The parameters of the shock adiabat of a porous material are calculated in the mesoscopic setting with the developed method of a moving window. The porous material is considered a framework of solid material that fills the space between pores, the mechanical properties and shock adiabat of which are often well known. The essence of the method is as follows: uncompressed material flows into the computational box with a constant velocity, while the outflow velocity from the box is chosen based on iterations so as to make the wave front immobile relative to the window, because the stationary mode of shock-wave propagation must be achieved to calculate the shock adiabats. The simulation of shock waves is performed both in the standard setting with an immobile piston (inverse-motion method) and in the system of a moving window. It is demonstrated that the wave profiles obtained with both methods are identical after the stationary mode is achieved. As an example, the shock adiabats of porous copper, which adequately reproduce experimental data for different porosities, are calculated. The proposed mesoscopic method of calculating the response of porous materials to shock compression in a moving window enables direct calculation of desired shock adiabats for porous materials that have not been studied experimentally.

The conditions for the excitation of current and voltage oscillations in the plasma of a three-electrode current and voltage stabilizer have been experimentally studied. It was found that the oscillations are due to negative conductivity of the plasma in the considered regimes. A highly efficient method is proposed for the suppression of plasma instabilities based on the control of the sign of differential plasma conductivity via adjustment of the concentration of thermal plasma electrons with an external electrode. The proposed method makes it possible to achieve a high level of stability of the stabilizer’s energy characteristics at a discharge current density of up to 5 A/cm2 and a power of 500 W/cm2.

The results of studies on the application of pyrolytic methods for the processing of solid municipal waste into liquid and gaseous fuels are presented. The features and types of pyrolytic processes are reviewed, and the key pyrolytic products are analyzed in detail with respect to the process pressure and heating rate of the initial mass of solid municipal waste. Since the liquid products produced with standard pyrolysis have a high content of oxygen-rich compounds and water, catalytic methods are employed to make high-quality boiler or transport fuels. The main types of catalysts, their properties, and their effects on the process are considered. The advantages of a two-stage process, in which the pyrolytic products at the second stage of the process undergo high-temperature catalytic cracking with the formation of synthesis gas (syngas), are analyzed.

Mathematical modeling of spectral-kinetic, thermal, and electrophysical characteristics, which are difficult to determine experimentally, has been carried out based on the available experimental data for a promising class of the latest high-temperature composite materials consisting of mullite−corundum fibers. The model based on the concept of a representative element makes it possible to take into account not only the structural regularities of the materials and the thermal and electrical properties of its constituents, but also the features (in particular, anisotropy) of radiation in their volume and a wide range of external conditions. After the model is adjusted to the experimental data (thermophysical or spectral), it is possible to calculate the necessary characteristics of materials as a whole and to study the physical processes in heterogeneous, highly porous structures on different spatial and temporal scales. In this study, the model was adjusted to the published results of a thermophysical experiment, which made it possible to determine over a wide temperature range the key parameters to take into account cooperative effects when the fragments of the material interact with electromagnetic radiation. New, important data on the thermal conductivity of materials and its conductive and radiative components, heat capacity, electrical resistivity, and dielectric permittivity have been obtained. A study on those external conditions that make experimentation substantially difficult has been carried out, and specific recommendations regarding the optimization of the properties of the materials are given. The results of the work clearly demonstrate the effectiveness of mathematical materials science as a tool that significantly expands the capabilities of experimental methods.

A chemical model for a nonideal atomic plasma consisting of electrons, ions, and atoms is proposed. The goal of this work is to build a reliable and simple version of a chemical model of an atomic nonideal plasma (“user-friendly”), the calculation with which would be available to any young researcher. It is considered to be reliable due to an accumulation of experience and the fact that theoretically substantiated, experimentally verified relationships are used to take into account the effects of nonideality. A critical analysis of the main problems in accounting for interparticle interactions in a chemically reacting atomic plasma with an emphasis on the Coulomb interaction is performed.

The present study covers results of non-stationary numerical simulation of three-dimensional flow in the junction region of a low aspect ratio circular cylinder entirely immerged in laminar free convection boundary layer developing over a heated vertical plate. To categorize the effects of the cylinder surface temperature on the dynamics behavior of the forming vortical structure, its size and position both upstream and downstream of the cylinder the results, which prove the presence of a complex coherent vortical structure, are analyzed. In particular, the influence of horseshoe vortex system formed upstream of the cylinder on the free convection heat transfer of the heated vertical plate in the junction area is evaluated. Finally, the importance of the forming vortical structure on the heat transfer computation for the junction region is demonstrated.

A physical and mathematical model, computational algorithms, and calculation results are presented for the ignition and detonation of methane–air combustible mixtures behind a reflected shock wave. The one-dimensional, unsteady equations of gas dynamics, supplemented with the equations of chemical kinetics, are solved numerically with the grid-characteristic and Godunov methods. An original modification of the simplified kinetic mechanism is used to describe the combustion of methane in air. The results of calculations of the ignition delay time of the combustible mixture are compared with the experimental and calculated data reported by other authors, and the results of calculations of the occurrence and propagation of the detonation wave are presented. The modes of the propagation of a detonation wave with a constant velocity and in oscillatory mode are obtained. The velocity of the detonation wave in the absence of oscillations accurately corresponds to the velocity of the overcompressed detonation wave obtained from the solution of the Rankine–Hugoniot equations under the assumption that the flow is frozen in front of the shock wave and equilibrial behind the shock wave and that the gas velocity behind the shock wave is zero.

This paper considers the problem of the numerical simulation of the propagation dynamics of a dispersed admixture and heat transfer in a swirling turbulent gas–droplet flow behind a sudden tube expansion. The gas phase is described by a system of three-dimensional Reynolds-Averaged Navier-Stokes equations with taking into account the effect of particles on the transport processes in the carrier phase. The gas-phase turbulence is calculated with the Reynolds stress transport model with allowance for the effect of the dispersed phase. The Euler and Lagrangian descriptions give qualitatively similar results for small droplet sizes of up to d1 ≤ 30 μm; it is only for the largest particles studied in this paper (with an initial diameter of d1 = 100 μm) did the difference in the calculation results exceed 15%.

The motion of the rear free surface of a titanium film target of submicron thickness under the action of an ultrashort shock-compression pulse generated by a femtosecond laser was studied by spectral interferometry with a picosecond resolution. The value of the titanium spallation strength was close to the theoretical ultimate tensile strength at a strain rate of ~109 s–1.

The temperature dependences of nickel, iron, chromium, molybdenum, and tungsten solubility in a liquid Sn–20% Li alloy are calculated with the thermodynamic simulation method based on information on the excess Gibbs mixing energies for a liquid phase in the form of polynomial Redlich–Kister expansion for corresponding binary systems. A thermodynamic estimation of the stability of a series of binary and ternary oxides in a liquid Li20Sn80 alloy at temperatures of 500 and 800°C is also performed.