bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical simulation of heat transfer during the liquid cooling of complex surfaces at unsteady heat release
Authors: Chernyavskiy A N , Pavlenko A N 
Published: December 2020

Abstract
The presented mathematical model allows simulating the heat transfer process during the liquid cooling of complex surfaces under conditions of unsteady heat release. The numerical simulation can be provided for the case of film cooling as well as for channel heat exchangers. The presented simulation approach is based on the Finite Volume Method (FVM) which makes it possible to perform the calculations for heat exchangers with complex geometry. Usage of the Volume of Fluid (VOF) method allows simulating the heater cooling by the liquid film with a free surface. The presented mathematical model was tested on a set of specific problems. The simulation results are in satisfactory agreement with the known solutions.
Peculiarities of the initialization and dynamics of the quench front on an extremely overheated plate cooled by a falling film of a cryogenic fluid
Authors: Starodubtseva I P , Pavlenko A N 
Published: December 2020

Abstract
Quenching is a generally accepted term for the process of rapid cooling of a solid body that is superheated above the temperature of the thermodynamic limit of a liquid superheat. The paper presents the results of computational experiments simulating the quenching of a high-temperature vertical copper plate by a gravitationally flowing film of liquid nitrogen. The peculiarities of the initialization and dynamics of the quench front in the transition process are investigated. The initial temperature of the test sample was higher than the Leidenfrost temperature and even higher than the critical temperature, which excluded the possibility of long-term stable liquid-solid contact. An improved numerical model of quenching is implemented, which assumes at the time of the quench front initialization an unsteady local contact of the liquid with the extremely overheated surface in the vicinity of the upper boundary of the heater. A dynamic pattern of the running quench front was obtained numerically, which satisfactorily correlates with that observed in cryogenic experiments by the high-speed digital video camera. The reliability of the results obtained numerically is confirmed by direct comparison with experimental data on the velocity and the shape of the quench front.
Numerical simulation of the energy-saving device for ventilation with periodic veering of an air flow
Authors: Aktershev S P , Mezentsev I V , Mezentseva N N 
Published: December 2020

Abstract
Two-dimensional mathematical model of energy-saving device for ventilation with cyclic veering of an air flow is developed. Results of calculations by two-dimensional model are compared with those obtained by one-dimensional model and with experimental data. It is shown that one-dimensional model [4] basically correctly describes the heat exchange in terms of temperature, averaged over cross-section. Parametrical researches are fulfilled by a method of numerical modelling to optimise the operating of the regenerative heat exchanger. Influence of parameters of the device on its energy efficiency is revealed.
Improving the energy efficiency of flaring in pulverized coal-fired boilers at TPPs of the Siberian Federal District by mechanochemical activation of coal
Authors: Chernova G V , Butakov E B , Burdukov A P 
Published: December 2020

Abstract
The heat power system of the Siberian Federal District is almost coal-based: energy generation at coal-fired TPPs makes up 87.2%. But due to low reactivity of coals fed to the pulverized coal boilers, expensive high-reactive fuel oil is used to ignite and light the pulverized coal flame, which is a technological and economic problem. To increase the energy efficiency of flame burning of coal, an increase in their reactivity due to mechanochemical activation is considered using the technology developed at IT SB RAS. For several different coals, experimental studies on burning were carried out at a 5 MW pilot setup using mechanochemical activation of coal. These studies showed reliable ignition and stable access to the autothermal coal combustion, which indicates an increase in coal reactivity and the ability to replace fuel oil with coal.
Mathematical modeling of plasma-thermal gasification of technogenic wastes
Authors: Domarov P V 
Published: December 2020

Abstract
The electrical and thermal characteristics of a plasma-resistive furnace in the drying zone during the utilization of industrial waste have been investigated. The dependences of the power released in the drying zone for various electrical resistivity of the mixture were obtained. It is shown that the introduction of additional resistive heating in the drying zone reduces the load on the plasmatron, increasing the lifetime of the electrodes.
Numerical investigation of coal-water fuel combustion in two-chamber furnace of a low-power boiler
Authors: Kuznetsov Viktor , Maltsev Leonid , Dekterev Alexander 
Published: December 2020

