bluuebunny/crossref_metadata_2025_split huggingface dataset:
Parameters of temperature disturbance triggering the propagation of the quench front on an extremely overheated surface
Authors: Starodubtseva I P , Pavlenko A N 
Published: December 2021

Abstract
The results of computational experiments simulating the triggering of the quench front propagation on the superheated vertically oriented metal plates are presented. The plates are quenched by a gravitationally flowing down liquid nitrogen film. The temperature of the test samples at the beginning of the process was higher than the critical temperature and the Leidenfrost temperature, which means that direct long-term liquid-solid contact is impossible. For this reason, the front is initially motionless. As a result of numerical simulation, a dynamic pattern of the quench front propagation on a high-temperature surface was obtained. Analysis of the results allowed to find the realistic values of heat sink into the cooling medium, as well as the parameters of the local temperature disturbance, its spatial extent and amplitude, at which the conditions are created for triggering the process of quench front propagation on the high-temperature surface. Direct comparison of the numerical simulations results with experimental data on the velocity, geometry of the quench front and on the dynamical pattern of the process confirmed the reliability of the results obtained.
Effect of the distance between the micro/nanostructures on pool boiling heat transfer with water on a copper heater
Authors: Vladimirov V Yu , Khmel S Ya 
Published: December 2021

Abstract
Copper heaters were made. On the surface of these heaters the arrays of micrococoons were synthesized from silicon oxide (SiOx) nanowires with different concentrations of micro/nanostructures and hence different average distances between them. Boiling curves were obtained for these samples and it was found that heat transfer enhancement during boiling occurs on them in comparison with a smooth copper surface. It was shown that the effect increases with decreasing concentration of micro/nanostructures and reaches a maximum for microrelief with an approximate concentration of microstructures equal to unity per square micron. It was found that surfaces with micrococoons are sufficiently stable and suitable for enhancing heat transfer during boiling.
Experimental study of heat transfer during boiling in a thin layer of liquid on surfaces with structured porous coatings
Authors: Shvetsov D A , Pavlenko A N , Brester A E , Zhukov V I 
Published: December 2021

Abstract
The paper presents the results of the study of evaporation and boiling in a thin horizontal layer of liquid on microstructured surfaces in a wide range of changes in pressure. It is found that the thermal conductivity of materials of microstructured surfaces significantly affects the mechanism of steam removal from the pores and circulation of liquid along the heat transfer surface. It is determined that the pressure change leads to three regimes of heat transfer: evaporation, transition regime, and bubble boiling. The lowest values of the heat transfer coefficients and CHF were obtained in the transition regime; the highest ones were obtained in the bubble regime on both surfaces. Due to the higher thermal conductivity, the higher heat transfer coefficients and CHF were obtained on the bronze coating than on stainless steel over the entire pressure range.
Effect of fluoropolymer spots on pool boiling heat transfer
Authors: Vladimirov V Yu , Khmel S Ya , Safonov A I , Semionov V V , Chinnov E A 
Published: December 2021

Abstract
In this paper, the investigation of pool boiling heat transfer on biphilic micro/nanostructured surfaces is presented. An array of micrococoons from silicon oxide nanowires was synthesized on the surface of a copper heater using the gas-jet electron beam plasma chemical vapor deposition method. The biphilic properties of the surface were achieved by applying fluoropolymer spots by hot wire chemical vapor deposition. Technology of creating biphilic surfaces was developed and boiling curves were obtained for used samples. The advantages of using a biphilic surface to enhance heat transfer were demonstrated in comparison with a smooth surface and a micro-nanostructured surface without local hydrophobic fluoropolymer regions. This technology can be applied to enhance boiling heat transfer.
Hollow cathode gun for electron beam annealing
Authors: Konstantinov V O , Shchukin V G 
Published: December 2021

