bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computation of equilibrium states for products of hydrocarbon combustion under oxygen lack
Authors: Prokhorov E S 
Published: December 2019

Abstract
A unified approach to the computation of equilibrium in combustion products of oxygen mixtures overriched with hydrocarbon fuel, when both gaseous and condensed carbon phases may appear simultaneously among the components of chemical reaction, has been formulated. Within the framework of this approach, the problem of determining the equilibrium parameters (pressure, density, temperature, etc) of chemical reaction products produced at explosion of acetylene-oxygen mixture in a closed volume as the values of molar fraction of fuel (acetylene) vary up to the values when oxygen in the mixture is almost absent has been solved.
Turbulent charge burning in SI engines
Authors: Briutov A A , Senachin A P , Senachin P K 
Published: December 2019

Abstract
The article describes turbulent combustion in the front of a spherical flame of the fuel-air mixture in a spark-ignition engine. The paper considers two mathematical models of the workflow : a well-known “entrainment or eddy burning model” and a “laminar model of turbulent combustion” in the authors’ version of this paper. Both models are based on the Damköhler hypothesis (Damköhler G., 1940) on the turbulent combustion of gas, but have a significant difference in the mathematical formulation. Although both models contain empirical parameters, the authors’ model is much simpler and clearer. In numerical simulation, both mathematical models produce similar results. The authors also propose a “combined mathematical model of frontal turbulent combustion”.
Numerical study of flow condensation of dielectric liquid in microchannel
Authors: Safonov S A , Kuznetsov V V 
Published: December 2019

Abstract
This paper presents a numerical analysis of flow condensation of dielectric liquid perfluorhexane in a rectangular microchannel using the annular flow model. It is shown that accumulation of liquid near the channel corners causes the heat transfer enhancement due to liquid film thinning. The numerical method is validated against experiments and predicts well the average heat transfer coefficients during flow condensation in a rectangular microchannel for vapor quality higher than 0.5.
Modeling the filtration of liquid with ultra disperse solid particles in porous media
Authors: Kuznetsov V V 
Published: December 2019

Abstract
This paper considers an approach for modeling the filtration of a viscous liquid, containing ultra disperse solid particles, through the porous sample. The mechanism of microparticle retention during filtration of the suspension at supported pressure drop is discussed and the dependence of reduction of average permeability on particles size is documented.
Dynamics of gas slugs in a vertical annular channel
Authors: Kashinsky O N , Kurdyumov A S 
Published: December 2019

Abstract
Experimental studies of gas slug motion in an annular channel were performed. The channel consisted of two concentric pipes with the diameters of 32 and 10 mm. Experiments were performed for different values of liquid velocity. Slug velocity was measured using optical sensors. Wall shear stress measurements were performed using an electrodiffusional technique. It was shown that the shape of the slug in the annular channel differs significantly from that in a pipe. The distribution of wall shear stress along the slug was presented for different positions of the slug.
Mathematical modelling of influence of the variable incidence at the supersonic flow around spherically blunted cone on the characteristics of the conjugate heat and mass transfer
Authors: Efimov K N , Ovchinnikov V A , Yakimov A S 
Published: December 2019

Abstract
Results of a numerical study of the three dimensional supersonic flow over a spherically blunt cone fluctuating in a pitch plane taking into account mass breaking down blowing and heat transfer between body and flow are presented. Influence of the body fluctuation with angular velocity in range of 0–100 deg/s on surface temperature distribution and heat transfer characteristics is considered. The effect of the body fluctuation on characteristics of conjugated heat and mass exchange in a thermal protection material is analyzed.
Interaction of pressure waves with a bubble layer near free surface of a liquid
Authors: Ogorodnikov I A 
Published: December 2019

