The instrumental accuracy of determining the model temperatures by the data of radiance temperature measurements at two and three experimental points is analyzed using model examples, when neither thermodynamic temperature nor emissivity of the sighting site is known. The instrumental accuracy of determining the desired temperature is estimated depending on the choice of a spectral window in the thermal

The flow with movement of single slugs in an annular channel was studied. The shear stress on both walls of the annular channel was measured using the electrodiffusion method. The averaged wall shear stress distributions along the channel length during gas slug motion are presented for different regimes. A significant difference in the values of shear stress on the inner and outer walls of the channel

For the conditions of flame combustion of the milled peat with natural gas support flaring, the spectral radiation energy flux densities and emissivity factors of furnace gases are calculated for a situation of a furnace in BKZ-210-140F steam boiler. From the analysis of emission characteristics, a strategy was determined and a pyrometer set was selected for measuring the furnace gas temperature. For

The paper presents the description and results for computational-and-parametric study for the simulation of heat and mass transfer for an water-oil mixture produced from a set of horizontal wells (at the example of high viscosity oil field). The purpose is the theoretical and numerical study of heat and mass transfer for water-oil mixtures with a focus on a set of scientific and production problems

A model for calculating the thickness and heat transfer of a turbulent film moving under the action of gravity and the shear stress of friction of a gas flow is constructed. The aim of this work is to supplement the previously proposed simple model of turbulent viscosity using a cubic law of damping in a viscous sublayer and a logarithmic asymptotic velocity far from the wall with additional linear

The work studies the turbulent fluid flow under the effect of natural convection within a solar chimney power plant (SCPP). This study is carried out by numerical simulation using the Saturne code coupled to the Syrthes code. Geometric modifications were brought upon the chimney outlet. Divergent shape with different exit sections was set at the tower outlet. The study is undertaken for two types of

The problem of the joint flow of a turbulent gas stream and a vertically falling wavy liquid film is considered. Tangential and normal stresses on the interfaces are calculated. The components of the Reynolds stress tensor are determined within the framework of the Boussinesq hypothesis. For the case of small Reynolds numbers of a liquid, the problem is reduced to a nonlinear integro-differential equation

The influence due to the shape of the expanding part of supersonic nozzles on the gas-dynamic structures formed in the ducts of high-altitude rocket and aerodynamic test benches has been studied. The research was carried out using the means of computational gas dynamics with the example of a model gas-dynamics tube with three replaceable supersonic nozzles having identical throat and outlet-section

The work describes regularities of the formation of waves in a jet of a viscous liquid, initiated by a sudden rupture of the jet. The possibility of the existence of fast growing disturbances in a viscous jet is established. The cyclic regularity of the dependence of the distance between the formed droplets on their number is observed. It is justified that he decisive role in the formation of growing

The efficiency of stationary air blowing/suction into the turbulent boundary layer of the NACA 0012 airfoil through permeable sections located at the adjacent sides of the wing in the vicinity of its trailing edge is studied numerically and experimentally. The flow rates in these sections are varied in the intervals 0 ÷ 9.33·10−4 and 0 ÷ 8.48·10−4, respectively. The studies are carried out at the Reynolds

The paper describes a study of the influence of Overfire Air (OFA) technology on heat and mass transfer parameters for a furnace chamber in the BKZ-75 boiler at the Shakhtinsk power plant (Kazakhstan); this plant is fueled with Karaganda high-ash coal. The computer simulation methods were applied for studying different air supply regimes through the air injectors operating in OFA design with different

This paper presents a numerical investigation on the concept for improving film cooling performance by placing a ramp upstream the film hole with compound angle. Eight cases with different geometry models are investigated, including the compound angles of 15°, 30°, 45° and the distances between the upstream ramps and film holes (upstream distances) of 5 mm, 10 mm, and 15 mm. The effect of compound

The solubility of heavy alkali metals in liquid lithium was investigated at temperatures from the melting point of Li to ∼1200 K by the method of gamma-raying of liquid samples by a narrow beam of gamma radiation. Even at high temperatures, the solubility of K, Rb, and Cs in liquid lithium has been found to be very insignificant. The potassium content in the lithium-rich phase is 0.2 at. % at 850 K

The development of a convective flow after sudden heating of a vertical wall that laterally bounds a layer of ethyl alcohol in a system consisting of vertical layers of alcohol and air, separated by a thin metal partition, is studied numerically in a conjugate problem statement. The equations of thermogravitational convection in the Boussinesq approximation, written in variables of temperature, vortex

The paper studies the transfer of angular momentum across the interface of two immiscible liquids in a closed vortex flow, generated in a stationary cylindrical container by a rotating disk, being the upper endwall of the cylinder. When the disk rotates, a centrifugal force begins to act on the upper less dense liquid, which leads to the appearance of a centrifugal circulation of the upper liquid.

