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The critical conditions of self-ignition under light of constant intensity were studied using explosive ozone decomposition. P - T diagrams of self-ignition for various light intensities were obtained. A two-stage process is typical of explosive ozone decomposition. The first stage corresponds to a photochemical reaction and is supported by light; the second stage corresponds to a “dark” reaction. For photochemical ignition, high preexplosion heatings were observed which exceed the characteristic interval RT 0 2 /E.

This paper describes an approach that includes: 1) construction of a geometric structure model in the form a loose packing of spherical particles of various types and sizes in a homogeneous matrix; 2) representation of the structure as a set of cubic cells with a given set of properties. Combustion wave propagation was calculated for a model system with an interface between the solid phase and gaseous products, in which all components are capable of self-sustained combustion. The cellular automata method is used. The burning time of a cell is determined by the individual burning rate of the material filling the cell and by the current surrounding of the cell. Due to differences between local burning rates, the burning surface is nonplanar, which leads to an increase in the burning rate compared to the homogeneous relay-race model.

Based on the theory of approximate similarity of soil-ejection underground explosions, a technique for laboratory modeling of this phenomenon by microexplosions has been developed. This paper describes the experimental setup and reports some results obtained from experiments on selection of a soil simulator and from experiments on elucidation of the atmospheric-pressure role with varied scales of the phenomenon. The results are interpreted by comparing them with full-scale explosions and theoretical data.

Theoretical and experimental approaches to the problem of combustion wave stability in gas filtration combustion are described. An approximate criterion of instability for an initially plane combustion wave front is suggested within the framework of a hydrodynamic model. It is shown that the wave instabiliry cannot be observed if the reactor diameter is under a critical value. The critical value of the diameter increases with increasing rate of gas filtration. A combustion wave propagating in the direction opposing the filtration flow is more stable than a cocurrent wave, which is consistant with experimental results.

Based on experiments on focusing shock waves in hydrogen-air mixtures and available publications, the critical shock-wave Mach number at which detonation is initiated near the apex of a concave reflector is analyzed as a function of the reflector size and reactivity of the mixture. The effect of the reflector shape and size on the value of this Mach number is studied.