bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical simulation of the formation of dry spots during film evaporation
Authors: Shebelev A V , Minakov A V , Kochkin D Y , Kabov O A 
Published: December 2021

Abstract
This paper presents a developed methodology for calculating heat and mass transfer processes in a cylindrical evaporation cell. The mathematical model reproduces all significant features of the evaporation cell geometry. In this cell, a layer of liquid is formed on a substrate with a diameter of 51 mm, heated below. To simulate heat transfer during film evaporation on a heated substrate, a numerical technique based on the Volume of Fluid method was used. The developed model was used to study the process of dry spot formation during film evaporation. The calculated data are compared with the experiment on the profile of the free surface of the film during evaporation and rupture. In general, results of this testing demonstrated good agreement with experiment. As a result, it was shown that developed numerical method makes it possible to describe process of formation dry spots.
Influence of vacuumetric pressure on thermal properties of high-temperature radioactive graphite-nitrogen system
Authors: Shavaleev M R , Barbin N M , Terentyev D I , Osipenko S I , Belkin D S 
Published: December 2021

AbstractTo improve and specify the method proposed by the authors for high-temperature processing of reactor graphite in a nitrogen atmosphere, the thermodynamic data of the formed nitride compounds are supplemented and the system is calculated at a vacuum pressure of 0.5 atm. The data obtained are compared with the values at atmospheric pressure.
Experimental and theoretical investigations of traditional solar still productivity in cold climatic
Authors: Alwan Naseer T. , Shcheklein S E , Ali O M 
Published: December 2021

Abstract
Solar distillation is an important technology to get potable water from saltwater using clean and free solar energy. In the current study, an experimental and theoretical investigation of a single-slope traditional solar still was carried out, and the freshwater productivity and thermal efficiency were evaluated for four typical days (19/06, 17/07, 22/08, and 15/09) of 2019 by implementing temperature parameters in different points of the solar still, and the weather parameters such as solar radiation, and ambient air temperature. The study showed an acceptable agreement between the experimental and theoretical results with an average of 6.6% measured deviation of the experimental data. It was noticed that the highest values of productivity were recorded on July 17, 2019.
Verification of the model for calculating conjugated heat and moisture transfer when moistening porous material
Authors: Sterlyagov A N , Nizovtsev M I 
Published: December 2021

Abstract
This paper presents a mathematical model used to calculate conjugated heat and moisture transfer in porous building materials. The initial region of the sorption isotherm for a given material was reconstructed based on the experimental data on moisture transfer in aerated concrete. The calculation results are compared with the experimental data on porous material moistening under different heat and moisture conditions. The calculations performed confirmed that model works well for sorption moistening, and not quite well with capillary impregnation. This does not exclude the possibility of engineering calculations using this model; however, at over-hygroscopic region their accuracy is not quite high.
Visualization in the Ranque-Hilsch vortex tube using high-speed video recording
Authors: Gordienko M R , Yavorsky N I , Pravdina M Kh , Kakaulin S V , Kabardin I K 
Published: December 2021

Abstract
Visualisation via video recording was carryed out in a Ranque-Hilsch vortex tube with a square cross-section. Video files were captured at recording speeds from 1000 to 10 000 frames per second. The best video files were obtained at a shooting frequency of 7600 frames per second with an input pressure of 1 bar. The video confirmed the presence of a double helix in the flow core in the second section of the tube. The video files showed the presence of a circulation zone between the flow core and the periphery, which is constantly changing over time. It can be clearly seen the angle at which the particles move in the peripheral flow.
Development of the method of laser Doppler anemometry for diagnostics of turbulent flows at high speed
Authors: Gordienko M R , Kabardin I K , Meledin V G , Kabardin A K , Pravdina M Kn , Rahmanov V V , Kakaulin S V , Pavlov V A , Yavorsky N I 
Published: December 2021

Abstract
The aim of the work was to develop a laser Doppler anemometry method for high-speed turbulent aerodynamic flow diagnostic. As a result, this allowed us to measure two projections of the velocity vector in the range of 0.1 - 400 m/s with a relative error not exceeding 0.5%. The measurement area was 0.1x0.1x0.5mm. The positioning device moved the measuring unit in the area of 250 x 250 x 250 mm with an accuracy of 0.1 mm. This method also provides the ability to measure local flow rate fluctuations.
Charged particles density distribution in the cathode fall region of the glow discharge in helium
Authors: Pinaev V A 
Published: December 2021