Abstract
The radiation of pressure waves by a bubble layer near the free surface of a liquid excited by a high-intensity sound pulse has been studied. It was shown that the bubble layer exhibits the properties of a resonator with one partially transparent boundary. Bubbles on the boundary of the layer due to the interaction through the self-consistent field with the bubbles inside the layer perform collective pulsations. It was found that the emission spectrum of the layer is ruled. The lines of the emission spectrum of a layer have a regular composition and lie above the frequency of the intrinsic pulsations of bubbles.
Drop entrainment in two-phase non concurrent film flow
Authors: Saushin I I , Goltsman A E , Salekhova I G 
Published: December 2019

Abstract
When the motion vectors of the media are collinear, well-known experimentally obtained empirical criteria are used to assess the conditions for the drop entrainment by the gas flow from the surface of a moving liquid film. However, blowing a liquid film at an angle with gas causes a tangential component in the film movement, which is an additional factor affecting its thickness and the velocity profile. The paper presents the correctness of the criterion of the conditions for the drop entrainment and the effect of the noncollinearity of the vectors of the media counterflow on the dynamics of a liquid film estimated from the results of numerical simulation.
Viscosity and rheology of the ethylene glycol based nanofluids with single-walled carbon nanotubes
Authors: Rudyak V Ya , Tretiakov D S 
Published: December 2019

Abstract
The work is devoted to the experimental study of the viscosity and rheology of nanofluids based on ethylene glycol with single-walled nanotubes. Polyvinylpyrrolidone is used as a dispersant. The weight concentration of nanotubes ranged from 0.01 to 1%. In all cases, the weight concentration of the dispersant was controlled. The measurements were carried out in the temperature range from 20 to 40°C. It was shown that at all weight concentrations the solution of ethylene glycol and dispersant is a Newtonian liquid, and at a maximum concentration (4%) the viscosity of the solution is two and a half times higher than the viscosity of ethylene glycol. At the same time, all the studied nanofluids turned out to be non-Newtonian and have a pseudoplastic character. It was established that ultrasonic treatment of nanofluids leads to partial degradation of the dispersant and a decrease the base fluid viscosity. The degree of this degradation increases with increasing ultrasonic processing power. With the considered low weight concentrations of nanotubes, the dependence of the viscosity coefficient of the nanofluid on temperature is determined by the corresponding dependence of the base fluid.
Numerical simulation of the oil displacement process from a porous medium by nanofluid
Authors: Minakov A V , Mikhienkova E I , Pryazhnikov M I , Zhigarev V A 
Published: December 2019

Abstract
Numerical simulation of the oil displacement process from a porous medium by nanofluid was carried out. To describe this process a flow model of two immiscible fluids taking into account the surface tension forces and the wetting angle was used. The simulation results of the penetration of fluid with nanoparticles into a porous medium are obtained using the example of the oil displacement. The nanoparticles addition to the displacing fluid affects the process of oil displacement from porous medium significantly. SiO2 particles with a size of 5 nm were used as nanoparticles. The concentration of nanoparticles ranged from 0 to 1 wt.%. The main reason for the increase in ORF (oil recovery factor) during oil displacement by nanofluid is the improvement of rock wetting.
Experimental study of heat transfer under flow boiling ozone-safe refrigerants in microchannels
Authors: Shamirzaev A S , Mordovskoy A S , Kuznetsov V V 
Published: December 2019

Abstract
This paper devoted to experimental measurement of heat transfer and critical heat fluxes into horizontal microchannels under flow boiling of refrigerant 141b. The copper experimental test section contains two microchannels with a 2x0.36 mm cross-section. Average heat fluxes versus wall superheat in the range of mass fluxes from 600 to 2100 kg/m2s and heat fluxes up to 140 W/cm2 are presented. A slight deterioration in heat transfer relative to pool boiling with heat fluxes close to critical was observed.
Exergetic evaluation of a thermal station “Central’naya” and Vladivostok thermal station – 2
Authors: Bibikov D R , Dorogov E Y , Goncharenko Y B , Shtym K A 
Published: December 2019

