bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of underexpanded jet flow conditions on the supersonic core length
Authors: Mironov S G , Aniskin V M , Maslov A A
Published: November 2019

The paper describes the results of measurements of the supersonic core length of underexpanded jets exhausted into a submerged space. Exhaustion of supersonic He, air, CO2, Ar, and SF6 jets into He, air, CO2, Ar, and SF6 at moderate Reynolds numbers for the laminar, transitional, and turbulent flow regimes is considered. These jets outflow from convergent nozzles with diameters of 0.52, 0.72 and 1.06 mm; the measurements are performed by a Pitot tube. The amplitude-frequency spectra of acoustic oscillations generated by the jets in the ambient space are measured. The experiments are performed in a low-pressure jet setup, which allows independently maintaining the Reynolds number of gas exhaustion from the nozzle and the jet pressure ratio. The jet setup is used to study exhaustion of a jet of one gas into the submerged space filled with another gas and the influence of the ratio of densities of these gases on the supersonic core length.
Investigation of heat transfer in a liquid metal upflow in the MHD-channels applied to tokamak reactor blanket module
Authors: Razuvanov N G , Luchinkin N A , Sardov P A
Published: November 2019

This article is devoted to experimental investigation of hydrodynamics and heat transfer in MHD flow configuration: upflow of mercury in a vertical round tube and rectangular duct with non-uniform heating in the transverse (coplanar) magnetic field. The problem is of interest for developing fusion reactor`s cooling systems. The liquid metal flow, in this case, will be complicated by influence of electromagnetic and thermogravitation forces. The experimental data were obtained by a proven probe technique for temperature measurements. The average temperature fields, wall temperature distributions, heat transfer coefficients and statistical characteristics of temperature fluctuations have been obtained and compared throughout the length of test section (pipe or duct) detecting the channel geometry influence.
Experimental study of interaction of two parallel circular jets
Authors: Philippov M V , Chokhar I A , Terekhov V V
Published: November 2019

The results of experimental study of interaction in a system of two turbulent circular parallel jets are presented. The studies were conducted using a two-component laser-Doppler anemometer with an adaptive time selection of the velocity vector. The distance between the jet axes in experiments was varied within s/D = 1.8-3.0 with Reynolds numbers Re = 5500 and 11000. Distributions of average and pulsating components of the velocity vector at distances from the nozzle H/D = 0-10 were obtained. These distributions were analyzed in the region closest to the nozzles and the region of the greatest jet interaction.
Large eddy simulation of two parallel round jets
Authors: Barsukov A V , Philippov M V , Chokhar I A , Terekhov V V
Published: November 2019

The results of large eddy simulation of flow dynamics in a system of two parallel round turbulent jets are presented. Twin jets are investigated at Reynolds numbers Re = 5500 and 11000; the cases with different distances between the jet axes s/d = 1.8 and 2.4 are examined. The data are compared with the classical case of a single round submerged jet.
Simulation of operation of an open geothermal system with seasonal variations
Authors: Yu Filimonov M , Vaganova N A
Published: November 2019

A mathematical model for the operation of an open geothermal cyclic system for two wells is presented. The production well is supposed to pump hot water from an underground geothermal reservoir. After the use for heating purposes the cooled water is pumped back into the aquifer through the injection well. Various options related to the seasonal needs for hot water are investigated for operating such a system. During the summer months hot water is required in less quantitites. The results of numerical calculations show that it is possible to choose such modes for greater efficiency and increase the time of operation of such a system.
Shear stress in downward adiabatic annular gas-liquid flow
Authors: Cherdantsev M V , Isaenkov S V , Cherdantsev A V
Published: November 2019

Time-averaged shear stress was measured in annular gas-liquid flow. The experiments were conducted in a wide range of phases flow rates, in two pipes of different diameters, with working liquids of different viscosities. The results were compared to a number of empirical correlations. It was shown that for a fixed gas superficial velocity the shear stress shows the same linear dependence on the inlet wetting density for all pipe diameters and liquid viscosities.
Calculation analysis of the processes of boric acid droplet entrainment during WWER emergency cooling
Authors: Sahipgareev A R , Morozov A V
Published: November 2019

This paper presents results of the calculation analysis of processes of droplet entrainment of boric acid by steam flow at a loss of coolant accident (LOCA) on nuclear power plant (NPP) with WWER. A review of the available literature data on the research of this process is presented. It has been found that the existing data do not cover all the parameters, such as temperature, pressure and acid concentration, which are characteristic for a possible emergency situation at NPP with WWER. The dependence obtained by analysis allows estimating the size of droplet entrained by steam flow during an emergency process in WWER reactor plant with operation of a complex of passive safety systems.
Model of mobile experimental stand for determine parameters of the gas-piston flow
Authors: Sazhin I A , Shumeiko V A
Published: November 2019

Optical research methods are widely used to study gas-liquid systems. In practice, mobile experimental stands are in demand. This article describes the work of an experimental stand for observation, measurement of parameters of a gas-liquid flow. The measured parameters of the gas-piston flow regime correspond to the known research results. The presented technique is applicable for the implementation of a mobile measuring stands.
Experimental and numerical modeling of a viscous incompressible fluid flow with dispersed particles in a rectangular channel
Authors: Zamula Yu S , Iulmukhametova R R , Musin A A , Shashkov A V , Kovaleva L A
Published: November 2019

