Mixing and initiating mechanism of internal injection oblique detonation engine

This paper presents the results of free-jet experiments conducted on an internal injection oblique detonation engine in a large-scale hypersonic shock tunnel. To overcome the challenges of non-uniform mixing and the failure of oblique detonation wave initiation when using liquid fuel, a combined strut-wall injection configuration was employed. Initiation was achieved by introducing a bump structure on the wedge. The results demonstrate that this strategy for mixing and initiation effectively establishes the oblique detonation wave combustion flow field. To further investigate the fuel mixing and initiation processes in the oblique detonation engine, three-dimensional numerical simulations consistent with the experimental conditions were carried out using the Reynolds-Averaged Navier-Stokes (RANS) method. The simulation results reveal that the high-speed gas flow generates shock waves as it passes through the central strut and transverse fuel jets. These shock waves are reflected by the wall, forming a series of shocks in the mixing section. The kerosene injected from the strut injectors does not react during the mixing phase. However, due to the influence of the high-temperature boundary layer, the kerosene injected through the wall undergoes pre-combustion. The separation zone upstream of the bump generates separation shock waves, allowing the multi-wave point to stabilize at a short distance from the leading edge of the wedge.