bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurements of pitch-off diameter of gas bubbles in liquid metal
Authors: Lobanov P D , Pribaturin N A , Svetonosov A I 
Published: November 2021

Abstract
To determine the separation diameter of bubbles in a liquid metal melt, an original technique based on the conductivity method is proposed. A thin electrode is installed in the center of the outflow channel, and the separation of bubbles is determined by closing and opening the electrical circuit. In this way, the separation frequency of the bubbles and their volume can be determined. Additional studies are carried out on a transparent liquid (water). It is shown that the presence of an electrode has little effect on the process of bubble detachment. The processing data of high-speed video filming and the proposed method in a transparent liquid coincide with high accuracy. Measurements of the frequency of bubble detachment in melts of the Rose and lead alloy are carried out. The results obtained are used to tune two-phase flow models when simulating fast neutron reactors with heavy liquid metal coolants.
Influence of channel to heater width ratio on flow boiling critical heat flux in mini- and microchannels
Authors: Zaitsev D V , Belosludtsev V V 
Published: November 2021

Abstract
Flow boiling experiments were conducted in mini- and microchannel with different ratio of heater width to a channel width. Decrease in critical heat flux is observed in transition from wide channel to channel with width equal to a heater width. Particularities of boiling phenomena in these conditions were observed by means of high-speed visualization, which provided an explanation to heat flux reduction.
Modeling of thermodynamic processes using the properties of matter presented in the form of spreadsheets
Authors: Ramazanov E R , Kosoy A A 
Published: November 2021

Abstract
New thermodynamic cycles are developed in which the working fluid used cannot be considered as an ideal gas. This applies to oxy-fuel combustion cycles. In these cycles, oxygen is separated from the air prior to combustion. The combustion chamber is supplied with fuel and pure oxygen. The required temperature at the outlet of the combustion chamber is achieved by supplying some other substances from which it is easy to separate the CO2 formed during the combustion of the fuel. Commonly, CO2, or H2O, or their mixture is used as such substances. Thus, there are no exotic substances in the composition of the working fluid, but such a range of parameters is chosen for such cycles that the working fluid at certain points of the cycle can be both gaseous and liquid, or in a supercritical state. To model thermodynamic processes in such cycles, it is unacceptable to use the polytropic equation of ideal gases. A technique for integrating differential equations describing the state of the working fluid is proposed. This technique is based on the presentation of the thermodynamic properties of pure substances that make up the working fluid in the form of spreadsheets. The proposed technique is implemented in a software-computing module.
Boiling of He-II on a cylindrical heater inside a porous shell with constant operation condition
Authors: Korolyov P V , Yachevsky I A , Volodin I V 
Published: November 2021

Abstract
This paper presents new efforts undertaken in the study of boiling in superfluid helium on the surface of a cylindrical heater located along the axis in a cylindrical cavity inside a porous shell. New experimental results are obtained with maintaining constant temperature of the helium-II and helium vapor pressure. The modernization of the experimental setup and vacuum system carried out to obtain a series of longer experiments with maintaining a stationary state are described. The basic experimental configurations are specified. Visualization of helium-II film boiling in constant operation condition is represented.
Experimental study of evaporation of droplets of water ethanol solution at high relative air humidity
Authors: Sterlyagov A N , Nizovtsev M I , Letushko V N 
Published: November 2021

Abstract
A change in the temperature of suspended droplets of a water solution of ethanol, evaporating at high relative humidity, is experimentally investigated using high-speed microphotography and infrared thermography. The data obtained for ethyl alcohol droplets show a significant dependence of the surface temperature of evaporating droplets on relative humidity of the ambient air. It should be noted that at high relative humidity, a significantly smaller decrease in the temperature of droplet surface than at low humidity was observed during evaporation. This relates to the processes of moisture absorption and condensation on the surface of an evaporating droplet of ethyl alcohol at high air humidity, accompanied by the release of heat.
Effect of boron on HEM radiant ignition characteristics
Authors: Korotkikh A G , Sorokin I V 
Published: November 2021