In this paper, a laminar flow of a viscous incompressible fluid with suspended spherical particles in a channel of rectangular cross-section is considered. Physical and mathematical modeling of the investigated process is conducted. The physical model is a vertical channel of rectangular cross-section into which fluid with solid particles is injected. The mathematical model is written in the diffusion approximation and includes the Navier-Stokes system of equations, the continuity equation and the diffusion equation which written, taking into account the effect of gravitational forces on particles.
Experimental research of flow characteristics of coaxially atomized coal-water fuel
Authors: Gvozdyakov D V , Zenkov A V , Gubin V E
Published: November 2019

Results of experimental studies of characteristics of coal-water fuel (CWF) stream in the process of its coaxial spraying in aerodynamic furnace simulator of a power boiler are presented in this paper. Mechanism of CWF atomization was researched at the following component ratios: 50% of coal and 50% of water. Coal fraction was 200 microns and less. Studies were conducted at pressures of 0.2 MPa (CWF) and 0.18 MPa (air). Visualization of CWF spray cone structure and assessment of the flow quality were made in the plane perpendicular to the axis of the cone on three segments. Geometrical parameters and velocities of CWF droplets in the process of spraying were established. Characteristic areas of CWF spray cone, which are formed in the process of atomization, were selected according to the obtained experimental results. Values of Weber number were calculated for corresponding velocities of CWF droplets. Characteristic stages of droplets breakup of the sprayed CWF were identified, and process conditions were formulated.
Theoretical study of stability zones of mixed H2 + CO2 gas hydrates CS-I and CS-II
Authors: Belosludov V R , Zhdanov R K , Bozhko Y Y , Subbotin O S
Published: November 2019

Using the original approach that utilizes statistical thermodynamic theory that has been developed in our group the phase p-T diagram and hydrate phase composition have been calculated for “CO2 + H2 + H2O”. Depending on the CO2 content in the gas phase two hydrates types can be formed: CS-I and CS-II. It has been found that increasing CO2 content in the gas phase drastically reduces hydrate formation pressure and in the same time reduces hydrogen uptake by the hydrate. While pure H2 hydrates have CS-II structure, addition of more than 2 mol.% of CO2 into the gas phase makes CS-I hydrate structure more stable, that displays worse maximum hydrogen content. These results could be helpful for practical use of hydrates for efficient CO2 utilization and H2 transportation.
Ice melting with account of selective source of radiation
Authors: Savvinova N A , Sleptsov S D , Grishin M A
Published: November 2019

A numerical simulation of the melting of an ice layer on a vertical substrate heated from a radiation source in the form of a halogen lamp in the single-phase formulation of the Stefan problem was carried out. Ice is presented in the form of a pure, non-scattering, selectively absorbing material with two spectral bands of bulk absorption. The computational model takes into account the selective nature of the radiation source. Analysis of the calculation results shows the dominant role of the incident radiation on the formation of the flux density field of the resulting radiation in the medium. Comparison of the results shows a satisfactory agreement with experimental data.
The dynamics of explosive vaporization of a two-component liquid mixture
Authors: Kozulin I A , Kuznetsov V V
Published: November 2019

The dynamics of explosive vaporization of the 2-propanol/water and ethanol/ water mixtures on the multilayer thin-film resistor with the size of 100×110 m has been investigated. An original optical method based on measuring the laser intensity reflected from resistor surface was used. The characteristics of the initial stage of the explosive vaporization of two-component mixtures were obtained. The dependence of the temperature of explosive vaporization on the rate of temperature growth and the dependence of the boiling time on effective heat flux were defined.
Multispark initiation of ring gas charges in water
Authors: Teslenko V S , Drozhzhin A P , Medvedev R N
Published: November 2019

The experimental results of studying in-water initiation of propane-oxygen charges in the form of ring bubbles by using 2, 4 and 6 electrical sparks have been presented. In discharge gaps, sparks were initiated from the single capacitor storage of energy 2 J and were located along the ring perimeter of diameter 52 mm at the same distance from each other. The difference between the processes of energy release in the combustion of gas charges has been revealed in the analysis of force pulses measured by the piezo-dynamometer with time resolution of 2.6 µs. It has been shown that for the same gas charges in the initiation of gas by multispark discharges, thrust characteristics have both qualitative and quantitative advantages. As the number of sparks increases from 2 to 6, the amplitude of force pulses rises to 30% and a specific pulse increases to 20% for the same gas charges.
Evolution of liquid-drop aerosol cloud during deposition in a high-temperature environment
Authors: Arkhipov V A , Zharova I K , Kozlov E A , Maslov E A , Perfilieva K G , Tkachenko A S , Bulavko A M
Published: November 2019

