bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental investigation of spray propagation under crossflow conditions with Shadowgraph and Schlieren techniques
Authors: Zueva T S , Weiss L , Wensing M , Garyaev A B 
Published: March 2021

Abstract
This paper is devoted to the description and analysis of the experimental results which were carried out to investigate sprays of liquid hydrocarbons under crossflow conditions. The experimental conditions corresponded to the injection conditions of gasoline sprays in a cylinder of an internal combustion engine. Two types of liquid hydrocarbons, isooctane and ethanol, were used as injected fuels. The injection pressure varied between 100 and 170 bar, the air crossflow velocity ranged from 0 till 50 ms-1 and the fuel temperature from 25 till 98 °C. Two optical methods, Shadowgraph and Schlieren, were used to visualize the spray movement over time. The boundaries of liquid and vapour spray phases as well as basic principles of spray propagation and evaporation under crossflow conditions were obtained after processing and analysing these images.
Experimental study of the shock wave influence on adiabatic wall temperature in a supersonic air-droplet flow
Authors: Popovich S S , Zditovets A G , Kiselev N A , Vinogradov Y A 
Published: March 2021

Abstract
The results of an experimental study of the thermal parameters of a supersonic flow around a flat wall in the presence of finely divided water droplets are presented. The relative mass flow rate of the liquid (mass concentration) varied in the range 0.05-0.5%. Liquid (distilled water) was sprayed through centrifugal nozzles into the air flow in the prechamber of the supersonic wind tunnel. Next, the adiabatic wall temperature for the given flow conditions was measured with the use of infrared thermal imager. The input flow Mach number was 2.5, the Reynolds number based on the dynamic boundary layer length from the nozzle throat was at least 2·107 at the nozzle exit section. The research was performed at the experimental facilities of the Institute of Mechanics of Lomonosov Moscow State University.
Analysis of experiments on condensation induced water hammers at KGU test facility by WAHA code
Authors: Volkov G J , Melikhov V I , Melikhov O I , Nikonov S M 
Published: March 2021

Abstract
Experiments at the KGU test facility, devoted to steam induced water hammers were analysed with the WAHA code. Test section of the KGU test facility is slightly inclined horizontal pipe of 3 m length and of 64 mm inner diameter. Subcooled water was supplied to the pipe inlet, pipe outlet was connected to separator vessel. Upper part of separator vessel was connected to steam source. Experiments were performed for different system pressure, different water subcooling and different mass flow rate of water supply. The WAHA code has been developed for simulation of condensation induced water hammers in pipelines. It is based on two-fluid approach, WAHA numerical scheme is based on Godunov numerical methods. Numerical simulations of the KGU tests revealed disagreement between numerical and experimental occurrences of water slug formations and water hammers events. Methodological calculations with variation of heat transfer to subcooled water showed, that this value significantly influences on water slug and water hammer formation.
Numerical simulation of the liquid film suction process through the slots of various geometry in the last stages of steam turbines
Authors: Gribin V G , Tishchenko A A , Alekseev R A , Gavrilov I Yu , Popov V V , Tishchenko V A 
Published: March 2021

Abstract
The liquid film suction process through the slot is considered. The stator blade row of the last stage of the steam turbine was used as an object of study. Based on the CFD modelling of two-phase flow in blades cascade the boundary conditions for slots modelling have been obtained. The numerical analyses of film removal were conducted in a domain including only a flow zone near the studied slot. The multi-phase VOF model was used to calculate the interaction between liquid and steam phases and model the interface evolution during the water removal process. Four different geometries of the slots were considered. For each of them, the unsteady calculations at two different operating regimes have been performed. The numerical results provide information about film suction details in a space of the slot. The behaviour of the film flow was analysed for each slot shape. The conditions of the film separation and its further breakup have been considered. For the studied slot designs efficiency analysis was performed. The results have shown how the way the liquid film moves in the slot effects on the removed water and steam mass flow rates.
Numerical simulation of pollutant dispersion in a test ventilated room
Authors: Ivanov N G , Podmarkova A D , Zasimova M A , Markov D 
Published: March 2021

