bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental study of wavy-annular flow in a rectangular microchannel using LIF method
Authors: Bartkus G V , Kuznetsov V V 
Published: December 2021

Abstract
This article aims at studying gas-liquid flow in a rectangular microchannel with a high aspect ratio (200 × 2045 μm). Liquid and gas phases were 95% ethanol and nitrogen mixture. Experimental flow characteristics are obtained using high-speed visualization and laser-induced fluorescence (LIF) methods. Using the LIF method for wavy-annular flow, the average film thickness, liquid film distribution, and liquid film width were measured. The dependences of the liquid film width and the average film thickness on gas superficial velocity are presented in graphical form and analyzed. An increase in gas superficial velocity causes growth of the liquid film width and thickness of the liquid film, which indicates the process of liquid transfer from the menisci area to the liquid film. For different liquid velocities and the same gas superficial velocities, close values of averaged liquid film thickness were observed for flow with 2D waves and 3D waves on liquid film.
Application of microfluidic technologies for enhanced oil recovery
Authors: Pryazhnikov M I , Minakov A V , Pryazhnikov A I , Denisov I A , Yakimov A S , Nemtsev I V 
Published: December 2021

Abstract
This paper presents the results of testing microfluidic technology for oil displacement problems using cheap and quickly manufactured chips made of polymethylmethacrylate (PMMA) by milling. The oil displacement process from a microfluidic chip simulating a homogeneous porous medium is studied. The microfluidic chip was manufactured by milling of polymethylmethacrylate. The size of the microchannels was 200 microns. The paper presents the results of visualization and microscopy of the oil displacement process. The effect of water flow on the efficiency of oil displacement from the microfluidic chip was studied.
CNN-based visual analysis to study local boiling characteristics
Authors: Chernyavskiy A N , Malakhov I P 
Published: December 2021

Abstract
Visual analysis allows an estimate of different local boiling characteristics including bubble growth rate, departure diameters and frequencies of nucleation, nucleation site density and evolution of bubbles and dry spots in time. At the same time, visual determination of the presented characteristics in case of big amounts of data requires the development of the appropriate software which will allow not only determination of bubble location, but also an estimate of their sizes based on high-speed video. The presented problem can be solved by using the instance segmentation approach based on a convolutional neural network. In the presented work Mask R-CNN network architecture was used for estimation of the local boiling characteristics.
Experimental investigation of water-nitrogen flow in microchannel with high aspect ratio (with the 20 µm gap)
Authors: Dementyev Y A , Ronshin F V , Chinnov E A , Evstrapov A A , Karpich S S , Gusev V S , Kabov O A 
Published: December 2021

Abstract
This study is devoted to the experimental investigation of two-phase water-nitrogen flow in the slit microchannel with a gap of 20 µm and a width of 10 mm. The technology of microchannel fabrication has been developed and described in detail. Experiments were conducted in adiabatic conditions. Using a modified schlieren system, four flow patterns have been observed and described: jet, bubble, churn, and annular. Flow pattern map was plotted according to obtained patterns. Moreover, a two-phase pressure drop was measured. Dependencies between two-phase pressure drop and superficial liquid and gas velocities have been investigated.
A review of modern numerical and analytical models of heat transfer in a dielectric layer during melting due to microwave radiation
Authors: Karelin V A , Salomatov Vl V 
Published: December 2021

Abstract
In this work, numerical and analytical solutions of heat transfer in a dielectric layer during melting in the microwave field were considered. We considered solutions, where the source term was obtained based on the solution of Maxwell equation, as well as using the Lambert law. The conditions applicable for analytical solutions, allowing the parametric analysis, are determined. The areas of application of the technology of microwave melting of dielectrics, in particular with melting ice on water, defrosting products, etc., were also considered.
Numerical simulation of the flow around a circular cylinder at Reynolds number Re = 3900 by means of the PANS model
Authors: Shebelev A. , Gavrilov A. , Dekterev A. , Sentyabov A. 
Published: December 2021

