Том 54, № 2 (2016)

Populations of argon atomic levels have been calculated within the meta-equilibrium model of a two-temperature quasi-stationary plasma. A specific feature of meta-equilibrium two-temperature plasma of inert gases is “broken” population level distributions of atoms making it possible to explain the results of spectroscopic studies of the arc discharge in argon at atmospheric pressure (the experiment by V.N. Kolesnikov).

Some thermodynamic relations that follow from the van der Waals equation are considered. It is shown that they are applicable to real substances and model systems described by absolutely different equations of state. These relations are associated with definite geometric lines on the density–temperature plane. The data for the model systems that substantiate the derived regularities were calculated by numerical simulation methods. For real substances, the relevant databases constructed according to experiments were used. It has also been established by numerical simulation that the limitations of the regularities under investigation are related to the nature of attraction in the interparticle interaction potential.

We performed experiments on shock compression up to pressures of 36 and 50 GPa of mixed samples of silicon nitride and potassium bromide, placed between copper plates that serve as walls of a recovery ampoule. For comparison, similar experiments were carried out by the conventional compression of a mixture of silicon nitride and copper powder. The loading of the samples was fulfilled by means of aluminum flyers accelerated by products of explosion to a few kilometers per second. The pressure profiles prior to a shock wave entering the sample and after its runout were measured with the use of manganin sensors. It is found that for the configurations of the experimental assembly used, the pressure in the samples, accumulated by circulating the shock wave, reaches the desired value before unloading. Based on estimates of the rate of heat transfer between the components, it is shown that thermal equilibrium can be set during the existence of high pressure in the mixed samples. Within the framework of the single-temperature medium model, the equations of state of the samples are derived, and the temperatures of their shock compression are calculated. Using these equations, we performed numerical simulations that showed good agreement with the experimental data.

The phase equilibria of immiscible binary systems (water–n-hexane, water–n-pentane) are investigated using a constant-volume piezometer. The measurements were performed under normal conditions, based on P,V,T,x-data obtained in the temperature range of 300–680 K, pressures up to 60 MPa, and in a wide range of densities. Based on the experimental data, we constructed phase diagrams in the P–T and T–x coordinates and determined the Krichevskii parameters for the system of water–n-hexane near the critical point of the pure solvent.

The process of investigation of a complex of liquid and gas thermophysical properties (heat capacity, PVT) by means of the Kh.I. Amirkhanov’s high-temperature adiabatic calorimeter is described. The technique of automation of that experimental facility by means of measuring and controlling devices and a personal computer is described as well.

This paper presents the results of two-dimensional calculation of radiative heating of the Fire-II, Stardust, Orion, and PPTS (Prospected Piloted Transport System, Russia) spacecraft entering the dense atmosphere of the Earth with orbital and superorbital velocities. A specificity of the simulation is the allowance for atom and ion spectral lines with use of the NERAT-ASTEROID computer platform. This computer platform is destined for solving the complete system of equations of radiative gas dynamics of viscous, heatconducting, and physically and chemically nonequilibrium gas and radiative transfer in two- and threedimensional geometries. The spectral and optical properties of high-temperature gases are calculated in the entire flow field by ab-initio quasi-classical and quantum mechanical methods. The selective heat radiation transfer was calculated by the line-by-line method on specially generated computational grids over the radiation wavelength, which make possible appreciable saving of computer resources while providing detailed description of the contours of atomic lines.

A generalized analysis of experimental data on suppression of the near-wall generation of turbulence under the influence of mass forces and polymer additions is carried out.

Heat transfer in conical expanding channels with different degrees of opening is studied for some Reynolds numbers. Numerical simulation of the heat transfer is carried out using the three-parameter differential turbulence model completed by the equation of transfer for a turbulent heat flux.

The processes of hydrodynamics and two-phase heat and mass transfer in an atmospheric tornado- forming cloud are simulated numerically. A model of a tornado is proposed with explanation of the main specific effects accompanying this poorly studied phenomenon.

The results of investigation on high-temperature gas-phase removal of impurities from a granulated quartz concentrate are presented. Various gaseous media and treatment methods are considered. The influence of the main process parameters on the impurities content in raw quartz are estimated and the optimal values are selected.

Measurement data are given for the thermal diffusivity of Zr–2.5% Nb and Zr–50% Nb alloys both with the usual polycrystalline structure and with submicro- and nanocrystalline structures at high temperatures, which were determined in the automated mode using the dynamic technique of plane temperature waves.

We describe the deviations of the concentration of dimers from ideal behavior, which are connected with a change in the molar volume of liquid as a result of an elementary chemical reaction both within the spherical simplified model and taking into account the dumbbell-like shape of a dimer. A generalization of the model for a dimerizing hard-sphere fluid in the presence of a solvent with its own diameter value is considered. It is shown that with an increase in the particle size of the solvent, the nature of the concentration dependence of the enthalpy of mixing can vary from purely endothermic to alternating-sign with a pronounced exothermic effect at low and moderate content.