Numerical study of detonation diffraction through 90-degree curved channels to expansion area

The adaptive mesh refinement program AMROC was adopted to conduct numerical study of detonation diffraction through 90-degree curved channels to expansion area. The detonation diffraction processes through straight and curved channels were compared. The effect of curved channel on the re-initiation of diffracted detonation and its mechanism were analyzed in depth. The influence of curvature radius on the deflection of detonation front was discussed. Results indicate that the detonation wave is highly asymmetric when diffracted through the curved channel, which results in the wave front deflection with a certain angle. The value of deflection angle θ decreases with the increase of inner wall curvature radius r0, while the deflecting direction is the same as the propagating direction of the triple point in the Mach reflection. The utilization of the curved channel can promote the re-initiation of diffracted detonation. The mechanism of this promoting effect is the redistribution of detonation energy produced by the interaction from the curved boundaries, which concentrates most of the energy into the compressed area to initiate local detonation and realizes re-initiation eventually. The promoting effect is weakened as r0 gets enlarged and the initial pressure p0 decreases. The critical condition for the re-initiation of diffracted detonation wave through the curved channels was obtained by analyzing the detonation re-initiation results.