Physical-mathematical model of the evolution of a liquid-drop aerosol cloud in the atmosphere during fire extinguishing with the help of aviation is presented. Some results of calculations of the motion, heating and evaporation of polydisperse water droplets during refrigerant medium discharge from the aircraft board are given.
Analysis of hydrophysical fields in the northern part of the Black Sea on the basis of assimilation in the hydrodynamic model of temperature and salinity observations in the summer season of 2016
Authors: Demyshev S , Evstigneeva N , Dymova O
Published: November 2019

A numerical experiment was conducted to reconstruct the fields of the currents, the level, temperature and salinity of the Black Sea for the summer season of 2016 on the basis of the hydrodynamic model that included nonlinear equations of motion, advection equations of heat and salt. We used a high spatial resolution (horizontal grid ∼1.6 ×1.6 km and 27 vertical layers) and real atmospheric forcing. The assimilation procedure of observational data was based on a modified Kalman filter taking into account the heterogeneity and non-isotropy of estimates of the temperature and salinity fields. Areas of generation of meso- and submesoscale features of hydrophysical fields were determined in the northern part of the Black Sea (eddies of different signs of rotation with a radius of about 30 km in the western part of the region, a cyclonic eddy with a radius of about 40 km in the eastern deep-water part of the region, anticyclonic eddy with a radius of about 25 km near the city of Yalta, intense jets along the Crimean coast and eddies of small scales of a different sign of rotation along the coast of Crimea and on the north-western shelf) and possible reasons of their formation were discussed.
Numerical simulation of the laminar-turbulent transition on a swept wing in a subsonic flow
Authors: Kirilovskiy S V , Boiko A V , Demyanko K V , Ivanov A V , Nechepurenko Y M , Poplavskaya T V
Published: November 2019

A subsonic (U∞=30 m/s) flow around a swept wing with a sweep angle of 45° and a chord of 700 mm aligned at an angle of attack in the test section of the T-324 wind tunnel based at the Khristianovich Institute of Theoretical and Applied Mechanics of the Siberian Branch of the Russian Academy of Sciences is considered. The experiments include measuring the static pressure on the model surface and thermal imaging of the laminar-turbulent transition (LTT). The numerical simulations of the laminar flow are performed by means of solving three-dimensional Navier-Stokes equations with the use of the ANSYS Fluent CFD software. The LTT position is determined by an LTT module developed by the authors on the basis of a LOTRAN 3.0 software package. The predicted results agree well with the experimental data and confirm that the favorable pressure gradient in the flow around the wing aligned at an angle of attack of −5° prevents the growth of the Tollmien-Schlichting waves and the LTT on the major part of the upper surface of the wing due to instability of crossflow vortices.
Reconstruction of the mesoscale variability of the Black Sea based on assimilation in the model of three-dimensional fields of pseudo-measurements of temperature and salinity
Authors: Lishaev P N , Kubryakov A A
Published: November 2019

The paper presents the results of the analysis of the hydrophysical fields of the Black Sea, reconstructed in the reanalysis through the assimilation in the model of pseudo-measurements of temperature and salinity. Much attention was paid to assessing the reproduction of mesoscale eddies. To perform a retrospective analysis of hydrophysical fields, three-dimensional temperature and salinity fields obtained by the original method of joint analysis of data on sea-level anomalies and rare contact measurements were acquired in the model. To identify the eddy structures, an automatic identification procedure is used, based on the definition of closed streamlines in the velocity fields. The coordinates of the eddy, trajectories of motion, velocity, time of life and vertical structure are calculated.
Simulation of the liquid fuel spraying based on Eulerian-Lagrangian model
Authors: Kuznetsov V , Shebelev A , Sharypov O , Dekterev A , Minakov A
Published: November 2019

The paper presents test results of the method for numerical simulation of liquid fuel spraying based on the Eulerian-Lagrangian model. This model describes the fluid flow inside the injector and directly behind it using the Euler-VOF method, while the dispersed medium (droplets) formed at a certain distance from the injector is described using the Lagrange approach. When using the VOF (volume of fluid method), the dynamical adjustment of the calculation grid at the phase interface is applied. Turbulence is modeled by the large eddy simulation (LES) method. The research results were compared with the data of direct numerical simulation (DNS) [1]. The calculation results based on the Eulerian-Lagrangian model show an acceptable agreement with the data of direct numerical simulation in terms of the main characteristics of the spraying. Thus, the structure of the two-phase flow, the parameters, and shape of the drops, as well as the speed and direction of their movement are determined qualitatively correctly.
Numerical simulation of the molten fuel relocation in fuel rod
Authors: Usov E V , Butov A A , Klimonov I A , Chuhno V I , Lobanov P D
Published: November 2019

Thermal destruction of fuel rods is one of the most hazardous accidents in nuclear power plants. Fuel melt contains a lot of fission products that can release and start to transport along reactor loops. Relocation of the fuel melt can change the power of reactor due to feedback between density of materials and neutron field in reactor core. The presented paper contains a brief description of the ways to simulate fuel melting and molten fuel relocation. Basic equations, numerical approximation and closing relation are presented in the paper. The results of the simulation of the molten fuel relocation as a result of the fuel rod thermal destruction are discussed.
Dynamics of the Azov-Black Sea basin by means of parallel ocean circulation modeling
Authors: Mizyuk A I , Puzina O S
Published: November 2019

