Effects of inner cylinder length on H2/air rotating detonation

• This study verifies the possibility of rotating detonation in the hollow chamber.
• The detonation at the wall of the hollow chamber is over-driven and its illustration has been given.
• The relative standard deviation of propagation frequency of CRDWs further validates the stability of rotating detonation waves in the hollow chamber.

To investigate the relationship between rotating detonation and tangential instability, H2/Air rotating detonation are experimentally achieved in a hollow chamber by decreasing the length of inner cylinder gradually. Continuous rotating detonation (CRD) patterns in both two types of chambers are presented. Two-peak phenomenon appears in the annular chamber, but it doesn't exist in the hollow chamber. The detonation in the vicinity of the wall of the hollow chamber is over-driven. The propagation stability of different patterns has been discussed. The results show that one-wave detonation is a stable mode. The low limit equivalence ratio (ER) of detonation in the hollow chamber is smaller than that in the annular chamber. It is easier to establish rotating detonation in the hollow chamber. The possibility of rotating detonation is verified in the hollow chamber and a good foundation is provided to investigate the same model with a nozzle.