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In this paper, we consider the classical Burke-Schumann problem as applied to the construction of a mathematical model of a diffusion flame spreading over a fuel film deposited on a thin substrate. This formulation is used to model the combustion of a gaseous fuel flowing from a thin slot (half-width x_in and mixed with oxidizer flowing from a parallel slot (with the outer boundary x_out). The key parameters determining the position of the flame front in the space are identified: the Peclet number Pe, the stoichiometric parameter A dependent on the equivalence ratio, and the geometric parameter X_in = x_in/x_out. The dependences of the flame length on these parameters, including x_out → 8, are analyzed. Comparison shows good agreement between calculated and experimental

This paper presents a model for the steady-state filtration combustion of carbon mixtures with a solid incombustible material in opposed gas flow containing an endothermic oxidizer such as steam and/or carbon dioxide. A computation scheme for calculating the characteristics of the process (combustion temperature and composition of the products) is proposed for the case where the product composition is determined by the thermodynamic equilibrium in the high-temperature zone. For stoichiometric regimes, finite analytical expressions are obtained that relate the combustion temperature and the composition of the products with the oxidizer gas composition and the proportion of carbon in the carbon/solid inert material mixture. Predictions of the model are in qualitative agreement with published experimental data.

The problem of calculating the characteristics of the agglomerates formed during combustion of high-energy composite solid propellants is considered. It is shown that the mathematical models developed by the authors can be used for different propellant formulations to evaluate not only the dispersion of agglomerates, but also their quantity, chemical composition, and structure. The rules (algorithm) of using the developed models for a wide range of propellant formulations are determined. Modeling results for a number of propellant formulations based on various components are analyzed.

A physicomathematical model within the framework of the approach of mechanics of reacting heterogeneous media is proposed to describe the combustion wave in a mixture of a gas and fine magnesium particles. The model is verified on the basis of dependences of the limiting temperature of ignition and combustion wave velocity on the radius and volume concentration of particles. It is guaranteed that the model is valid in the range of particle radii from 7.5 to 35 μm and in the range of volume concentrations of particles (1.2–2.4)·10^–4.

An explanation for multiple repetitions of a nonisothermal wave process in one sample is proposed. The explanation is based on synthesis and decomposition of a metastable product. A mathematical model of this phenomenon is constructed and studied. The resultant characteristics of synthesis and decomposition waves are compared with available experimental data.

A method of correction of particle image velocimetry (PIV) data for reconstruction of the gas velocity based on the particle velocity in supersonic underexpanded jets is considered. The method is based on estimating the velocity lag of tracer particles on the basis of their velocity relaxation parameter as a correction to PIV data in the Newton approximation of interphase interaction. It is shown that the velocity relaxation parameter of tracer particles in flows with velocity jumps can be determined from the initial PIV data. Correction with the found parameter of velocity relaxation of the phases provides good accuracy.

A method of shock wave overpressure reconstruction is presented, which allows overcoming the drawbacks of the previous approaches associated with the lack of shock wave velocity measurement points and the limitations of the empirical formula. An optimal design of the testing system is proposed. Based on the optimal system, the shock wave velocity field is inverted with the use of the generalized inversion theory, and the overpressure distribution is obtained. The inversion results are preferable to empirical results because the experimental data are confirmed in a limited area. Methods of overpressure computation and visualization are described.

The effect of high-temperature shock compression conditions on the degree of transformation of silicon nitride into a cubic gamma-modification at pressures of 36 and 50 GPa in planar recovery ampoules is studied. The x-ray Rietveld method is used to determine the quantitative phase composition before and after shock compression. The temperature reached during compression and the residual temperature after unloading are calculated. It is shown that the use of high-temperature shock compression at 36 GPa provides a higher transformation level compared to the classical approach based on the addition of copper powder into the samples.

This work presents the results of experiments on the compression of a spherical copper shell loaded by the detonation of a plastic explosive layer. A U-70 accelerator is used for radiographic recording of the convergence of the shell to the center, and metallographic analysis of the copper shell preserved after the experiment is performed. The results of multiframe proton radiography of the convergence of the inner boundary of the copper shell to the center are compared with the results of numerical simulations.

It is proposed to carry out burning of the launch vehicle nose fairing after it has completed its mission on the descent trajectory from the moment of separation to an altitude of 5-10 km. Burning is carried out in the Earth atmosphere with additional heating of the faring material due to the reaction of pyrotechnic mixtures. Various pyrotechnic mixtures for use in the nose fairing are discussed.