bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental determination of turbulence models applicability limits for the fluid dynamic computation in rotary divergent flow
Authors: Kabardin I K , Yavorsky N I , Meledin V G , Pravdina M Kh , Gordienko M R , Ezendeeva D P , Kakaulin S V , Usov E V , Klimonov I A , Krotov S V , Kabardin A K , Sadbakov O Yu 
Published: December 2019

Abstract
Such fundamental scientific problem arises in much industrial application. The turbulent fluid dynamic characteristics were analyzed experimentally in a rotary-divergent flow. The laser Doppler anemometry was used for turbulent mass transfer diagnostics. The verification of numerical calculations by computational hydrodynamics has been carried out according to the results of experimental studies. Verification has shown that turbulent models describe the rotational-divergent flow well only until generation of flow gaps and formation of recirculation zones.
Simulation of transonic low-Reynolds jets using quasi-gas dynamics equations
Authors: Kraposhin M V , Epikhin A S , Elizarova T G , Vatutin K A 
Published: December 2019

Abstract
In this paper application of the OpenFOAM solver QGDFoam for numerical simulation of transonic viscous flows is considered. The developed solver, which implements regularized or quasi- gas dynamics (QGD) algorithms, is validated using the transonic low-Re jet flow case (Ma=0.9, Re=3600). The conducted numerical simulations allow the assessing applicability of the solver for modelling hydrodynamic instabilities and their interaction with transonic flow. Results of the numerical simulations are compared with experimental observations and Navier-Stokes-based code simulation. Results of the present study formulate a guideline for choosing (values of) QGD-algorithm tuning parameters.
Visualization of instability processes in pure thermal plume
Authors: Kuznetsov E A , Kolesnik E V , Khrapunov E F 
Published: December 2019

Abstract
In the paper, the results of physical and numerical simulation of a natural convective flow formed over a heated horizontal disk are presented. The main purpose of this study is to analyze the occurrence of various stable states of a free-convection plume depending on the temperature of the heated surface. The presented flow patterns make it possible to determine the critical value of the temperature factor at which a change of stable states is observed. The visualization data obtained in the framework of physical modeling are compared and supplemented with data on flow patterns obtained numerically. A mechanism for the formation of separate air masses (“puffs”), which destroy both the near-wall layer and the formed upward flow is proposed. It was found that the emerging soft bifurcation is characterized by a sharp increase in the amplitude of perturbations with a slight increase in the value of the temperature factor: initial fluctuations of the plume boundary lead to further disruption of the heat balance and formation of puffs.
MHD and heat transfer in downflow and upflow of a liquid metal in the vertical pipe applied to tokamak reactor blanket module
Authors: Razuvanov N G , Luchinkin N A , Sviridov V G , Sardov P A 
Published: December 2019

Abstract
The studies of hydrodynamics and heat transfer were carried out with the upflow and downflow of liquid metal in a vertical pipe with one-sided heating affected by a transverse magnetic field. The task simulates a liquid metal flow in a cooling system channel of a TOKAMAK type fusion reactor blanket. The experimental data on heat transfer provided by detailed probe measurements were obtained using mercury MHD facility.
Experimental determination of circular fin effectiveness
Authors: Sapozhnikov S Z , Mityakov V Yu , Gusakov A A , Seroshtanov V V , Subbotina V V 
Published: December 2019

Abstract
The flow and heat transfer at the surface of a single circular fin and a finned cylinder were investigated comprehensively. The technique was carried out by combining PIV (Particle Image Velocimetry), gradient heat flux measurement and thermometry. The experiments were performed for a hollow (isothermal) fin and a fin made of titanium alloy VT22. The fins with a height of 20 and 60 mm were alternately mounted on a hollow cylinder. The cylinder was heated by saturated water vapor at atmospheric pressure. The angling device allowed us to investigate both the cross and non-cross flows around the model. The yaw angle β was 5, 10 and 15°. Visualization of the flow and measurement of the heat flux per unit area was carried out separately and independently in the same experiment. The PIV results revealed the influence of the yaw angle and intercostal space on the flow between the fins. Gradient heat flux sensors made it possible to obtain a distribution of the heat flux per unit area. Then the local heat transfer coefficients were calculated using thermometry data. It was possible to determine experimentally the effectiveness of the circular fins. This approach opens up new opportunities for study of convective heat transfer at surfaces of various shapes and purposes.
Mechanism of counterflows and circulation cells in swirling flows
Authors: Shtern V N 
Published: December 2019