The influence of ice crystals in an airflow on evolution of run-back ice on the surface of the wing model is numerically investigated for the conditions of experiment in an icing wind tunnel. The results confirm that a change in the mass of ice deposits upon introducing crystals into the flow observed experimentally is associated with absorption of some mass of ice crystals by the water film formed

Relations for the coefficients of transformation of disturbances to pressure oscillations for the case of long-wave disturbances of the external flow are derived from the general analytical solution of the inviscid problem of disturbance interaction with an oblique shock wave on a wedge. Numerical simulations of interaction of long-wave disturbances with a shock wave on a flat plate aligned at an angle

Transient processes are experimentally investigated at the initial stage of heat and mass transfer with steam absorption on the surface of 57.8 % water solution of lithium bromide in a bath with a diameter of 70 mm. The experiments were carried out both with a pure solution and with a solution where n-octanol surfactant was added. It is shown that with a sharp steam pressure increase in the volume

The heat-induced variations in material properties for a layered glass-metal composite material were studied for the case of induction heating and the subsequent composite annealing of the sample. A cylindrical sample of the composite (outer metal cylinder covering the glass cylinder) was used in our experimental study. This sample is an imitation of a brittle rock under a high stress. The simulation

The paper describes how the acoustic impact on an impinging jet induces a maldistribution in the radial velocity field within the nearwall zone of spreading jet. The r.m.s. velocity pulsation level in the nearwall jet is lower than in the natural jet. A higher length of the laminar flow zone in a microjet was noted. The development of sinusoid-type instability facilitates a higher combustion efficiency

A brief description of measuring means, a free-oscillation setup with a transverse sting of the model, and test conditions is reported. A procedure for processing experimental data is described. Quasi-steady and damping aerodynamic characteristics of the pitching moment of the model in the range of Mach numbers M = 1.75–6 are obtained. A comparison of research results with calculated data, as well

The paper presents the experiments on irradiation of the yttrium oxide powder target with a relativistic electron beam and evaporative production of yttrium oxide nanopowder. The phase and chemical consistence, specific surface and particles geometry of nanopowder was studied. A model of mass productivity of nanopowder vs. input e-beam power was tested qualitatively. The effect of continuous operation

Based on the known calculated and experimental data on distribution of temperature and gas compositions near the flame front in jets, it is shown that the nature of a change in the total enthalpy during combustion of mixed and unmixed reagents depends on the molecular properties of gases to different extents, but in the same way. Systems with Lewis numbers less than one have a maximum in the enthalpy

A turbulent circular jet with variable density caused by the mixing of air with gases of different densities (air, helium, and carbon dioxide) is studied. The Reynolds number is fixed for all cases: Re = 5300. Using proper orthogonal decomposition and direct numerical simulation data, a comparative analysis of the three gases under consideration is carried out. It is shown that with a decrease in the

A new and intuitive method for evaluating the efficiency of the compression process in a supersonic air intake is proposed. The method is based on a comparison of the geometric compression ratio of the flow tube in the air intake under consideration with the maximum possible isentropic compression. It is shown that a higher value of the geometric compression ratio in the air intake allows obtaining

The influence of the stagnation temperature of the accelerating gas flow and that of nozzle travel speed on the deposition efficiency are studied when depositing single Cu-coating tracks by the cold spray technique. The experiments performed clearly show that the nozzle traverse speed substantially affects the value of measured deposition efficiency: the higher is the nozzle traverse speed, the lesser

The effect of rotational nonequilibrium on the macroscopic parameters of the flow behind a normal shock wave in oxygen gas flow has been examined. The electron thermal equilibrium was taken into account where the electron temperature was equal to the vibrational temperature according to Park’s assumption. Therefore, only the effect of rotational nonequilibrium on the translational and vibrational temperature

The experiments are performed on R21 freon at a reduced pressure of 0.04 under conditions of natural convection. The propagation velocity of a self-sustaining evaporation front over a heat transfer surface is measured in the presence of a substantial temperature gradient along the heat transfer surface. The stabilization of the front propagation velocity is shown in accordance with the isotherm propagation

The original experimental data on axial distributions of the shear stress on the surface of a rod - a fuel element simulator - during fluid flow through a model of fuel assembly (FA) are presented depending on the rod diameter (9, 10, 15 mm), relative distance between the rods (1.2, 1.3, 1.4, 1.45), and number of rods (7 and 37) for the laminar, transient, and turbulent liquid flows in fuel assemblies

A developed mathematical model offers a study of methane-carbon dioxide replacement in gas hydrate through injection of liquid carbon dioxide into a porous stratum with final sizes. Depending on the parameters of injected carbon dioxide flow and depending on the stratum boundary conditions, the process of formation of the gas hydrate comprising carbon dioxide can occur through methane replacement in

