Table of contents

D M Markovich and S V Golovin

The origins of the Conference start from 1970 in the Soviet Union, Novosibirsk. It was organized by Kutateladze Institute of Thermophysics SB RAS. The name of the conference was «Actual problems of thermophysics and physical hydrodynamics». The conference has been organized under this name up to 2015. The conference chairs were academicians V.E. Nakoryakov, S. V. Alekseenko and corresponding member of RAS D. M. Marckovich. Peer reviewed proceedings of the conference have been published in the format of printed books. In 2016 the conference is reorganized in a new format with a shorter name: «Thermophysics and physical hydrodynamics».

The conference takes place in Yalta, a beautiful city in Crimea on the bank of the Black Sea. Lavrentev Institute of hydrodynamics and the National committee on heat and mass transfer are among other conference organizers besides Kutateladze Institute of thermophysics. The present Conference covers the following topics: heat transfer and hydrodynamics in single phase flows, hydrodynamics and heat and mass transfer in multiphase flows, phase transitions, reacting flow dynamics, detonation processes, numerical methods in thermophysics and physical hydrodynamics, techniques of thermophysics and hydrodynamics experiment, thermophysical properties of substances and new materials, heat transfer and hydrodynamics on micro- and nanoscales, electrophysical phenomena in gaseous and liquid media, heat transfer and hydrodynamics in industrial processes and environment protection.

There are more than 200 participants. The proceedings contain 156 papers grouped by topic. The scientific committee appreciates the enormous work of the editorial board and reviewers in the preparation of this volume. We would like to express our sincere thanks to all authors for their research contributions, and also to organizers of the conference for their valuable spadework.

List of Photos and Sponsor acknowledgements are available in this PDF

Chair

D M Markovich, Corr. member of the RAS (IT SB RAS, Novosibirsk, Russia)

Co-chair

S V Golovin, Professor of the RAS (LIH SB RAS, Novosibirsk, Russia)

Scientific secretary

M S Makarov, PhD (IT SB RAS, Novosibirsk, Russia)

Scientific committee

S V Alekseenko, Academician of RAS (IT SB RAS, Novosibirsk, Russia)

A A Vasilev, Professor, PhD (LIH SB RAS, Novosibirsk, Russia)

A A Gubaidullin, Professor, PhD (TB ITAM, Tyumen)

S G Demyshev, PhD (MHI RAS, Sevastopol)

S L Elistratov, Professor, PhD (NTSU, Novosibirsk, Russia)

S A Isaev, Professor, PhD (SPb GUGA, Saint Peterburg)

V K Kedrinskii, Professor, PhD (LIH SB RAS, Novosibirsk, Russia)

G K Korotaev, Corr. member of the RAS, (MHI RAS, Sevastopol)

A I Kubrykov, PhD (MHI RAS, Sevastopol)

V V Kuznetsov, Professor, PhD (IT SB RAS, Novosibirsk, Russia)

P A Kuibin, PhD (IT SB RAS, Novosibirsk, Russia)

A L Kupershtokh, Professor, PhD (LIH SB RAS, Novosibirsk, Russia)

A I Leontev, Academician of RAS (BMSTU, Moscow)

A.N. Pavlenko, Corr. Member of RAS (IT SB RAS, Novosibirsk, Russia)

E R Pruuel, PhD (LIH SB RAS, Novosibirsk, Russia)

V V Pukhnachev, Corr. Member of RAS (LIH SB RAS, Novosibirsk, Russia)

A F Ryzhkov, Professor, PhD (UFU, Ekaterinburg)

A S Samodurov, PhD (MHI RAS, Sevastopol)

E M Smirnov, Professor, PhD (SPbSTU, Saint Peterburg, Russia)

S V Stankus, Professor, PhD (IT SB RAS, Novosibirsk, Russia)

V M Titov, Academician of RAS (LIH SB RAS, Novosibirsk, Russia)

M P Tokarev, PhD (IT SB RAS, Novosibirsk, Russia)

M P Fedoruk, Corr. member of the RAS (NSU, Novosibirsk, Russia)

G A Habahpashev, PhD (IT SB RAS, Novosibirsk, Russia)

O Y Tsvelodub, Professor, PhD (IT SB RAS, Novosibirsk, Russia)

A A Chernov, Professor of RAS, PhD (IT SB RAS, Novosibirsk, Russia)

Technical committee

V S Naumkin, PhD (IT SB RAS, Novosibirsk, Russia)

R N Medvedev, PhD (LIH SB RAS, Novosibirsk, Russia)

D V Smovzh, PhD (IT SB RAS, Novosibirsk, Russia)

I V Savchenko, PhD (IT SB RAS, Novosibirsk, Russia)

All papers published in this volume of Journal of Physics: Conference Series have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

The experience of using the technology of Fast Automatic Differentiation (FAD) is described to restore the initial data of a model hydrodynamic flow with a free boundary based on the results of spatial-temporal monitoring of velocity, density and free surface components. The solution of the direct problem is realized according to the CABARET scheme, for which the construction of the conjugate system is a serious independent task. Currently, there are available open computer codes that allow the implementation of FAD technology in the "black box" mode, submitting to its input the executable "author's" code for solving a direct problem. The model problem was solved with the help of the Adept 1.1 package, while using the 3-pass algorithm, which reduces the requirements for the amount of RAM.

A method for calculating the permeability of a porous medium is proposed and realized using the example of a rhombohedral porous structure. The method is based on the Darcy equation, while the flow rate is found by numerical simulation of a three-dimensional flow of a viscous incompressible fluid in a pore channel. Computational experiments are performed using open SALOME-OpenFOAM packages. The results of the calculations allow estimating the accuracy of previously obtained analytical estimates of permeability.

The main results obtained on boiling heat transfer enhancement over the past two decades are reviewed. The methods and ways to intensify the boiling heat transfer are traditional: influence on the internal boiling mechanisms; increase of the heat exchange surface; creation of conditions that suppress the least efficient processes during boiling. Today, the methods of influence have become much more selective and precisely tuned. The use of nanofluids and nanomaterials, femtosecond laser irradiation, plasma and ion processing allows obtaining a significant number of new results.

The final stage of the reaction of the coastal currents on intensive short-term wind effects is considered in the framework of nonlinear equations of shallow water on the f - plane. An exact analytical solution describing the steady state that occurs after radiation to infinity of the inertial-gravity waves is obtained using specific lagrangian invariants. Analysis of the solution shows that coastal jet shifts onshore or offshore against its original position, depending on the wind direction. Asymmetry of stationary regimes depending on the direction of the coastal currents appears with considerable wind intensity. The most significant is the influence of the currents on the development of coastal upwelling. In particular, upwelling occurs with weaker winds if the current intensity increases when the coast is on the right side of the jet. Upwelling can be blocked if the beach is located to the left of the jet, and if it is initially close enough to the shore.

The paper considers the mechanisms of the development of large-scale instability in counter-current gas-liquid flow in complex channel systems of the structured packing, contributing to deterioration of the separation efficiency for a gas mixture. The paper discusses the contribution of the gravity-induced convective flows and capillary-gravity flooding to the development of the maldistribution of the fluid velocity and concentration fields in the distillation columns filled with Koch 1Y and Mellapak 500Y structured packings. The correlation for prediction of the gas and liquid capacity factors corresponding to the packing flooding is proposed based on the experimental data.

Heat transfer coefficient was experimentally estimated in the separation region behind a spanwise rib in a channel with forced flow pulsations. The same channel but without the rib was used for SIV measurements of dynamics of flow velocity vector fields that yielded in variations of normalized turbulent energy production, diffusion and dissipation over the flow rate pulsation period. High sensitivity of convective heat transfer, turbulent production, diffusion and dissipation to the forced flow pulsations have been revealed.

Purpose of the study is to obtain fundamental knowledge about Kuznetsk bituminous coal entrained-flow gasification in O₂-CO₂ mixtures for oxy-fuel IGCC. To achieve this purpose, it is necessary to carry out experimental and numerical studies. To obtain universal knowledge, "CKTI" single-stage gasifier with fuel consumption of 5-15 kg/h was chosen as an experimental installation. In order to identify the most interesting and informative experimental regimes, a number of computational studies have been carried out, whose results are given in the paper. A numerical (CFD) model has been developed, which includes all the submodels necessary for the study. Two series of numerical calculations were carried out. In the first series, the composition of the blast (O₂ = 0-100%, CO₂ = 0-100%) and the oxygen ratio were varied at constant consumption of coal and blast. In the second series, the composition of the blast (O₂ = 0-100%, CO₂ = 0-100%) and the coal consumption were varied at constant oxygen ratio and blast flow rate. The study allowed predicting and analyzing the temperature distribution and the syngas components content along the gasifier height with different CO₂ concentrations in the blast.

Liquid metals are prospective coolant and working media for fission and fusion applications. In latter case they will be affected by very high magnetic fields. By now there is no possibility to recreate these conditions directly, and research is being made using numerical simulations and model liquids. Special care is taken to the possible thermogravitational phenomena in the presence of magnetic field. Temperature and temperature fluctuations are used to describe the flow structure as they can be obtained from experiments with high accuracy and localization. Area of intense fluctuations existence was explored using several experimental facilities including a new HELME Facility with magnetic fields of up to 2.7 Tesla. Area where fluctuations occur and specific of transition regions have been explored for the round vertical pipes with down flow and uniform heating (Grashof number of up to 1.2·10⁸) as a basic configuration with explicit boundary conditions.

In this study, a fully coupled fluid–structure interaction computational model for a pulsatile flow in the venous valve was developed. An arbitrary Lagrangian–Eulerian formulation is used in the coupled model, considering two domains, specifically the blood flow and the valve leaflets. The effect of the gap width between the valve leaflets (venous valve incompetence) on the valve reverse flow (reflux) has been investigated.

In this paper we present the results of a comparison of calculated and experimental data on the main regularities of the evolution of a three-dimensional wave on vertically falling liquid films in the range of film flow Reynolds number 5 < Re < 30. Numerical calculation based on the Shkadov model equations shows both experimentally observed scenarios of the evolution of three-dimensional waves: propagation of a single wave or wave train evolution. Comparison of the wave shape shows good qualitative agreement between experiment and calculation for both scenarios.

The sequence of turbulent energy production, diffusion and dissipation processes in the region of the boundary layer of y/δ≈0.45 under conditions of streamwise adverse pressure gradient has been described for the first time using the Smoke Image Velocimetry (SIV) technique with a good spatial and temporal measurement scale commensurate with the linear and temporal scales of the Kolmogorov vortex dissipation. Considerable increase in the third-order moments of the turbulent velocity fluctuations and their spatial gradient describing the turbulent diffusion energy transport in the region of y/δ≈0.45 has been observed.

The paper presents the data of the effect of distributed and single roughness on a blunted nose of a cone on the position of the laminar-turbulent transition and the development of perturbations in the boundary layer. The experiments were performed at M = 5.95, stagnation temperature T₀ = 360 ÷ 418 K and stagnation pressure P₀ = 3.5÷ 46 atm. Unit Reynolds number varied in the range (4.2 ÷ 69,7)×10⁶ m⁻¹. The study was carried out in the boundary layer of a cone with half-angle of 7º with different zones of applying a single and distributed roughness on blunted nose-tip of radii 2 and 5 mm. For all types of roughness, the effective Reynolds numbers corresponding to transition on the model's nose are obtained. The effect of surface roughness on the growth of perturbations in the boundary layer is studied experimentally.

Planar flow of shear-thinning fluid in a T-shaped channel is investigated assuming slip occurs along the wall. Motion of the fluid is caused by pressure difference between inlet/outlet boundaries. On the solid walls, two models of fluid interaction with solid walls are employed: no slip boundary condition and Navier slip boundary condition relating the wall shear stress to the slip velocity. The problem is solved numerically using a finite difference method based on the SIMPLE procedure. The parametric studies of the flow pattern depending on the main parameters of the problem have been performed. Dependences describing kinematic and dynamic characteristics of the flow have been shown.

