Numerical simulation of detonation reflections over cylindrical convex-straight coupled surfaces

Abstract

Detonation reflections over cylindrical convex-straight coupled surfaces were numerically analyzed using the density-based compressible–reactive solver DCRFoam developed on the framework of OpenFOAM-V7. The two-dimensional reactive Euler equations were adopted to calculate the reflection dynamics, considering a detailed chemical mechanism. Effects of the global wedge angle (ranging from 20° to 50°) and the radius of the former convex section (ranging from 25 mm to 125 mm) on the detonation reflections were discussed. It was founded that the original regular reflection could transform into the Mach reflection on the former cylindrical convex section for coupled surfaces with global wedge angles smaller than 50°. The peak pressures of the reflection points in the configurations of the regular reflection were much larger than those in the Mach reflection, and the increase in the wedge angle led to the increase of the average peak pressure of the reflection points in the Mach reflection on the following straight section. For a coupled surface with a global wedge angle of 50°, no Mach reflection configurations were established on the former cylindrical convex section. The existence of the convex section was proven to delay the establishment of the Mach reflection on the following straight section. For coupled surfaces with the same global wedge angles, the transition angles from the regular reflection to the Mach reflection increased with the increase in the radius.