Abstract
The detonation propagation phenomenon in a bend has not yet been sufficiently understood due to its complexity. In order to examine the detonation propagation in a bend, the detonation waves of a stoichiometric ethylene/oxygen mixture gas propagating through rectangular cross-section bends with different inner radii are visualized. The cell structure and wave front shape of the detonation are observed simultaneously using a new visualization technique developed in the present study. The ratio of inner radius of bend (r_i) to detonation cell width (λ) is an important factor determining the detonation propagation characteristics in the bends. The detonation propagation mode transitions from unstable to stable in the range 20 ≤ r_i/λ ≤ 33. The cell structure and smooth wave front of the detonation can be sustained in the stable propagation, however large-scale collapse of the cell structure and fluctuation of the detonation wave front shape are observed in the unstable propagation.