Abstract
An electron gun with a hollow cathode was tuned to be used in electron beam annealing. Electron beams with an energy of 1 keV and a current of 100 mA were obtained. It is shown that the diameter of the electron beam varies in the range from 7 to 5 mm, while the specific power is from 2·105 to 2·104 W/m2. Such electron beams have a soft, non-destructive effect on the surface and are suitable for electron beam annealing of various films.
Improving the efficiency of carousel wind turbine using aerodynamic shield
Authors: Serov A F , Mamonov V N , Nazarov A D , Miskiv N B 
Published: December 2021

Abstract
The problem of increasing the efficiency of using the oncoming air flow for a wind wheel with a vertical axis of rotation, which is a mechanical drive of the wind heat generator, is considered. It is proposed to increase the efficiency of the device by installing an aerodynamic shield for the air flow oncoming the wind wheel. Such a shield is a cylindrical body in which a heat generator is placed. The shield creates an effect of confuser, leading to an increase in the speed and, consequently, in the kinetic energy of the air flow acting on the rotor blades. It is shown experimentally that the presence of an aerodynamic shield under the conditions of the experiments carried out at an incoming air flow velocity of ~ 1 m/s leads to a practical doubling of the wind wheel torque.
Study of dispersed composition of spray during atomization of water-fuel emulsion with a superheated steam jet
Authors: Shadrin E Yu , Kopyev E P 
Published: December 2021

Abstract
Using the method of direct shadow photography the dispersed composition of fuel spray was studied when water-fuel emulsion is sprayed with the superheater steam jet. For emulsions with a mass water content of 5 and 10%, the characteristic droplet size in the flow is 1–2 μm and sufficient for effective combustion.
The unsteady swirling jet in a model of radial burner
Authors: Litvinov I V , Gorelikov E U , Shtork S I 
Published: December 2021

Abstract
The experimental study of an isothermal swirl flow with the formation of a precessing vortex core in the radial swirler upon non-confinement and confinement conditions is carried out. Velocity profiles are obtained with varying Re and guide vane angle, changing the swirl number S. Four acoustic sensors and LDA system are used to measure Strouhal number as the function of the integral swirl number in the range from 0.5 <S <0.8. It is shown that the unsteady flow with PVC effect significantly changes upon non-confinement and confinement conditions.
Numerical simulation of pulsed planar evaporation into background gas based on direct Monte Carlo simulation and solution of the BGK model kinetic equation
Authors: Morozov A A , Titarev V A 
Published: December 2021

Abstract
A numerical study of the planar gas expansion under pulsed evaporation into the background gas is carried out. The chosen conditions are typical for nanosecond laser deposition of thin films and nanostructure synthesis, with the saturated gas pressure at the surface of 5.4 MPa and the background pressure of 50 and 500 Pa. The problem is solved based on the direct simulation Monte Carlo method and direct numerical solution of the BGK model kinetic equation. A generally good agreement was obtained for all computed macroscopic quantities, with the exception of the higher density peak in the compressed layer and a wider shock front in the background gas for the BGK model.
Molecular diffusion in gases and liquids
Authors: Kharlamov G V 
Published: December 2021

Abstract
The diffusion coefficients in gases and liquids calculated by the molecular dynamics method with the use of the hard absolutely rough elastic spheres model are compared with those calculated using the Lennard-Jones potential. It is shown that dependences of reduced diffusion coefficients on density are similar, but differ numerically for different intermolecular interaction models. The simulation results have been compared with the experimental data on the diffusion in gaseous and liquid argon and in liquid benzene.
Numerical investigation of energy transfer efficiency from microwave radiation to plasma in a cylindrical resonant cavity
Authors: Hrebtov M Y , Bobrov M S 
Published: December 2021