Abstract
This paper reviews counterflows, double counterflows, and circulation cells in swirling flows and argues that all these seeming paradoxical phenomena can be caused by a common swirl- decay mechanism (SDM). It is shown that SDM explains (a) the counterflow of water and oil in hydrocyclones, (b) the elongated counterflow of hot and cold air in vortex tubes, and (c) the double counterflow occurring in vortex combustion chambers. SDM also explains the development and disappearance of circulation cells, often referred to as vortex breakdown bubbles, in sealed cylindrical containers where the flow is driven by rotation of one end disk. In a few words, SDM is the following. The balance of the centrifugal force and the radial gradient of pressure in a fast- swirling flow results in that pressure at the rotation axis is smaller than pressure at the periphery. If swirl decays downstream, pressure grows along the axis. This axial gradient of pressure decelerates the near-axis flow and can reverse it thus developing a local or global counterflow. It is shown that SDM also works in two-fluid flows modeling vortex bioreactors.
Simulation of turbulent wakes in model wind farm with arbitrary location for wind turbines
Authors: Strijhak S V , Koshelev K B , Kryuchkova A S 
Published: December 2019

Abstract
Wind energy is an important part of renewable energy sources in the Russian Federation. A new modern wind farm with 28 wind turbines was built on the territory of the Russian Federation, in the Ulyanovsk region in 2017-2018. When designing and operating a wind farm, it is necessary to assess correctly the power of each individual wind turbine. In this paper we used the open SOWFA library based on OpenFOAM 2.4.0 and URANS approach with k-e model of turbulence. The Actuator Line Model for the calculation of the forces from the wind turbines was used in pisoFoamTurbine.ALM solver. To set the boundary conditions at the input, the Precursor method was used. The unstructured grids with different number of cells were built. As a result of the calculation for 14 simulators of wind turbines, the values of the power coefficients Cp and thrust coefficients Ct were also determined. The maximum Cp value was in agreement with the Bets-Zhukovsky law for an ideal wind turbine. The new numerical case with 28 wind turbines was prepared for future simulations. The calculations were performed on a cluster of the UNICFD web-laboratory of ISP RAS. Each calculation was performed on 48-72 cpu cores.
Combustion model of boron-air suspension
Authors: Moiseeva K M , Krainov A Yu 
Published: December 2019

Abstract
This paper presents a physico-mathematical combustion model of the boron-air suspension. The oxidation mechanism and combustion of boron particles are based on the study by King M. K. The physico-mathematical formulation of the problem implies the approaches by R.I. Nigmatulin for the mechanics of two-phase reactive media. The paper provides numerical investigation on the effect of mass concentration and boron particle size on the apparent and normal combustion front velocity of the boron-air suspension.
Influence of soluble surfactant on wave evolution on falling liquid films
Authors: Bobylev A V , Guzanov V V , Kvon A Z , Kharlamov S M 
Published: December 2019

