Numerical Study of Detonation Expansion from a Small Channel to a Large One

This presentation reports on numerical results for the evolution of a detonation wave that is expanded from a small channel to a larger one. In accordance with experimental data, the simulations predict three different types of evolution, supercritical, critical and subcritical ones. In a supercritical detonation, the reaction zone remains always attached to the precursor shock. A critical detonation is characterized by temporary extinction and reinitiation at later times. In a subcritical detonation, the extinction is permanent, i.e., there is a permanent decoupling of the reaction zone from the leading front. The presentation concludes with a parametric study on the effects of the activation energy of the fuel and the channel-width ratio.