The resistance to a flow in open channels of river type depends on a variety of parameters. The coefficient of bottom roughness is an integral quantity accounting for the geometric and physical features of the river bottom. Definition of the channel cross-section variability contribution to the roughness coefficient is the aim of our research. We have applied the 2D numerical model of surface water dynamics in the shallow water approximation to our task. The Manning roughness coefficient for non-prismatic open channels has been estimated depending on the parameters of the variable cross-section of the water flow in the range n = 0 ÷ 0.02.

The present paper considers new experimental results on quenching of stainless steel spheres in liquid argon and nitrogen. The experiments were performed on polished, hoarfrost and iced surfaces. The experiments on hoarfrost surface demonstrated higher cooling rates in comparison with corresponding experiments on polished and iced surfaces. This result could be explained by the model of incipience of highly intensive film boiling regime in subcooled liquid.

We perform Large-eddy simulations (LES) of turbulent variable-density jets. A fully developed turbulent pipe flow of air at the Reynolds number of Re = 5300 enters a large reservoir of air, helium or carbon dioxide. The impulsely starting jets as well as the fully developed stationary flows are considered. In the first case we show that the air stream propagates faster in the light medium of helium as compared to other gas pairs, while in the fully developed case the same helium-air pair exhibits the lowest level of turbulent fluctuations.

In the present work, mixed convection was studied using the direct numerical simulation (DNS) method for the upward flow of a liquid metal (Pr = 0.025) in a vertical rectangular heated channel. The Reynolds number (Re) varied from 10⁴ to 2·10⁴. The criterion for the appearance of thermogravitational convection, as well as the characteristic of the intensity of its influence, was the Grashof number (Gr), which varied in the range from 0 to 4·10⁹. A significant and ambiguous effect of free convection on hydrodynamics and heat transfer, which depends on the ratio Gr/Re² and the Prandtl number, is obtained.

The heat transfer intensity through the separation wall in Leontiev tubes depends on many factors, in particular, the thermal resistance of the separation wall and the external thermal resistances of the near-wall thermal boundary layers. The thermal resistance of the separation wall can be reduced by choosing a highly conductive material and by reducing the wall thickness. External thermal resistances can be reduced by enhancing heat transfer, in particular, by means of finning. In this paper, a theoretical study was carried out on the influence of the thermal resistance of the separation wall, as well as finning on the part of the supersonic and subsonic channels of the Leontiev tube on the efficiency of energy separation.

In agreement with a recent experimental study by Xi et. al. [1], we also observed the sloshing mode of the large scale circulation (LSC) in our experimental investigation of turbulent Rayleigh-Benard convection of liquid sodium in a cylindrical cell of aspect ratio one. The Rayleigh and Prandtl numbers vary within the range of (0.5 – 2.6)·10⁷ and (8.7 – 9.9)·10⁻³ respectively. The characteristic times and corresponding Reynolds numbers of the general and sloshing modes of global circulation were estimated by analyzing the cross correlations of temperature oscillations and by determining the locations of peaks on the spectra of temperature fluctuations.

The article considers heat transfer in a flow of helium-xenon mixture in straight and twisted tubes with square cross sections. The main attention is paid to the heat transfer at large Reynolds numbers for tubes with small effective diameter. Such flows are often found in compact heat exchangers, assemblies of heat-generating elements, and energy-separating devices. CFD simulation data serve to analyze the influence of the cross-section shape and the twist step of the tube on hydraulic resistance and heat transfer. Various methods of generalization of heat exchange data are analyzed, taking into account the effect of gas compressibility on the flow acceleration in the tube and dissipative effects on the equilibrium wall temperature.

Direct numerical simulation of flow and heat transfer behind a spanwise rib in a pulsating flow in a channel has been performed at the Reynolds numbers that correspond to transition to turbulence in the separation region behind the rib in a steady flow case. Good agreement between the calculations and experimental data has been demonstrated. The effect of forced unsteadiness parameters on heat transfer behind the rib has been analyzed. It has been shown that forced flow pulsations are able to augment heat transfer. The correlation between the heat transfer level and the vortical structure of flow behind the rib has been demonstrated.

A method for experimental observation of turbulent exchange between vortex ring and surrounding medium is proposed. The method is based on a shadow visualization of the process. For this purpose a vortex ring containing liquid more dense than outside is created. It is established that there is a characteristic distance for turbulent exchange and this distance depends on vortex velocity. The dependence of characteristic distance on Reynolds number of vortex is obtained.

The high temperature gas turbine vane has the leading edge convective cooling. This study discloses investigation of thermal and hydraulic performance of closed whirler, or cyclone edge cooling. Its mass and heat transfer are simulated with the ANSYS CFX model of the leading edge with closed whirler dome. Changes in air supply and discharge orifice areas change the heat transfer distribution. Test results show the influence of the whirler configuration parameters on heat transfer intensity. The obtained criteria equations allow calculations of local and mean heat transfer coefficients with 8% accuracy.

The paper discloses investigation of flow turbulator thermal and hydraulic performance. The turbulator intensifies heat transfer in heat exchangers. Two modifications of pin turbulators allow decay of the pin "shadow" zone with low heat exchange coefficient downstream the pin. The intensifier main structural parameters influence thermal and hydraulic channel performance. The results show that the developed intensifiers increase the Nusselt number for 11–36% in the staggered pin-fin arrays. The obtained criteria equations allow the analysis of cooling air heat transfer with ±8% error.

A supersonic (M_∞=5.95) flow around a blunted cone with a cylindrically shaped single roughness element located in the bluntness region is considered. Numerical simulations are performed by means of solving the unsteady three-dimensional Navier-Stokes equations with a computational module that takes into account the action of external acoustic waves on the flow. Numerical data are obtained for the mean flow characteristics and evolution of disturbances formed in the wake behind the roughness element. It is shown that intense interaction of steady streamwise vortices occurs behind the single roughness element (Re_kk=4880, k/δ=3.95) on the cone with a bluntness radius of 5mm. This interaction is accompanied by formation of three-dimensional finger-shaped structures in the azimuthal direction, which testifies to the initial stage of the laminar-turbulent transition.

The problem of the long-wave disturbance interaction with a shock wave on a wedge at an angle of attack is considered. Numerical simulations are performed by solving two-dimensional unsteady Navier–Stokes equations with the module addition created by the user and allowing taking into account the vibrational nonequilibrium of carbon dioxide molecules within the two-temperature model of relaxation flows. A parametric study on the effect of Mach numbers, Reynolds numbers and angles of attack on the disturbance transformation coefficients is carried out for the following gases: equilibrium air, equilibrium vibrationally excited CO₂, and nonequilibrium CO₂. The calculation results on the pressure pulsations on the model surface were compared with the data obtained for long-wave disturbance from the general solution of the inviscid problem of the disturbance interaction with a shock wave on a wedge [1]. It is shown that the obtained long wavelength disturbance transformation coefficients are practically the same as for the inviscid case in the studied range of Mach numbers (M_∞=4.5÷8.9).

In this paper, numerical simulation of steady power-law fluid flow through axisymmetric sudden expansion under non-isothermal conditions is implemented. Mathematical model of the flow accounts for viscous dissipation effects and temperature-dependent consistency coefficient in the Ostwald de Waele power law. The problem formulated is solved using the finite-difference method. Two-dimensional flow zones are found in the vicinity of expansion plane including recirculating region in the corner. Variation in the length of these zones is analysed in respect to power-law index and dimensionless criteria of the problem. The effect of viscous dissipation on the flow structure formation and viscosity and temperature distribution is estimated in a wide range of the main parameters.

Due to studying of the flow parameters in the downcomer, the bottom plenum of the nuclear reactor can be carried out with the help of CFD programs. The work is devoted to experimental researches in the field of pressurized water reactor with the purpose of creation of benchmarks for verification of domestic codes of computational hydrodynamics. Such data must have high spatial resolution, high resolution and high accuracy of the measurements. It makes necessary to apply complex experimental methodologies, measurement instrumentation and careful adjustment of experimental methodology. So, a brief description of the experimental stand and its research methodology is given. A spatial conductometric measuring system that allows studying the processes of turbulent mixing of flows in the complex geometry of the nuclear reactor is presented. The description of experimental research and their results are presented. Conclusions about the prospects of using spatial conductometry as a vortex-resolving measurement method are drawn.

Experimental study results of two parallel turbulent jets and a set of discrete jets evenly distributed over a circle are presented. Distributions of averaged velocities and their pulsations were obtained and analysed. It was shown that in the case of a discrete annular jet, the flow structure changes significantly, and the distribution of average velocities indicates the presence of the large-scale vortex structure on the jet axis.

A new concept of construction of integral relations for approximate solving problems on heat and mass transfer is proposed. This concept is based on the introduction of local functions for the heat flow or the temperature that are determined directly from the differential equation of heat conduction with boundary conditions at the temperature disturbance front. This made it possible to obtain a number of new efficient integral relations, mainly an improved integral relation for the temperature momentum and integrals of the square-law heat flow and the square-law temperature function. New schemes for optimization of the exponent n in the parabolic description of the temperature field with the use of the error norms E₁ and ${E}_{1}^{{\rm{L}}}$ introduced for the first time are proposed. In comparison with the Langford norm E_L (the scheme of T. Myers), the effectiveness of determining optimum parabolic solutions has been substantially increased. On the basis of the integral relations proposed in combination with the new schemes for minimizing an error, optimum solutions of simple parabolic form have been obtained with an error of 1.23% and an integral error E₁ = 0.0301. The solutions obtained are much better in approximation representation and error than the solutions obtained by known integral methods.

Formation pressure of mixed hydrogen + methane, hydrogen + ethane and hydrogen + propane hydrates can be controlled by the gas phase composition allowing these hydrates to be considered as promising hydrogen storage containers. At low methane (ethane) concentration in the gas phase, the hydrate of the cubic structure II is formed, and at the methane concentration exceeding 6 mol.% (1 mol.% for ethane) the cubic structure I is formed. The mass percentage of hydrogen in the hydrate phase depends on the second gas concentration in the gas phase as well as on the thermodynamic conditions of hydrate formation. At a low concentration of methane (ethane) in the gas phase, the mass percentage of hydrogen in the hydrate can reach 2.5 wt% at 250 K. The curves of the monovariant equilibrium "gas-hydrate-ice Ih" for double hydrates are calculated and found to be in agreement with the available experimental data. Thermodynamic properties of mentioned mixed hydrates allow to considering mixed hydrates as appropriate materials for hydrogen storage.

In the framework of this paper, an investigation of the vertical axisymmetric pipe filling with a viscous fluid against the gravity force is implemented. The fluid flow is described by Navier-Stokes and continuity equations. On the free surface, the shear stress is equal to zero and the normal stress is equal to the sum of external and capillary pressure. The free surface motion is defined by the kinematic condition. On the solid wall, the velocity is set to zero. At the inlet section, the Poiseuille profile is used. Along the symmetry axis, the symmetry condition is assigned. A numerical solution to the problem is obtained using the control volume method and SIMPLE algorithm. The method of invariants is applied for compliance of the natural boundary conditions on the free surface. The effect of dimensionless criteria on the steady-state shape of the free surface was parametrically studied.

Interaction between the rising vapor bubbles was investigated. The experiment was carried out in acetone under natural convection on a vertical heater 2.5 mm in diameter. Overheating of the heater surface before boiling-up varied from 30 to 120 degrees at saturation pressure from 20 to 40 kPa. Experiments have shown that the field of velocity and pressure behind a rising bubble has a strong influence on the growth dynamics of vapor bubble located below. This influence depends on the distance between the bubbles and growth phase of the upper bubble. When bubbles coalescence, high acceleration (100 m/s²) of particular parts of the interphase surface are observed. When the lower bubble coalescences with the upper bubble, the vapor spreads like a jet, and as a result, a conical perturbation is formed on the opposite side of the upper bubble.