Abstract
The paper presents a simplified numerical model of the hydrogen plasma generation process in a microwave resonant cavity. The model assumes electroneutrality and the prescribed electron temperature of the plasma, thus significantly reducing the computational cost. This allows for the parametric study in a wide range of operating pressures end electric field magnitudes (at a frequency of 2.45GHz). The prescribed model allows finding the effective range of operating pressures for the plasma generation. At low pressures, the collision rate is too low to effectively absorb all the emitted energy while at high pressures the electron conductivity drops which also reduces the absorption efficiency.
Experimental Achievements in Mini- and Micro- Channel Cooling
Authors: Pukhovoy M. V. , Bykovskaya E. F. , Kabov O. A. 
Published: December 2021

Abstract
There are a significant number of cooling techniques for micro- and mini-sized devices. One of them is mini-channel cooling. In this review, a large amount of experimental work on mini-channel cooling by various liquids is conceptually considered, in which the threshold in the removal of specific heat flux of >1 MW/m2 has been reached. A comparison of mini-channel cooling with other cooling techniques is performed. It was established that 1) micro-channel cooling has practically no thermophysical advantages over macro- or mini-channel one; 2) single-phase cooling in mini-channels gives comparable results compared to two-phase cooling; 3) only a small set of conceptual techniques allows the mini-channel heat exchanger to overcome the limit of 10 MW/m2 or to reach the heat transfer coefficient larger than 0.2 MW/(m2*K).
Heat capacity of Inconel 617 alloy
Authors: Samoshkin D A , Agazhanov A Sh , Stankus S V 
Published: December 2021

Abstract
In the present article, the heat capacity of Inconel 617, one of the most promising superalloys, was investigated. The measurements were carried out in the temperature range from 300 to 1270 K of the solid state. The method of differential scanning calorimetry was applied using DSC 404 F1 Pegasus calorimeter. The estimated error of the received data was 2-4% depending on the temperature. The fitting equations for the temperature dependences of the heat capacity and the reference table of recommended values have been received for use in various engineering and scientific tasks.
Non-contact heat transfer models identification for laser hyperthermia of semi-transparent materials
Authors: Semenov D S , Nenarokomov A V 
Published: December 2021

Abstract
The identification of mathematical models of heat transfer traditionally involves the installation of temperature sensors inside the sample under study and registration of the response to external thermal effects. In cases where the use of contact methods for measuring temperature is impossible, it is necessary to develop new approaches to determining the unknown thermophysical and radiation-optical characteristics. Laser hyperthermia of superficial tissues is one such case. The paper proposes a method for identifying a model of one-dimensional unsteady heating of a semitransparent sample using non-contact thermometry. A feature of the physical process under consideration is the possibility of its discretization. Due to this, a two-stage iterative procedure for solving the inverse heat transfer problem was formulated. The implementation of the proposed algorithm using software made it possible to carry out a computational experiment. The results showed the effectiveness of this approach. The presented method can be used in the development of means for monitoring and regulating the laser hyperthermia procedure.
Development of unsteady boundary layers on the generatrices of a vertical silicon rod heated by electric current in the mode of conjugate radiation-convective heat transfer
Authors: Mitina A. V. , Berdnikov V. S. , Mitin K. A. 
Published: December 2021

Abstract
The nonstationary conjugate radiation-convective heat transfer of a single silicon rod heated by an electric current with the surrounding gas medium is studied numerically in the axisymmetric formulation by the finite element method. The calculations were carried out at the Prandtl number Pr = 0.68, and the range of the Grashof number, determined by the temperature difference and the radius of the rod 9 703 ≤ Gr ≤ 261 977. It is shown that after a short incubation period, a circulation flow is formed. As a result, a significantly inhomogeneous temperature field in the longitudinal direction is formed in a silicon rod heated by an electric current. As the Grashof number increases, the inhomogeneity of the longitudinal distribution of the temperature field increases.
Laminar-turbulent transitions during thermal gravitational-capillary convection in horizontal liquid layers heated from below
Authors: Berdnikov V S , Grishkov V A , Mikhailov A V , Ryabov V O 
Published: December 2021

