Bifurcation structures in gas detonation

The possibility of existence of two-scale (bifurcation) structures of detonation in ammonia-oxygen, ammonia-air, and ammonia-nitrous oxide mixtures with wide-range variations of the initial parameters is analyzed. It is established that ammonia-oxygen mixtures are characterized by a classical irregular structure. Bifurcation properties are manifested if nitrous oxide or hydrogen peroxide is added. This shows that systems with bifurcation properties have certain flammability limits in terms of fuel, which are responsible for the multiscale character of the structure. The critical diffraction diameter of the detonation wave with bifurcation properties in mixtures close to a stoichiometric composition depends on the greater cell size; the presence of small-scale cells and additional “hot spots” at the points of collisions of transverse waves does not lead to any noticeable improvement of initiation. This fact contradicts the “hot spot” hypothesis, which implies that detonation initiation is facilitated if a greater number of “hot spots” are available.