Unburned Gas Pockets in Detonations with Irregular Structure

A two-dimensional numerical simulation is performed in the present work to study the structure of a detonation wave in high activation energy mixtures, which are characterized by their turbulent reaction zone structure and unreacted pockets. The process of transverse wave and triple point collision with the channel walls, formation and consumption mechanism of unburnt gas pockets is examined using very high-resolution numerical simulation. Results show that as the triple point collides with the channel wall, the transverse shock interacts with the unreacted pocket. After reflection of the triple point off the wall, the transverse wave interacts with the wall. During the collision and reflection process, the shear layer detaches from the shock front, producing a pocket of unburnt gas. Energy resealed via consumption of unburnt pockets by turbulent mixing due to hydrodynamic instabilities (Richtmyer-Meshkovnad Kelvin-Helmholtz instabilities) found to have profound role in re-initiation mechanism of detonations at the end of a detonation cell.