Abstract
The paper presents a study of various versions of PANS approach for turbulence simulation using a flow around a cylinder at Reynolds number Re = 3900 as an example. The considered models were implemented in the in-house CFD package. The influence of the method of determining the parameter f
k on the flow behind the cylinder was studied. The first method assumed a constant value of f
k. In the second method, the f
k value depended on the local computational mesh scale and the shear scale.
Calculation of heat transfer coefficients for explosive boiling of a liquid under conditions of low pressure
Authors: Brester A E , Zhukov V I , Shvetsov D A , Pavlenko A N 
Published: December 2021

Abstract
The paper discusses the problem of determining the temperature head for calculating the heat transfer coefficient during explosive boiling of a liquid on a smooth horizontal surface under conditions of low pressure. The task of the work is obtaining the method for determining the characteristic pressure for calculating the temperature of saturated vapors. As a result, it is found that the difference between the heat transfer coefficients calculated at the pressure specified at the beginning of the experiment and the pressure averaged over time differ on average by 5%.
Investigation of heat transfer during evaporation of droplets of Fe3O4 nanofluids from biphilic surfaces
Authors: Starinskaya E M , Miskiv N B , Lei M K , Terekhov V V 
Published: December 2021

Abstract
In this work, unique biphilic substrates were prepared with a sharp spatial gradient of the contact angle of wetting. Experimental studies of the process of evaporation of liquid droplets lying on the structured surfaces have been carried out. In the experiment, the dynamics of the temperature of an evaporating droplet was compared depending on its orientation in space. It was found that suspended droplets of 0.1 wt % Fe3O4 nanofluid have a higher evaporation temperature and a higher evaporation rate as compared to sessile droplets.
The heat supply object thermal regime under conditions of gas infrared emitter and air exchange system joint operation
Authors: Kuznetsov G V , Maksimov V I , Nagornova T A , Vyatkin A V 
Published: December 2021

Abstract
The paper presents the results of experimental studies on the formation of thermal comfort conditions in large premises with the joint operation of gas infrared emitters and air exchange ventilation system. The values of temperatures and heat fluxes on the clothing surface under natural and mixed convection conditions were obtained. It has been established that the air exchange system operation in the premises reduces the temperature drop of the person clothes surface, respectively, a more favorable temperature condition is achieved in the working area.
Numerical analysis of the equipment position influence on the premises thermal regime under gas infrared emitter operation and mixed convection conditions
Authors: Borisov B V , Kuznetsov G V , Maksimov V I , Nagornova T A , Vyatkin A V 
Published: December 2021

Abstract
The analysis of mathematical modeling results on premise heating by a gas infrared emitter (GIE) during supply and exhaust ventilation operation is presented in this article. The model is presented in a one-dimensional non-stationary setting for an incompressible medium with allowances for the radiant heat flux transfer between opaque solid surfaces in the air. The air is transparent to thermal radiation. The traditional k-ε model is used for turbulence modeling. The possibility for creating comfortable conditions in the area of a horizontal surface with different heights, imitating laboratory equipment, is analyzed.
Dual axis solar tracking system for a parabolic dish CPU water heater
Authors: Alwan Naseer T. , Milia H. M , Shcheklein S E , Matveev A V 
Published: December 2021

Abstract
The solar parabolic dish water heater is highly efficient but has limited hours of work only when sunlight is perpendicular to its surface. Therefore, this work aims to continue the work of the solar parabolic dish in the daytime using a dual tracking system, depending on the geographic location of the system (longitude and latitude angles) and using the C # programming language. To verify the effect of the dual-axis solar tracking system, the current study considered two types of solar parabolic dishes, the first was fixed, and the second was a rotating dish (by the dual tracking system). It was observed that the water temperature at the outlet of the tracking type solar water heater is 22% higher than that for the fixed dish type; this means that the proposed system has improved the temperature of water in the heat exchanger. Therefore, the highest water temperature value of about 51.4ffiC was at the outlet of the heat exchanger for the tracking type at 1:00 pm, while the temperature recorded for the fixed type was about 46.1ffiC. The highest energy gained from the solar heating system was at 1:00 pm for both types, which was about 76.9 W from the tracking type and 54.7 W from the fixed type. It was also observed that in the fixed dish type, most energy losses occurred during the daytime, while for the tracer of the dish type, useful energy was gained during most of the sunny working hours depending on the solar radiation intensity.
Numerical estimation of thermal ignition conditions for reactive medium with Gaussian distribution of activation energy
Authors: Donskoy I G 
Published: December 2021

