Effects of injection schemes on H2–air cold flow mixing characteristics in rotary detonation engine

Rotating detonation engines (RDEs), with their inherent capabilities of local self-pressurization and continuous thrust output, represent a promising propulsion technology for aerospace applications. The nozzle plays a crucial role in RDE performance. This study examines the effect of different nozzles on the internal flow field and explores how the inlet equivalence ratio (ER) influences optimal injector selection. Three-dimensional non-reactive flow fields were simulated using large eddy simulation to analyze cold-flow characteristics under various equivalence ratio conditions. Research findings indicate that the axial fuel inlet (AFI) configuration yields superior performance in non-premixed combustion chambers. Specifically, when the equivalence ratio reaches 1.0, the AFI nozzle not only achieves a more uniform equivalence ratio distribution but also attains a volumetric fraction of the near-stoichiometric mixing zone reaching 74%, thereby promoting the formation and stable propagation of detonation waves. Research indicates that altering the slit structure alone can reduce head turbulence energy while maintaining a mixing efficiency greater than 0.6, which facilitates ignition and the formation of rotating detonation waves.