Rotating Detonations in Hollow and Flow-Through Combustors

This paper focuses on rotating detonation combustor (RDC) experiments involving two configurations, a hollow and flow-through RDC, using hydrogen–air and ethylene–air mixtures. Two air injection areas with gaps of 1.778 and 3.81 mm were used at different air mass flow rates of 0.2, 0.3, 0.4, and 0.5 kg/s and equivalence ratios from 0.6 to 2 in 0.2 increments. Results show repeatable detonations for hydrogen–air mixtures in both configurations; however, the detonative range is wider, stronger, and faster in the hollow configuration. Speeds exceeding the Chapman–Jouguet velocity and pressures matching the ideal model were observed. Sustained detonations for ethylene–air mixtures were not attained with the flow-through configuration. Installing a back plate to convert the configuration into a hollow combustor promoted rotating detonations with the ethylene–air mixture at select operating points. The results of this study showcase the strong promise of producing and sustaining rotating detonation in nonannular RDC configurations.