Ignition Criteria for Oblique Detonation Waves in a Hydrogen-Air Premixed Freestream

Oblique detonation wave engines have promising characteristics for hypersonic airbreathing propulsion, most notably reduced combustor lengths and the high pressure ratios that can be achieved. There has been significant work in understanding the initiation, stability, and structure of oblique detonation waves anchored to wedges. This work emphasizes the importance of chemical kinetic timescales in modeling and understanding the initiation of oblique detonation waves along a wedge surface. An ignition delay study was performed with a specific chemical model and used to consider ignition timescales behind oblique shock waves. These results lead to an ignition criteria for oblique detonation waves, the efficacy of which is confirmed with high-fidelity numerical simulations of a hydrogen-air reacting flow. The initiation is shown to be predicted by the ignition criteria.