Abstract
In the present work, the mechanism of formation and propagation of the group of high energy electrons in the cathode regions of a glow discharge in helium is discussed. Using the method of the Monte Carlo collisions simulation, the beam electron energy distribution function in the cathode fall region of a glow discharge has been determined in the gas pressure range of 30−70 Pa. It is shown that the electron distribution function at the end of the cathode fall region contains a lot of electrons which have no any collisions and have energies close to the cathode fall potential. On the basis of the obtained results the distribution of the ion density was simulated using the Poisson equation. It is shown that the ion density distribution stays almost constant in the cathode fall region. The beam and ion density increased with the pressure growth.
Interaction of a liquid jet with a co-current gas flow inside the nozzle and under ejection into vacuum
Authors: Prikhodko V G , Yarygin V N , Yarygin I V 
Published: December 2021

Abstract
The structure of a gas-droplet flow arising under gas outflow with liquid jet injected into it from a supersonic nozzle into vacuum is studied experimentally. Possibility of the flow structure control in order to obtain droplets of a certain size, composition, and velocity, is considered. The liquid was injected into the co-current gas flow in the prechamber of the supersonic nozzle and then flowed out into the vacuum chamber in the form of a gas-droplet jet. Using the developed technique of droplet deposition on paper substrates, the effect of the Reynolds number of the gas and the pressure in the vacuum chamber on the angular distribution of droplet phase behind the nozzle exit is investigated.
Modelling corners flow in rectangular microchannel
Authors: Gluzdov D S , Gatapova E Ya 
Published: December 2021

Abstract
Rectangular microchannels are most common configuration in microfluidics. They can be used in many industries, for example in lab-on-chip devices. Despite standard fluid dynamics, microfluidics has a significant impact of wall boundary conditions on fluid flow. And in microfluidics, we cannot simply set no-slip boundary conditions if our goal is accurate modeling results. In rectangular microchannels, there is another important moment in modeling that is not present in circular pipes. The velocity profile of the fluid depends on the shear stress at the edges and the velocities at the walls of the microchannel change at different points of the cross-sectional wall of the microchannel. The fluid velocity is lower at the corners of a rectangular microchannel. In this paper, a solution is proposed to find a more accurate way to model the fluid flow in a rectangular microchannel by knowing the friction factor without shear stress distribution.
Effective cooling of substrates with low thermal conductivity under conditions of gas-jet MPCVD diamond synthesis
Authors: Emelyanov A A , Plotnikov M Yu , Timoshenko N I , Yudin I B 
Published: December 2021

Abstract
The paper presents the results of an experimental study of heating molybdenum and silicon substrates under the conditions of gas-jet deposition of diamond structures using the precursor gases of a microwave discharge to activate. A cooled substrate holder using a metal melt to improve heat removal by reducing the thermal resistance between the substrate and the substrate holder has been developed. The use of the melt allowed lowering the temperature of the silicon substrate under the conditions of gas-jet deposition to a level that ensures the preservation of its structure. The developed substrate holders were used to carry out gas-jet synthesis of diamond structures on molybdenum and silicon substrates.
Applicability of gas-jet MPCVD polycrystalline diamond films on silicon with NV centers in quantum magnetometry
Authors: Tarkov S M , Antonov V A , Podlesny S N , Yemelyanov A A , Rebrov A K , Popov V P , Volodin V A , Vdovin V I , Timoshenko N I , Yudin I B , Nadolinny V A 
Published: December 2021