The paper presents the methodology of free-run simulations for investigation of joint circulation of the Black and Azov Seas with high and ultra-high spatial resolution (4.5 and 1.1 km) and general characteristics of hydrophysical fields based on the results of simulations. Regional configurations used for numerical experiments are almost identical and differ only in spatial resolution with the corresponding tuning of the parameters of lateral turbulent mixing. We analyze the spatial variability of the results as well as water exchange between two basins through the Strait of Kerch. Enhancement of the resolution changes the structure of the basin circulation significantly and has to be validated using high resolution satellite data.
An adaptive PID controller with an online auto-tuning by a pretrained neural network
Authors: Chertovskikh P A , Seredkin A V , Gobyzov O A , Styuf A S , Pashkevich M G , Tokarev M P
Published: November 2019

This paper describes an intelligent adaptive PID controller design procedure. The controller consists of a discrete time PID and an auto-tuning neural network unit. First system identification with a nonlinear autoregressive model (NARX) was performed. This model was then used to train the neural PID tuner. A special MATLAB toolbox “SmatPID Toolbox” was developed to automate the process of controller synthesis. The resulting controller was tested in a laboratory coal-gas furnace control system to track specified air flow rates.
Small-disturbance temperature diagnostics in vortex tube with a square cross-section
Authors: Gordienko M R , Yavorsky N I , Kh Pravdina M , Polyakova V I , Ezendeeva D P , Kakaulin S V
Published: November 2019

The temperature diagnostics in the Ranque-Hilsh vortex was based on the scanning with the special temperature sensor of small size. The temperature profiles in different cross-sections were recorded. The temperature profiles were also measured in the swirler chamber. The difference in temperature at cold and hot outputs was about 50 ° C. Three measurement series carried out for each profile show that the temperature profiles in the Ranque tube is significantly nonstationary.
Cone nose-tip roughness effect on the transition at M=5, 6, 8
Authors: Gromyko Y V , Bountin D A , Polivanov P A , Maslov A A
Published: November 2019

The article presents data on the effect of distributed and isolated roughness on the blunt nose of the cone on the laminar-turbulent transition position. The experiments were performed at M=4.95, 5.95, 7.95, stagnation temperature T
0=361–465 K and stagnation pressure P
0=2–72 atm. The unit Reynolds number varied in the range Re1=(4.2–69.7)×106 m-1. The study was carried out in the boundary layer of cones with a half-angle of 7º with different zones of applying isolated and distributed roughness of the blunt nose R=5 mm. For all types of roughnesses, the effective values of Reynolds numbers are obtained, at which the transition occurs immediately after the roughness area.
Modelling the stressed state of thermal protective coating of turbine blades taking into account action forces from the gas flow
Authors: Lepeshkin A R , Nazarov V V , Ilinskaya O I , Kartavtsev A S , Guanghua Z
Published: November 2019

A mechanism for the destruction of a ceramic heat-protective coating of a fiber structure is proposed. The stress state of heat-protective ceramic coatings with a fiber structure of a turbine blade of an engine has been calculated taking into account the effect of forces from a gas-dynamic flow. In the calculation, the stresses in the coating fibers are determined taking into account different cases of their fixing under the action of bend from the forces of the gas-dynamic flow. The results of the calculation of the stress state of the fibers taking into account the taper are presented. The stress distributions over the height of single fibers and fibers located in the blocks of the ceramic coating when exposed to gas-dynamic forces are obtained. The estimation of the permissible thickness of the ceramic coating of the turbine blade GTE under the influence of gas-dynamic forces is resulted.
Using the copper-foam for thermal conductivity improvement of La0.9Ce0.1Ni5-alloy bed during interaction with hydrogen
Authors: Romanov I A , Borzenko V I , Kazakov A N
Published: November 2019

One of the main obstacles to the development of hydrogen energy is the problem of heat transfer inside metal hydride beds. Thus, the problem of increasing the metal hydride beds thermal conductivity is of great interest. This study is devoted to the investigation of the hydrogen sorption properties of an intermetallic compound placed in a matrix of foam material. Copper-foam with mass of 8 g was chosen as a matrix for 50 g of powder of activated AB5-type alloy with composition of La0.9Ce0.1Ni5. PCT-isotherms of hydrogen absorption and desorption were measured at temperatures 313, 333 and 353 K. Also, the dynamics of temperature change in the sample was studied when it was heated under vacuum conditions. The obtained data were compared with the results of previous studies conducted under the same conditions for samples of pure alloy and a mixture of alloy with copper powder. It has been concluded that the use of copper-foam to improve the thermal conductivity is promising, but it is necessary to take into account its influence on the hydrogen sorption properties of metal hydrides.
Determination of Thermophysical Parameters of the system C32-Ar
Authors: Barbin N M , Dan V P , Terentiev D I , Alekseev S G
Published: November 2019