Abstract
The paper presents the numerical study of 3D flow and neutrally buoyant pollutant transport in a model atrium under conditions of test experiment by Thatcher et al. (2004) with a controlled uranine dye spill. For the Reynolds number of 2160 the Reynolds-Averaged Navier-Stokes approach was applied. Analysis of CFD predictability for a steady-state fully-developed regime and a transient process was done in comparison with the experimental data on contaminant concentration fields. For various positions of the contaminant source the ventilation effectiveness was computed and discussed.
Heat transfer enhancement by surface vortex generators. New basic mechanisms and industrial technologies
Authors: Isaev S A , Son E E , Leontiev A I , Popov I A , Nikushchenko D B 
Published: March 2021

Abstract
New energy effective surfaces structured by vortex generators – inclined oval-trench dimples (OTDs) – and the controlling physical mechanisms of heat transfer enhancement are explored. The narrow 7 × 1 channel with a package of one-row OTDs at Re=104.is considered. Turbulent heat transfer is studied at the channel length where the flow is steady. The OTD width is 1, its depth is 0.3, its length is 7 0.3, and its dimple step is 6. The rounding radius of the dimple edge is 0.2. The influence of the OTD inclination angle θ on the mechanisms of separated flow intensification and heat transfer enhancement in the dimple is analyzed when θ is varied from 42° to 55.5°. The optimal angle θ of order 53° is revealed, at which the relative thermal performance is close to 70% for the heated wall with a very loose packing of dimples equal to 0.235. The optimal angle θ, at which the highest thermal and hydraulic performance (THP=0.175) has been achieved, appears to be close to 47°. The maximum local value of the 4.5–5-fold relative heat transfer growth coincides with that of static pressure in the separated flow zone on the section, where relative friction grows, after it has reached its minimum value up to -4.5.
Results of calculations from a linear source with variable noise characteristics along the length
Authors: Tupov V B , Skvortsov V S , Kuzminova S A 
Published: March 2021

Abstract
Results of calculations from a linear source with variable noise characteristics along the length are discussing. On one hand, the issues of calculations from linear sources are well studied and the results are presented in many works. On the other hand, problems of calculations from linear sources with variable characteristics along the length have not been studied enough, and there are no results of calculations from linear sources with variable characteristics along the length. This article deals with the case when the radiated sound energy along the length of a linear source is not constant but varies along its length. Results of calculations from a linear source with variable noise characteristics along the length are given. Various factors that affect to calculation results are discussed. The results have of practical interest. For example, this concerns the calculation of noise from a gas pipeline after a gas control point (GCP). The noise from it along the length of the pipeline decreases. The results of calculations allow to make the necessary decisions to create a low-noise object and select the necessary measures for its sound attenuation.
Numerical analysis of heat transfer and hydraulic resistance during an upward turbulent flow of supercritical pressure carbon dioxide in a heated tube
Authors: Artemov V I , Kudimkin I S , Yankov G G 
Published: March 2021

Abstract
This paper presents the wall temperature distribution, averaged velocity, turbulent statistics, and hydraulic resistance investigated using large eddy simulation for CO2 at supercritical pressure flowing upward in a heated vertical tube for the deteriorated heat transfer regimes simulated by Bae et al. using a direct numerical simulation (DNS). Numerical simulations were performed using the “in-house” computational fluid dynamics code ANES. We discuss the reasons for certain inconsistencies in wall temperature distribution between the DNS data of Bae et al. and others, the mechanism of formation of an M-shaped profile of the averaged axial velocity, and the features of turbulent kinetic energy generation due to deformation of the averaged velocity field and buoyancy forces. We show that the return to the normal heat transfer regime after the wall temperature reaches its local peak is due to the action of buoyancy forces.
Investigation on heat transfer enhancement in a circular pipe with artificial roughness
Authors: Koroleva A P , Kuzmenkov N V , Frantcuzov M S 
Published: March 2021