Abstract
The paper presents the ignition characteristics of high-energy materials (HEMs) containing ammonium perchlorate, butadiene rubber, and a mixture of Al/B nanopowders with different component ratios. Bimetallic systems based on aluminum with boron increase the reactivity and intensify the ignition of boron particles, which helps to decrease the critical ignition conditions of HEMs during heating. It is shown that the use of systems based on aluminum-boron reduces the delay time (by 17–52 %) and the ignition temperature of propellants in comparison with a HEM containing aluminum powder, and increases the activation energy of HEM during radiant heating.
Numerical determination of the combustion rate of a gas suspension of coal dust in a propane-air mixture
Authors: Moiseeva K M , Krainov A Yu , Kantarbaeva A 
Published: November 2021

Abstract
The results of the numerical solution of the problem of the combustion rate of a coal-propane-air mixture are presented. The physical and mathematical formulation of the problem is based on the approaches of the dynamics of multiphase reacting media. The method for solving the problem is based on the algorithm for the decay of an arbitrary discontinuity. The dependences of the visible and normal combustion rate of the coal-propane-air mixture on the radius and the volumetric content of propane in the gas are obtained.
Numerical study of continuously rotating detonation in two-fuel gaseous mixture
Authors: Trotsyuk A V 
Published: November 2021

Abstract
Numerical simulation of continuously rotating detonations of stoichiometric two-fuel mixture with air has been carried out for the cylindrical annular detonation chamber (DC) of the rocket-type engine. The syngas (1-α)СO+αH2, a binary mixture of hydrogen H2 and carbon monoxide CO, is taken. We studied the global flow structure in DC, and the detailed structure of the transverse wave (TW) front in the continuous rotating regime. Integral characteristics of the detonation process − the distribution of average values of static and total pressure along the length of the DC, and the value of specific impulse have been obtained. The region of existence of stable continuous detonation regime in coordinates of the stagnation pressure - temperature in injection manifold (receiver) and the geometric limit of stable TW have been determined.
Estimating the applicability of kinetic schemes in hydrogen combustion simulation in combustion chambers of aircraft engines
Authors: Sokolova E I , Studennikov E S , Chelebyan O G 
Published: November 2021

Abstract
This paper presents the results of numerical simulation of hydrogen combustion in a supersonic flow of an oxidizing medium in a model combustion chamber using various models of chemical kinetics. The best scheme, which most accurately describes the combustion processes, is revealed. Comparison of the calculated distribution of molar fractions with experimental data is carried out, and relative deviations for the piloted mode of operation of the chamber are obtained.
Development of a mathematical model of diesel-generator units with a valve-inductor generator
Authors: Zhigarev V A , Minakov A V , Guzei D V , Pryazhnikov M I , Panteleev V I 
Published: November 2021

Abstract
The paper presents a comprehensive mathematical model of a diesel-generator units with a valve-inductor generator. The calculated data obtained using this model allows optimizing the operation of fuel injectors and adjust the injection characteristics. The electromagnetic part of the model allows taking into account the power losses and efficiency of the generator, calculating the phase windings and their connection schemes, methods for setting the voltage or current of any shape that feeds the windings of the valve-inductor generator, as well as the characteristics of the rotor, stator, and winding materials to obtain the most effective operation parameters of the engine in various operating modes as part of the generator unit.
Validation of a laminar-turbulent transition prediction technique for a swept-wing boundary-layer flow
Authors: Boiko A V , Borodulin V I , Ivanov A V , Kirilovskiy S V , Mischenko D A , Poplavskaya T V 
Published: November 2021

Abstract
The laminar-turbulent transition in the boundary layer of a 45° swept wing model installed at zero attack angle in the test section of a subsonic wind-tunnel was detected with the help of an infrared camera. The camera recorded sequences of frames, the evolution of the preheated model surface temperature acquired and used for differentiating between the laminar and turbulent regions. The transition onset was evaluated at both sides of the model. Corresponding main flow computations in the virtual wind tunnel test section were performed at the same flow conditions with ANSYS Fluent. The computed main-flow velocity profiles along inviscid streamlines were used for analysis of hydrodynamic stability of the boundary layer with respect to Tollmien-Schlichting waves and stationary cross-flow vortices to obtain N-factor distributions along the model chord. A comparison of the experimental and the computed transition onsets was performed.
Hydrodynamic simulation of laser-induced shock waves using the Turbulence Problem Solver software package
Authors: Shepelev V V , Fortova S V 
Published: November 2021

