Vol 61, No 3 (2023)

The characteristics of a plasma flow around the descent vehicle of a Soyuz spacecraft when passing through the Earth’s atmosphere are studied. For the first time, the chemical composition of the compressed layer and the plasma flow in the downstream area, accessible for instrumental examinations through the descent vehicle porthole, are estimated. The characteristics of the equipment developed for conducting the space experiment to study the emission spectrum of the plasma layer around the descent vehicle are described.

The occurrence of microstructures on the surface of tungsten and titanium electrodes during discharge in an electrolyte in the presence of a magnetic field has been studied. Electrical characteristics of the discharge at various modes were obtained. The plasma temperature in the near-electrode region was measured using spectral methods. Conical and pointed formations with sizes up to 10 µm occurred on tungsten electrodes. The appearance of microspheres and porous surfaces was observed on titanium electrodes. The growth of these surface structures accelerated and their characteristics improved under the effect of a magnetic field. The mechanism of growth of the observed microstructures are discussed.

A closed interpolation equation is derived based on exact relations of quantum statistical theory for Coulomb systems and the Born–Oppenheimer approximation. This equation relates pressure and its derivative to density at a fixed temperature for a simple quasi-classical liquid, in which the effective pair potential of particle–particle interaction has a Fourier transform.

Using an evacuated two-capillary pycnometer, the density and molar volume of liquid solutions of thallium, lead, and bismuth in mercury were measured. The measurements were carried out over the entire range of compositions at temperatures from liquidus to 400–500°C.

The mechanism of proton conduction of defect-free perovskite LaScO3 was investigated by ab initio molecular dynamics. The effects of the initial location and speed of a proton, the electric field, and the temperature of the system on the behavior of a proton in metal oxides of the perovskite type are considered. It is shown that the temperature of the system is the main factor affecting the speed of proton movement. The Arrhenius temperature behavior of proton conduction is found. In the absence of oxygen vacancies, the direction of proton movement in a crystal with a perovskite structure is determined by its interaction with lattice phonons; i.e., proton migration through metal-oxide perovskite has a polaronic character. Better understanding of the nature of proton migration along the perfect perovskite is one of the ways to improve the characteristics of clean energy devices.

The heat and mass transfer between the dissociating boundary layer and the surface of blunt nose cones of high-speed aircraft in a wide range of Mach numbers is considered. Using Dorodnitsyn–Liz variables, the system of boundary layer equations is reduced to a system of nonlinear ordinary differential equations. Using reasonable assumptions, approximate analytical solutions were obtained for dynamic, thermal, and diffusion boundary layers, which made it possible to determine thermal and diffusion heat fluxes, which at the gas–solid boundary are coupled with the equation of heat conduction in the body with the coupling parameter being the temperature of the gas–solid boundary. From the found heat fluxes, the temperature fields in the body were determined in a wide range of free-stream Mach numbers and the catalytic recombination coefficient. The resulting heat fluxes on the frontal part of the nose cone exactly coincide with the experimental data.

The study considers generation of a dispersed coolant flow; the size distribution of droplets in the flow depending on the flow rate, pressure, and thermophysical properties of the coolant; the breakup and coagulation of droplets; and droplet size ranges resistant to breakup. A computer code for calculating the evolution of the spray cone parameters was developed based on the momentum equation and distribution of droplets along the radius in the flow at the atomizer nozzle.

The possibilities of the formation and characteristics of a special type of stationary concentrated vortices 
 are studied with respect to the Earth’s atmosphere. A generalization of this type of vortices to a spherical coordinate system is presented, belonging to the class of Gromeki–Beltrami, N.E. Zhukovsky, and S.G. Chefranov flows. Two types of new solutions to the problem of a concentrated vortex with two and three velocity vector components are constructed: (1) the centers of the Cartesian and spherical coordinate systems coincide; (2) the spherical vortex is located above a solid surface. The distributions of vector fields of velocities and pressure in a concentrated vortex are found. This solution expands the problem of a concentrated vortex in a cylindrical coordinate system studied previously by the authors. The influence of the thickness of the spherical layer on the change in flow characteristics is analyzed. The use of the obtained characteristics of concentrated vortices to interpret a number of observed anomalous phenomena in the atmosphere, such as UFOs and ball lightning, is discussed, the explanation of frequently involves mechanisms that lie beyond the boundaries of modern physics.

The article studies the applicability of the Baer–Nunziato two-fluid model to the problem of interaction of a shock wave with a foam layer. The determining system of equations is formulated. A computational algorithm based on the Harten–Lax–Van Leer scheme with contact discontinuity resolution, including phase velocity and pressure relaxation stages, is proposed and described in detail. Using the proposed computational technology, the problem of propagation of a weak perturbation in a two-phase medium is considered. The propagation velocity obtained is close to the estimate using Wood formula. The problem of the interaction of a shock wave with a foam layer near an impenetrable wall is also considered. The formulation corresponds to full-scale experiments. The nonstationary wave dynamics realized in this problem using the proposed model is described. Good qualitative and quantitative agreement is obtained between the calculation results and experimental data.

The work presents an example of a passive solar heating system, which utilizes direct solar energy to heat the water for domestic use. A passive thermosyphon heating system was designed, fabricated, and tested for its thermal performance in the semi-arid and four-season climate of the Faisalabad district of Pakistan. The heating system design was based on two-stage storage and natural thermosyphon circulation of water. An enhancement of the thermal performance of the thermosyphon systems by using a semicircular steel pot collector (covered with water carrying copper coil), two-step water storage, and side mirror reflectors was investigated. The experiments were conducted from April to July, 2014 when the ambient temperature was reported approximately between 30 to 45°C. For the cited time duration, the cold-water temperature remained in the range of 18 to 25°C. The maximum water temperature, during the intermittent flow mode operation of the system, remained between 48 and 88°C. In continuous flow mode operation, the hot water temperature remained between 46 and 78°C. Since water temperature in the range of 45 to 50°C is considered suitable for domestic use, the presented design is acceptable for domestic use.

The study describes the thermodynamic properties of aluminum in a wide range of high-energy states. The form of the functional relationship between the pressure, specific volume, and specific internal energy of the condensed phase is proposed for the metal. The calculated adiabats of shock compression of aluminum are compared with the available data from shock-wave experiments. The constructed equation of state can be used to simulate the processes of intense pulse action on metal.