Abstract
In this work, a 1 MW hot water boiler equipped with a two-chamber combustion chamber for droplet-flame combustion of a coal-water fuel (CWF) is studied numerically. The effect of the second chamber with screen tubes on aerodynamics of the exhaust gas flow and temperature redistribution in the furnace volume is shown.
Analysis of the influence of heat and mass transfer processes in the WWER equipment on the duration of effective operation of passive safety systems
Authors: Shlepkin A S , Sakhipgareev A R , Morozov A V 
Published: December 2020

Abstract
The paper presents the results of an experimental study of the possibility of increasing the autonomous operation of passive safety systems of the WWER-1200 reactor facility. In the course of experiments conducted at IPPE JSC, processes that have a significant impact on the performance of these systems were studied. Non-condensing gases coming from the reactor negatively affect the operation of the steam generator in emergency condensation mode. They can significantly reduce the intensity of the condensation process and the duration of cooling the core. At a large-scale test facility HA-2M, the experiment was conducted to determine the maximum duration of a steam generator in the absence of removal of non-condensable gases from its tube bundle.
Employing one-dimensional approach to calculate mixture composition evolution caused by gas-phase reactions for the gas flowing through a cylindrical channel
Authors: Gorbachev Yu E , Leschev D V , Plotnikov M Yu , Shkarupa E V 
Published: December 2020

Abstract
Two approaches to evaluate the mixture composition with a small reactive admixture for the gas flowing through a cylindrical channel are compared. Both are based on solving the Navier-Stokes equations. In the first one, the Navier-Stokes equations are solved for the reacting gas mixture. In the second one, they are solved for non-reacting mixtures and gas-phase reactions are taken into account by solving the one-dimensional (along the flow axis) chemical kinetics equations. Comparison of the obtained results for CH4+H2 mixture have shown the possibility of using of one-dimensional approach for correct description of the mixture composition evolution caused by gas-phase reactions.
Effect of pressure on the hydrogen dissociation degree in a hot tube
Authors: Morozov A A , Plotnikov M Y , Rebrov A K , Yudin I B 
Published: December 2020

Abstract
The effect of pressure decrease on the degree of dissociation of hydrogen flowing inside a hot tube was studied. The experimental data were analysed using the previously developed thermal model of the reactor. The heat exchange of gas with the tube wall was estimated based on the direct Monte Carlo simulation. It was shown that decreasing the pressure from 20 mm Hg down to 1 mm Hg leads to a slight increase in the degree of hydrogen dissociation, from 11% up to 13%.
Effect of temporal evolution of the evaporation surface temperature on the plume expansion under pulsed laser ablation
Authors: Morozov A A 
Published: December 2020

Abstract
The effect of the temporal evolution of the evaporation surface temperature on the neutral plume expansion under pulsed evaporation into vacuum has been studied. Two-dimensional calculations have been performed based on the direct simulation Monte Carlo (DSMC) method. The Gaussian distribution of the temporal evolution of the surface temperature is assumed. The regimes with the constant and varying temperature of the evaporation surface have been compared. It is shown that for evaporation of more than ten monolayers the varying temperature leads to a considerable change in the plume dynamics with up to 9% decrease in the average energy of particles passing through a time-of-flight detector on the normal to the surface.
The formation of nonlinear sound fields in the boundary region of the bubble medium
Authors: Ogorodnikov A I 
Published: December 2020

