Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures. The numerical method used is based on the three-dimensional Euler equations with detailed finiterate chemistry. The results show that the calculated streak picture is in qualitative agreement with the picture recorded by a high speed streak camera from published literature. The three-dimensional flow field induced by a continuously rotating detonation was visualized and distinctive features of the rotating detonations were clearly depicted. Owing to the unconfined character of detonation wavelet, a deficit of detonation parameters was observed. Due to the effects of wall geometries, the strength of the outside detonation front is stronger than that of the inside portion. The detonation thus propagates with a constant circular velocity. Numerical simulation also shows three-dimensional rotating detonation structures, which display specific feature of the detonationshock combined wave. Discrete burning gas pockets are formed due to instability of the discontinuity. It is believed that the present study could give an insight into the interesting properties of the continuously rotating detonation, and is thus beneficial to the design of continuous detonation propulsion systems.
How to confine a detonation in a combustor is a key issue of detonation applications in propulsion systems.Based on achieving schemes,detonations applied in the combustor,including pulse detonation wave(PDW),oblique detonation wave(ODW) and rotating detonation wave(RDW),are different from that described by the classic CJ theory in fine structures and its self-sustaining mechanisms.In this work,the cellular structures and flow fields of ODW and RDW were obtained numerically,and the fundamental characteristics and self-sustaining mechanisms of the detonations were analyzed and discussed.ODW front consists of three parts:the ZND-like front,the single-headed triple point front and the dual-headed triple point front.Cellular structures of RDW are heterogeneous,and the cell size near the outer wall is smaller than that near the inner wall.
