Investigation of Pre-Ignition Propellant Mixing in Rotating Detonation Rocket Engine

Abstract

Pre-ignition propellant mixing was simulated using computational fluid dynamics in various rotating detonation rocket engine (RDRE) configurations. Two different RDREs were used for the simulations, a 25.4 mm diameter RDRE and a 10 mm diameter RDRE. The 25.4 mm diameter RDRE used multiple configurations, with different core plug sizes producing a 3 mm, 5 mm, and 7 mm wide annular combustion chamber, as well as a coreless cylindrical 25.4 mm diameter combustion chamber configuration. The 25.4 mm RDRE used methane and oxygen propellants. The 10 mm diameter RDRE was operated and simulated only in a coreless configuration, but with both methane and oxygen propellants, and hydrogen and oxygen propellants. Four cases for each configuration were simulated, three with similar total mass flow rates and equivalence ratios near stoichiometric, fuel rich, and fuel lean, and the fourth varying total mass flow rate. Mixing was simulated in ANSYS Fluent using a standard k-omega turbulence model, and a non-reacting species transport model. Simulation results were verified by comparing simulated wall pressure data and injector discharge coefficient data with experimental data. Average mixedness and mixed layer location versus distance from the injector face were compared across the simulated RDREs, propellant combinations, configurations and cases. Frames from high speed video of experimental hot fire tests were compared with simulations, comparing radial mixing trends with radial luminosity profiles.