Abstract
The problem of irradiation of a semi-infinite bulk metal target by a single laser pulse, being important for many lase technology applications, is considered. The model for simulating the propagation and attenuation of shock waves, occurring when metals are irradiated with single laser pulse, is presented. The paper describes the computational algorithm based on the model and features of its implementation in C++ in a software package Turbulence Problem Solver (TPS) for modeling a wide class of problems described by hyperbolic equations. The problem is modeled using different approaches and the results are compared. The object-oriented polymorphic architecture of the software complex accelerates and facilitates the process of model development and calibration, allowing for flexible configuration and combination of elements of numerical models: Riemann solvers, various types of and reconstructions, and equations of state of matter.
Estimation of the turbulent Schmidt number in a model gas turbine combustor
Authors: Savitskii A G , Sharaborin D K , Lobasov A S , Dulin V M 
Published: November 2021

Abstract
This article presents the estimation of turbulent Schmidt number in a model gas turbine combustor. Different gases are used as the model fuel while maintaining the mass flow rate. The simplest closure models for Reynolds stress and turbulent flux are considered. The anisotropy of turbulent viscosity is demonstrated.
Measuring the diameter of a cylinder with automatic calibration
Authors: Dvoynishnikov S V , Bakakin G V , Meledin V G , Rahmanov V V , Sadbakov O Yu 
Published: November 2021

Abstract
The work aims at developing a method for measuring the diameter of cylindrical objects, eliminating the need for calibration and verification of the measurement system during operation. The system for measuring the diameter of cylindrical objects contains a photodetector and a light source located on opposite sides of the measured object to implement the shadow method. The proposed method is based on the measurement of two reference cylinders located in the measuring area for automatic calibration of the system at each measurement. It is shown that the proposed method provides stable reliable measurements with an error of less than 2 μm for the diameter of the measured cylindrical objects of up to 10 mm.
A software and hardware system for synchronous control of the optical system for visual control of dynamic objects
Authors: Semenov D O , Dvoynishnikov S V , Kulikov D V , Meledin V G , Chybov A S 
Published: November 2021

Abstract
This work deals with the development of the software for the system of synchronous control of the optical system of visual control over dynamic objects and the creation of algorithms for resolving conflicts of simultaneous illumination by several light sources. The software for the microcontroller for the system hardware is created as part of the work. An application for remote configuration of the device is developed. Algorithms for time-separation of signals for switching on lighting are implemented.
Developing the software and hardware complex to diagnose the ascent of gas bubbles in a liquid metal by the Doppler anemometry method
Authors: Strelnik A S , Dvoinishnikov S V , Meledin V G , Rahmanov V V , Bakakin G V , Kabardin I K , Kabardin A K 
Published: November 2021

Abstract
The complex method of ultrasonic diagnostics of two-phase flows in a liquid metal medium is developed. It allows measuring the dynamic and structural characteristics of the floating inhomogeneity. A software and hardware complex that implements the proposed method is developed and tested for ultrasonic diagnostics of two-phase flows in water and liquid metal medium.
The effect of model material properties on thermal imaging measurements
Authors: Kutepova A I , Polivanov P A , Sidorenko A A 
Published: November 2021

Abstract
The temperature distributions arising on the surface of the solid model are investigated. A flow with a shock wave and laminar boundary layer interaction is considered as the main flow. Calculations of the conjugate problem are performed based on RANS approach. The investigated cases correspond to homogeneous material of the solid model and the model consisting of two materials with different thermal conductivity. In this study, the model designs are found to obtain a temperature distribution suitable for thermal imaging measurements. In addition, in the calculations, the effect of forced heating of the model wall on the temperature distribution is investigated.
Correlation analysis for the research of local characteristics of a turbulent flow
Authors: Sardov P A , Belyaev I A , Listratov Ya I , Razuvanov N G 
Published: November 2021