Abstract
This paper presents a numerical analysis of convective heat transfer enhancement of transverse ribs in circular tubes. Several CFD simulations are carried out for turbulent airflow to analyze heat transfer and pressure drop provided with transverse rectangular ribs. The rib height and pitch are widely varied along with the flow Reynolds number. The effect of each parameter is examined and discussed. To accurately predict major parameters (Nusselt number, friction factor, and thermal hydraulic performance parameter) a deep neural network is developed, trained, and tested by current CFD data. The result demonstrates that artificial neural network shows better performance compared to other methods of prediction (e.g. power-law approximation) and can offer an economical and powerful approach for modeling optimal heat enhancement parameters.
Study of MHD stability limits of reactor-scale spherical tokamak
Authors: Chirkov A Yu , Lopez J E , Orozco E A , Fedyunin D E 
Published: March 2021

Abstract
The MHD equilibria in low aspect ratio tokamak plasma are studied. The parameters correspond to the regimes of a system of relatively large sizes, which can be considered as the concept of a reactor (or source of fusion neutrons) on deuterium fuel. The efficiency of such a system substantially depends on the limitations associated with the conditions of MHD equilibrium and stability.
A slit-based method of a high-current ion beam transversal distribution diagnostic
Authors: Golubev S V , Skalyga V A , Izotov I V , Shaposhnikov R A , Razin S V , Bokhanov A F , Kazakov M Yu , Shlepnev S P 
Published: March 2021

Abstract
This article presents the results of experimental studies that are part of the research aimed at the development of a point-like neutron source for fast neutron tomography. In frames of the used approach neutrons are produced in D-D fusion at the deuterium-loaded target bombarded with the focused deuterium ion beam. It was proposed to use a high-current ECR ion source to obtain the ultimate beam intensity at the target and maximize the neutron density yield. An important parameter of the neutron source is the size of the emitting region, which, in turn, is determined by the quality of the ion beam focusing. The presented work is dedicated to the development of the diagnostic system able to measure the ion beam transverse distribution. This system is based on the movable plates with orthogonal slits as an alternative to previously used scintillator-based method. The proposed system allows to determine the high-current deuterium ion beam size with an accuracy higher than 1 mm. This work presents verification of the previously obtained results of the high current focused deuterium ion beam formation by means of a slit-based method reliable in measuring beams of high intensity.
Investigation of the electric field of the plasma ball
Authors: Yunusov R F , Yunusova E R 
Published: March 2021

Abstract
Currently produced plasma balls have various design features and purposes. At the same time, the principle of operation of the plasma ball (PB) is described only in general terms and is of both scientific and practical interest. For the possibility of using PB in various technological areas [1-6], including in medicine, it is necessary to investigate the electric field created by this device. In this work, experiments were conducted on the study of the electric field PB: the interaction of PB with the conductor, gas-discharge light sources, and the propagation of the electromagnetic field PB over a distance. The values of the electric field strength outside PB and its dependence on distance were obtained experimentally.
High-current gas discharge with a water-solution cathode as a source of plasma flow for gasification of carbon-containing waste
Authors: Tazmeev G K , Tazmeev K K 
Published: March 2021

Abstract
A gas discharge with a water-solution cathode was experimentally studied in the current range 10–25 A. A bulk plasma was obtained in an extended (up to 20 cm) discharge gap. The choice of an aqueous solution of sodium chloride for use as a cathode was justified. The concentration range of an aqueous solution of sodium chloride was established to obtain a homogeneous bulk plasma. A plasma generator has been developed that allows the formation of a powerful plasma flow from the substance of a water-solution cathode. The possibility of supplying gaseous raw materials to an extended discharge gap in a plasma generator has been established. A technical system for the gasification of carbon-containing waste in two stages has been created. In the first stage, the waste was subjected to thermal degradation using an arc plasma, and in the second stage, the volatile components were converted to synthesis gas in a gas-discharge plasma with a water-solution cathode.
Probe researches of glow discharge in argon
Authors: Prokhorova E I , Platonov A A , Nazarov A I 
Published: March 2021