Abstract
The article investigates the solutions of the one-dimensional stationary integro-differential heat equation. The source of heat release is determined through the Gaussian distribution function of the activation energy. In such a statement, the critical conditions for the existence of a bounded solution depend on the distribution variance. With the help of numerical methods, such dependences are obtained; for their explanation, the analytical approximations of the thermal explosion theory are used.
Study of the dependences of coal-wood composition, identification of combustion features of the obtained composite materials
Authors: Kuznetsov A V , Gorelikov E U 
Published: December 2021

Abstract
In the study of the combustion of samples, it was found that, other things being equal, under the experimental conditions and with the fixed technical characteristics of the fuel, different parameters of the flame are observed, namely, the speed of reaching a stationary mode, the completeness of fuel combustion, the size and distribution of temperature zones strongly depend on the methods used to carry out the mechanical fuel processing. Comparison of the results showed that under the same experimental conditions, the temperature distribution along the length of the experimental stand, in a stationary mode of operation, is higher for the composite fuel. In the case of composite fuel, 70 percent of the fuel burned up was observed at a 1 m section, which is indicative of these fuel consumption and kindling processes at industrial thermal power plants.
Synthesis of methanol in microchnnel
Authors: Dimov S V 
Published: December 2021

Abstract
Systematic experimental data have been obtained on the results of catalytic chemical reactions in a microchannel reactor for the synthesis of methanol from synthesis gas. Synthesis gas contains hydrogen, carbon monoxide and dioxide, as well as nitrogen in the ratio 58/29/5/8. The experiments were carried out at different flow rates in the temperature range 190-260C. Experiments were also carried out for methanol synthesis in fixed bed reactor at different synthesis pressures.
Distributed ferromagnetic enhanced inductive plasma source for plasma processing
Authors: Isupov M V 
Published: December 2021

Abstract
New experimental data on the plasma density profiles have been obtained for a low-frequency (100 kHz) distributed ferromagnetic enhanced inductive plasma source at different locations of inductive discharges. An ability to control the plasma density profiles in a large gas discharge chamber in order to achieve a uniform treatment of a substrate is demonstrated. The differences between the obtained results and literature data for a distributed ferromagnetic enhanced inductive plasma source combined with a radio-frequency inductive discharge are discussed.
Influence of synthesis parameters and thermal annealing on grain size of polycrystalline aluminum thin film
Authors: Merkulova I E 
Published: December 2021

Abstract
The thin polycrystalline aluminium films were synthesized on monocrystalline silicon substrates by ion-plasma sputtering. The synthesis was carried out at temperatures of 80 and 160°C and deposition rate of 10 and 110 nm/min. As-deposited films were annealed for 15 h at 550°C. The morphology of aluminium films before and after annealing was obtained using SEM images. The surfaces of as-deposited Al thin films, synthesized at high temperature, were uneven, while for low temperature films they were smooth enough with Al hillocks on the top of the film. After thermal annealing, morphology of the films was changed slightly. XRD patterns were obtained to calculate the average Al grain size of as-deposited and annealed films. The XRD analysis showed that an increase in the synthesis temperature leads to an increase in the average grain size from 50 to 84 nm and that increase in the rate of Al film synthesis leads to an increase in the average grain size from 50 to 63 nm. As the result of annealing, the average grain size increased for all samples and the final meaning was from 78 to 140 nm.
Numerical simulation of domain wall motion in a surface discharge over a ferroelectric
Authors: Bobrov M S , Hrebtov M Y , Yudin P V 
Published: December 2021