The effect of static pressure on regularities of turbulent friction reduction by means of a bubble method at gas injection through a permeable wall has been experimentally studied in this work. The flat model (955 mm long) with gas saturation of the turbulent boundary layer was tested at the hydrodynamic setup of the Institute of Mechanics of Moscow State University within the ranges of flow velocity U = (4-11) m/s and static pressure P = (10-200) kPa. The Reynolds number along the plate varied within the range of (3 - 8)×10⁶. Tangential stresses on the plate surface (plate on bottom) were measured directly by the "floating wall" sensor on tensoscales, located at the distance of 50 mm behind the porous coating. This paper presents data on local friction on the plate vs. gas flow rate, flow velocity and static pressure. It is shown that reduction of local friction at gas saturation of a turbulent boundary layer depends essentially on the static pressure, which should be taken into account by integral evaluation of method's efficiency, considering energy losses for gas blowing through the permeable coating.

In the framework of the method for producing gas hydrates based on the self-organizing cyclic boiling-condensation process of a hydrate-forming gas in a water volume, a study was conducted aimed at determining the effect of the boiling intensity of liquefied gas in the water volume on the hydrate formation process.

Some options of coupling filtration models are suggested using irreversible state equations in differential form. State equations include explicitly the coefficient of compressibility, coefficients of concentration expansion and other physical properties affecting rheological properties and composition. To construct the models, the improvement of thermodynamic relations is used. New physical factors are introduced with the help of new thermodynamic variables. The chemical viscosity, pressure diffusion and concentration expansion phenomena are taken into account. The simplest particular problems illustrating the role of new effects are distinguished for stationary filtration regime. The revealed nonlinear effects can be important when considering biology liquid flows in porous biomaterials where deviations from classical laws are possible.

The simulation of air injection into a liquid (water, liquid lead) at large pressure drops (ΔP = 160 × 10⁵ Pa) has been carried out. A significant difference in the formation of the air volume during injection into water and liquid lead is demonstrated. The shape of the resulting air volume formed during injection into liquid lead is shown to depend on the nozzle diameter. It is established that the presence of interfacial heat transfer at short times does not affect the dynamics of the air jet outflow.

Experiments on obtaining Freon 134a gas hydrate were carried out by a method based on explosive boiling of a liquefied gas layer in the water volume during decompression. It is shown that this method combines several factors leading to an intensification of the hydrate formation process, which leads to a rapid growth of gas hydrates. The influence of the ratio of the initial mass of the gas to the initial mass of water in the vessel on the fraction of the gas hydrate in the resulting sample was studied experimentally.

This paper presents the results of mathematical modeling of liquid carbon dioxide injection into a porous reservoir of a finite length, initially saturated with methane and its hydrate. Calculations show that when forming the carbon dioxide hydrate, different situations are possible: an area is formed, saturated with water and methane; and such area is absent in a porous medium. It has been established that the main parameters determining the different hydrate formation regimes are the temperature and pressure of the injected carbon dioxide, as well as the reservoir permeability.

The work is devoted to the analysis of physical mechanisms of lifting a layer of granular material in the flow behind shock wave. Based on experimental data physical processes are considered behind a shock wave traveling above a dust layer, leading to its rise: the escape of single particles from the layer and the formation of an intermediate layer or fluidized bed between a dense layer and a suspension, the collision of particles in the fluidized bed and its ascent, the influence of a dense suspension on the flow behind the shock wave, and the effect of unsteady flow on the rise of the layer. A physical model of the process is proposed that allows predicting the rate and height of the rise of a layer of granular material at an early stage of interaction with the flow behind incident shock wave.

The processes of heat and mass transfer during cooling of heated sphere in the subcooled liquid are studied. When a heated solid surface is submerged in a liquid with a considerably lower saturation temperature, a vapor film can be formed around the heater. Using of non-equilibrium boundary conditions gives the possibility to solve this problem with taking into account peculiarities of the transport processes at the vapor–liquid interface. The Fourier thermal conductivity law is used for description of heat transport process in vapor film. The heat from external boundary of vapor film is removed through natural convection. Pressure balance is provided by hydrostatic pressure and non-equilibrium boundary condition. The obtained calculation results are compared with the previous calculation data and known experimental results.

The two-phase flow of the refrigerant in the condenser pipe of a vapor compression refrigerating plant is considered. The magnitude of the refrigeration coefficient depends directly on the efficiency of the condenser. To increase the heat transfer in the condenser pipe, it seems expedient to increase the length of the region of the annular regime of the coolant flow with a turbulent film, subjected to intense entrainment of liquid droplets into the gas core. Using Kutateldze-Sorokin and Baker flow regime maps, it is possible to reliably determine the state of a two-phase flow in a condenser tube, and to form certain regions of working fluid flow. The controller, temperature and pressure sensors system in the condenser pipe, and actuators can increase the cooling capacity of the installation in general from 8 to 11%, depending on the type of refrigerant.

The paper deals with the problem of numerical simulation of the modes of pulse air outflow into a vertical pipe, filled with liquids with different physical properties (water, ethanol, glycerol), implemented in the OpenFOAM software package. This problem has a wide range of technical applications, ranging from the modeling of emergency operation of the liquid-metal nuclear reactors to the depressurization of underwater pipelines, functioning of the shipboard technical systems, etc. For obtaining verification data visualization experiments were carried out. The results of numerical simulation and experimental data are in satisfactory agreement.

Motion and heat transfer of bubbles with liquid metal have been investigated in the present paper. Theoretical studies have been provided with help of modern numerical approaches and the HYDRA-IBRAE/LM code to simulate two-phase flows. Two-fluid model has been used in the presented code to calculate thermal hydraulic processes into two-phase liquid metal coolant. To close two-fluid model, the system of constitutive relation has been used. The brief description some of the constitutive relations has been presented in the current paper. For example, some features of the wall friction coefficient calculation have been discussed. Gas injection experiments and experimental investigations of the bubbles motion and heat transfer have been provided on a liquid metal test facility. Obtained results can help to receive new information about two-phase liquid metal flows. On the base of this information a validation of numerical codes, which are already have an industrial application, can be carried out.

An experimental setup has been created, and a laboratory sample of the pneumatic nozzle with a special design based on the use of the properties of cumulative jets, toroidal vortices and the Coanda effect has been tested. This nozzle may be used for dispersion of liquids and suspensions, in particular, coal-water slurry. The experimental setup allows obtaining a supersonic gas-droplet flow: with carrier phase velocity up to 500 m/s, at gas pressure up to 0.4 MPa, and liquid flow rate up to 500 kg/h. Shooting was used to determine a range of regime parameters, providing stable operation of the injector. Beyond this range, strong pulsations of the gas-droplet flow were observed. It has been established that in this range of modes the operating angle of a gas-droplet jet weakly depends on the liquid flow rate and gas pressure. The developed experimental and methodical base allows further measuring the dispersed composition of the generated gas-droplet flow with a view of optimizing the operation modes of the injector.

Conjugated heat and mass transfer during nonisothermal absorption on a liquid film, flowing over nonuniformly cooled wall under the action of gas flow, is numerically investigated in this paper. The intensity of the tangential stress and that of the wall cooling were varied. The absorption efficiency was determined by the conjugation of two factors: the intensity of heat removal and the action of shear stress.

The use of modern structured packing in the distillation columns allows much more even distribution of the liquid film over the packing surface, but it does not completely solve the problem of uniform distribution of flow parameters over the entire height of the packing. Negative stratification of vapor along the packing height caused by different densities of vapor mixture components and higher temperature in the lower part of the column leads to formation of large-scale maldistributions of temperature and mixture composition over the column cross-section even under the conditions of uniform irrigation of packing with liquid. This work presents the experimental results obtained at periodic packing irrigation with total blocking of the spray nozzle. The experiments were carried out in the distillation column with the diameter of 0.6 m on 10 layers of the Sulzer 500X packing with the total height of 2.2 m. The mixture of R-21 and R-114 was used as the working liquid. To irrigate the packing, the liquid distributor with 123 independently controlled solenoid valves overlapping the holes with the diameter of 3.6 mm, specially designed by the authors, was used. Response of the column to the action of liquid distributor was observed in real time according to indications of 3 groups of thermometers mounted in 3 different cross-sections of the column. The flow meter located at a fixed point of the column cross-section allowed registration of dynamics of a change in the local flow rate density of liquid flowing from the packing.

The thermo-hydrodynamic processes, preceding and accompanying the crisis of the film boiling regime of subcooled water on superheated liquid metal and solid surfaces, were studied by physical modeling. The main models of liquid-metal droplet fragmentation are analyzed. Experiments with liquid metal droplets have been carried out. The results of the experiments indicate a significant dependence of the shape of the fragments formed on the melt temperature, which confirms the assumption of different mechanisms of their fragmentation. It was also found that when the steel droplets are heated in air, intensive sparking is observed, which prevents explosive fragmentation of the melt. It was found that the film boiling regimes of subcooled water on liquid metal drops and metal spheres differ in the cooling rate of heated bodies (for liquid metal drops it is much higher). In experiments with solid metal samples, the process of contact of water with a hot (170-620°C) surface was studied in detail using a conductometric technique. The results of measurements of oscillograms of the electric current in the regimes of film, transition, and bubble boiling are presented and their amplitude-frequency characteristics are investigated with the help of wavelet analysis. It is established that the contact between the cooler and the hot surface is preceded by a short (several millisecond) process, characterized by intense generation of waves at the vapor-liquid interface. The physical nature of waves developing on the phase surface in the film boiling regime and contributing to the pulsation of the electric current is discussed.

The Rayleigh–Taylor instability, complicated by heat and mass transfer, is studied for a thin vapor film covering the horizontal surface of a flat heater, which is immersed in a subcooled volume of liquid. A correction to the nonlinear inviscid model of the instability suppression by a phase transition is proposed. It is based on the fact that, at finite Prandtl numbers, the strength of the phase transition effect can have the limitation described before for the linear problem. It is shown that the nonlinearity alone, without taking the viscosity into account, is able to stabilize the thin vapor film, but only for the situations when the convective heat exchange in the liquid obeys the Newton–Richman law.

The experiments on film boiling of superfluid helium (He-II) on the surface of a cylindrical heater inside a cylindrical porous shell are considered in this paper. The methodology and results obtained in a number of experiments, in particular, video footage of the boiling process is presented. The conclusions about the influence of the experimental cell structure on the character of boiling regimes, namely on the shape of the vapour film around the heater and its integrity are drawn. In the constrained conditions only the boiling with "open" film was implemented. While the noise film boiling with closed vapor film and boiling with "open" film were observed when the glasses on the end caps of the porous shell were removed.

The influence of a modulated traveling magnetic field on the process of crystallization of a liquid conducting medium is experimentally investigated. The crystallization process is carried out in a vertical cell with a constant temperature difference between the narrow walls of the layer. A traveling magnetic field produced by a linear inductor generates a vortex flow in the medium. This flow leads to redistribution of temperature and change in the position of the crystallization front. Low-frequency modulation of the traveling field leads to generation of significantly pulsating flow. This has a positive effect on the stirring efficiency of the medium. In addition, the flow smoothes the crystallization front, reducing the speed of its movement.

The paper presents a physical and mathematical model of nonstationary sublimation of single spherical particles of volatile chromium (III) and zirconium (IV) β-diketonates, floating in the flow of a binary argon-helium mixture in a reactor with cold walls. The influence of the carrier gas composition and radiative heat transfer on the kinetics of sublimation has been analyzed. The addition of helium to the carrier gas is shown to increase the intensity of sublimation. The cold walls of reactors decrease the temperature of a particle and increase the time of its sublimation due to the radiative cooling.