Abstract
The gas-discharge media with an inverse distribution of neutral and charged particles are of great interest for science and practical applications. A striking example of this is the laser operation. In the second half of the last century, a number of articles used to consider the possibility of forming an inverse electron distribution function (EDF), resulting in negative plasma conductivity. By analogy with the inverse population of excited states in lasers, such a medium will amplify electromagnetic waves. One of the first papers was the work [1]. The most complete theoretical study was presented in [2]. It is shown that with an inverse EDF in the low-energy part in gases with a Ramsauer minimum of the elastic scattering cross section stationary absolute negative conductivity will be formed.
Electrical resistivity of pyrolytic graphite at 2200-3200 K
Authors: Kostanovskiy A V , Zeodinov M G , Kostanovskaya M E , Pronkin A A 
Published: March 2021

Abstract
The electrical resistivity of UPV-1 grade pyrolytic graphite has been experimentally studied in a direction perpendicular to the deposition surface at temperatures of 2200–3200 K. It is shown that the electrical resistivity decreases by more than an order of magnitude at first heating in the temperature range from 1500 to 3200 K. The influence of the heating temperature on the electrical resistivity has been investigated in the range T = 2500-3000 K too. It is shown that the temperature dependence of the electrical resistivity coincides with the reference data at heating to T = 2700 K, and it becomes similar dependencies for a monocrystal at heating to T = 3000 K.
The problem of reproducing thermodynamic temperatures above 5000 K and generating intense infrared radiation to achieve them
Authors: Khodunkov V P , Zarichnyak Yu P 
Published: March 2021

Abstract
The feasibility of the operation of reproduction and transfer of a unit of thermodynamic temperature at the level of 5000 K in the metrology of temperature measurements is analyzed. A brief analysis of the current capabilities of temperature metrology is presented, the reality of reproducing high temperature and generating intense infrared radiation for its implementation is shown. The theoretical justification of the methods, schemes for their implementation, as well as brief descriptions of hardware systems are presented.
Density, specific heat capacity and viscosity of fullerene C60 solutions in tetralin
Authors: Motovoy I V , Zhelezny V P , Khliyeva O Ya , Melnik Ye Yu , Diachenko I A , Dmitriev Ye D 
Published: March 2021

Abstract
By combination of thermophysical and optical properties the solutions of tetralin with nanoparticles such as fullerene C60 can be considered as promising heat transfer agents for solar energy. The paper presents the results of experimental investigation for the density, viscosity and specific heat capacity of tetralin / fullerene C60 solutions. The study was performed in the temperature range 237…434 (K) and concentrations of fullerene C60 up to 1.043 (wt.%). The obtained results have shown an increase in the density and viscosity, as well as a decrease in the specific heat capacity of tetralin after adding C60. The obtained temperature dependences for the thermophysical properties of tetralin / C60 solutions are equidistant to theirs for tetralin. Obtained data on the density and viscosity were accurately fitted by a few-constant correlations for non-associated substances. The experimental data on the specific heat capacity of both tetralin and tetralin / C60 solutions indicate to significant effect of supramolecular structures in a liquid phase of aromatic hydrocarbons on this property. This effect is most significant in the temperature region close to the triple point. A new correlation for predicting the specific heat capacity of aromatic hydrocarbons containing fullerene C60 on the boiling line using a limited initial empirical data is proposed.
Characteristic features of nanofluids application in power engineering
Authors: Shatskikh Yu V , Kostanovsky A V 
Published: March 2021

