Numerical investigation on the flow field and propulsion performance of rotating detonation afterburner with dual injection scheme

Rotating detonation afterburners have gained increasing attention for their potential to enhance propulsion performance. Traditional outer injection scheme tends to be employed to maintain the rotating detonation. In the study, the feasibility of the dual injection scheme for organizing stable detonation is numerically verified based on the hollow chamber. The differences between the two injection schemes are analyzed. Results show that additional inner injection creates an air column, resulting in a flow field similar to that in an annular chamber, excluding the mixed layer around the injection interface. Thereby, higher pressure gain is achieved. Based on this dual injection scheme, influences of nozzle structure and injection direction are discussed. It is found that detonation waves, different streams, and the nozzle affect the outer mass flux differently. Compared to axial injection of bypass flow, radial injection can maintain both stable detonation and deflagration. However, it tends to have a lower detonation fraction. Net thrust is used to analyze the propulsion performance. The dual injection scheme reduces fuel consumption with little change in net thrust. Moreover, parallel injection within the dual injection scheme is conducive to realizing the detonation dominant burning, resulting in more significant performance improvements. This study provides valuable insights and support for the optimal design of rotating detonation afterburners.