Том 53, № 4 (2017)

Energetic polymers containing nitro, nitrato, and azido groups release high energy during combustion and thereby increase the performance of the systems. A number of energetic polymers have been found suitable for use as binders in high-performance propellant and explosive formulations. This review describes the synthetic and application aspects of various modern energetic polymers for explosive formulations and propellants.

A mathematical model, laboratory setup description, and results of a numericalexperimental study of specific features of an unsteady two-phase flow of the ethanol–air mixture in the duct of a resonance gas-dynamic system (RGS) are presented. The basic specific features of ignition of the fuel mixture in the resonance cavity are detected. The conditions of ignition are determined, and the ignition delay time of the fuel composition in the RGS is estimated. The data obtained in this study can be used for modeling physical and chemical processes and for choosing liquid fuel injection modes satisfying the conditions of ignition of two-phase fuel mixtures in the RGS.

This paper describes the model of the propagation of solid phase exothermic reaction in a layer between inert materials with various thermal and physical properties. The model is implemented numerically. The relationships between the ignition time and the model parameters, as well as the behavior of some energy characteristics under various conditions in time (heat reserve in the heated layer and excess of enthalpy) are investigated. The influence of the thermal and physical properties of inert materials on the temperature distribution in the sample in stationary and nonstationary regimes is demonstrated.

Results of modeling the propagation of a shock wave formed by an explosion of a spherical charge of a high explosive in a semi-infinite space bounded by a flat substrate are reported. Problems of the action of such a wave on objects rigidly fixed on the substrate (a single prism and a set of prisms simulating an urban area) are considered. The computations are performed in a three-dimensional inviscid formulation with the use of the AUTODYN module of the ANSYS commercial software package. These numerical predictions are compared with experimental data on the static pressure measured by sensors mounted on the prism walls. It is demonstrated that an adequate description of the unsteady flow pattern formed around the obstacles mounted on the substrate can be provided. Based on these numerical data, the intensity of the shock wave action on various objects is estimated.

The influence of mineral additives (6.2–70%) and water (15–54%) to lignite on the possibility of its burning in an air flow in a continuous detonation regime in a radial vortex combustor 500 mm in diameter is studied. A syngas with a composition CO + 3H₂ is used for transporting the coal mixture and for promoting the chemical reaction. It is shown that regimes of continuous spin detonation, conventional combustion, and pulsed combustion may occur depending on the amounts of the mineral (TiO₂) added to coal, water, and syngas. The boundaries between the domains of existence of detonation and combustion are determined in the coordinates of the ratio of the syngas flow rate to the rate of consumption of the combustible portion of coal and the mineral component of coal and water. It is seen that the continuous spin detonation regime persists if the mineral additive fraction in the lignite mixture is up to 65% and the water fraction is smaller than 30%. It is also demonstrated that the syngas flow rate should be increased with increasing mineral additive fraction and increasing coal humidity in order to ensure burning of the combustible component of syngas.

This paper describes the problem of the behavior of a mixture of small graphite particles with water in the conditions of shock-wave action at a pressure of 32 GPa and a temperature of up to 1200–1600 K. Graphite particles at these pressures and temperatures are capable of transforming into cubic diamonds or at least into their hexagonal form that is lonsdaleite. It is shown that, for sufficiently small graphite particles of the order of 1 μm, their mixture with water for about 10 μs can heat up to the above-mentioned temperatures and undergo phase transformation, remain in those conditions for about 50 μs, and then efficiently cool down during the next 50 μs to the temperatures below 300 K, while remaining in the diamond phase.

Analytical formulas for calculating the maximum velocity of penetration of doublelayer cermet and ceramic/organic-plastic targets are obtained taking into account the structural characteristics of the target and the physical and mechanical properties of the projectile and target materials. Using these formulas, the ballistic resistance of targets was studied and the possibility of optimizing their structure was shown. The results agree qualitatively with available experimental data. The optimal relative thickness of the ceramic layer which provides maximum penetration velocity was determined at areal densities of the target of 30–50 kg/m² for different substrate materials. It is found that these velocity values depend weakly on the areal density of the target and are mainly determined by the properties of the substrate material.