Abstract
The formation of sound fields in the boundary region of a bubble medium under the influence of a powerful sound pulse for different volume concentrations of bubbles is studied. Two characteristic ranges of the volume concentration of bubbles, to the limits of which different types of wave fields are formed, are determined. At low values of volume concentrations in the boundary region, a long-lived space-limited standing sound wave is formed. A standing sound wave contains an order of magnitude more energy than other areas of the bubble medium. At large values of the volume concentration of bubbles in the boundary region of the bubble medium, an excitation zone forms. The structure of the zone is a periodic wave propagating deep into the bubble medium. The wavelength in the excitation zone increases with increasing distance from the boundary.
Comparison of different approaches to simulation of heterogeneous reactions by dsmc method
Authors: Plotnikov M Yu , Shkarupa E V 
Published: December 2020

Abstract
The present work is devoted to simulation of hydrogen dissociation on the surface of a heated wire in a resting gas by the direct simulation Monte Carlo (DSMC) method. Two approaches to simulating heterogeneous reactions are investigated: with and without regard to the velocities of particles impinging on the surface. A numerical study was performed based on a two-step hydrogen dissociation-recombination model.
Control of droplet phase angular distribution under near-wall liquid film ejection with co-current gas flow from the supersonic nozzle into a vacuum
Authors: Prikhodko V G , Yarygin V N , Yarygin I V 
Published: December 2020

Abstract
Flow structure behind a supersonic nozzle under near-wall liquid film ejection with the co-current gas flow into a vacuum is studied experimentally. Quantitative measurement results on the angular distribution of the droplet phase behind supersonic nozzle are obtained using the developed spectrophotometry technique. The authors have revealed the effect of near-wall liquid film parameters (Reynolds number of the film) and co-current gas flow parameters (Reynolds number of gas flow) on the formation of droplet phase backflows. The capability of controlling the droplet phase backflows, using the screens installed on the nozzle exit has been shown as well.
Experimental study of the contact line friction coefficient
Authors: Sibiryakov N , Zheng W , Kabov O , Bai B 
Published: December 2020

Abstract
Industrial applications use surfactants to control surface tension and wettability of surfaces. Instead of studying prepared solutions, we focus on the movement of the contact line after adding the surfactant. We placed the pedant drop with surfactant to a sessile drop of pure water and filmed the spreading process to obtain friction coefficient of the contact line. Our results confirmed that adding surfactants to sessile droplets drives the contact line movement. Small concentrations of LHS and SDBS as well as high concentrations of SDBS pin droplet and increase the hysteresis. Friction coefficient for cationic CTAB and zwitterionic LHS drops with the concentration increase. Anionic SDBS decreases contact angle, making the surface more hydrophilic and intensifying hysteresis.
Critical indexes of the nickel thermal diffusivity
Authors: Agazhanov A Sh , Samoshkin D A , Kozlovskii Yu M 
Published: December 2020

Abstract
Using the laser flash method, the thermal diffusivity (a) of nickel was measured in the temperature range of 300–1680 K with a detailed study of the region near the Curie temperature Tc
= 628 K. The initial experimental data in the field of magnetic phase transformation were processed by the scaling dependence, and the critical thermal diffusivity indexes (α, α’) were obtained below and above Tc
: α = 0.86 and α’ = 0.26, which in absolute value significantly exceed the critical heat capacity index. The possible reasons for this difference have been briefly discussed.
Features of thermodynamic properties of single crystals on the basis of lithium tungstate: «thermodynamics – structure – functional characteristics» correlations
Authors: Matskevich N I , Stankus S V , Samoshkin D A , Shlegel V N , Grigorieva V D , Kuznetsov V A 
Published: December 2020

Abstract
On the basis of obtained experimental data, the features of thermodynamic properties for lithium tungstate single crystals doped by molybdenum have been revealed. Correlations between enthalpies and structural parameters have been found. The relation between lattice energies and scintillation characteristics has been revealed.
The use of pulsed infrared drying in the processing of leafy plant raw materials
Authors: Sapozhnikov A N , Sleptsov S D , Grishin M A , Kopylova A V , Levin T A 
Published: December 2020