Abstract
The evolution of the spatial form of the flow versus the Rayleigh number in layers with two rigid horizontal boundaries and layers with a free surface is experimentally investigated depending on the Rayleigh and Marangoni numbers. The experiments were carried out with layers of ethyl alcohol and water. A thermal imager was used to measure temperature fields on free surfaces of liquids.
Approximate determination of the plasma potential spatial distribution in the isolated dust particle vicinity
Authors: Salnikov M V 
Published: December 2021

Abstract
In this paper, results of two numerical models are compared. The main purpose of these models is to determine the self-consistent spatial distributions of plasma (electric potential and space charge) near isolated spherical dust particles. In the first model, the spatial distribution of the self-consistent plasma potential is determined by expanding the plasma space charge spatial distribution in Legendre polynomials; in the second model, it is determined by direct numerical integration of the Poisson equation solution. The results show that the dependences of the system main parameters (wake magnitude and position, dipole moment of the ion cloud) coincide for small values of the external electrostatic field. With an increase in the external field strength, the dependences for two models cease to coincide, which is due to the inapplicability of Legendre polynomial decomposition in the case of strong anisotropy.
Strength analysis of warship hull’s bottom loaded by the pressure wave from a non-contact explosion of sea mine explosion of sea mine
Authors: Szturomski B , Kiciński R 
Published: December 2021

Abstract
The study was based on the analysis of stamina of steel flat bottom section of transport warships, burdened by the spherical pressure wave from the non-contact explosion of TNT at a distance of 20 m under the keel. This study aims to determine the TNT mass required to break the hull. The task was solved by finite element method (FEM) explicite using CAE program [1], in which the hull’s bottom was modelled as thin shell space. The hull’s burden with pressure wave was modelled as a pressure impulse specified by the formula introduced by T.L. Geers, K.S. Hunter and R.S. Price [2]. To describe the material properties, considering high-speed strain, the Johnson-Cook model was used [3]. Therefore, the main goal of the hereby paper is to present how to correctly model the impact of large, concentrated masses of the ship’s equipment on its hull. The study presents the results of the calculated stress and strain states of the analysed section of the construction of the hull.
Comparison of laser beam, oxygen and plasma arc cutting methods in terms of their advantages and disadvantages in cutting structural steels
Authors: Írsel G , Güzey B N 
Published: December 2021

Abstract
The laser beam, plasma arc, and oxygen cutting methods are widely used in metal cutting processes. These methods are quite different from each other in terms of initial setup cost and cutting success. A powered laser beam is used in laser beam cutting, plasma is used in plasma arc cutting, flammable gas - oxygen mixture is used in the oxygen cutting method. In this study, the cutting success of these methods was investigated on tensile specimens. Microstructure, hardness (HV 0.1), surface roughness, and strengths were investigated after the cutting process. The tensile test implemented with tensile samples cut from the same material by these three methods, it was observed that the strength values of the samples changed by about 8% in tensile strength depending on the cutting process. The hardness of the cut surfaces in plasma arc cutting increased from 150 HV to 230 HV for S235JR material. For this reason, it is difficult to perform machining operations after plasma cutting. The hardness value reached after laser beam cutting is 185 HV. Plasma arc cutting is more cost-effective than laser beam cutting. 1-3° vertical inclination (conicity) occurs on the cut surface in plasma arc cutting, while this inclination almost does not occur in laser cutting. In plasma cutting benches, cutting is done with oxygen, and in cutting with oxygen, the taper is seen in a small amount.
Influence of spent drilling mud on sedimentation time of activated sludge flocs
Authors: Cel W 
Published: December 2021