Abstract
We have investigated the effect of soluble surfactant Triton X-100 on the initial development of waves on vertically falling liquid films. Field method of laser induced fluorescence was used to obtain instantaneous wave patterns forming at different concentrations of the surfactant. These concentrations were chosen on the basis of simple consideration that most pronounced influence of the surfactant on the wave characteristics should be observed when relaxation time of surface tension (dependent on surfactant concentration) is comparable with characteristic time of wavy motion. At low and moderate surfactant concentrations damping of waves is observed, which coincides with the results of other authors. At large surfactant concentration the waves start to grow again, but without initial stage of two dimensional wave development typical of pure liquids. The absence of this initial stage is due to the formation of rivulets on the free surface of films in the presence of the surfactant. The influence of the surfactant concentration on characteristics of rivulets and waves is described.
Energy characteristics of a radiating thin layer of bubbles in a liquid
Authors: Borodulin V Yu , Ogorodnikov I A 
Published: December 2019

Abstract
The radiation of a thin bubble layer in an infinite liquid excited by a single wave of large amplitude is studied. It is shown that, after excitation, the layer emits a strong nonlinear wave in both directions. The radiation of the layer becomes close to sinusoidal with one line in the spectrum at large times. It is shown that in the nonlinear phase of the sound wave radiation, the time variation of the bubble energy in the layer is characterized by a stepwise dependence.
The propagation of temperature pulsations along the free surface of a liquid layer from a linear heat source
Authors: Berdnikov V S , Grishkov V A , Markov V A 
Published: December 2019

Abstract
The evolution of the temperature field on the free surface of a fluid near a periodically heated wire is experimentally investigated. The wire was heated by rectangular current pulses with specified duration and pulse repetition period. The data on the spatial characteristics of thermal waves and the propagation velocity of a thermal wave are presented. Using digital video of the visualized fluid flow, the structure of the unsteady convective fluid flow was studied
On the modes of cuttings transport in an inclined annular channel
Authors: Ignatenko Ya , Gavrilov A , Bocharov O , May R 
Published: December 2019

Abstract
The paper presents the results of the simulation of cuttings transport (solid spherical particles) by water through a long annular axisymmetric inclined channel. At the inlet uniform distribution of particles and fluid velocity was set. Inclination angle varied from 0 to 90 degrees. Modes of stationary and moving dunes and their transition into wave-shaped and stationary sediment were observed. Moving dunes could oscillate laterally and did not form a crest that occupied the entire width of the channel. In this case, dense sediment formed an S-shaped path, moving along the stream. Despite the general downstream movement of the S-shaped track (dune), a downward flow might occur in the low area with high concentration. Five basic flow regimes were identified: constant sediment, moving wave-like sediment, separated stationary dunes, S-shaped sediment and homogeneous flow. The basic flow pattern could be complicated by lateral motion and backward flow in a region of high concentration. A variant of the flow pattern map is suggested.
Change in wave characteristics during the transition from gravitational to shear flow of gas-sheared liquid films
Authors: Isaenkov S V , Cherdantsev M V , Cherdantsev A V , Markovich D M 
Published: December 2019

Abstract
The evolution of thin liquid films sheared by a co-current gas flow in a vertical cylindrical channel with an internal diameter of 11.7 mm was studied using a high-speed implementation of the laser-induced fluorescence method. The main purpose of the work was to study the characteristics of the waves during the transition from the gravitational to the shear flow regime. The effect of gas velocity, liquid Reynolds number, and liquid viscosity on wave characteristics has been studied.
Stochastic simulation of transport processes in liquids
Authors: Rudyak V Ya , Lezhnev E V 
Published: December 2019

Abstract
The subject of this paper is molecular stochastic modeling the transport processes in liquids. The proposed method and the corresponding algorithm are an alternative to the molecular dynamics method. However, unlike the latter the system of Newtonian equations is not solved for modeling the phase trajectories of the system studied. The phase trajectories of the molecular system are simulated stochastically. For this purpose, the database of the intermolecular forces acting on each molecule of the system during the considered time interval has been created. The distribution function of these forces has been built. It was shown that this distribution function can be approximated by certain analytic function. The dependency of the parameters of this function on the liquid temperature and parameters of the intermolecular interaction potential (the Lennard-Jones interaction potential is used) is determined. Using this distribution function the force acting on each molecule at given time is determined. After that the coordinates and velocity of all molecules of the system are calculated. As a result, the full information about the phase variables of the molecular system is obtained. All macroscopic characteristics of the system (temperature, pressure, transport coefficients etc.) are calculated by means of the methods of nonequilibrium statistical mechanics. The transport coefficients are calculated using fluctuation-dissipation theorems that relate transport coefficients to the evolution of the corresponding correlation functions. The algorithm was tested on the calculation of the viscosity of several simple liquids.
Individual bubbles moving in an inclined flat channel
Authors: Randin V V , Chinak A V 
Published: December 2019