The paper deals with the analysis of the structural and phase content of the laser welded joints and basic alloy 1424 of the system Al-Mg-Li by electronic microscopy and X-ray analysis. The total comparative investigation has been carried out to evaluate the influence of the thermal processing such as quenching and artificial ageing on the mechanical properties and structure of welded joints and basic alloy. The investigation shows that the welded joint structure is dendritic. In the welded joint, the two-phase state of the solid solution is observed after the re-melting (α-Al+S1(Al2MgLi)), the strengthening phase δ'(Al3Li) is diluted. The thermal processing (quenching and artificial ageing) of the welded joint (alloy 1424) results in the increased tensile strength of up to 0.95 of the basic alloy strength.

Experimental studies of evaporation of water droplets lying on hydrophobic surfaces were carried out using non-contact measurement methods. The behavior of a contact angle and contact spot size was investigated using high-speed micro photography. The dynamics of the change in an average temperature of the surface of evaporating droplets was studied by the method of infrared thermography. For a theoretical study of the evaporation of liquid droplets, the previously developed emission-diffusion model, which takes into account the influence of the contact angle on the droplet evaporation rate, was used. The results of computations and experiments were compared and satisfactory agreement was obtained.

The dynamics of the geometric parameters of droplets of a water-ethanol solution suspended on polypropylene filaments was investigated using high-speed microphotography. It was found that all suspended droplets had a spherical shape during the main time of evaporation. The higher the concentration of ethanol in the drop, the faster the droplet evaporates. The dynamics of the temperature of droplets of a water-ethanol solution suspended on polypropylene filaments was investigated using the method of infrared thermography. Three stages of temperature change of evaporating droplets of a water-ethanol solution were found. At the initial stage of evaporation, the droplet temperature changed like the temperature of an ethanol droplet, and then its behavior was similar to the temperature change of water droplets. The higher was the ethanol concentration in the droplet, the more similar was the temperature change with a change in the ethanol droplet temperature.

The paper shows the results of studying the effect of structures formed on the metal surface during laser, plasma, ion and electronic treatment by Leidenfrost temperature value. A description of the experimental unit and the measurement procedure is given. Also in the course of the study limiting wetting angle and roughness parameter were measured.

Silicon oxide (SiO_x, × ≤2) nanowires were synthesized on indium (In) catalyst particles by gas-jet electron beam plasma-enhanced chemical vapor deposition through the vapor-liquid-solid (VLS) mechanism. The synthesis was carried out on substrates of different average particle sizes in the range from 42 to 710 nm. Arrays of oriented microropes of nanowires were grown on catalysts with a particle size of 42 and 79 nm. On 170 nm catalyst particles, cocoon-like structures from nanowires were formed, and on 710 nm particles, the synthesis proceeded in the same way as on an indium tin oxide (ITO) film. The chemical composition of the synthesized nanostructures was studied by Fourier transform infrared spectroscopy. Under the assumption of a uniform distribution of silicon and oxygen atoms, the nanowires were found to consist of SiOx with x = 1.9. Energy dispersive spectroscopy showed that the catalyst particles consisted of non-stoichiometric indium oxide, rather than of pure indium. Therefore, during the synthesis of silicon oxide nanowires on an indium catalyst, hydrogen should be used.

New experimental data on superheated water atomization are presented. It is shown that the new nozzle design with expanding relatively long duct provides droplet size distributions which differs much from those in the case of short conic nozzles (at the same inlet temperatures). Mass fraction of submicron mode is significantly greater – up to practically mono- modal submicron distribution. The new method of result data treatment is proposed. According to it the submicron mass fraction is function of dimensionless parameter, which is the vapor clusters surface tension ratio to chemical potential of "explosive" phase transformation.

This paper by the example of spent automobile transmission oil investigates the combustion of sub-standard liquid hydrocarbons in a straight-flow burner, implementing a promising method of liquid fuel dispersion by a superheated steam jet. The aim of the work is to study the influence of regime parameters on the thermal and environmental characteristics of the combustion process. Gas composition of combustion and heat release products was measured. A flow calorimeter was used to measure heat release. The measurement of the amount of generated heat was based on determining the coolant temperature difference at the inlet and outlet as well as the flow rate of the coolant and fuel under stationary experimental conditions. TESTO 350 gas analyzer was used to control the composition of gaseous combustion products. Sampling of reaction products cooled to room temperature was carried out at the calorimeter output. Dependences of specific heat release on steam and fuel flow rates have been obtained. The regimes with low CO content in the combustion products have been found.

The simulation of a cellular detonation wave propagating along a hydrogen-air mixture with a cloud of alumina microparticles was carried out. The gas dynamics was modeled by the system of Navier-Stokes equations describing the motion of a viscous compressible heat-conducting gas, with allowance for multicomponent nature of the gas mixture and chemical kinetics. A methodology has been developed for calculating detonation currents in ANSYS Fluent using the reduced kinetics. The reduced kinetics was verified by the size of the detonation cell. The interaction with inert particles with a diameter of 0.3÷100 μm and volume fraction of 10⁻⁴÷10⁻² was investigated using a continuum approach. Values of the volume fraction resulting in a change of the detonation cell size, weakening of the detonation wave, and detonation suppression have been obtained.

The development of new promising technologies based on coal fuel is certainly topical. This article is devoted to application of new technology of gas and fuel oil replacement by mechanically activated micronized coal in power engineering: ignition and stabilization of pulverized coal flame combustion. Enhancement of coal reactivity at its grinding with mechanical activation is associated with an increase in the reaction rate of carbon material. The process of combustion was studied on the 1-MW setup with tangential scroll supply of pulverized coal-air mixture and cylindrical reaction chamber. Experiments were carried out by using brown coals. Coal, ground by the standard boiler mill, was fed to the input of high-energy mills and then was directed to the scroll inlet of the burner-reactor with the transport air. The suspension was ignited by a gas igniting device with the power of 50 kW. Experimental studies on air gasification of micronized coal were conducted in the reaction chamber at the temperature of 1000-1200 °C and air excess ratio α = 0.5. Intensive mechanical activation of coals led to increase the chemical activeness. This effect can be used for development of new highly boosted processing methods for coals with various levels of metamorphism. The obtained results of visualization were used to train the state-of-art deep convolutional neural network. It was shown that the developed neural network was able to automatically determine the combustion regimes from flame images.

Results of experimental investigations in a flow-type annular cylindrical combustor with an outer diameter d_c = 503 mm are reported. The influence of air addition to products of continuous spin detonation of a CH₄ + 8H₂ - air mixture on detonation wave parameters, pressures in the combustor, and specific impulse is studied. The range of existence of continuous spin detonation in terms of the specific flow rate of the mixture through the combustor cross section is extended to 1360 kg/(s·m²), whereas the equivalence ratio is reduced to φ_∑ = 0.4. It is shown that addition of air to detonation products up to the level of the air flow rate in the main injection system increases the velocity of continuous spin detonation, pressure in the combustor, and thrust, whereas the specific flow rate of the fuel decreases.

The influence of aluminum on the detonation and electrical characteristics of an explosive has been studied experimentally. Comparison of the data obtained by different methods allowed us to formulate conclusions about the course of the chemical reaction of the emulsion explosive with aluminum.

Results of experimental research of thermal decomposition of composite fuels based on 2B brown coal (Borodinskoe deposit) and wastes of timber industry (finely dispersed wood) are presented. Elemental composition of researched fuels has been defined and technically analyzed. Kinetic constants have been calculated within Arrhenius model of the first order. It has been determined that with an increase of wood concentration up to 50% in composite fuel, its energy characteristics decrease by less than 2%, the maximum temperature of fuel thermal decomposition reduces by 9%, while SO_x and NO_x yield reduces by 50%, and fly ash – by 75%. An effective composite fuel composition of 50%/50% has been established. Results of performed experimental studies illustrate possible applications of composite fuels based on brown coal and wood at thermal power plants.

Thermal decomposition of ammonium nitrate (NH₄NO₃) containing 5% (by weight) of catalytic additives in the form of metal oxides (NiO, CuO, Co₂O₃) has been studied. The experiment was performed by thermogravimetric analysis at a heating rate of 5°C/min to a maximum temperature of 800°C in argon atmosphere. Based on the results of DTA, physical and kinetic characteristics of thermal decomposition we analytically assessed. The addition of catalytic agents was found to lead to a decrease of onset temperature of active NH₄NO₃ decomposition, which promotes the reaction shift to the low-temperature region. The effect of the initiation additive manifested in a significant reduction of sample residence time within preheating stage (Δt_i = 5.2 min). In presence of catalytic additives the total time of thermal decomposition t_f was found to decrease. The greatest change of Δt_f (2.8 minutes) was recorded for the sample modified by addition of Co₃O₄. The maximum decrease of the average activation energy (for decomposition of 5%Co₃O₄/NH₄NO₃) was 14.2 kJ/mol.

Thermal sustainability of zinc oxide was studied. Experiments were conducted in atmosphere of syngas components. Thermogravimetrical analysis was used as the main method of investigation. Zinc oxide based sorbents were tested in methane, hydrogen, carbon and hydrogen sulphide atmospheres. Experimental data has shown intensification of reactions between zinc oxide and methane, hydrogen and carbon in temperature range from 650 to 800 °C and zinc evaporation and sorbent chemical destruction. Experiments did not reveal significant change of rate constant of reaction between zinc oxide and hydrogen sulphide. Ten probable reactions were numerically analysed. Equilibrium constants were calculated for all ten reactions. The temperature influence on equilibrium constants were calculated. Some elements of hot gas clean up desulfurization unit simulation model were also presented. Experimental rate constants for both four reactions were used in the model. Outlet gas composition and efficiency factor were calculated. Sorbent mass flow was determined. Recommended temperature range was identified.

This paper represents a study of thermal characteristics for the flame of a liquid-fuel vaporizing burner during diesel fuel combustion in a high-temperature air jet, using the IR thermography. A thermal imaging camera FLIR (JADE J530SB) was used in the experiments. The studies carried out for different operating parameters have revealed the dependence of the effective flame emission coefficient on the air flow rate. The influence of the air flow rate on the temperature of external flame of the burner has been found. Comparison of the results was conducted for combustion in an air jet and in a jet of superheated steam.

In this paper, we investigate the effect of mechanically activated coal grinding by two different methods - determination of the flash time in a vertical tubular furnace and thermogravimetric analysis. In the experiments, the coals processed in a disintegrator and initial coal were compared. The experiments have shown a decrease in the ignition temperature of mechanically activated coals, as well as the effect of mechanical activation on further thermal-oxidative degradation.

The influence of the method for determining the specific heat coefficient on the processes of aluminium melting and propagation of heterogeneous detonation in a mixture of gas and ultrafine aluminum particles is analyzed. Melting process is described within the phenomenological approach for particles with a radius of 6 and 15 nm. An insignificant effect of the relation between the heat capacity and the particle temperature and radius on melting time and temperature distribution inside the particle has been established. The detonation process is studied for stoichiometric suspensions of 50-nm and 1-µm aluminum particles, taking into account the transition from diffusion to kinetic regime of combustion with decreasing particle size. An insignificant influence of the specific heat coefficient representations on the results of detonation structure calculations is established for nanoparticles. For micron aluminum particle suspensions, the 20% difference in the Chapman-Jouguet pressure has been obtained.

Oxidation of brown coal containing 5% by weight of (Cu(NO₃)₂) initiation additive has been studied. The experiment was conducted using thermogravimetric analysis at a heating rate of 2.5°C/min up to a maximum temperature of 600°C in air. Based on DTA results, the oxidation characteristics were analytically evaluated. It has been discovered that addition of (Cu(NO₃)₂) initiation agent leads to a significant decrease of initial temperature of oxidation, which serves to shift the reaction to the low-temperature region. The effect of the initiation additive also manifested in significant reduction of sample residence time within sublimation of volatile compounds. Mass-spectrometric analysis has revealed the presence of NO_x (intense peak at 180°C) in oxidation products of the modified sample, which is explained by decomposition of copper nitrate. SEM results for the coal partially oxidized in the muffle furnace indicate significant change of surface and internal structure of the modified sample particles.