In this paper, the thermophysical characteristics of the fullerene-argon (C32-Ar) system at atmospheric pressure are studied by thermodynamic modeling using the TERRA software system. Two groups of processes occurring in the system under consideration are determined: sublimation reactions with thermal dissociation and thermal dissociation reactions in the gas phase. The thermal physics of carbon vaporization in the gas phase is studied, the graphs of the dependence of the thermal characteristics of the C32-Ar system on temperature are constructed; the regularities in the inflection points of the graphs and changes in the compositions of the gas and condensed phases are revealed.
Probe supply of methane in gas-jet synthesis of diamond structures
Authors: Emelyanov A A , Yu Plotnikov M , Yudin I B
Published: November 2019

The present work is devoted to a numerical and experimental investigation of the probe supply of “cold” methane on the growth of diamond structures during gas-jet deposition. The analysis of results of experiments on the diamond gas-jet synthesis from methane and hydrogen mixture flows are presented. The direct simulation Monte Carlo method for numerical analysis of gas-dynamic aspect of these experiments was applied. A one-dimensional approach based on the solution of equilibrium chemical kinetics equations was used to analyze gas-phase methane decomposition. The obtained results can be useful for investigation of gas-jet deposition of diamond structures.
Influence of the substrate temperature on the jet diamond depositon
Authors: Rebrov A K , Timoshenko N I , Emelyanov A A , Yudin I B
Published: November 2019

The gas-jet diamond deposition with the activation of H2 + CH4 mixture by microwave discharge has been implemented. The maximum crystal size was observed at the substrate temperature of 850°C. The dependence of a film structure on the substrate temperature has been established. Diamond coating was received at a low substrate temperature (524°C).
Experimental and numerical study of the natural convection in dispersed systems in a heated rectangular cell
Authors: Tukhbatova E R , Zamula Yu S , Valiullina V I , Musin A A , Kovaleva L A
Published: November 2019

In this work, we study the appearance and development of convective flows in a dispersed medium by the experimental methods and mathematical modeling. An experimental study of the dynamics of thermoconvective flows is carried out in a specially designed cell, which is a rectangular vertical cavity with the possibility of heating the walls. A series of experiments were carried out at different temperature gradients. Various modes of convective flow have been obtained. To simulate the dynamics of convective flows in a rectangular cavity, a mathematical model based on the equations of thermal convection in the diffusion approximation has been created. Convective flow patterns for a dispersed medium have been obtained. Numerical calculations coincide with the experimental results. Numerical simulation of the problem allows us to estimate the distribution of velocities, temperature, and concentration of the dispersed phase inside the cell during the formation of convective flows and the established convection regime.
Synthesis of gold nanoparticles by annealing its thin film under a layer of fluoropolymer coating
Authors: Safonov A I , Starinskiy S V , Timoshenko N I
Published: November 2019

Gold thin films were deposited on the substrate of silicon and fused silica by method of Vacuum Gas Jet Deposition. Obtained films were coated with a fluoropolymer and annealed in a rarefied inert gas atmosphere at the temperature of 400 °C. The film morphology and composite were studied by the scanning electron microscopy. Optical properties of obtained coatings and composites were investigated. The influence of the fluoropolymer coating on formation of gold nanoparticles in the result of annealing of its thin films is established. The critical gold film thickness coated with fluoropolymer is determined, below which the presence of fluoropolymer lends to the formation of spherical nanoparticles during annealing of the composite in a studied range of parameters.
Dynamics of bubbles in liquid dielectrics under the action of an electric field: lattice Boltzmann method
Authors: Kupershtokh A L , Medvedev D A
Published: November 2019

The initial stage of deformation of bubbles before partial discharges under the action of the electric field is studied. The bubbles are placed on the surface of the electrode. The lattice Boltzmann method is used for 3D computer simulations of dielectric liquid dynamics. The electrostatic forces acting on a dielectric fluid in an electric field are taken into account as complete Helmholtz formula that includes the electrostriction forces. After the application of the electric field, the bubbles begin to elongate in the field direction. Above the critical value of the electrical Bond number, the bubbles can detach from the surface of the electrode and float.
Spectral characteristics of inductively coupled plasma of water vapor
Authors: Medvedev R N , Savenko R A , Churkin D S
Published: November 2019

The paper presents the results of experimental measurements of the emission properties of water plasma in an inductive discharge. The power of the inductive discharge was 600 W at a frequency of 27 MHz and a pressure from 0.25 to 4 mbar. Plasma temperature was estimated from the Balmer hydrogen series using relative intensities method. It is shown that in this pressure range, the plasma is not in equilibrium and the energy difference between individual excited states increased with distance from the tube axis. The plasma heating time was estimated from the dynamics of the spectral line intensities to be 200 ms.
The influence of dissipative effects on dynamic processes in a rotating electrically conductive liquid medium
Authors: Peregudin S , Peregudina E , Kholodova S
Published: November 2019