Abstract
The results of an experimental study of single bubble movement in an upward bubble flow in an inclined flat channel are presented. The measurements were carried out for a liquid Reynolds numbers 2000÷22700 and for channel inclination angles 0÷90. It is shown that in a gas-liquid flow the channel inclination angle has a significant effect on the flow characteristics. The data obtained in the experiments show that bubble rise velocity is lower than that in a large volume of a quiescent liquid and is affected channel inclination angle. With an increase in the Reynolds number, the influence of the channel inclination angle on the two-phase flow decreases.
Particle Reynolds stress model for wall turbulence with inertial particle clustering
Authors: Sikovsky D Ph 
Published: December 2019

Abstract
The modification of Zaichik particle Reynolds stress transport model for turbulent particle-laden flows is developed taking into account the clustering phenomenon of inertial particles. The main novelty is the new boundary condition for the particle Reynolds stress, which is posed at some distance from the wall in the viscous sublayer and is consistent with the power-law singularity of particle concentration at the wall. The modified model avoids the spurious bifurcation of the solution, which observed for non-modified Zaichik model with the near-equilibrium wall boundary condition.
Evaporation of non-ideal binary solution drops
Authors: Borodulin V Yu , Nizovtsev M I , Sterlyagov A N 
Published: December 2019

Abstract
The study of the evaporation process of multicomponent liquid droplets was carried out in the work. In the simulation and experiments, an aqueous solution of ethanol of various concentrations, which is a binary non-ideal mixture with known physicochemical properties, was used as a mixture. The deviation of the solution properties from ideal was taken into account using the generalized dependence of the pressure of vapor components saturated above the solution on their concentration in the solution. Using an example of an aqueous ethanol solution, a deviation of the change in the diameter of the droplets from the “law d2” was shown, which is associated with a two-speed evaporation mode. During evaporation at a low concentration of ethanol, the temperature of the droplet was close to the temperature of adiabatic evaporation of water; at a high concentration of ethanol, it was close to the temperature of adiabatic evaporation of ethanol. Comparison of the results of the simulation with experiment showed satisfactory agreement.
Chaos under interface oscillations during boiling and sea surface agitation
Authors: Kuzma-Kichta Yu A , Bondur V G 
Published: December 2019

Abstract
Results of investigation of the phase interface fluctuations at film and bubble boiling and sea surface agitation are presented. The vapor film thickness and vapor bubble growing on the wall were determined with the aid of laser diagnostics. Oscillations of a growing vapor bubble and simultaneous pressure oscillations in liquid were detected using optical (laser) and acoustic diagnostics. For the very first time volume and shape oscillations of a vapor bubble growing on a wall were determined. An approached model of volume oscillations of a vapor bubble, growing on a heat transfer surface is presented basing on experimental data. The system of model equations and bubble dynamics were presented considered, accounting simultaneous evaporation and condensation at the interface. It has been found that the growth of a vapor bubble is accompanied by its volume oscillations, which become chaotic under certain circumstances.
Dynamics of heat transfer at the coalition of the drops on a horizontal heated surface
Authors: Ponomarenko T G , Cheverda V V 
Published: December 2019