This paper considers development of the model of wood pyrolysis in a screw reactor as the first stage of the multistage gasification process. To prevent clinkering of particles and thermal inhomogeneities, screw-type transportation is used to transport fuel. In order to describe kinetics of pyrolysis and transport of volatiles within the wood particles and their transition to the gas phase, we carried out the studies using a complex of synchronous thermal analysis. A detailed numerical modeling of pyrolyzer was performed with the use of Comsol Multiphysics Software, which enables optimizing the design and operating parameters of the pyrolysis process in a screw reactor.

Influence of the granule size and composition on methane hydrate decay was studied experimentally. It was shown that the maximum dissociation rate is achieved for the granule diameter of 0.1 mm and for the uniform powder composition. The dissociation was realized at negative temperatures and in the region of "self-preservation". The granules dissociation rate decreased significantly with increasing the powder layer thickness from 1 mm to 30 mm. It was demonstrated that the nonuniform distribution of granules and the thick layer leads to a decrease in the methane hydrate dissociation and to different kinetic dissociation curves.

An effective sorbent is activated carbon having a developed nanoporous structure with an average pore diameter about 2-4 nm. Perspective method of activated carbon production is the partial steam conversion of the coal bed in boiler furnaces of power plants. The additional thermal energy is produced by burning the syngas. The aim of this work is to study the co-production of activated carbon and syngas by partial steam-air conversion of charcoal. Due to the presence of oxygen in the flow, intensification of conversion occurs. In the laboratory bed reactor, the mass loss curves and the syngas composition were obtained at temperatures of 800°C and 900°C. Two zones with different reaction mechanisms were identified on the height of the bed. The reactions between carbon and steam shift toward hydrogen formation in the oxygen zone. The dependence of the porous structure of the activated carbon on the conversion degree of the raw material is obtained. The maximum of micropores is formed at a conversion degree of 0.5. The material and energy balance of the partial conversion in the laboratory reactor was estimated.

The gas products yield for the thermal decomposition of coal-bitumen composite materials was experimentally studied. The effect of temperature change on the product distribution was investigated using FTIR spectroscopy. The influence of atmosphere composition on the release of different gaseous products was analysed at different temperatures.

The results of experimental study concerning a continuous spin detonation of hydrogen-oxygen mixture in a flow-through plane-radial combustor with a diameter of 10 cm and with exhaustion toward the periphery in the regime of oxygen ejection are presented. In the experiment, the regimes of continuous spin detonation with one and two transverse detonation waves rotating with velocity D = 1.3÷1.43 and 1.45÷1.54 km/s, measured relative to the inner cylindrical surface of the combustor, respectively, and two near-sonic waves rotating with velocities of about 0.7 km/s have been observed. The waves of pulse combustion with frequencies of 4.4 – 3.6 kHz have been found for the first time. The structure of waves and flow in their vicinity has been studied.

The influence of two different methods of kinetic analysis on obtained values of kinetic constants of coal oxidation process was studied. The oxidation of T-grade bituminous coal of Kuznetskiy deposit and 2B-grade lignite of Borodinskoe deposit was investigated by means of thermogravimetric analysis. All measurements were carried out with heating rates 2,5, 10, 25 and 40 K/min in temperature range 300-1100 K in air medium. The dependences of activation energy and frequency factor on conversion were obtained using two isoconversional methods: differential method of Freidman and integral method of Kissinger-Akahira-Sunose. The average values of activation energy which were obtained by KAS method were higher by 14.5 % for bituminous coal and 23.3 % for lignite in comparison with values obtained by Freidman method. The same relations were observed for frequency factor values.

The article presents the results of experimental studies of thermal processes in combustion and evaporation chambers of an experimental hydrogen-oxygen steam generator with a thermal capacity up to 25 MW developed at the Joint Institute for High Temperatures of the Russian Academy of Sciences (JIHT RAS). The studies have shown that the design of the mixing element has a significant effect on the heat fluxes in the combustion chamber. The effect of several designs on heat fluxes near the fire wall and on the completeness of the combustion of hydrogen in oxygen have been investigated experimentally. The result of experimental study of thermal processes in a hydrogen-oxygen-steam generator with a thermal capacity of up to 25 MW allowed estimating the real heat fluxes and correction factors for the calculations.

The flow structure for various detonation regimes is numerically studied in a new flow-type supersonic annular detonation combustor. In the combustor with a new design, detonation burning of the reacting mixture is organized by using a compression body, shaped as a continuous monofilar helix with a constant pitch angle. Numerical simulations are performed for a supersonic flow of a stoichiometric hydrogen-air mixture with Mach number M₀ = 3 at the combustor entrance. A mathematical model of the reacting flow in the combustor is developed in a two-dimensional unsteady formulation. The flow dynamics at the beginning of combustor operation and the structure of the steady flow in the combustor are numerically studied. Simulations are performed for various helix angles and combustor sizes. A bifurcation of the steady flow structures with respect to the initial conditions of combustor operations is detected for some combinations of the geometric parameters of the combustor.

The problem of detonation propagrtion in channels with linear expansion filled with nano-sized alumunium mixture dispersed in oxigen was investigated. Transition from diffusion to kinetic regime of combustion with variation of the activation energy was taken into account in the description of the chemical reactions. Specific features of detonation failing in subcritical regimes and propagation in critical regimes have been revealed. The detonation propagation was found to be more unstable then in microdisperse aluminum suspensions.

The paper presents the results of studies of conversion process on the laboratory pyrolysis reactor and the results are compared with data, obtained in model experiments by thermogravimetric analysis (TGA). The heating rates were compared in the pyrolysis reactor and in the laboratory furnace of TGA in the pyrolysis process of wood biomass conversion. The laboratory pyrolysis reactor, as a part of the multistage gasification facility of low-grade solid fuel, was launched in several modes. Three experimental modes of the device operation with different screw speeds and fuel flow rates through the reaction shaft were tested. The temperature profile of fuel and wall along the length of the pyrolysis reactor was shown. The temperature up to 600 °C was recorded in a mode with a low fuel flow rate, and in the end of the reaction zone the fuel temperature was close to that of the wall. The kinetic coefficients and conversion rates for the wood biomass pyrolysis were calculated from the obtained equation. Therefore, the calculated data of the conversion rate and the pyrolysis parameters, based on the TGA data, can be used to further develop the pyrolysis reactor and evaluate the parameters of its operation.

Experimental studies of ignition delay time for mixtures of dispersed hard coal of two types and milled wood over a wide temperature range have been performed. Time of total completion of organic part pyrolysis of both components at different concentrations have been established in order to assess the prospects for such fuels application in large- and small-scale power engineering (combustion in boiler furnaces of different capacities). It has been established that simultaneous thermal decomposition of mixture of coal and wood particles leads to a significant change of pyrolysis temperature range and release of anthropogenic gases (sulfur and nitrogen oxides) in case of high-temperature heating of the mixture based on lean coal. The same effect, but in much smaller scale, has been recorded for a mixture based on long-flame coal. A hypothesis has been formulated on the mechanism of sulfur and nitrogen oxides precipitation during thermal decomposition of the mixture of lean coal and wood particles as a result of interaction between transitory gaseous and solid pyrolysis products of coal and wood in the temperature range up to 1000°C. Prospects of applying the milled coal and wood mixtures as fuel for steam and hot water boilers have been substantiated. With a small decrease of energy characteristics of such fuels, compared to homogeneous coals, significant improvement of ecological and economic characteristics of the fuel combustion processes can be achieved. It has been shown that vital synergistic effect of co-combustion of coal and wood particles is achieved only with certain coals.

We have numerically solved the spark ignition problem of aluminum-air suspension. The aim of the research was to determine the critical ignition conditions for an aluminum powder depending on the size and mass concentration of the particles. According to the obtained result an increase in the particle size leads to an increase in the minimum energy which is required to ignite the suspension and make it possible the combustion front to propagate. With an increase in the mass concentration of the particles and under the excess oxidant ratio close to unity the minimum energy of the spark ignition tends to the same value and becomes independent on the mass concentration of the particles.

The solutions to a divergent system of equations were studied numerically for a freely flowing fluid film. Various families of steady-state traveling solutions in a wide range of wave numbers were found. The shapes of the fluid film surface corresponding to these solutions are given. Specific ranges of parameter values, where re-closing of different families occurs, were determined. It is shown that they are the singular points of the saddle type.

Ozone is a gas in demand in industry and medicine. The issue of its storage is acute so far and is connected with the search for the most suitable second guest gas enhancing ozone storage. This paper is devoted to the study of the stability of the SI and SII cage structures in the presence of a mixture of ozone and argon using the density function method. Carried out modeling allowed finding stable molecular structures and determining the thermodynamic conditions of hydrate stability for the O₃ + Ar gas mixture. In addition the electron density distribution and stabilization energies were calculated that could be useful in experimental investigation.

We performed Large-eddy simulations (LES) of the flow around a low-aspect-ratio wall-bounded 2D hydrofoil at the zero angle of attack using spectral-element method (SEM). The flow was considered for several Reynolds numbers Re_C = 500, 5.0 × 10³, 5.0 × 10⁴ and 1.2 × 10⁶ based on the foil chord to reveal the influence of the test channel sidewalls and viscous effects. The laminar-turbulent transition of the boundary layer was registered. A comparison of the numerical results with experimental data for the highest Reynolds number was performed and showed an excellent agreement.

The thermodynamic properties of the carbon dioxide clathrate hydrate as well as hexagonal ice Ih have been calculated using Quasiharmonic Lattice Dynamic framework in connection with Molecular Dynamic methods in order to show the existence of the self-preservation effect in the carbon dioxide hydrates. The statistical thermodynamics theory has been applied to calculate the thermal expansion coefficients for hydrate and ice systems. The calculations clearly show that because the thermal expansion of the hydrate phase is limited by the thermal expansion of ice it is possible to keep the hydrate in a stable region within the phase diagram. The differences in thermal expansion should lead to the self-preservation effect with the application of additional pressure on the hydrate phase. This effect allows using the self-preservation effect for the storage and transportation of gas in the hydrate form.

The method of constructing a hydrodynamic model of a large river is described in the work using the example of a section of the Volga River south of the Volzhskaya HPP. The construction of reliable hydrodynamic models of real river systems requires actual digital elevation models (DEM). Natural changes in the characteristics of river bed with time require updating and subsequent verification of DEM. We consider 100-kilometers section of the Volga River south of the Volzhskaya HPP, which determines the hydrological regime of the entire Volga-Akhtuba floodplain (VAF) right up to the Caspian Sea. The algorithm for constructing the DEM of bottom topography, based on a comparative analysis of the results of numerical hydrodynamic modeling and data on the dynamics of water levels at gauging stations, is proposed. In order to reconcile the changes in the water level H(t) in the numerical hydrodynamic model with the observed dependence, we vary the characteristics of the local sectors of the bottom.

A specialized numerical model of the heat transfer process in a vacuum electric furnace is described. The model is based on neglecting factors weakly affecting the main technological processes, on development of specialized methods of the mesh construction, and on usage of effective algorithms of the radiative heat transfer calculation. A specialized mathematical model of the electric furnace allows reduction of the mesh size about three times in comparison with the initial model.

Based on numerical experiments we investigate 2D flow of a weakly conductive inviscid compressible medium under the influence of the periodic external force. Direct numerical simulation using Euler equations allows you to simulate periodic vortex structures in the flow, which are similar to the mode of «parquet» in the Kolmogorov's flow [1].

