are based on detailed H-2/air chemistry. The simulation shows that, unlike rocket-mode RDEs, an upstream oblique shock wave is induced by detonation. This oblique shock wave is then prevented from propagating upstream further by the normal shock wave in the inlet. In addition, two instabilities in RDREs, namely, backflow and strip-type fresh fuel layer, are analyzed for the first time. Results indicate that the backflow is related to reflected shock waves and the upstream oblique shock wave that induced by detonation. While the strip-type fresh fuel distribution is formed due to the unstable propagation of detonation. Detonation waves interact with fresh fuel layer, transverse waves, and the normal shock waves, making the irregular fresh fuel layer remains in the combustion chamber.