Abstract
The problem of increasing the intensity of heat transfer is an urgent and important task. Methods of increasing the heat transfer coefficient in cooling systems of power equipment are of particular interest. Over the past two decades, a promising area of research in this area is the study of heat transfer using nanofluids. To date, domestic and foreign authors have performed a large amount of research. The scientific search is conducted in several directions: the choice of a heat-conducting material and a base fluid; the study of the influence of nanoparticle concentration and size on the intensity of heat exchange. To increase the thermal conductivity of the heat transfer agents, it is proposed to use both pure metals (Au, Cu, Fe), their oxides (CuO, Al2O3, TiO2), and carbon nanomaterials. The base fluid is mainly distilled water, mineral oil, or ethylene glycol. Almost all authors note an increase in the thermal conductivity of the nanofluid up to 40% on average compared to the base fluid. The concentration of nanoparticles in experiments does not exceed 4%. However, the studies performed often give results that significantly contradict the theory of convective heat transfer. Thus, many authors note that the heat transfer coefficient in the laminar mode of the nanofluid is greater than that of the base fluid, and the reverse is observed in the turbulent mode. A convincing explanation for this phenomenon has not yet been found. There is also no reliable data on the portable properties of materials used for the manufacture of nanofluid, in particular, there is little data on the properties of nanographene. In the article, the authors review the studies of heat transfer using nanofluid, consider the possibility of using nanotubes and multigraphen to increase the thermal conductivity of the heat transfer agent. The authors also analyze existing models of heat transfer in nanofluids.
Methodology of selecting a molecular substantiated optimal cubic equation of state
Authors: Petrik G G 
Published: March 2021

Abstract
The results related to the possibility of choosing the optimal cubic equations of state (ES) are presented. The study is carried out in the framework of a new model among three-term ES based on the molecular model of interacting point centers (IPC) and the well-known two-term ES of the van der Waals type. Manifestations of acting between molecules-points of attraction and repulsion forces are reflected in the structure and parameters of the ES belonging to the basic one-parameter family. The selection technique presented earlier was based on the possibility to obtain a consistent set of parameters that form the optimal equation. As a generalization of the limit variants of the ES with various manifestations of forces, a simple three-term four-parameter ES is proposed and investigated. All parameters make sense. Two relative parameters form the equation. It is shown that the known ES of Ishikawa, Chang, and Lu after the transformation become a special case of the ES of the IPC and cannot be considered as a general one. The technique was tested by calculating the critical isotherms of a number of substances, including argon, isopentane, carbon dioxide, etc. The next step should be to connect to the analysis a more finely structured control parameter.
p,ρ,T–Relations of Equimolar Ternary Water–1-Propanol–n-Hexane in Supercritical State
Authors: Bazaev A R , Bazaev E A , Osmanova B K , Dzhapparov T A G 
Published: March 2021

AbstractNew values of critical state parameters and p,ρ,T-relations of equimolar ternary homogeneous water–1-propanol–n-hexane (x=0.333… molar fraction or 0.1097, 0.3658, 0.5246 mass fraction of water, 1-propanol and n-hexane respectively) system in supercritical state are given. These values were carried out by using high-temperature, high-pressure, constant-volume piezometer along the isochores. The dependence of pressure from temperature and density at supercritical region (510.85–673.15 K, 255.7–615.62 kg/m3, 6.09–60 MPa) is described polynomial equation of state represented by expansion of the compressibility factor Z=pVm/RT=p/RTρminto a power series of density ω=ρ/ρcand temperature τ=T/Tc,Z=p/RTρm=1+∑i=1m∑j=0naijωi/τj;p=RTρm[1+∑i=1m∑j=0naijωi/τj], where ρm-molar density mole/m3, R=8.314–gas constant (J/mol·K).The average relative deviation of calculated values of pressure from experimental ones is not more than 0.6%.
Comparative analysis of properties of working fluids of power installations based on extended thermodynamic similarity
Authors: Chirkov A Yu , Lola D E , Luo T , Boronovskiy E G 
Published: March 2021

Abstract
The influence of the thermophysical properties of the working fluid on the efficiency of the working cycle is considered. Using methods of thermodynamic similarity, it is shown that one of the important factors affecting the efficiency of the thermodynamic cycle is the ratio between the slope of the saturated vapor line in the entropy–temperature diagram and the slope of vapor isobars. The influence of the composition of the working fluid and the ability to control it for maximum efficiency is discussed.