Abstract
An experimental study was carried out to investigate heat transfer during the coalition of two drops of the same volume. The falling of a water drop to other drop sitting on a heated horizontal foil made of constantan with a thickness of 25 μm from a distance of 10 mm was recorded with a high-speed video camera. An infrared scanner was used to measure the temperature field on the surface of the foil. Measurements taken with the infrared scanner will be used to determine the heat flux density in the region of the dynamic contact wetting line at the coalition of drops.
The regenerative heat exchanger with periodic veering of the flow
Authors: Aktershev S P , Mezentsev I V , Mezentseva N N 
Published: December 2019

Abstract
In the given work numerical simulating of the regenerative heat exchanger with a cyclic flow veering is executed in application to the ventilation system. The heat exchanger contains the grained medium consisting of solid spherical elements, storing heat. During a half cycle the entering cold air passes through the grained medium, heating it up to the room temperature. Then the air flow direction is reversed and during another half cycle the exhaust warm air refunds heat to the grained medium. Unlike the former researches, the case of low thermal diffusivity of spherical elements, when heat transfer is determined by the properties of a grained medium, is investigated. The mathematical model describing a cyclic mode of heat exchanger operation is developed. The basic criteria determining heat transfer and their influence on heat regeneration efficiency are revealed.
Simulation of orthogonal rotors with dynamic pitching blades
Authors: Dekterev D A , Dekterev Ar A , Lobasov A S , Platonov D V , Sentyabov A V , Dekterev A A 
Published: December 2019

Abstract
An adaptation of the mathematical model for the investigation of the parameters of orthogonal wind turbine has been performed. The simulation of Darrieus H-type rotor operating modes was performed and compared with experimental data. A kinematic scheme with dynamic blades was used for optimal tip-speed ratio. The results of numerical simulation with different deflection angles at fixed tip-speed ratio 1.6 showed that maximum rotor efficiency is reached for a blade pitch angle equal to 8 degrees. One can see that the use of the kinematic scheme, which allows changing the pitch angle of blades, leads to an increase in the efficiency of the rotor in the range from 12 to 50% (depending on the tip-speed ratio).
Simulation of heat and mass transfer in a shaft plasma furnace for the processing of municipal solid waste
Authors: Anshakov A S , Domarov P V , Faleev V A 
Published: December 2019

Abstract
A mathematical model of the process of heat and mass transfer in two penetrating media (gas stream and waste mixture) during plasma gasification of organic waste is presented in the article. The model takes into account many parameters: the total pressure of the vapor-gas mixture, partial pressure, humidity of the waste, etc. The effect of humidity during heat and mass transfer in the reaction zone of a mine electric furnace on the temperature distribution in the waste charge and the gas phase is shown.
Method of research on heat exchange for parallel plates with low thermal conductivity in short-time processes
Authors: Kirsanov Yu A , Makarushkin D V , Yudakhin A E , Kirsanov A Yu 
Published: December 2019

Abstract
Temperature of coolant was measured at the input and output of an alternating regenerator. Additionally, the temperature was measured both at several points on the surface of the parallel plates and along their geometrical axis. The package of the parallel plates was used as a nozzle of the regenerator. The method of determining heat transfer coefficients was described for the side and butt end surfaces of the plates in short-time processes. The mathematical models were created for the following two non-stationary processes. The first process is convective energy transfer in heat carrier flows. The second one is the process of thermal conductivity of two-dimensional body (plate) washed cyclically by cold and hot heat carrier flows. The coefficients of cyclic heat exchange with the cold and hot heat carrier flows were obtained for the side and butt end surfaces of the plates in short-time processes.
Optimization of the cyclic pumping of high pour point and high viscosity oil mixtures through main oil pipelines
Authors: Bekibayev T T , Zhapbasbayev U K , Ramazanova G I , Makhmotov E S 
Published: December 2019

Abstract
This paper presents the optimization results of the cyclic pumping of batches of high-pour-point and high-viscosity oil mixtures at the Uzen-Atyrau section of the Uzen-Atyrau-Samara main pipeline, taking into account on-route heating, boosting and pumping-out. The optimization criterion was the minimum total cost of power consumption by the pumping units and the preheaters.