Abstract
The paper describes the temperature-correlation velocimetry technique applied to the flow of water or liquid metal. The method allows simultaneous measurement of temperature signals and local values of a longitudinal velocity component in the flow. This approach is a simple and reliable method for measuring velocity in flows of optically impermeable fluids. At the same flow conditions, different coolants have different spatial-temporal characteristics that are processed using a temperature-correlation technique. This work is devoted to the development of an algorithm for formulating a set of practical recommendations for the use of this technique to measure velocity and to determine a metrological characteristic in various conditions. For calibration, water and mercury are used as model liquids. The data obtained are presented in the form of fields of temperature and intensity of temperature fluctuations. Autocorrelation and cross-correlation functions are compared for two investigated liquids under the same conditions.
Convection in an evaporating drop of aqueous solution at a high concentration of microscopic particles
Authors: Misyura S Y , Bilsky A V , Gobyzov O A , Ryabov M N , Morozov V S 
Published: November 2021

Abstract
This article presents the performed experimental studies on the effect of the concentration of microparticles on free convection in a water drop located on a heated smooth and textured wall surface. It is shown that at a high concentration of particles, their aggregation and deposition take place on the wall and on the free surface of droplet. As a result, the average convection velocity in the droplet decreases significantly. Suppression of convection is important to consider when simulating heat transfer and droplet evaporation. The results obtained are important for technologies that use colloidal solutions (drops, films).
Experimental study of the thermophysical properties for aluminum-magnesium alloy AMg3
Authors: Agazhanov A Sh , Samoshkin D A , Kozlovskii Yu M , Stankus S V 
Published: November 2021

Abstract
The thermal diffusivity (a), the thermal coefficient of linear expansion (α), the isobaric heat capacity (cp
) and the fusion enthalpy (ΔH) of aluminum-magnesium alloy AMg3 were investigated by laser flash method, dilatometric method and method of differential scanning calorimetry in the temperature range of 300–773…1000 K. The thermal conductivity (λ) has been calculated from the measurement results. The estimated errors of the obtained data were 2–5%, 3–5%, 2–3% and (1.5–2.0)⋅10-7 K-1 for a, λ, cp
and α, respectively. Approximation equations and a table of reference values for the temperature dependence of the studied properties have been obtained.
Optical pulses in carbon nanotubes with strong electron-electron interaction due to impurities
Authors: Konobeeva N N , Belonenko M B 
Published: November 2021

Abstract
In this paper, we investigate electromagnetic pulse propagation in a medium with impurity carbon nanotubes, which are associated with the acoustic subsystem. The electron spectrum for the carbon system is obtained from the model that takes into account Coulomb impurities. Based on the Maxwell's and the wave equations for the vector of the medium displacements, we obtain the effective equations for the vector potential of the electromagnetic field and the component of the displacement vector of the medium. The dependence of the pulse shape on the various system parameters is analyzed.
Density and speed of sound in refrigerant vapor R-125 (31 wt. %) + R-134A (69 wt. %)
Authors: Komarov S G , Stankus S V 
Published: November 2021

Abstract
Using a constant volume piezometer and ultrasonic interferometer methods, the density and speed of sound in gaseous mixture R-125 (31 wt. %) + R-134a (69 wt. %) were measured within the temperature range from 293 to 393 K and at pressure from 0.18…0.47 to 2.5 MPa. The errors in the measuring temperature, pressure, density and speed of sound were ±20 mK, ±4 kPa, ± (0.15–0.3) %, ± (0.1–0.2) %, respectively. It was shown that the speed of sound values increase with temperature and decrease with pressure. The obtained results were compared with the calculations using the REFPROP software.
Hydrodynamic approach to the processing of core sample tests considering microstructural changes
Authors: Kravchenko M N , Ivlev M I , Dieva N N 
Published: November 2021