The present study is concerned with dynamical processes in a rotating layer of electrically conducting incompressible liquid located in a magnetic field which is parallel to the normal vector to the boundary surfaces. We take into account not only the convective terms, but also the diffusion terms in the magnetic field induction equations. This problem, as well as the geophysical hydrodynamics problem, calls for the construction of approximate variants of the principal hydromagnetic equations and rigorous mathematical analysis of these approximate equations. Moreover, advancements in the above problems depend on the approximations to be introduced. To this end, by introducing characteristic scales of variation of the variables in the original equations and estimating the magnitude orders of the terms involved in the equations, one can single out the principal and secondary terms, simplify the equations, and build a model of the process under consideration. By introduction of auxiliary functions, the system of partial differential equations is reduced to one scalar equation. This suggests the conclusion about the analytical structure of magnetohydrodynamic characteristics. From the results obtained it follows that the magnetic field generation in an electrically conducting liquid stems from the instability characterized by the corresponding relations between the gravitation force, the Coriolis force, the magnetic force, and the peculiarities of the relief topography.
Destruction of water-in-oil emulsions in electromagnetic fields
Authors: Zinnatullin R R , Kovaleva L A , Sultanguzhin R F , Gabdrafikov A F
Published: November 2019

In this paper, we study the degree of exposure of electromagnetic fields to water-oil emulsions with different physical and chemical properties, as well as the characteristics of their heating and delamination when exposed to radio frequency and microwave frequencies in electromagnetic fields. Experimental research methods are described. The results of experimental studies of heating emulsions in radio frequency and microwave electromagnetic fields under dynamic conditions and the results of their separation are presented. As a result of the research, it has been found that when exposed to radio frequency or microwave electromagnetic fields on oil-water emulsions, the degree of heating and the efficiency of emulsion stratification depend on the total content of asphaltene and resins, the water content in the emulsion, and the operating frequency of the generator in the region of resonant frequencies for emulsions. For all types of emulsions, radio frequency action is more effective than a microwave field, with low water contents. With increasing water content the efficiency of microwave exposure increases. Also, with an increase in the water content, the intensity of heating the emulsion in the microwave field increases with the same energy inputs.
Localization of a combined pulse discharge within a gas with a rectangular obstacle on the channel wall
Authors: Znamenskaya I A , Tatarenkova D I , Ivanov I E
Published: November 2019

Analysis of plasma energy redistribution was conducted on the basis of experimental study of combined volume discharge of submicrosecond duration at its initiation in a gas-dynamic flow in rectangular channel with an obstacle. Shock wave diffraction on the obstacle (parallelepiped) on the channel wall was visualized. Effects of plasma localization at upward facing step and backward facing step were experimentally discovered and studied. CFD simulation patterns of the gas dynamic non stationary flow were compared to instant flow glow images.
Investigation of the spatio-temporal variability of the Black Sea upper mixed layer thickness based on the results of numerical calculations
Authors: Ratner Yu B , Kholod A L
Published: November 2019

The results of the Black Sea uniform mixed layer (UML) thickness determination were used for investigation of its spatio-temporal variability based on numerical calculations of the monitoring and forecasting center of the Black Sea (BS MFC). The spatial distribution of the mean and standard deviations of the UML depths in the Black Sea has been studied over the seven-year period. The time series analysis of UML thickness was performed by their spatial averaging over the Black Sea area for each day of the seven-year period. The principal components of the variability of the spatio-temporal UML depths field have been studied. The areas of high and low UML depths variability and the frequency-time characteristics of their variations have been determined.
Motion of a single vapor Taylor bubble in the vertical tube of small diameter
Authors: Slesareva E Y , Dekhtyar R A , Ovchinnikov V V
Published: November 2019

An experimental study of the dynamics of the Taylor vapor bubble in water and in an aqueous solution of lithium bromide at vapor saturation pressure was carried out. The Taylor bubble was formed after boiling-up of the overheated degassed liquid in 16 mm diameter tube. The study has shown that the dynamics of the vapor cavity during boiling up leads to a qualitative difference from the dynamics of the vapor bubble in a large volume. There are also qualitative differences in the nature of motion of the vapor bubble and that of the gas bubble. This is due to the fact that the mass of the gas bubble and the temperature of the liquid do not change during the rise near the bubble, whereas the mass of the vapor bubble and the temperature of the vapor in the bubble and the liquid near the bubble can vary significantly due to evaporation of the liquid and steam condensation. This is due to the change of bubble height and level of fluid in the tube. The liquid level in the tube depends on the height of the bubbles, but the height of the liquid level in the tube depends on the volume of the bubbles.
On efficiency of metal hydride extraction of hydrogen from a mixture with methane
Authors: Dunikov D O , Blinov D V
Published: November 2019

Extraction of hydrogen from dilute mixtures with natural gas differs from traditional separation processes, since hydrogen is the minor component with low partial pressure. Metal hydrides absorb hydrogen selectively and can be used for purification. Exergy analysis shows that the metal hydride separation of binary mixture of a gas with hydrogen has a maximum at hydrogen content of 5-15%, and the main factors affecting efficiency are the need to spend heat to compensate the reaction enthalpy and pressure losses of methane during filtration through the metal hydride bed. We have experimentally demonstrated successful separation of the hydrogen (10%) – methane (90%) mixture at inlet pressure of 9.5 bar by the LaNi4.8Mn0.3Fe0.1 intermetallic compound in one step with roundtrip (absorption/ desorption) hydrogen recovery of 74% and absorption hydrogen recovery of 76%, which is close to the value of 77% calculated based on the thermodynamic analysis.
Simulation of evaporation of mixtures and solutions in the spheroidal state
Authors: Elistratov S L , Mironova N V
Published: November 2019