Abstract
The article presents a simplified numerical simulation of a vacuum ferroelectric cathode operating in a low-current mode (without surface plasma formation). The field emission from the cathode was simulated for the range of applied electric field magnitudes. The polarization domain growth process during the charging of ferroelectric surface was simulated using Landau-Ginzburg-Devonshire model. Interaction of the electrons with a depolarization field of a domain wall led to an attraction of the electrons to the polarization domain boundaries. A close to the linear dependence of the equilibrium domain wall position from the applied electric field was found with the total emitted charge proportional to the domain size.
Investigation of the effect of air humidity on the condensation growth of levitating liquid microdroplets
Authors: Zaitsev D V , Shatekova A I 
Published: December 2021

Abstract
Two-dimensional structured arrays of liquid microdroplets levitated over a hot liquid surface have been investigated in several recent papers, but the nature of this phenomenon has not yet been fully understood. In this work we investigate the effect of air humidity on the condensation growth of levitating liquid microdroplets. It was found that the higher the relative humidity of the surrounding air, the lower the rate of the droplet growth.
Evaporation of levitating liquid microdroplets over a dry heated surface
Authors: Kunts K A , Zaitsev D V , Kabov O A 
Published: December 2021

Abstract
The present work is devoted to the study of the evaporation process of micro-sized water droplets levitating over a heated dry substrate. The study of this process is relevant in connection with the development of spray cooling systems. Due to the extreme complexity of this phenomenon the mechanism of spray cooling is still not fully understood. In this work we studied the evaporation of micro-sized water droplets levitating over a dry substrate heated from below. The working area was open to the atmosphere. Evaporation was studied in the temperature substrate range from 23 to 95°C. During the experiment local values of the substrate temperature and geometric characteristics of the drop were determined. In the experiment a shadow method with high spatial resolution was used, shooting was performed with a high-speed camera.
Experimental setup for studying two-phase flows in micro-and minichannels at ultra-high heat fluxes: methodology and first experimental results
Authors: Zaitsev D V , Belosludtsev V V 
Published: December 2021

Abstract
The study of phase-change phenomena under high and ultra-high heat fluxes is urgent because of fast development of electronics and microelectronics. We have developed a test section with power of 3.5 kW with a heater of 1x1 cm2 and adjustable geometry of the channel for achieving ultra-high heat fluxes in flow boiling and shear-driven liquid film experiments. The methodology of calculating heat losses in the test section is proposed and verified by flow boiling experiment versus another well studied test section. Observed trend of decrease of relative heat losses with increase in the heat flux makes it possible to assume that the heat flux as high as 2.5 kW/cm2 can be reached by this test section.
The low temperature heat capacity of Li2Mo0.05W0.95O4
Authors: Musikhin A E , Bespyatov M A , Kuzin T M , Grigorieva V D , Shlegel V N 
Published: December 2021

Abstract
The heat capacity of a lithium tungstate single crystal doped by 5% molybdenum Li2Mo0.05W0.95O4 in the range of 78.5–302.8 K was measured by the adiabatic method. No anomalous behavior of heat capacity was found. The heat capacity function was obtained in the range of 0–303 K by extrapolating to zero temperature and fitting experimental points. Thermodynamic functions of entropy, enthalpy increment and Gibbs free energy at 298.15 K were calculated using the obtained data.
Heat capacity of bismuth cobalt oxides doped by neodymium and holmium in the temperature range of 319-1000 K
Authors: Matskevich N I , Samoshkin D A , Stankus S V , Tkachev E N , Zaitsev V P , Trifonov V A , Semerikova A N , Anyfrieva O I 
Published: December 2021

Abstract
The heat capacity of bismuth cobalt oxides doped by neodymium and holmium was measured for the first time by differential scanning calorimetry in the temperature range of 319-1000 K.
The interdiffusion in liquid alloys of alkali metals with lead
Authors: Abdullaev R N , Khairulin R A , Stankus S V 
Published: December 2021