Abstract
The paper presents the results of research of leafy plant raw materials drying with pulsed infrared (IR) radiation by the example of spinach (Spinacia oleracea L.). The efficiency of the selected method for weight and humidity changes in the processed material has been analyzed. The specific energy consumption for removal of 1 g of moisture as well as ascorbic acid concentration in dried product have been calculated. The results of the analysis show that IR-drying of leafy plant raw materials is efficient and can be carried out in production environment.
Influence of thermal conductivity of the partition wall on non-stationary conjugate natural convective heat exchange and temperature fields in the walls of a rectangular fuel tank
Authors: Berdnikov V S , Mitin K A 
Published: December 2020

Abstract
The non-stationary conjugate heat transfer in a rectangular model of a fully filled thin-walled tank, divided by an internal vertical partition wall into two compartments of 1/3 and 2/3 of the tank volume is studied numerically in the conjugate formulation. The outer surfaces of the end walls and the upper wall of the tank are heat-insulated. The lower wall suddenly warms up under the influence of a uniform heat flux. The calculations are performed at the ratio of the thermal conductivity of solid walls to the thermal conductivity of fuel λs/λf = 1041.3 and λs/λf = 1 (low-heat partition wall) and thermal parameters of fuel T1 (Prandtl number Pr = 25.66). The influence of internal vertical partitions wall on the spatial shape of convective flows and the regularities of non-stationary conjugate heat exchange is studied. The temperature fields in the liquid and in the tank walls are calculated.
Investigation of fluorescence spectra of various types of plastics for the purpose of sorting and further processing
Authors: Maslov N A , Dulin V M 
Published: December 2020

Abstract
Excitation-emission matrices of various plastic package samples were studied. A tuneable 210-310 nm laser was used as an excitation source. The samples of polyethylene terephthalate, polypropylene, and high-density polyethylene of various colour and transparency showed multipeak wideband fluorescence spectra dependent on the excitation wavelength. Principal component analysis demonstrated that the excitation-emission matrices of most samples are well described by two principal components, individual for their types and colorant additives. Despite complex structure of the excitation-emission matrices of different types of the plastic, appropriate linear combinations of the principal components allowed finding a characteristic component for each of them.
Experimental research and development of drilling fluid formulations to reduce the rate of the permafrost thawing
Authors: Mikhienkova E I , Pryazhnikov M I , Neverov A L , Zhigarev V A , Guzei D V 
Published: December 2020

Abstract
The paper is devoted to complex experimental studies of methods to reduce the rate of permafrost thaw during the construction of oil and gas wells in the fields of the Krasnoyarsk territory. Laboratory physical and chemical studies on the development of drilling fluid formulations for drilling in permafrost conditions were carried out. The most significant results were obtained for clay-polymer solutions with the addition of ethylene glycol and propylene glycol. It was shown that it is possible to control the thermal, hydration and filtration characteristics of drilling fluids by introducing ethylene glycol and propylene glycol without deterioration of their rheological properties.
Effect of a uniformly rotating crystal length on radiation-convective heat transfer in the Chokhralsky method
Authors: Mitin K A , Berdnikov V S 
Published: December 2020

Abstract
Radiation-convective heat transfer from silicon crystals to the environment was investigated with the Chokhralsky method. The systems of equations of thermogravitation and mixed convection in the term vortex, stream function and temperature were solved numerically by the finite element method. The influence of crystal rotation on the spatial forms of convective flows of the surrounding gas and on non-stationary temperature fields in the gas and in the crystals was studied. Calculations were made for crystals of different lengths. The calculations were performed with the Prandtl number equal to 0.68 (argon) and the Grashof number 16000, typical for a real technological process.
The effect of coolant temperature at the inlet on heat transfer enhancement for LED module cooling by a micro-jet system
Authors: Trofimova V V , Gatapova E Ya 
Published: December 2020