The paper presents experimental data on convective heat and mass transfer during sublimation of a single spherical particle of a mixture of organometallic compounds Zr(dpm)4/Y(dpm)3 in a high-temperature flow of an inert gas (He, Ar). The influence of the carrier gas velocity and composition on the characteristics of the mass transfer processes is considered. Data on dynamics of changes in the size

A method is developed for secondary data processing of the results of simulation of two-phase flow in an afterburner with a complex geometry. This method offers a prediction for mixing process efficiency (quality estimate) and combustion efficiency in an afterburner of a power plant. The opportunities of this method were demonstrated at the example of simulation of mixing the two-phase fuel with air

The study is aimed at investigating the diffusion of single-walled nanotubes in liquids with the weight concentration of nanotubes varied from 0.00001 to 0.01%. Water solutions of sodium dodecylbenzene sulfate and polyvinylpyrrolidone, which are usually used as surfactants, are applied here as a carrier liquid. Their concentration is either equal to the concentration of nanotubes or twice greater.

A simple mathematical model of the dynamics of a non-stationary liquid jet (NSLJ) is presented to describe the injection of diesel fuel in a diesel engine, supplied under pressure to the combustion chamber. The proposed model describes the dynamics of the NSLJ as a motion of the center of mass of a material point of variable mass based on the laws of Newton’s mechanics. In this case, the mass of the

In the present paper, a method for choosing the parameters of a wing-surface waviness intended for use on small aircraft is introduced. We propose choosing the waviness geometry based on the parameters of the boundary layer for the given regime of the flow around the classical wing installed at zero angle of attack, α = 0°. We propose to check the result of the choice of the waviness parameters by

The paper deals with the experimental study of the process of subcooled liquid boiling up on a transparent microheater with pulsed heat release. Dependences of the maximum bubble diameter, rates of their growth and times of boiling incipience on the heat flux density and liquid subcooling in the ranges of 11–32 MW/m2 and 50–75 K, respectively, were obtained. The nucleation temperature was calculated

The paper presents a study in stability of ceramics of hafnium carbide-nitride subjected to impact of a nitrogen plasma jet in air atmosphere. The best thermal resistance was demonstrated for ceramics with N/C ≈ 0.698, which is determined by the maximum of surface temperature and minimum mass loss in the series of HfC-HfN solid solutions.

The conclusions about the nature of bed fluidization and the rate of polyfractional material entrainment in the cylindrical vortex chamber with the air supply through the lower and upper end swirlers were drawn, based on the visual observation of the fluidized bed, the determination of entrainment of the bed dispersed material by weighing the material after a given time of vortex chamber operation

On the basis of the analysis of a large array of experimental data on average heat transfer and hydraulic resistance, calculations of the dynamic velocity on the wall in deep rows of in-line and staggered tube bundles transversely streamlined by the turbulent flow of the coolant are performed. In addition, energy consumption is calculated based on experimental data on the hydraulic resistance of rod

The work is devoted to the study of a vortex system formed in a flow past a streamwise-aligned external dihedral corner due to the drop of pressure between the corner faces. A detailed comparison of experimental and calculated data on the visualization of the flow and on the distribution of pressure over the model surface obtained at Mach number M∞ = 2.27 in the range of angles of attack α = 0–20°

The effects of the groove size on the dynamical and thermal behavior in a round jet impinging on an axisymmetric corrugated surface are investigated numerically. The geometry is similar to that considered in the experimental study Sagot et al. (2010, Inter J. Therm. Sci., 49, 1026–1030). Three side lengths of the square groove cross section are tested, 1/8, 1/4, and 3/8 of the jet diameter. A comparison

The energy security of Russia is at threat due to recent trends of dependency of national power industry on imported technologies, equipment, spare parts, and materials. The next challenge is a tendency of more strict environmental standards and restrictions for power generation equipment. The paper considers one option to meet these challenges — using technologies based on compressorless combined

In the present study, a numerical investigation was conducted to enhance the film cooling efficiency by using anti-vortex designs. Four configurations are considered in this paper, which are the configuration with the streamwise cylindrical injection, the case with an upstream Barchan dune shape ramp (BDSR), the case with sister holes and the configuration that combine the Barchan dune shape with sister

Mathematical modeling is offered for describing the effect of variable incidence between the body axis and the high enthalpy air flow on conjugated heat and mass transfer in a heat shield material at the thermochemical decomposition of the shield. Results of numerical simulation were obtained for spatial supersonic flow near a body with pitch variations. The effect of body oscillation with the rates

The influence of a local change in surface temperature of a contoured nozzle corresponding to the Mach number M = 6 on the boundary layer stability and laminar-turbulent transition is numerically studied. The profiles of the laminar boundary layer are obtained by solving the Navier-Stokes equations with the use of the Ansys Fluid software system. N-factors of the growth rates of the Goertler vortices