Abstract
The article discusses the issue of increasing the efficiency of the main equipment of thermal power plants. Currently in power systems, different types of power plants are used. The projecting and choice of the power plant is performed mainly based on criterion of efficiency. The primary indicator is the thermic efficiency calculated traditionally by heat balance method. The current article proposes the use of exergy method of determining of energy efficiency, allowing performing relative (exergetic efficiency) and absolute evaluation of the degree of thermodynamic perfection of the system. The exergy losses in elements of the equipment were calculated on the example of a gas turbine installation.
Influence of gas flow rate on the synthesis of gas hydrate of freon 134a by the method of explosive boiling of liquefied gas in water volume
Authors: Meleshkin A V , Bartashevich M V , Kozlov A N 
Published: December 2019

Abstract
This paper is part of the work aimed at finding the optimal parameters of the method of explosive boiling of liquefied hydrate-forming gas in a volume of water during decompression. The paper presents an experimental study of the effect of gas flow during decompression on the synthesis of gas hydrate. The studies were carried out at constant operating parameters, with a change in gas flow during decompression. The studies were conducted on hydrate-forming gas Freon 134a.
Simulation of thermal characteristics of heat supply systems in variable operating modes
Authors: Rafalskaya T A 
Published: December 2019

Abstract
The operation of heat supply systems is often associated with the inefficient use of heat energy. New formulas have been obtained for calculation of variable thermal and hydraulic modes of heat exchangers of heat supply systems. The rather high correlation coefficient of the operational and design parameters of the heating system operation makes it possible to use the obtained formulas to optimize the variable operating modes of heat exchangers when using programmable regulators.
Investigation of steam-air gasification of mechanically activated coal fuel at a setup with thermal capacity of 1 MW
Authors: Butakov E , Burdukov A , Siniakov I , Chernova G 
Published: December 2019

Abstract
In this work, steam-air gasification of mechanically activated coal was studied experimentally. To increase the energy efficiency of coal flaring, a technology with mechanochemical activation of coal by the mills is being developed at the Institute of Thermophysics SB RAS. The technology is aimed at increasing coal reactivity and can be used to replace high-reactive expensive and difficult-to-obtain fuel oil for ignition and lighting of pulverized coal boilers of thermal power plants (TPP) using mechanically activated microground coal. In experiments, we used brown coal from a deposit in Siberia. The results on the effect of steam flow rate to the continuous gasifier and the point of injection were obtained. During the experiment, the time of autothermal regime stabilization was measured, and it was 105 s. Five different regimes of continuous gasifier operation have been tested. For steam-air gasification with a steam flow rate of 32 kg/h and air excess coefficient of 0.5, concentrations of combustible gases at the end of the continuous gasifier were obtained: H2 (vol.%) = 6.3; CO (vol.%) = 10.7; CH4 (vol.%) = 0.4.
Analytical investigation of the fuel rod destruction and melt relocation along the surface of the fuel rod
Authors: Usov E V 
Published: December 2019

Abstract
To simulate fuel rod thermal destruction, analytical approaches were developed. Approaches are based on solving the Stefan problem and solving the equation of motion of the molten materials. The paper contains a brief description of the ways to obtain analytical solutions and applicability limits of the solutions. Calculation of the mass of the melt that left the central part of the fuel rod is presented. Proposed analytical solutions can be used only to simulate the first stage of the accidents from melting inception of the cladding to destruction of the whole fuel assembly.
Low temperature plasma-assisted nitriding of austenitic steel in a ferromagnetic enhanced inductive discharge
Authors: Isupov M V 
Published: December 2019

Abstract
Plasma-assisted nitriding of austenitic stainless steel AISI 321 has been performed with the use of a ferromagnetic enhanced inductive discharge as the source of nitrogen ions and radicals, in the temperature range of 300–400°C, gas pressure of 50 mTorr and ion densities of about (2.5–7.7)·1010 cm−3. A significant increase in the nitriding rate was achieved, in comparison with a low temperature glow-discharge nitriding process. A possible mechanism of the nitriding rate increase is a high atomic nitrogen density achieved in the ferromagnetic enhanced inductively coupled plasma.
Formation of nanostructures on the surface of KTP single crystals by argon cluster ion beam
Authors: Nikolaev I V , Korobeishchikov N G , Roenko M A 
Published: December 2019