Abstract
Polycrystalline diamond film optical and electrical properties are investigated after the growth on <001> and <111> Si substrate by gas-jet MPCVD deposition in the presence of nitrogen in the gas mixture. Negatively charged NV− center formation was observed at the ~1.0 ppm level with the substitutional nitrogen concentration of 70 ppm. A comparison with the IIa type monocrystalline diamond plates with implanted and annealed nitrogen atoms at the 90 ppm concentration shows three times higher NV center formation efficiency by gas-jet MPCVD deposition than by ion implantation. CW optically detected magnetic resonance (ODMR) demonstrates the NV contented polycrystalline film application in a quantum magnetometry.
Deposition of fluoropolymer coating on stainless steel surface from plasma of glow discharge
Authors: Petrova A V , Bogoslovtseva A L , Safonov A I 
Published: December 2021

Abstract
The present work investigates the application of the plasma of glow discharge to deposit the fluoropolymer coatings. Two series of experiments were carried out in which the influence of pressure and current strength on surface coatings morphology during its surface treatment with glow discharge plasma was investigated. The surface morphology is investigated by a scanning electron microscope (SEM), and the water contact angle (WCA) is measured. The fact that the choice of pressure significantly affects the morphology and properties of the deposited coating is established.
Modification of the copper wettability by nanosecond laser texturing
Authors: Vasilev M M , Shukhov Y G , Rodionov A A , Li Y P , Lei M K 
Published: December 2021

Abstract
Nanosecond laser microstructuring of copper surfaces was performed in this work. The contact angle value immediately after laser treatment decreased sharply and all samples were hydrophilic or superhydrophilic. Hydrophobization of the textured samples occurs as a result of environmental exposure over time. Oxidation and adsorption of carbon and its compounds from the atmosphere leads to a change in the wettability of the irradiated surfaces. The acceleration of hydrophobization process with decrease of fluence was found. It is shown that the stable contact angle, reached after one month, does not depend on the value of the fluence and is about 140°.
Device cooling features in wiggler synchrotron workstations
Authors: Kabov O A , Zubavichus Ya V , Cooper K E , Pukhovoy M V , Vinokurov V V , Finnikov K A , Ronshin F V , Nikitin A A , Bykovskaya E F , Vinokurov V A , Mungalov A S , Marchuk I V 
Published: December 2021

Abstract
Construction of the 4+ generation Siberian circular photon source (SKIF synchrotron) has started in Novosibirsk. It will initially be equipped with six research workstations. For two stations, synchrotron radiation is generated by superconducting wigglers, whose radiation power approaches 49 kW, and the power density on the axis is 92 kW/mrad2. Most of the optical devices of the stations operate in a vacuum. The high energy density of the synchrotron beamline and the requirements for the values of thermal deformations lead to difficult conditions for the thermal management of optical elements. The article provides an overview of the applied and promising cooling systems; an example of a 3D calculation of a thermal diamond filter of workstation 1-5 is given, the limit for the thermal load of the filter, at which the temperature of the diamond plate will not exceed 600 °C, is estimated.
Numerical simulation of thermal diamond filter for working station 1-5 of synchrotron “SKIF“
Authors: Vinokurov V A , Vinokurov V V , Kabov O A 
Published: December 2021

Abstract
Numerical 3D-simulations of thermal loads of thermal diamond filter for the working station 1-5 of synchrotron “SKIF” has been performed. An efficient version of a water-cooling system of a CVD diamond by means of mini-channels in copper flanges with a total heat release power of 1290 W is presented. The influence of various configurations of the cooling system, different boundary conditions (thermal insulation, radiation heat exchange), water supply pressure on the maximum temperature in diamond wafer has been investigated. The influence of the temperature dependence of the properties of diamond glass has been studied. The maximum temperature on the diamond wafer is found to be 317.6 °C absorbing 1290 W of power correspond to the safe mode for some specific cooling system configuration. The corresponding flow rate of 7 °C cooling water was 13.1 l/min.
Contact line dynamics on a substrate coated with a fluoropolymer
Authors: Kochkin D Y , Bogoslovtseva A L , Kabov O A 
Published: December 2021

Abstract
This work investigates the dynamics of the contact line during the propagation of a dry spot in a water layer on a solid substrate. The substrate is coated with fluoropolymer by using a hot wire chemical vapor deposition method. The dry spot is generated using a thermocapillary mechanism caused by the heating of the substrate from below by the laser. By analyzing schlieren images, the dependence of the velocity of the contact line during the propagation of a dry spot was obtained for various initial thicknesses of liquid films.
Thermodynamic properties of single crystals based on lithium tungstate by reaction and DSC calorimetry
Authors: Matskevich N I , Shlegel V N , Samoshkin D A , Stankus S V , Semerikova A N , Grigorieva V D , Zaitsev V P , Kuznetsov V A , Ponomareva S A , Novikov A Yu 
Published: December 2021