Abstract
Co-treatment of drilling muds with municipal wastewater in the reactors operating on the activated sludge principle constitutes a potentially safe method of their disposal. The method is based on the process of biological degradation of pollutants by assemblages of activated sludge organisms (prokaryotic and eukaryotic), which include different species described as functional and trophic groups. When the ecosystem in the bioreactor is in equilibrium, high wastewater treatment efficiency and process stability can be achieved. Analysis of qualitative and quantitative changes occurring in assemblages of activated sludge organisms may facilitate understanding the causes and mechanisms involved in the observed processes. In such a context, using a model of an SBR wastewater treatment plant, a study was performed to assess the feasibility of co-treating spent drilling mud with municipal wastewater using the activated sludge method. The floc constitutes the basic structural and physiological unit forming activated sludge. In this study, the sedimentation velocity of activated sludge flocs was analysed, and the obtained results were subjected to statistical analysis.
Numerical analysis of the support platform for an unmanned aerial vehicle
Authors: Czyż Z , Suwała S , Karpiński P , Skiba K 
Published: December 2021

Abstract
The study investigates a thin-walled support platform for an unmanned aerial vehicle, i.e. aluminum beams connected by flat bars and angle irons. The construction is a kind of frame for a propulsion unit of the designed aircraft which is a combination of a multi-copter and a gyrocopter. This construction was tested for various load patterns to investigate the stresses and strains its profiles are connected. The load patterns correspond to different operation modes of the propulsion system, and the finite element method (FEM) and the SolidWorks software were used for the numerical calculations. The research was done for elastic operation of the individual components of the support platform. The analysis enabled to verify the state of stresses on the critical spots of the construction and to develop a construction for ground and flight tests to verify the correct operation of the propulsion control system and optimize its operation in different flight states.
Research Self-balancing UAV Takeoff and Landing Control System Based on Quadruped Robot
Authors: Yang Kaiwen , Huang Sinuo , Li Siqi 
Published: December 2021

Abstract
Aiming at the advantages of UAVs in field survey and search as well as their difficulties in taking off and landing in poor ground environment in the field, a simple self-balancing UAV take-off and landing control system based on a quadruped robot is proposed. Firstly, the simple physical model of the system is established and the mathematical analysis is carried out. Secondly, the inverse kinematics of the single leg model is derived. Thirdly, the attitude sensor is used to measure the attitude angle data of the system platform, and the Kalman filter is used in the software design to filter the attitude angle data, and the PID control algorithm is used to control each leg joint. Finally, The design is simulated by MATLAB and experimentally analyzed, and the test results meet the design requirements.
Research on Civil Aircraft Flight Test of Power Supply Quality Analysis
Authors: Wu Jingtao , Wang Pei , Cai Jin , Liu Ying 
Published: December 2021

Abstract
In the process of civil aircraft airworthiness, analyzing power quality is the key to verify whether the power supply system meets the requirements of the clause. This paper makes deep research on the domestic and foreign power supply quality standard files and detailed introduces the characteristics of the power supply quality standard files. Then, comparative and analysis give suggestions which tally with power supply quality test requirements. Finally, define the special power supply quality test method for the practical engineering specifically, and power supply quality test characteristic in civil aircraft flight test, to provide guidance help for the future civil aircraft models.
Grid-Connected Resonance Suppression Of Group-Series Photovoltaic Cluster Inverters Based On Hybrid Damping
Authors: Li Shengqing , Wang Zhijian 
Published: December 2021

Abstract
Grid-connected group-series photovoltaic cluster inverter system will cause resonance, which will adversely affect the system. To suppress grid-connected resonance, the mathematical model, resonance mechanism and resonance characteristics of the cluster inverters are analyzed, and a global resonance suppression strategy based on hybrid damping is proposed. In the current loop of the inverter, capacitive current feedback and parallel voltage proportional feed-forward are introduced as active dampers to reduce the harmonics of the parallel current. On this basis, RLC type second-order resonance suppression circuit is added as passive damping to suppress system resonance, so that the output current of the inverters can meet the grid-connected conditions when the cluster is connected to the grid. The simulation and experimental results show that the total harmonic distortion of the grid-connected current decreases from 10.54% to 1.97% after three series photovoltaic cluster inverters adopt this strategy, which effectively suppresses the grid-connected resonance.