Abstract
In this paper, authors propose a method to create a complete hydrodynamic model of the polymer displacement process. It is based on the processing of the laboratory tests with core samples, considering the polymer substance properties and microstructural changes occurring in the porous matrix during the adsorption of polymer particles. Based on the adaptation of the mathematical model to the results of tests with polyacrylamide Flopaam and polysaccharide Gum Arabic, calculations of the effectiveness of polymer flooding application on samples of terrigenous deposits are carried out.
Description of the liquid-vapor phase equilibrium line of pure substances within the bounds of scale theory based on the Clapeyron equation
Authors: Rykov S V , Kudryavtseva I V , Rykov V A , Ustyuzhanin E E 
Published: November 2021

Abstract
On the basis of the Clapeyron equation and the scale theory, expressions are developed for the “apparent” heat of vaporization r
* = r
* (T), vapor ρ- = ρ- (T) and liquid ρ+ = ρ+ (T) branches of the saturation line of individual substances for the range of state parameters from the triple point (pt,Tt,ρt
) to the critical (pc,Tc,ρc
). The peculiarity of the proposed approach to the description of the saturation line is that all exponents of the components of the equations ρ- = ρ- (T) and ρ+ = ρ+ (T) are universal up to the universality of the critical indices α, β and Δ. In this case, the order parameter ds
= (ρ+ − ρ-)/(2ρc) and the average diameter df
= (ρ+ + ρ-)/(2ρc) − 1 of the saturation line satisfy the saturation line model [2β,1−α], which follows from the modern theory of critical phenomena. The method is tested on the example of describing the phase equilibrium line of refrigerant R1233zd(E) in the range from Tt
= 195.15 K to Tc
= 439.57 K. It is found that in the temperature range [Tt,Tc
], the developed system of the mutually consistent equations ps
= ps
(T), r
* = r
* (T), ρ- = ρ- (T) and ρ+ = ρ+ (T) allows describing the data on the saturated vapor pressure ps
and densities ρ- and ρ+ on the saturation line within the experimental uncertainty of these data.
Simulating diffusion in the conditions of vapor-liquid phase transition by the molecular dynamics method
Authors: Kharlamov G V 
Published: November 2021

Abstract
The molecular dynamics calculations of diffusion coefficients in binary Lennard-Jones systems have been carried out. The parameters of Lennard-Jones potentials correspond to argon and krypton atoms. The universal dependence of the reduced diffusion coefficient of krypton atoms on density for the homogeneous systems of low and middle densities is found. The deviations of the diffusion coefficients from the universal function are observed for the systems in the vapor – liquid phase transition region. The simulations have shown that almost all krypton atoms have situated inside the liquid phase of argon. Special numerical experiments have shown that the nanodroplets of argon are formed as a result of homogeneous nucleation and then the krypton atoms are captured by these droplets. This phenomenon decreases the diffusion coefficient of krypton atoms greatly.
Comparing the methods of copper substrate polishing for CVD graphene synthesis
Authors: Kostogrud I A , Boyko E V , Matochkin P E , Sorokin D V 
Published: November 2021

Abstract
This paper presents a comparison of chemical and plasma electrolyte polishing methods for preparing a copper substrate for graphene synthesis by chemical vapour deposition. It is shown that in order to achieve the most uniform morphology of the surface of the copper substrate, it is preferable to use the electrolyte-plasma polishing method. With its help, the proportion of multilayer regions in the graphene coating obtained as a result of CVD synthesis decreases. The obtained results may serve a recommendation for creating a graphene coating with specified parameters.
Thermal regime of the local working zone in the industrial premises under radiant heating conditions
Authors: Kuznetsov G V , Maksimov V I , Nagornova T A , Vyatkin A V 
Published: November 2021

Abstract
The results of experimental studies on recording temperatures and heat fluxes for the local working zone in industrial premises under radiant heating conditions and supply and exhaust ventilation operation are presented. The characteristics are measured on the surface of the horizontal remote panel directly under the radiator and along the wall with the ventilation inlet. Experimental results show that mixed convection caused by the operation of air exchange systems leads to mixing of air masses and more intensive cooling of the horizontal panel surface, as well as air, compared to the natural convection regime.