Abstract
In this work, the surface of potassium titanyl phosphate (KTP) single crystals has been processed by argon cluster ions having low energy per atom E/Nmean
= 12.5 eV/atom. The formation of periodic nanostructures has been studied using atomic force microscopy (AFM) and the power spectral density (PSD) functions. To evaluate the processing efficiency, the dependence of the etching rate of KTP on the incident angles of cluster ions has been investigated. It is shown that the average etching rate 〈Vetch〉 varies between 0.46 and 1.1 nm/min with an incident angle change from 0° to 70°.
Investigation of the effect of an acoustic field on the flow regime of a microjet
Authors: Perepelitsa B V 
Published: December 2019

Abstract
A detailed visual study of the structure of a circular laminar micro-jet flowing into the atmosphere under the influence of an acoustic field was carried out. A jet of air flowed out of the profiled glass nozzle with a diameter of 500 microns. Characteristic vortex and coherent structures and zones with intense turbulent mixing were found in the flow. The features of the formation of vortex structures in a laminar jet under the influence of the acoustic field and the vibrational-rotational flow regime in the jet at the outlet of the nozzle were identified.
Investigation of electrophysical and thermophysical characteristics of a low frequency nitrogen inductive discharge
Authors: Pinaev V A , Isupov M V 
Published: December 2019

Abstract
A low-frequency (100 kHz) ferromagnetic enhanced nitrogen inductive discharge has been experimentally investigated in the nitrogen pressure range of 5–55 Pa and discharge current density of 20–80 mA/cm2. Dependence of the discharge electric field strength E on the gas pressure was measured for various discharge currents. Dependence of the neutral gas temperature on the gas pressure and discharge current was determined using optical emission spectroscopy, from the measured 0–0 vibro-rotational band of the second positive system of molecular nitrogen (C3Πu–B3Πg). Based on the determined neutral gas temperatures, values of the reduced electric field strength E/N were calculated.
Temperature distribution of gas flows in a grid area activated by chemical vapor deposition
Authors: Safonov A I , Panin D Y , Timoshenko N I 
Published: December 2019

Abstract
The scheme of gas temperature measurements in flows of rarefied precursor gases by HW CVD was elaborated. The gas flow temperature of air, argon and hexafluoropropylene oxide was measured at different mass flow rates. The presence of a large well-heated area in gas flows forward the activator was discovered. Asymmetric heating of the gas flow in areas above and under an activator was observed. Cooling of gas flows by increase in the precursor gas mass flow rate was confirmed. The parameters, optimal for the formation of the area with uniform temperature flows above the surface of substrate holder, were determined.
Mutual diffusion in liquid alloys of heavy alkali metals with bismuth
Authors: Abdullaev R N , Khairulin R A , Stankus S V 
Published: December 2019

Abstract
Interdiffusion coefficients for liquid cesium–bismuth alloys containing from 20 to 40 at. % Bi are measured using a gamma-ray attenuation technique. The obtained results are compared with the data on mutual diffusion in the rubidium–bismuth melts studied earlier. The comparison shows that the concentration dependences of the interdiffusion coefficient for Rb–Bi and Cs–Bi liquid systems demonstrate common features, namely, pronounced maxima at certain compositions. The origin of these features is briefly discussed.
Thermal conductivity of rubidium–bismuth alloy of equiatomic composition
Authors: Agazhanov A Sh , Abdullaev R N , Samoshkin D A , Stankus S V 
Published: December 2019

Abstract
Experimental data on the thermal conductivity and thermal diffusivity of a liquid alloy RbBi of the equiatomic composition in the temperature range from the liquidus line to 1174 K have been obtained. The measurements were carried out on the basis of the laser flash method using a sealed steel cell. For studied properties the approximation equations and a table of recommended values are presented. The analysis of the obtained results confirms the existing assumption about liquid rubidium-bismuth alloys as associated solutions.
Experimental study of boron nitride in a wide temperature interval
Authors: Agazhanov A Sh , Samoshkin D A , Kozlovskii Yu M , Stankus S V 
Published: December 2019