Abstract
For the first time, single crystals of undoped lithium tungstate and lithium tungstate doped by 1.25% molybdenum were grown by the low-temperature-gradient Czochralski technique. The standard formation enthalpies, lattices enthalpies, stabilization energies, and the heat capacity were determined in the temperature range of 320-997 K. The lattice enthalpy dependence on Mo content was constructed.
Low -parametric equation for calculating the viscosity coefficient of nitrogen in liquid, gas and fluid states
Authors: Dutova O S , Meshalkin A B 
Published: December 2021

Abstract
The formulation for the viscosity coefficient of nitrogen is obtained. In the developed equation the dependence of the residua viscosity of various states of substance on the internal energy density is used. The new correlation represents the viscosity of nitrogen at temperatures from 70 K to 1000 K and pressures of up to 50 MPa within the limits of experimental uncertainties.
Radiation heat transfer between human and cryocabin walls
Authors: Burkov I A , Khutsieva S I , Voronov V A 
Published: December 2021

Abstract
The paper considers the particular case of intensive radiation heat transfer in the system consisting of a human body and cryocabin walls of cryosauna. Calculations for three models have been made, namely, human-vertical wall, which is arranged parallel to a human, human-vertical wall, which is positioned at a certain angle, and a human-cryosauna. Analytical calculations are compared with Ansys-bassed numerical calculations. The impact of radiation heat transfer in this radiation-convective heat transfer problem is estimated. Conclusions are drawn about taking into account the radiation heat transfer and a rational method for calculating this heat transfer problem.
Calculation analysis of heat transfer in a four-vortex furnace of a pulverized coal boiler when operating at various loads
Authors: Dekterev A A , Kuznetsov V A , Tepfer E S 
Published: December 2021

Abstract
The work is devoted to the mathematical modeling of heat and mass transfer processes during flare combustion of coal dust in a four-vortex combustion chamber. For modeling, a set of interrelated models is used that describes the gas movement, thermal and radiant energy transfer, the processes of destruction and burnout of coal particles, and the formation of NOx. The simulation results showed that in a wide range of changes in the boiler load in the furnace, a stable four-vortex flow structure is formed with a fairly uniform temperature distribution in the furnace volume and a low level of NOx formation.
Modeling heat and mass transfer processes during evaporation of a water film in a horizontal channel with a cocurrent flow of moist air
Authors: Gorbachev M V , Terekhov V I 
Published: December 2021

Abstract
Modeling of heat and mass transfer processes in a horizontal channel during evaporative cooling of a moist air flow with regard to the finite thickness of the liquid film is considered. The mathematical model consists of a system of differential equations in the boundary layer approximation. The simulation results have been obtained in a wide range of initial parameters: temperature T
0 = 10÷50°C, humidity φ0=0÷100%, Reynolds number Re=100÷2000. Calculations were carried out at atmospheric pressure. Quantitative analysis of influence of initial parameters of flows on values of parameters of wet air flow at the outlet of the channel with and without taking into account the final thickness of the water film was carried out.
The study of a consistent pattern of heat and mass transfer at drying fiber-forming polymers
Authors: Geller Yu A , Efremov G I , Antanenkova I S , Shatskikh Yu V 
Published: December 2021

Abstract
In this article, the consistent pattern of mass transfer in the process of drying granular polyethylene terephthalate (PET), polycaproamide (PCA), and polyamide 66 (PA 66) were studied. A modified quasi-stationary method was used to analyze the data. The characteristic time and the hydrodynamic intensity index were obtained based on experimental data. Some features of water sorption and desorption by fiber-forming polymers were studied.
Computational fluid dynamics as a method for studying wind comfort
Authors: Meshkova V D , Dekterev A A 
Published: December 2021