The paper presents the theoretical dependences of evaporation in the spheroidal state of pure liquids, liquids containing insoluble and partially soluble impurities. The conditions are formulated, upon the occurrence of which a change in the crisis regime of film evaporation to an intensive regime of partially bubble boiling may occur upon contact with a heating surface.
Numerical simulation of the heat transfer of staggered drop-shaped tubes bundle
Authors: Deeb R , Sidenkov D V
Published: November 2019

Tube bundles can be used as a separation heat exchanger in the “organic” Rankine cycle power plants (ORC), while the hot gas passes over the outer surface, and the working substance ORC flows inside the tubes. A numerical study has been conducted to clarify heat transfer and hydrodynamics of a cross-flow heat exchanger with staggered drop-shaped tubes at different flow angles of attack (θ). A mathematical and numerical model in software package ANSYS has been developed for numerical evaluation of heat transfer and flow field of a bundle of drop-shaped tubes, with taking into account the strain caused by different pressures inside and outside the tubes. The results of numerical simulation of pressure, velocity, temperature distribution in the tube’s bundle had provided the development of equation to determine the average Nusselt number (Nu) in terms of Reynolds number (Re), Prandtl number (Pr) and angle of attack.
Reasons for tangerine peel utilization in the composition of mixed fuels based on bituminous coal
Authors: Yankovsky S A , Tolokolnikov A A , Cherednik I V , Kuznetsov G V
Published: November 2019

Application analysis of processed tangerine peel in a mixture with T grade coal (lean) as a fuel for hot water boilers is presented. Technical characteristics, as well as conditions and ignition delay times for such mixed fuels at different mass concentrations of the initial components, have been experimentally determined. The experiments were carried out in air at temperatures from 600 ° C to 800 ° C. Record of ignition and combustion processes of composite fuel samples was carried out using a high-speed video camera (image format — 1024 × 1024 pixels, frame rate — up to 1000000 per second), which ensures high discretization of the recording results of characteristic process times. A temperature limit has been identified for the stable ignition of such fuels. It has been established that an increase of tangerine peel proportion in the mixture leads to acceleration of ignition processes of the studied mixed fuels. Reasons for application of fuel mixtures based on bituminous coal and food waste in the small energy sector have been provided.
Two-dimensional steady-state heat conduction problem for heat networks
Authors: Nemirovsky Y V , Mozgova A S
Published: November 2019

The method of determining the level of heat losses through structures of heat networks and the two-dimensional steady-state heat conduction problem for multilayer structures of heat networks have been considered, given that each of the layers has its own physical properties and heat transfer coefficients depend on r and z coordinates. The definition of heat losses is an important practical task, since they are one of the main indicators of energy efficiency in the operating heat networks and are included in heat tariffs.
Formation of the lamellar structure and recrystallization at the disorder → order transition in Au35.3Cu52.6Pd12.1 alloy
Authors: Aleksandrova S S , Medvedeva E V
Published: November 2019

The atomic ordering in the Au35.3Cu52.6Pd12.1 alloy was studied by field ion microscopy. It was found that the removal of internal stresses in the alloy during the disorder → order transition occurs due to the formation of c-domain lamellas from 2 to 10 nm wide at the early stages of ordering. The use of computer modeling for the interpretation of ion images provided with the identification and evaluation of the superstructural defects quantitative characteristics.
Mechanoluminescence of composite layer applied on polymer surface excited by short acoustic pulses in water
Authors: Banishev A F , Shubny A G , Banishev A A
Published: November 2019

A composite mechanoluminescent layer has been produced on the surface of polymethylmethacrylate by liquid-phase embedding of SrAl2O4:(Eu2+, Dy3+) phosphor microparticles into the polymethylmethacrylate surface layer. The photoluminescence and mechanoluminescence of the obtained layer have been investigated. The mechanoluminescence was excited by the short acoustic pulses. A possible mechanism of mechanoluminescence excitation is under discussion. The produced composite layer is shown to exhibit high efficiency of “mechano-optical” transformation.
Increasing of an electrostatic probe capacity and efficiency for metal dust collection in ITER
Authors: Begrambekov L B , Bidlevich O A , Grunin A V , Voityuk A N
Published: November 2019

Formation of dust particles and clusters is observed in almost all modern fusion devices. Accumulation of dust in next-generation thermonuclear installations can significantly affect plasma parameters and lead to accumulation of unacceptably large amounts of tritium. The use of a specially developed electrostatic probe is planned in the international thermonuclear experimental reactor ITER to collect dust for further analysis. The article describes a numerical model of dust particles movement in an electrostatic probe. Dust particles trajectories inside the probe were analyzed. Several electrostatic probe design modifications were proposed on the basis of the analysis in order to increase the efficiency of dust collection.
Thermal desorption study of hydrogen isotopes trapping and its diffusion in tungsten coated with aluminum/beryllium layer during plasma irradiation
Authors: Begrambekov L B , Kaplevsky A S , Dovganyuk S S , Kasimova N N
Published: November 2019