Abstract
In the present work thermal conductivity (λ), thermal diffusivity (a), heat capacity (cp
) and linear thermal expansion coefficient (LTEC, α) of boron nitride (BN) with hexagonal modification were studied in a wide temperature range of 298–1273…1474 K. The experiments were performed on the samples made from the same starting material with a density of 1.64 g/cm3 at room temperature. For all studied properties the approximation equations were obtained and the tables of recommended values were developed that can be used for various scientific and practical applications.
Low-parametric equation for calculating the methane viscosity coefficient of liquid, gas and fluid states
Authors: Kaplun A B , Dutova O S , Meshalkin A B 
Published: December 2019

Abstract
A low-parametric equation for calculating the CH4 viscosity coefficient in liquid, gaseous, and fluid states was derived using previously obtained unambiguous dependence of the “excess” viscosity of liquids and dense gases on the density of internal energy. The equation describes the viscosity of methane at the temperatures from 91 K to 620 K and pressures of up to 50 MPa in the limits of experimental error.
Investigation of thermal conductivity coefficient of aqueous suspension with carbon nanotubes
Authors: Pryazhnikov M I , Minakov A V , Guzei D V , Lobasov A S , Platonov D V 
Published: December 2019

Abstract
The dependence of thermal conductivity of suspension on the concentration of single-walled carbon nanotubes was investigated. Mass concentration of nanotubes ranged from 0.05 to 0.5%. Sodium dodecyl sulfate was used as a surfactant. The enhancement of 34.8% were achieved for thermal conductivity coefficient of suspensions at 0.5wt.% of CNT.
Waves of large amplitudes in geophysical and technical applications
Authors: Derzho O G 
Published: December 2019

Abstract
The paper addresses the asymptotic models that explicitly describe the structure of solitary waves with recirculation zones for some special but important incident stream configurations, which occur in geophysical and industrial applications . The key feature that allows building a theoretical model is that shear and/or stratification of the media in geophysical applications or axisymmetric swirling incoming flows in technical applications have an almost linear equation for vorticity. It happens when the upstream flow is almost linearly stratified in the case of geophysical applications and a swirling flow has almost solid body rotation if industrial applications are considered. It is shown that the resulting equation for the stationary amplitude function of the solitary waves is described by a generalized Korteweg-de Vries equation in the outer zone, consistenty matched with a new complicated equation in the inner zone, which contains the recirculation core. This recirculation zone exists for wave amplitudes that are slightly greater than a certain critical amplitude, for which a wave breaking initially occurs. The recirculation zones have a universal structure, so that their width increases up to the semi-infinite bore as the amplitude of the wave increases from a critical amplitude to a certain maximum amplitude. This amplitude may be sensitive to the actual configuration of the incident flow. Regardless of the physical nature, solitary waves are described by two types of equations with different non-linearities. The type of nonlinearity in the inner zone where the vortex core is located is then caused by the position of the vortex core at the outer boundary or in the middle of the flow.
Analysis of cycles of air-cooling machines with multi-step compression and expansion
Authors: Gorbachev M 
Published: December 2019

Abstract
The technique has been developed for estimating and analysing the thermodynamic efficiency of reversible cycles of air-cooling machines of multi-step compression and expansion using the exergy method. Analytical dependences have been obtained, and the influence of initial parameters on the main energy characteristics and thermodynamic efficiency of the cycles, expressed by exergy efficiency, has been analyzed. Numerical studies were carried out with number step compression and expansion from n = 1 to ∞. Shown that with n = ∞ the cycle of the air cooling machines with multi-step compression and expansion were transformed in to Carnot cycle, and with n = 1 it goes into a cycle with isobars supply and removal of heat to the working body.