The contribution covers results of direct numerical simulation of transitional processes and turbulence developing in the vertical-plate free convection boundary layer downstream of a periodic row of 3D obstacles. The Prandtl number is set at 0.7. Periodicity conditions are prescribed in the spanwise direction. Steamwise position of the obstacles being spanwise-elongated rectangular parallelepipeds corresponds either to the local Rayleigh number, Ra_x equal to 10⁹ or to Ra_x = 2.5·10⁸ . In the first (basic) case, 3D vortex structures of a wide spectrum start to develop at a relatively short distance from the obstacles. The largest-in-size vortices, occupying the outer part of the layer, have a hairpin-like shape, and their heads are oriented opposite to the main flow direction. Steamwise evolution of the transitional and turbulent flow structure is analysed based on iso-surfaces of the Q-criterion covering the flow region up to Ra_x = 2.6·10¹⁰. The predicted mean Nusselt number dependence on Ra_x is in a good agreement with the known measurement data, both for the transitional and the turbulent flow regions. For the second case, nonlinear spatial development of a nearly 2D instability wave occupying a large portion of the computational domain is predicted. Rapid destruction of this wave and occurrence of chaotic 3D eddies are observed in this case at Ra_x = 3 • 10⁹.

A new approach to the construction of computational algorithms for atmospheric and ocean dynamics problems is considered. The approach is based on the integral form of recording the laws of conservation of mass and angular momentum, geodetic grids with quadrangular cells and the cabaret scheme guaranteeing the absence of computational dissipation in flows in which the characteristics of one family are not crossed. The quality of the new algorithm is demonstrated on test and model problems.

Numerous papers are devoted to the problem of irradiating thin films on the substrate for surface nano-modification. But all of them concern the dynamics of the dynamics, paying almost no attention to substrate just as object of the first shockwave absorption. A different point of view with an emphasis on the dynamics of a substrate is presented. Under powerful laser action upon a thin metal film a hole arises. Its radius depends on the absorbed laser energy. Experimental results, quantitative theoretical model and numerical research are presented and show that the hole formation is influenced by propagation of the shock wave in the substrate, but not in the film itself. Four stages are considered. (i) Shockwave generation in a support because of an impact of a contact. (ii) Transition from one-dimensional to two-dimensional propagation of the shockwave. (iii) Lateral propagation of the shockwave along a film-support contact. And (iv) calculating pressure in the compressed layer behind the decaying shockwave. This positive pressure acting from substrate on the film accelerates the film in direction to vacuum. Above some threshold, velocity of accelerated film is enough to separate the film from support. In these cases the circle of separation is significantly wider than the focal laser spot on film surface.

The paper presents the results of using the PTV method to study the motion of the liquid phase in the interblade channel of the turbine blade cascade in a wet steam flow. A method for processing vector fields of a polydisperse droplet flow is developed on the basis of machine learning algorithms (namely, the Bayesian Gaussian Mixture Data Modeling and the Kernel Density Algorithm). Using the PTV method together with these algorithms makes it possible to study complex polydisperse wet steam flows in more detail. On the basis of this, characteristic droplet streams and their trajectories are determined in the interblade channel of the turbine blade cascad.

As an auxiliary apparatus for calculations, the geometric radiation factors for the spiral are presented. The gas-phase deposition method using the thermal activation (Hot-Wire Chemical Vapor Deposition (HWCVD)) of precursor gases is widely used for the synthesis of diamond structures. The gas-jet modification of this method consists in activation of hydrogen and methane flows through a heated cylindrical channel and a spiral of tungsten [1, 2]. A peculiarity of this approach is the use of heterogeneous dissociation processes that occur during multiple collisions of molecules with a hot surface. This allows a significant increase in the dissociation of hydrogen. Tungsten is widely used in the deposition of diamond-like structures from mixtures of carbon-containing gases with hydrogen, both as a heating element, and as a catalyst for the dissociation of hydrogen [3].

The paper describes the method of restoring heat flux values on the surface of high-temperature nickel ball 45 mm in diameter at process of its intensive cooling by water in 1D and 2D formulation.

We have considered the features of the supersonic underexpanded flows formation under conditions of developed condensation, as well as measurements in such jets by electron-beam and molecular-beam methods. It is shown that under the conditions of large clusters formation both the geometry and the structure of supersonic jets may change. It is determined that the use of a mass-analyzer for recording monomers and clusters in a molecular beam has a number of peculiarities caused by the molecular beam formation from a jet containing large clusters. A method of mass spectrometry of clustered flows during the ionization of gases in a jet before the formation of a molecular beam is proposed. The features of this method are illustrated.

Turbulent characteristics have been measured in the near wake of a circular cylinder in a cross flow. Smoke Image Velocimetry (SIV) technique has been employed yielding the dynamics of velocity vector fields with high spatial and temporal resolution. Profiles of turbulent statistics have been plotted for some representative locations of the cylinder near wake. The SIV measurements have been compared with experimental and numerical results obtained by other authors.

The study aims at an experimental estimation of turbulent diffusion transport of Reynolds stresses in a developed turbulent zero-gradient boundary layer. Estimates were derived from dynamics of two-component instantaneous velocity vector fields measured by an Smoke Image Velocimetry (SIV) optical method. The obtained profiles were compared with DNS results at a similar value of Re_τ.

This paper provides results of measuring the conductivity of explosives pentaerythritol tetranitrate and trinitrotoluene composites containing single-walled carbon nanotubes. The conductivity depends on the applied voltage nonlineary and irreversibly changes under the influence of current loads about several amperes for milliseconds.

The method of producing nanopowders of Si and SiC by pyrolysis of a silicon-hydrocarbon mixture by compression in a cyclic process in a flow reactor is proposed and implemented. The obtained powders are characterized by X-ray diffraction and transmission electron microscopy. The new design solutions and use of ceramic coatings obtained by applying microarc oxidation for the piston-cylinder assembly – a compression unit of the reactor - allowed avoiding the use of compression rings and lubricants, achieving a high compression ratio and pressure and temperature in the reactor needed for monosilane pyrolysis. Pyrolysis in the flow reactor is convenient, technological and efficient in terms of its use in the production of high purity nanopowders.

The work is devoted to the study of thermophysical properties, elemental and technical composition of brown coal of the Talovskoe deposit in Siberia. This kind of coal can be used as power fuel for thermal power plants, boilers, etc. However, according to the preliminary analysis, this type of fuel requires additional processing, namely activation, drying, crushing, enrichment, removing toxic impurities, etc. From the available known methods of coal processing, one of the most promising and innovative technology may be exposure of coal to microwave radiation. With this treatment, intense drying of the material, grinding, yield of nitrogen, sulfur and other toxic components during processing takes place. This significantly increases the energy efficiency and environmental friendliness of the further use, of the final product processed in this way. Design and efficient engineering systems for heating, drying, grinding and using microwave energy requires a more in-depth information about the parameters of this type of coal and the changes in the course of technological processes. This work aimes at finding and studying such regularities for brown coal of the Talovskoye field.

The process of elastoplastic deformation is considered for materials whose symmetry of elastic properties is modeled by means of five or more independent elastic constants. In the simulation of shock loading of a zinc single crystal characterized by a transversal isotropy of elastic and plastic properties, it was assumed that there is no volume isotropy of compressibility. Different equations of state are applied in a three-dimensional arrangement in the condition of plastic deformation in the direction of each axis. They reflect the relationship of hydrostatic stress to the degree of compression of the material. It is shown that the application of various equations of state changes the propagation velocity of volume waves and introduces a change in the wave pattern of deformation in anisotropic materials.

The results of experimental studies of the thermophysical properties (density and kinematic viscosity) of boric acid solutions in the concentration range of 2.5-400 g/kg H₂O at a temperature of 289-403 K is considered in the paper. The problem of boric acid accumulation and crystallization in case of the accidents with main coolant circuit rupture and operation of passive safety systems (the hydroaccumulators systems of the first, second and third stages, as well as the passive heat removal system) is formulated. The review of the available literature data about thermal physical properties of the boric acid solutions is presented. The fact that available data are of a general nature and do not cover the entire parameters range specific for the possible accidents at NPP with WWER is established. The methods of experimental research are described. Two stages of experimental studies of boric acid solutions density are presented: measurements at atmospheric pressure and at parameters typical of NPPs with WWER emergency modes. A description of the test facility used to the density measurements of highly concentrated boric acid solutions is presented. Experimental values of the kinematic viscosity of boric acid solutions in the concentration range of 2.5-200 g/kg H₂O at a temperature of 289-363 K are obtained by capillary viscosimetry method. The approximating dependences for the density and kinematic viscosity experimental values of the boric acid aqueous solutions are obtained.

The paper presents the structural mathematical model of thermal conductivity of radial layered circular and ring composite plates. An analytical solution method is proposed for specified plates. The method is based on finite integral transform method.

High reaction heat of an interaction between intermetallic compounds and hydrogen along with low thermal conductivity of fine dispersed metal hydride powders lead to crisis phenomena in metal hydride hydrogen storage facilities. Thus investigations of composite materials with improved heat transfer are of great interest for development of hydrogen storage technologies. A composite material was made of powders of activated La_0.9Ce_0.1Ni₅-alloy and copper. PCT-isotherms of hydrogen sorption and desorption was measured and compared for the composite and the pure alloy at temperature of 313, 333 and 353K. Values of ΔH and ΔS of the hydrogen sorption and desorption reactions were calculated, and temperature and pressure relaxation in the pure alloy and the composite material beds were studied. A significant difference between hydrogen storage behaviour of the pure alloy and the composite has been revealed.

This paper deals with a fundamental equation of state for matter (FEoS). When constructing FEoS, the method of pseudocritical points (PCP) is used. The PCP method is based on the Benedek hypothesis and a new representation of the scale hypothesis of the critical point. We show the possibility to construct FEoS of argon based on the PCP method with the following characteristics: (i) FEoS is transformed into the virial equation of state in the region of small densities; (ii) FEoS is transformed into the Widom equation in the region of the critical point; (iii) FEoS has its working area with pressure (0 ≤ p/p_c ≤ 740), density (0 ≤ p/p_c ≤ 3.2) and temperature (83.8058 ≤ T ≤ 2300∼K) in. We compare FEOS with a number of known equations of argon state and discuss the results.

An approach is presented that allows predicting the transport properties of metallic melts without involving data on the electrical conductivity. To determine the thermal diffusivity, only information from the Mendeleev table is required. It is sufficient to know the molar mass and the number of valence electrons. To determine the thermal conductivity, additional information is required on the density and heat capacity of the metal.

The articles presents new experimental data on the heat capacity of hard magnetic materials of brands N35M, N35H, N35SH, as well as YX18, YX24 and YXG22, YXG30 with main components represented by the crystalline phases of Nd₂Fe₁₄B, SmCo₅ and Sm₂Co₁₇ type, respectively. The temperature range from 190 to 800...1270 K has been investigated by the method of differential scanning calorimetry with an error of 2–3%. The approximation dependences of specific heat coefficient have been obtained. The character of changes of the heat capacity in the region of the Curie point has been specified, and its critical indices and critical amplitudes have been defined.

The influence of annealing dynamics on the size and orientation of copper foil grains used for graphene synthesis at chemical deposition from the gas phase was studied. Annealing was carried out in argon and hydrogen atmospheres setting a constant temperature profile on the processed substrate and temperature gradient along the substrate. The temperature range and times were chosen in accordance with the regimes effective for graphene synthesis. It was shown that hydrogen has a significant effect on the growth of grains. Orientation of large grains, formed on the copper surface due to secondary crystallization, was random in the studied regimes.

The peculiarities of the use of the Jaumann and Green-Naghdi corotational derivatives were investigated for modeling deformation processes in isotropic and anisotropic materials under shock loading. Using the aluminum alloy 2024 as an example, it has been shown that taking into account the anisotropy of mechanical properties affects the values of the Jaumann and Green-Naghdi corotational derivatives upon returning the alloy to an unstressed state. It was proposed to use the combination of the Jaumann and Green-Naghdi corotational derivatives to increase the accuracy in numerical calculations of the stress tensor components.