The influence of irradiation in hydrogen plasma with oxygen impurity on the penetration of hydrogen isotopes through the surface of tungsten, through the surface of beryllium and aluminum layers on tungsten, and through the tungsten-coating interface was studied. It was shown that all these processes are accelerated in the presence of oxygen impurity in plasma. A conclusion is made that detritisation of the surface of both in the conditions of a fusion reactor tungsten and beryllium is possible.
Structural features of V-1469 alloys compounds produced by friction stir welding
Authors: Betsofen S Ya , Gordeeva M I
Published: November 2019

This article is about the distribution of hardness, texture, phase composition, and residual stresses in various zones of the joint of sheets of alloy V-1469 obtained by friction stir welding (FSW).
Elaboration of pulsed X-ray laser on base of radiation fluxes waveguide-resonance propagation phenomenon
Authors: Egorov V K , Egorov E V
Published: November 2019

The work presents short characteristics of the radiaiton fluxes waveguide-resonance propagation phenomenon opened in result of X-ray characteristic radiation transportation peculiarities study by planar extended slit clearance functioned in frame of its total external reflection phenomenon. There are showed that the waveguide-resonanec phenomenon must become apparent in frame of the Bragg reflection phenomenon and can be used for elaboration of the Bragg-Laue waveguide-resonance cells (BLWRC). Set of BLWRCs can be used for construction of compact pulsed X-ray laser in form of circular radiation storage. There are presented and discussed its expected parameters.
Effect of duration of titanium microarc treatment on morphology, composition and electrochemical behavior of coatings
Authors: Gerasimov M V , Bogdashkina N L , Kondratsky I O , Peretyagin P Yu , Suminov I V , Filonova E V , Shcherbakov A I , Apelfeld A V
Published: November 2019

Microarc oxidation (MAO) of titanium grade VT1-0 was carried out in the alkaline electrolyte with the addition of nickel sulfate. The effect of duration of titanium microarc treatment on morphology, composition and electrochemical behavior of coatings was investigated. It was found that nickel appears in MAO coatings only after a certain duration of the MAO treatment process (from 5 to 10 min), when the temperature in the micro-discharges becomes high enough for thermolysis of nickel sulfate and incorporation of its oxide into the coating (respectively, with a thickness of 2 to 5 μm). MAO coatings, despite their relatively small thickness, significantly increase the corrosion resistance of titanium in 25% sulfuric acid (anodic passivation currents are reduced up to 2 orders of magnitude).
Mechanism of internal stress formation in titanium alloy samples, obtained by additive manufacturing
Authors: Grushin I A , German M A , Kuzmina D A
Published: November 2019

The paper presents the results of residual stress formation study in Ti-6Al-4V alloy samples, obtained by additive manufacturing. An analogy of residual stress formation mechanism observed in samples during 3D-printing and laser beam welding technology is shown. The effect of annealing on residual stress level is investigated.
Tribological behavior of coatings deposited by reactive magnetron sputtering of silicon in acetylene-nitrogen gas mixtures
Authors: Khrushchov M M , Marchenko E A , Antonova O S , Atamanov M V , Petrzhik M I , Sulandziga D A
Published: November 2019

The composition, micromechanical properties and tribological behavior of silicon-based coatings obtained by reactive magnetron sputtering of silicon have been investigated. The results of the friction fatigue tests and the peculiarities of the friction surface failure in several types of vapor-deposited silicon-based coatings have been discussed.
Low-temperature ion nitriding of VT6 titanium alloy with UFG structure
Authors: Khusainov Yu G , Nikolaev A A , Agzamov R D , Ramazanov K N , Esipov R S
Published: November 2019

This work describes the effect of low-temperature ion nitriding on the mechanical and operational properties of the titanium alloy VT6 with the ultrafine-grained structure. Ion nitriding of the alloy was carried out atT=450-600 °C andp=300 Pa in a gas mixture of argon and nitrogen during 6 hours. Low-temperature nitriding at the temperature ≥550 °C leads to a decrease in the microhardness of the material base. The optimum processing temperatures are 450-500 °C. The formation of the UFG structure and subsequent nitriding increases wear resistance by 28%.
Change of photoelectric elements power characteristics by silver nanoclusters modification of receiving surface
Authors: Krit B L , Fedotikova M V , Sleptsov V V , Kukushkin D Yu , Gorozheev M Yu , Kuvshinov V V , Morozova N V
Published: November 2019

The values of power characteristics of modern photovoltaic cells are considered. Possibility of their increasing with the aid of surface plasmon resonance reached by modification of the receiving surface with silver nanoclusters is presented. The effect of nano-coating on the power and stability of energy generation is shown.
Study of the ion assisted sputtering process parameters influence on the structure and morphology of TiPb coatings
Authors: Lozovan A A , Betsofen S Y , Lyakhovetskiy M A , Lesnevskiy L N , Bespalov A V , Nikolaev I A , Pavlov Y S , Aleksandrova S S
Published: November 2019

The paper presents the study’s results of the composition, structure and morphology of Ti-Pb coatings formed by magnetron co-bombarded with the help of ions. The effect of the relationship between magnetron currents on the structure of Ti and Pb coatings is shown.