Abstract
The paper presents a comprehensive analysis of the wind flow interaction with a high-rise building, considering various types of streamlined flow acceleration, as well as an assessment of the aerodynamic shadow behind the building, and areas with increased wind speeds. The authors analyze risks caused by these zones, as well as suggest measures to minimize them.
Optimization of the operation mode of regenerative heat exchangers
Authors: Shatskikh Yu V , Sharapov A I , Arzamassev A G , Geller Yu A 
Published: December 2021

Abstract
The paper considers the operation of regenerative heat exchangers with a fixed checkerwork. Such a checkerwork allows for high-temperature heating of gases and is made of refractory materials with a relatively high heat capacity, but low thermal conductivity. The article presents calculations of regenerative heat transfer for devices with block checkerwork. It is shown that a decrease in the equivalent diameter of the channel d

e
leads to an increase in the average air heating temperature over the period. An increase in the relative water section of the checkerwork f also leads to an increase in the air heating temperature, but only to a certain limit. On the one hand, with an increase in the relative water section, the specific heat exchanger surface increases. On the other hand, at a certain value f, the accumulating mass of the checkerwork significantly decreases, and as a result, the air heating temperature decreases. For the same reason, for checkerwork with a high value of the relative water section, it is necessary to reduce the duration of the heating/cooling periods of the checkerwork. The paper also examines several types of compact checkerwork, which are very promising, including in heat storage systems. It is noted that the use of such attachments in conventional regenerate heat exchangers is impossible. First, it is necessary to increase the water section of the heat exchanger and significantly reduce its height, otherwise, the pressure loss will increase sharply. Secondly, it is necessary to significantly reduce the duration of the heating/cooling periods, otherwise, due to more intense heat exchange, the air temperature at the outlet of the regenerative heat exchanger changes much more than in the block checkerwork.
The swirl number as a method for determining the optimal operating mode of the micro hydro turbine
Authors: Suslov D A , Litvinov I V , Gorelikov E U , Shtork S I 
Published: December 2021

Abstract
The paper presents the data of a detailed study of the flow characteristics behind the runner of an air model of a propeller-type micro hydro turbine with varying operating modes from partial load to severe overload. Detailed measurements of the flow field distributions were carried out using an automated system for contactless optical diagnostics (LDA). The obtained data made it possible to link the identified features of the development of the flow structure when changing the operating mode of the installation with the nature of the evolution of the integral swirl number that determines the state of the swirled flow. Eventually, the work results can be used in the elaboration of recommendations for extending the regulation range of the operating regimes of hydraulic microturbines and providing their high efficiency.
The influence of conjugate natural convective heat transfer on the temperature field in a monocrystalline sapphire tape in the Stepanov method
Authors: Mitin K. A. , Berdnikov V. S. , Mitina A. V. 
Published: December 2021

Abstract
Natural convective heat transfer in the system “monocrystalline tape – environment – walls of the growth vessel”, geometrically similar to the simplified scheme of the upper part of the heat node in the Stepanov method, is studied numerically by the finite element method in the conjugate formulation. The calculations were performed with a Prandtl number equal to 0.68 (argon), in the range of Grashof numbers 1000 ≤ Gr ≤ 25000 and with a discrete set of tape lengths in the range from 1 to 5.
Gas dynamic protective devices for orientation thruster jets of space vehicles and orbital stations
Authors: Gerasimov Y I , Balakin A S , Prikhodko V G , Yarygin V N , Yarygin I V 
Published: December 2021

Abstract
Here is a brief review of model and on-orbit experiments on the problem of contamination of spacecraft and orbital station external surfaces, including the International Space Station, by jets of orientation thrusters.
Numerical simulation of the surfactants effect on the Taylor bubble in the PHP
Authors: Alekseev M V , Vozhakov I S , Cheverda V V 
Published: December 2021

Abstract
Numerical simulation of the motion of a Taylor gas bubble in a heated small-diameter tube is carried out. Two models are used to describe the dependence of surface tension on temperature. In the first model, the surface tension decreases with temperature, and in the second, it increases, which corresponds to pure water and an aqueous surfactant solution. It is shown that the derivative sign affects the thickness of the liquid film around the bubble.