Abstract
Jet cooling is one of the effective and active methods for thermal control of electronic devices. The paper presents experimental data of the study of heat transfer during multi-jet cooling of a LED module at a power of 100 – 300 W. The influence of the coolant temperature at the inlet on the heat transfer enhancement is investigated. It is shown that with increasing power, the temperature inhomogeneity along the LED surface increases. A significant effect of the coolant inlet temperature on the heat transfer enhancement is shown. Water is used as a coolant. The surface temperature of the LED module is shown to be by 10 °C lower for the coolant inlet temperature of 10 °C in comparison with the coolant inlet temperature of 25 °C at a LED power of 300 W.
Application of GaN in 5G Technology
Authors: Wang Kun , Sheng Chenxu 
Published: December 2020

Abstract
With the progress of informatization, the development of communication technology and the wide application of wide bandgap semiconductors represented by GaN, the application of GaN in 5G technology has received increasing attention. In this paper, various characteristics of GaN application in 5G technology were emphatically introduced and a detailed analysis of these characteristics was conducted on the basis of the GaN application in 5G technology via literature searching and combining what we have learned. In addition, the development and innovation of GaN power devices in recent decades and some problems encountered at the present stage were explained and a certain prediction of the GaN application in 5G technology were proposed that this area will be a great part of industry in 21th century.
Life Cycle Assessment of a New Steel-making Process for Sustainable Steel Industrial Development in China
Authors: Du Shuxuan 
Published: December 2020

Abstract
With the increasing emphasis on sustainable development, the development of green industry has become particularly important. The steel industry, as a key industry with high pollution and high emission, is bearing a huge environmental pressure. In China, the traditional steelmaking industry of blast furnace-converter has the problems of huge energy consumption and carbon emission, which is contrary to the requirements of sustainable industrial development. Therefore, based on the resource characteristics and technical basis of China, the theory of replacing the traditional steel-making process with coal-to-gas-gas-based shaft furnace-electric furnace steel making process is proposed in this paper. At the same time, this paper will establish an LCA model for the new process, objectively evaluate its relationship with the environment, and deeply analyse the relationships between each unit process in coal-to-gas-based shaft furnace-electric furnace process and environmental protection, energy consumption, pollution emission. Through the simulation of steelmaking process and life cycle assessment, the impact of new process on environment and energy is analysed quantitatively. It provides a new research direction and a reliable theoretical support for optimizing steel refining process and developing sustainable steel refining industry.
Graphene quantum dots and polypyrrole incorporated polyacrylic acid hydrogels with enhanced conductivity
Authors: Yongqiang Yang , Qun Wang , Xiaochen Wu 
Published: December 2020

Abstract
Highly conductive hydrogels of functional graphene quantum dots (FGQDs) and polypyrrole (PPy) incorporated polyacrylic acid (FGQDs/PAA20/PPy) were fabricated through chemical cross-linking and in-situ polymerization. The amount of FGQDs, PPy and cross-linker affecting on the morphology, swelling ratio and electrical properties of FGQDs/PAA20/PPy composite hydrogels was investigated. FGQDs produced smaller-sized pores on the structure of PAA hydrogels, but hardly affected their porosity and swelling ratio. A high conductivity of 0.29 S/m was achieved for FGQDs/PAA20/PPy hydrogels, which promised high possibility in various fields.
Research on the Key Technology Application of Industrial Robot in Grinding and Polishing of Pen and Electronic Industry
Authors: Qi Yunxia 
Published: December 2020

Abstract
Taking grinding and polishing industrial robot as the research object, three key technologies in the process of machining are analyzed. Firstly, the selection method of grinding mode is introduced. Secondly, the tool calibration and workpiece calibration method in the process of robot running program editing are introduced. Finally, the singularity phenomenon and improvement method in the process of industrial robot operation are introduced. Through the analysis, the optimization of robot in control, programming, process and other technologies can be improved to meet the actual production needs of grinding and polishing robot seek.