In network heaters the tubes are exposed to negative impact of the working medium leading to their corrosion, abrasive attrition and destruction. Nowadays to cut their repair costs and to increase the efficiency of heaters in energy objects, a priority task is to recover and protect heat exchange tubes without full substitution of tube bundle, by application special protective materials on an internal surface. For repairing the tubes several protective coatings were formed, they are based on epoxide and phenol-formaldehyde resin. Same of the main characteristics of these materials are their thermal conductivity and thermal resistance. In this work the results of the got coating thermal resistance and thermal conductivity research that investigated by balance method on experimental installation are given.

Experimental and numerical results on the effect of an external axial magnetic field on the structure of the flow which occurs when an electric current passes through a conducting medium between two hemispheres are presented. Results show that for high external axial magnetic field it is absolutely necessary to take into account the induced currents generated by the flow. These results can be used in electrometallurgy for a priori estimates of the flow structure in the direct-current-arc furnaces.

A simplified model of low-frequency inductively coupled plasma generated in a U-shaped discharge tube has been developed. The model is based on the simultaneous solution of radial continuity equations for electrons and metastable atoms, gas temperature and electron mean energy. New data on plasma parameters of a low-frequency inductively coupled gas discharge have been obtained, for the case of argon plasma forming gas, in the range of discharge currents from 1 to 10 A and low argon pressures from 1 to 20 Pa. The numerical results agree with the present experimental and numerical data and describe the main discharge features, i.e. the low values of electric field strength from 0.2 to 0.6 V/cm, the decreasing voltage-current characteristics, and the decreasing electric field strength pressure dependencies.

Partial discharge features in cavities in a condensed dielectric was studied. Two models for description of the electric charge transfer during partial discharge were used that are model of constant conductivity of a cavity and a diffusion-drift model. The numerical methods for both models were realized for parallel computations with GPU that accelerates the calculations significantly. The three-dimensional calculations of apparent and true charge in cavities of the shapes of different size spheres and prolate spheroid were conducted. The simulation of the initial stage of streamer development in elliptic helium filled cavity was performed.

The hybrid physico-mathematical model based on the two-component lattice Boltzmann method is proposed for computer simulations of "plasma" channels and vapour-gas cavities at electrical discharges in liquid dielectrics. In this model, two different states of matter are considered separately. The first component describes the flows of a dielectric liquid. The second component describes the "plasma" substance during its heating inside the channel.

Experiments were performed to generate water vapor plasma in a microwave discharge using a household magnetron (frequency 2.45 GHz). Plasma was ignited in a discharge tube during evaporation from the vessel, and also at the liquid-gas interface. The input power ranged from 1 to 2 kW, and the vapor pressure ranged from 1 to 10 mbar. The time dependence of the emission intensity for the first three lines of the Balmer series of hydrogen was constructed. It was revealed that the time required to heat the plasma to a steady state was 2 ms. A change in the anode current by 15% did not lead to an appreciable change in plasma emission intensity. The plasma temperature estimated using the Boltzmann method was about 4000 K. The plasma was shown not to be in thermodynamic equilibrium.

This work presents the design and characteristics of the 700-kilovolt pulsed X-ray apparatus, based on a principally new electro-physical structure. The main idea of this structure is that Blumlein pulse-forming system (transmission line, PFL), the primary and secondary circuit inductances and the capacitance of the secondary circuit of the Tesla transformer, running in the first half-wave occupy the same volume in space and do not impede each other. This kind of circuit design and the packing density as related to the pulse output dose is unrivalled throughout the world. The dependences of dose on the forming line voltage, and the flash duration on the different apparatus construction are measured.

Partial discharges in free bubbles floating in transformer oil and in a glass sphere are studied both experimentally and theoretically. Optical, electrical and optoelectronic registration was performed to obtain partial discharge pattern. The time duration of electrical and optoelectronic signals were practically the same and equaled to 50 ns. PDs in bubbles were rare events even at the electric field two times higher than required by Pashen's law. In the case of rigid sphere the voltage of PD inception was practically the same as the value given by Pashen's law. Simulations of PD gave the values of "true" and the "apparent" charges close to those measured at the experiments. Simultaneous PDs in bubble and closely situated sphere were not recorded.

A global integral model of an arc discharge in a helium medium with a sputtered graphite anode is presented. The main feature of the model is the simultaneous consideration of the plasma of the discharge gap, the cathode and anode layers, the current transfer, the thermal regime of the electrodes, and the evaporation of the anode. Both the calculated and experimental results show that the discharge voltage linearly increases with the inter-electrode distance, as in a classical positive column where the voltage drop is proportional to its length with a constant electric field. The calculated data also show a good agreement with the experimental and calculated data of other authors, in particular, a good correspondence between the absolute values of electron density and temperature, the discharge voltage and the anode ablation rate as a function of the discharge current.

The paper presents experimental results of thermal processes investigations in flow type metal hydride hydrogen storage and purification reactor RSP-8(I). Thermal processes in the reactor during hydrogen separation from carbon dioxide are studied. Optimal operation parameters for hydrogen purification and performance efficiency of metal hydride reactor RSP-8(I) are defined experimentally. Investigations of heat and mass transfer inside a vertical metal hydride reactor RSP-8(I) with 1 kg of LaFe_0.1Mn_0.3Ni_4.8 show considerable non-uniformity of pressure inside the bed. If the reactor is charged from the top, the hydrogen pressure at the bottom is lower by 0.2-0.3 MPa, which results in earlier occurrence of heat and mass transfer crisis.

Many different sources are used for obtaining and supplying heat, which do not require immediately fuel combusting. However, as a rule, such sources do not allow independently controlling an amount of heat to be supplied, while heat consumption is an independent process. Matching heat production and consumption curves is usually done using heat accumulators. Heat-recovery accumulator for utilizing waste-gases heat of a small-capacity power station was developed, fabricated and tested. To exclude superheating of the accumulator working fluid, a system of "thermodynamic" self-controlling of heat utilization was applied. The tests conducted confirmed the rated characteristics of the developed heat-recovery accumulator, as well as a reliability of self-control system.

The paper presents the results of an experimental study of the efficiency of heating with the injection of steam on the surface of the stator blades of the last stages of steam turbines operating in the wet steam flow conditions. The major task of the research was to determine the main mechanisms of the heating temperature influence on the kinematic characteristics of the polydisperse flow of a liquid phase downstream an isolated nozzle blade cascade. Measurement of the characteristics of the liquid phase particles was carried out using a laser flow diagnostic system implemented on the basis of the "PIV-IT"complex and processing the obtained images using the PTV method (particle tracking velocimetry). It is established that heating leads to evaporation of the liquid film formed as a result of the deposition of liquid phase on the surfaces of the nozzle blades, as well as to the increase in the velocities of droplets, and as a consequence, a decrease in diameters and wetness.

Making highly efficient recuperator, that will have minimal dimensions, high recovery rate, and low-pressure loss is one of the key tasks in a micro gas turbine design process. This paper presents recuperator with Frenkel-type heat-exchange matrix. Design and dimension choice of envelopes, which comprise recuperator heat-exchange surface is validated through gas-dynamic calculations, which are described in this paper.

Nowadays due to the development of computer technology and the creation of specialized software packages 2-D and 3-D the design of technical devices and modeling their operations in various operating systems is practically available for technical engineers. This work considers the possibility of studying the numerical simulation technology in the ANSYS package for the temperature distribution of a thermally-insulated pipeline equipped with a cable heating system.

An innovative core with an increased energy resource was used when designing RITM-200 reactor unit. The paper presents the results of experimental and numerical simulation of hydrodynamic processes occurring in the inlet region of the RITM reactor fuel assembly model. Computational mesh of fuel assembly, containing ∼ 22 million elements was created using Ansys ICEM CFD. The values of relative axial velocities in several cross sections at the inlet to the bundle of fuel elements are obtained. At the inlet to the fuel rods bundle the velocity field is not uniform, due to the complex geometry of the fuel assembly. The obtained results of CFD-simulation can be used to determine the input boundary conditions for subchannel programs of the core thermal-hydraulic analysis. This allows taking into account uneven flow rate distribution in subchannels due to the complex geometry of the fuel assembly inlet region.

Reversible metal hydrides are efficient solution for energy storage for distributed and autonomous power. Heat transfer is the major limiting factor for performance of metal hydride devices. Exothermic hydrogen absorption creates significant temperature gradients due to low effective thermal conductivity of powdered metal hydride beds. As the result of a strong dependence of absorption equilibrium pressure on temperature, this gradients lead to heat and mass transfer crisis and compositional inhomogeneities with high concentration of hydride phase near heat sinks and low concentration in the hot core of the bed. Development of the compositional inhomogeneities is accompanied by significant pressure drops over the bed, which can be measured experimentally. We performed experiments on hydrogen absorption in 1 kg metal hydride bed of of La_0.9Ce_0.1Ni₅ inside a water cooled reactor during charge at constant hydrogen flow within the range of 10-30 st.L/min at 0.59 MPa. Results show that heat and mass transfer crisis starts, when pressure in the reactor near hydrogen inlet becomes close to supply pressure, while pressure on the other side of the bed is lower by 0.15-0.25 MPa. These results confirm development of the hot core inside the bed, where reaction almost stops due to high temperature.

Two different types of ejectors used for pumping gas, liquid and two-phase flows, as well as for evacuation of enclosed spaces have been analyzed. The results of CFD simulation of Dubinsky's Vortex ejector operation process are presented. The results of numerical simulation and experiment for different modes of ejector operation for passive flow and total back pressure are compared.

The paper considers a method of temperature stabilization of the limiter in the T-10 Tokamak with capillary-porous structure on the side facing of the plasma and saturated with liquid lithium, by dispersed gas-liquid flow. The spray pattern, formed by the spray generator, is directed along the axis of the limiter. The results of preliminary experiments for determining the geometric characteristics of a torch, a dispersed flow, the distribution of the velocity and the size of water droplets depending on the pressure of water and air entering the generator nozzle are presented. The paper presents the technique developed by the authors for processing experimental data, which makes it possible to calculate the heat flux density, as well as the temperature on the outer (heated) and internal (cooled) surface of the target walls. The design of the working area - limiter simulator is developed. It was experimentally established that the temperature of the target sharply decreased when air was supplied to the generator nozzle. The main experiments were carried out at excess water pressures (0.5 ÷ 1.0)·10⁵ Pa, air (0.3 ÷ 2.8)·10⁵ Pa, and heat flux densities of up to 4.9 MW/m² applied to the target.

This paper describes different ways of efficiency improvement in pellet fuel bed combustion and proposes methods of pellet fuel combustion, ensuring high environmental and energy performance. The constriction in the form of a convergent-divergent passage in the furnace chamber with simultaneous delivery of the secondary air at the point of maximum dispersal of the exhaust gases has reduced unburned combustible losses by 39%. At the same time, the constriction has reduced heat transfer surface area and residence time of hot gases in the furnace chamber, which increased the exhaust gases temperature at the combustion chamber outlet by 98°C. Ansys CFX software package was actively used for numerical simulation during the development of innovative furnace chamber design. To verify simulation results, the firing test bench was designed.

In accordance with the new environmental legislation, the majority of large thermal power plants are classified as the 1st category facilities subject to the strictest environmental requirements. In particular, such enterprises should obtain integrated environmental permits and adopt the best available technologies. In addition, all objects of the 1st category must be equipped with an automatic system for the continuous monitoring and accounting of emissions. The paper analyzes the main methodological and technical problems encountered in the practice of enterprises in the transition to the new principles of environmental valuation and the implementation of the best available technologies, as well as proposes solutions to these problems. The necessity of the National standard development allowing to carry out the choice of the best available technologies for the concrete enterprise taking into account economic expediency of their introduction is shown. A generalized algorithm for determining the compliance of thermal power plants with the principles of the best available technologies in the framework of obtaining a comprehensive environmental permit is developed.