The results of an experimental study of a bubble diameters variation with a distance from the gas injection point in an upward bubbly flow in an inclined flat channel are presented. The measurements were carried out for a superficial liquid velocity of 0.51 m/s (Re = 12400) and various volumetric gas flow rate ratios. It is shown that at low values of volumetric gas flow rate ratio (β < 2 %), there

In this paper, a numerical study is performed to investigate the influence of adding glycol or alcohol to water on the thermal protection of a channel wall from hot air by evaporating this binary liquid film. The coupled governing equations in both phases with the boundary and interfacial conditions are solved using a finite difference numerical scheme. The effectiveness of adding a fraction of glycol

Controlled disturbances are inserted into the wind tunnel flow, and probing measurements of the fields of the amplitudes of pressure and phase velocity oscillations of these disturbances are performed. Based on the relations for inviscid interaction of long-wave vortex, entropy, and acoustic disturbances with the shock wave on a wedge and numerical simulations, the coefficients of conversion of various

The article presents the results of studies of the coolant flow in fuel assemblies behind the intensifier grids of FA-Square reactors of the PWR type. The aim of this work is to evaluate the effectiveness of using various designs of the intensifier grid for the flow mixing. To achieve this goal, a number of experimental studies are carried out on an aerodynamic stand with scale models of fragments

Using the laser flash method and the drop method, the thermal conductivity and the enthalpy increment of the eutectic K-Pb alloy (with a Pb content of 90.7 at.%) were measured in the temperature range from the liquidus point up to 1077–1175 K. The specific heat capacity and thermal diffusivity of the alloy were calculated. Approximation equations for the studied properties were obtained, and a table

The direct shadow photography method was applied for study of the size distribution of droplets produced in liquid fuel atomization by a high-speed jet of superheated steam. This approach for fuel spraying allows eliminating the clogging of fuel lines and atomizers used for combustion of substandard liquid hydrocarbons. The setup has a long-focus microscope lens with optical magnification 7:1; this

The motion of a helical vortex and the movement of the fluid particles along its axis are analyzed. The same form of the helical axis of the vortex and the trajectory of the particles sometimes leads to a false assumption of equality of these two different motions. The correct identification of both motions, however, is essential when considering the helical vortices in the wakes of rotors, or the

Formation of a temperature field and melting rate of ice vertically located on an opaque substrate and scattering radiation at radiant heating were studied numerically. To solve the part of the problem concerning radiative heat transfer, we used a modified method of mean fluxes, which takes into account volumetric absorption and scattering of radiation in the medium, as well as the selective nature

The paper presents an analytical solution for helical vortices with a Gaussian vorticity distribution in the core, which is confirmed by experimental and numerical simulations. This result is obtained by extending the Dyson method to the Biot–Savart law. Previously, analytical solutions were found and studied only for vortices with constant vorticity distribution in the core (a Rankine-type vortex

The paper presents a study for conditions for hydrogen self-ignition and flame spreading in a supersonic combustion chamber at the Mach number for the inlet flow equal to 4. The experimental model is a rectangular channel with a flame stabilizer performed as a backward-facing step. The fuel was injected before the step at the top and bottom walls through 8 round orifices which were oriented at angles

Turbulent flow of thermoviscous liquid is studied in a three-dimensional region with periodicity in two directions. Flow characteristics are described in the terms of equation for turbulent kinetic energy: this allows to differentiate contributions from different components related to generation, transport, and dissipation of turbulent kinetic energy. Those terms can be calculated from averaging the

Numerical studies of the aerodynamic characteristics of the “Federation” reentry vehicle are performed by the direct simulation Monte Carlo method for an altitude of 90 km. Quantitative effects of a number of physical and chemical models of this method on the aerodynamic performance of the vehicle are demonstrated.

Hydrophobic and highly hydrophobic zirconia coatings are obtained by air-plasma spraying of powder and suspension materials. The proposed method and the developed equipment make it possible to obtain nanostructured surfaces with water-repellent properties. The high hydrophobicity of the coating is achieved by creating a hierarchical texture of its surface obtained by the combined method of plasma spraying

The present study is aimed at the development of a laser Doppler anemometer (LDA) for investigating high-velocity multiphase flows. Based on the analysis of the Doppler anemometry methods, requirements to modern LDAs for solving the above-mentioned problems are formulated, and the ways of their implementation with allowance for the present status of laser engineering and spectroscopy are outlined.

Results of a numerical study of the flow structure in the rectangular duct of a model air inlet with the interaction of the shock wave generated by the inlet cowl with the turbulent boundary layer on the inner duct surfaces are reported. A configuration involving a convergent entrance section and a constant-cross-section throat was analyzed. The numerical simulation of the three-dimensional flow with