Ammonia/oxygen-enriched air continuous rotating detonation in the hollow chamber

Abstract

As a carbon-free and renewable energy source, ammonia can help to mitigate global warming. However, the utilization of ammonia is currently limited by its low chemical reactivity and flame consumption velocity. In contrast to deflagration, detonation has the inherent advantage of a faster heat release rate, which makes it a promising approach for ammonia utilization. In this study, the ammonia/oxygen-enriched air continuous rotating detonation (CRD) was first realized in a hollow chamber. The ammonia CRD wave propagated in single-wave mode with a velocity of 1753 m/s, which accounts for 77.16% of the theoretical Chapman–Jouguet (C-J) velocity. An analysis of the integral of chemiluminescence (ICI) was conducted based on images obtained using high-speed photography to reconfirm the stable propagation of the CRD wave. In the experiment, the ammonia CRD could be realized when the oxygen mass fraction (OMF) was at least 43%. The operating range clearly decreased as the OMF decreased from 83% to 43%. The axial ICI peak gradually moved downstream with reductions in OMF and equivalence ratio, indicating afterburning of the ammonia CRD. The enhanced combustion downstream led to a circumferential excess of the CRD wave structure downstream, which was verified through CRD flow-field reconstruction.