Abstract
The mutual diffusion in liquid cesium-lead alloys containing from 20 to 70 at.% Pb is investigated by a gamma-ray attenuation technique. The obtained data are compared with the results of similar studies for Li-Pb, Na-Pb, and K-Pb melts, carried out by us earlier. The concentration dependences of the interdiffusion coefficient for alkali-lead liquid systems demonstrate pronounced maxima in the vicinity of 20 or 50 at.% Pb. These phenomena confirm a tendency for chemical short-range ordering in liquid alloys.
Experimental study of R-32/R-125 (75/25 wt.%) thermal conductivity in the vapor phase
Authors: Raschektaeva E P , Stankus S V 
Published: December 2021

Abstract
The article presents the investigation of the thermal conductivity of binary mixture R-32/R-125 (75/25) in the gas state. Measurements were taken with a coaxial cylinders method in the temperature range of 305-426 K and the pressure range of 0.1-1.8 MPa. The dependence of thermal conductivity on pressure and temperature was discussed. The equations for thermal conductivity on the dew line and in the ideal gas state were obtained.
Thermal diffusivity of corrosion-resistant coating SDP-1
Authors: Agazhanov A Sh , Samoshkin D A , Stankus S V 
Published: December 2021

Abstract
In the present work, the thermal diffusivity of the SDP-1 grade nickel alloy was investigated in the wide temperature range of 300-1476 K. The SDP-1 alloy (Ni-Co-Cr-Al-Y) is the heat-resistant coating for blades of gas turbine plants, providing protection against sulfide-oxide corrosion in the temperature range of 1070-1220 K. The measurements were performed by laser flash method using LFA-427 apparatus. The estimated errors of the obtained data were 2-5% depending on temperature. The thermal diffusivity approximation equations and a table of reference values for various scientific and practical applications were obtained.
Experimental studies of in-line gasification of mechanically activated coal fuel
Authors: Bondarchuk E N , Pochtar A S , Vinogradov S V , Popov V I 
Published: December 2021

Abstract
The 1 MW experimental stand was modernized with a scroll swirler and a crushed fuel supply system. Comparative data on combustion and gasification of coal fuel crushed in high-stress mills - disintegrator, vibrocentrifugal and hammer mill - at a stand with a thermal power of 1 MW were obtained. The experiments used coal of the Kuznetsk Basin, grade D, with technical characteristics: Wr, % = 5.4; Ar, %=22.3; Vr, % = 32.3; Qsr, MJ/kg = 20.0. Elemental analysis showed that: Cr, %=54.6; Hr, % = 4.1; Nr, % = 1.3; Sr, % = 0.5; Or = 11.8. In experiments with grinding coal on a disintegrator mill, the value of H2 = 4.5 vol.% and CO = 9.4 vol.%, when grinding in a vibro-centrifugal mill, the values of H2 = 0.6 vol.% and CO = 5.8 vol.%, when grinding in a hammer mill, the values of H2 = 0.3 vol.% and CO = 2.8 vol.%. When studying the combustion of mechanochemically treated coal samples, it was found that, all other things being equal, the gasification parameters, namely, the gas concentration and the distribution of temperature zones, depend strongly on the type of equipment used for processing. In particular, processing to approximately the same degree of fineness in mechanical mills-activators with constrained impact and in free impact mills (disintegrators) resulted in different flame parameters.
Monitoring and control of polymer production line based on machine learning
Authors: Abdurakipov S 
Published: December 2021

Abstract
The work is devoted to the development of an application for monitoring and controlling the state of equipment (extruder) for the petrochemical industry based on sensor readings using a machine learning model. The statistical relationships of the technological process parameters are analyzed, the most significant parameters influencing the occurrence of failures are determined using SHAP values. The hypotheses regarding the effectiveness of various machine learning algorithms in relation to the real problem of predicting the technical state of the extruder are tested. A gradient boosting model has been developed to predict the probability of extruder shutdown due to the formation of polypropylene agglomerates. The developed application allows interpreting the results of the model, which makes it possible to select the most important process parameters that have the greatest impact on the probability of extruder failure, and also proposing a prototype of an extruder monitoring system based on sensor readings using a machine learning model.