Spherical and cylindrical tanks for storage of liquefied gases and oil products are considered in the article. Tanks are represented as a multilayered structure each layer of which has its own physical properties. In this work the stationary problem of thermal conductivity of multilayered tanks is considered. In the solution of the problem the coefficient of thermal conductivity is not a constant, and is presented in the function form.

The paper presents results of experimental study of the effect of air-droplet flow swirling on evaporation of moisture contained in the flow. The tests were conducted in a round 30 mm tube within the range of Reynolds number (15-50)10³ at the wall heat flux ranged from 14 to 23 kW/m² and water-spraying density 10-20 g/(m s). It was demonstrated that the swirling inserts enhance droplet deposition from the flow core to the wall and recover the evaporated liquid film at a length equal to several tube calibers. Followed by dried zones appearing at the wall again. This is due to the processes of liquid film rupture and liquid entrainment accompanying liquid deposition enhancement. The overall effect of the flow swirling appeared to be less effective than it was anticipated.

The paper presents laboratory model of tropical cyclone with controlled forcing and describes the technology to integrate a measurement system and a supercomputer. Procedures of real-time data acquisition, storing and processing, specifics of PIV and heating control systems integration are described. A series of experiments with laboratory analogue of tropical cyclone using feedback between velocity and a heating is carried out. It is found that imposed temperature difference defines the mean radial velocity and intensity of the vortex. It is shown that the relationship between velocity and heat release is of crucial importance for the cyclonic vortex formation.

The paper presents the results of an experimental study of the local ventilation system. It is shown that the use of radially swirled counter-flow jet leads to significant increase in the efficiency of gas removing. This fact is confirmed by the flow visualization for different operating regimes of the device (with and without swirling). The velocity distribution along the central axis of the device was also measured. It is also shown that the use of swirling flow leads to significant increase in the velocity of removal flow. Study of the system operating parameters for different direct and counter flow ratio was carried out.

The study analyzes main ways of air flow cooling in closed-circuit wind tunnels (subsonic and transonic): subject to air exchange (continuous partial exhaust of warm air and its change for colder outside air) and by means of the use of liquid-coolant stationery heat exchanger. It is shown that additional equipment is not required when applying air exchange to cool the flow and, in general, it can reduce costs of wind tunnel maintenance and, consequently, test prices. Based on an example of subsonic wind tunnel designed in TsAGI the evaluation of gas-dynamic and thermo-dynamic circuit flow properties are evaluated. The study also proposes options of air exchange arrangement for high-power operations at w=160 ms^-1 in closed test section provided that the outside air temperature is T_f=20 °C. The paper represents the results of numerical simulation for air flow in the segments of wind tunnel duct in presence of air exchange holes.

In this paper we present the results of numerical simulation of the processes occurring in cooling reservoirs. The goal of the work is to analyze the possibility of predicting the degree of exposure to thermal discharges under different conditions. The study is performed using one of the largest thermal power plants in Europe – the Permskaya Thermal Power Plant (Permskaya TPP) as an example. The computational scheme that combines 2D and 3D approaches is implemented.

The numerical model describing the interaction of coarse droplets with the surfaces of inter-blade channels is presented. This method uses a statistical approach to simulate the splashing process of primary droplet after its collision with the wall. This technique was verified by experimental investigation of wet steam flow in the studied nozzle blade cascade using the flow laser diagnostics system and PTV method. Numerical studies of wet steam were performed in order to investigate the structure of liquid particles streams and liquid film formation conditions in the nozzle blade passage. The influence of primary droplets inlet angle and steam density on the liquid phase parameters has been considered.

Development of modern intelligent monitoring and control systems in energy, allowing reducing the level of harmful emissions and energy intensity production is relevant. In the scientific literature usage of new efficient machine learning techniques for automatic extraction of features for the classification of combustion regimes is insufficiently covered. In this paper we describe a method for determining combustion regimes based on images of flames. To determine the combustion regimes, a convolutional neural network is trained using labeled data. It is shown that in the gas flame colour images the accuracy of the classification of regimes is up to 98%. Results of the convolutional neural network are compared to classification results of various linear models.

Geothermal energy is a promising type of renewable energy. To analyze and improve the efficiency of the system, a three-dimensional mathematical model of an open geothermal loop system is developed. The proposed model takes into account thermophysical characteristics of the geothermal aquifer and the most important technical parameters of the wells. The pump pressures in producing and injection wells, as well as the distances between these wells are considered as parameters to be optimized in terms of achieving the longest period of effective operation of the geothermal loop. The results of numerical calculations are discussed.

A discussion is presented of the propagation of trapped waves over continental shelves having the idealized and realistic topography. The emphasis is made on the investigation of influence of the shelf shape and width on the lower modes edge wave parameters. The conclusions were based on the solution of the complete boundary-value problem using the difference approximation algorithms. A three-dimensional model was used to reproduce waves generated on the Turkish coast of Black Sea caused by the climatological wind. The model, simulated sea-level time-series, was subjected to Fast Fourier Transform to compute the power spectral density of water oscillations. It is found that the absolute maximum of the first mode wave takes place near the shore and over the edge of the shelf. Increasing the width of the continental slope leads to slower attenuation of the wave towards the open sea. The most resistant wave processes were computed on the Cape Inceburun.

A numerical experiment with a high horizontal resolution for 2016 was carried out on the basis of a discrete eddy-resolving model, taking into account a real atmospheric forcing. The work of the main forces that support the baroclinic circulation of the Black Sea has been analyzed on the basis of the calculation results and in comparison with the energetics, obtained for other years (2011 and 2006). They included the wind work, buoyancy, pressure, turbulent friction, advection and turbulent diffusion. The wind force, buoyancy and vertical turbulent exchange brought contribution in the average annual balance of kinetic energy, the work of pressure and advection forces was small. The variability of potential energy was mainly specified by two factors - vertical turbulent diffusion and buoyancy work, which approximately compensated each other. The main contributions to the evolution of kinetic energy on the average seasons were made by four forces. These are the wind work, buoyancy, vertical and horizontal turbulent exchange. The most intensive work of wind forces was observed in the winter and autumn seasons, which was compensated by vertical turbulent friction. The buoyancy work was the most intense in the spring.

The Black Sea dynamics during 25 years is analysed using numerical simulation and assimilation of remote sensing data. Numerical circulation model has horizontal space resolution of 4.8 km and 40 vertical levels. It includes a turbulent model of the Mellor-Yamada type. Results of simulation were validated by comparing with temperature and salinity profiles from hydrological surveys. Analysis of the results shows that the temperature of the sea upper layer grows. Salinity of upper 30m layer also increases, but in the layer 30-100m it decreases. The results of simulation reproduce authentically circulation in the upper layer of the Black Sea. According to simulation, mean currents, directed opposite to the surface one, are observed at a depth of more than 400 m.

The paper analyzed the simulation results of the Black Sea circulation in 2011 and 2016. Numerical experiments were carried out with a horizontal resolution of 1.6 km and took into account the real atmospheric forcing SKIRON. The simulated temperature and salinity were compared with observations. It revealed the correspondence to real data except some deviations caused by the movement of intensive mesoscale eddies. Analysis of velocity fields showed that the reducing of the wind influence in 2016 led to the weakening of the Rim Current in contrast to 2011. The Sevastopol anticyclone in the spring-summer of 2011 was weaker than in 2016, but the Batumi anticyclone was stronger in 2011 due to intensification of coastal circulation near the Anatolian coast. The eddy energy associated with mesoscale variability had been growing in 2011 due to both barotropic and baroclinic instability processes. The eddy energy had been decreasing during 2016 and started increasing only at the end of 2016 due to development of baroclinic instability processes.

The ensemble Optimal Interpolation (EnOI) method is considered for assimilation of observational data in the INMIO ocean model of high spatial resolution. Its parallel implementation is described in the form of the Data Assimilation Service (DAS) based on the Compact Modeling Framework (CMF3.0). The on EnOI based parallel algorithm is designed to assimilate data from various sources (drifters, satellites, etc) with the ability to construct cross-covariance matrices (between different model values) for adjusting all model fields and the model forecast as a whole, including those functions, for which there is no measurements. This method based on EnOI is planned to be used for all observational data available to date for the World Ocean.

Results of the Black Sea hydrophysical field reanalysis for the period of 1992-2012 are considered. The simulation was carried out using z-coordinate non-linear ocean model of the Marine Hydrophysical Institute. The hydrophysical fields were calculated with resolution of 4.8 km horizontally and by 38 vertical levels along the depth from the sea surface to the bottom. In contrast to a number of previous works, the focus now is on studying the variability of the Black Sea circulation below the main pycnocline (horizon of 300 m and deeper). Analysis of instantaneous and mean velocity fields is carried out, and main structural features are found in deep layers of the sea. It is shown that the most intensive dynamic structures are mainly the cyclonic mesoscale eddies moving from 33-38°E westward and passing through the abyssal central part of the sea. The problem of the existence of reverse (anticyclonic) deep currents opposite to the surface ones is also considered. It is shown that along the narrow north-eastern continental slope such currents exist occasionally. They are formed on the background of topography regional features mainly in summer and could be associated with the weakening of the overlying cyclonic Rim Current.

Verification of the Black Sea temperature in the upper layer from three leading prognostic systems is carried out using in-situ measurements and satellite sea surface temperature (SST) observations. Preliminary accuracy estimates are compared between the systems allowing a choice of a strategy for developing a new Black Sea nowcasting/forecasting system. It needs additional tuning of the ocean circulation model used, improvement of the satellite temperature assimilation procedure and implementation of the procedure for assimilation of observed temperature profiles.

The results of the Black Sea uniform mixed layer (UML) thickness determination are presented in the article and based on using the vertical profiles of seawater temperature obtained by three-dimensional numerical model over a five-year period. The method of adjusting the parameters of automated algorithms to determine the UML depth is proposed with the help of which three known methods of determining this parameter were implemented. The obtained results were used to study the relationship between the UML depth and the changes in the parameters of the atmospheric boundary layer at night time. It is shown that the data of heat fluxes, short-wave solar radiation, wind stress and bulk Brunt-Vaisala frequency can explain of up to 65% UML depth dispersion on the basis of regression analysis by using factor models.

On the basis of experimental physical field's microstructure data in the upper stratified layers of the Black Sea, the annual variability of the vertical turbulent exchange coefficient in the seasonal thermocline is investigated. The data were collected during eight expedition periods in 2007 – 2017, and they cover the north-western part of the Black Sea. The studies were conducted in different hydrological seasons from April to November. The measurements were carried out by the probing complex "Sigma-1", the evaluation of turbulence energy dissipation was made by velocity pulsation gradients. The desired coefficient of vertical turbulent diffusion was calculated on the basis of the obtained experimental estimates of energy dissipation by known Osborn's relationship. The analysis of these measurements makes it possible to calculate and use the vertical turbulent diffusion coefficient dependence on stratification to evaluate the vertical fluxes of heat, salt and other dissolved chemical and biological substances in the studied Black Sea region.

The regional configuration with coarse spatial resolution for the basins of the Black, Azov and Marmara seas is developed for NEMO ocean circulation model. Long-term simulations are carried out to reconstruct the inflow of the Marmara Sea highly saline waters into the Black Sea freshwater basin. Effects on the haline stratification and the Bosphorus outflow of different values of river runoff are investigated.

The paper considers the matters of numerical modeling estimation accuracy of temperature and salinity three-dimensional fields in the monitoring and forecasting center of the Black Sea. Automatic system of analysis and forecast of the Black Sea state is run in the center in an operational mode. The data of in situ measurements from ARGO profiling floats regularly provided by the European Marine Forecasting Service – Copernicus – were used to solve the problem. Spatial and temporal mismatch between the model data and in situ measurements was eliminated to form a joint sample of these two data sources. Comparison is performed for the time period from 2012 to 2015. The results show quite good simulation accuracy of the ther-mohaline fields, however, the problems of modeling the temperature fields in the 5-30 m layer were detected where there is a fairly narrow seasonal thermocline in late spring, summer and early autumn.