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2023 year, number 4
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M.V. Salnikov1, K.S. Kinzin1,2, I.V. Naumov1,2, R.I. Mullyadzhanov1,2
1Kutaledaze Institute of Thermophysics SB RAS, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
Keywords: multicomponent liquid, lattice Boltzmann equations, swirl flow, vortex breakdown
Abstract >>
Numerical simulation is performed for a cylinder-bound two-component liquid flow. Simulation model is based on the method of lattice Boltzmann equations (LBM). The collision integral in this model is defined from the MRT approximation. The interaction between liquid components is described by the diffusion interface model with the pseudopotentials approximation. The main deficiency of this known approach is disbalance for discrete forces of two-component interaction; this would generate a pseudo-current in the transition zone. The presented numerical study offers a qualitative view for the pseudopotential function providing a smallest value for intercomponent interaction coefficient. This means the low pseudo-currents and the smallest size for the diffusive transition. The example simulation is presented for a problem of rotation of two components in a cylinder. The simulation gives also the Reynolds number rage and the cylinder aspect ratio that ensure the start of flow recirculation at the cylinder axis. It was demonstrated that simulation results comply with experimental data with a high accuracy.
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V.I. Kornilov, I.V. Menshikova, A.A. Pivovarov
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
Keywords: plane surface, turbulent boundary layer, air blowing, microholes, friction, pressure
Abstract >>
Results of numerical investigations of the characteristics of a turbulent boundary layer in the case of air injection through a smooth flat perforated surface with a single hole and also through a similar surface with a group of staggered holes 0.18 mm in diameter (d/δ) in a low-velocity flow are reported. The Reynolds number Re** based on the momentum thickness δ** ahead of the perforated region is 2600. The blowing coefficient Cb is varied in the interval from zero to 0.0438. The influence of some geometric parameters, in particular, the distance between the hole centers, on the properties of the transverse shear flow for identical intensities of blowing in situations with one hole and with a group of holes is analyzed. All observations reveal stable reduction of local friction whose value varies depending on the number of holes and their arrangement on the surface.
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I.A. Davletshin1, N.S. Dushin1, O.A. Dushina1, N.I. Mikheev1, R.R. Shakirov1, S.A. Isaev2
1Institute of Power Engineering and Advanced Technologies, FRC “Kazan Scientific Center RAS”, Kazan, Russia
2State Marine Technical University, Saint Petersburg, Russia
Keywords: dimples, heat-transfer intensification, hydraulic resistance
Abstract >>
An experimental study of heat transfer and hydraulic losses in a channel with one wall being a surface with trench dimple, was carried out. The working surface had four rows of dimples located alternately at angles of 45° and -45° to the channel axis. In the laminar regime, the transfer of heat and the losses of pressure turned out to be close to the parameters of a smooth channel. In the turbulent regime, a 1.5-fold intensification of heat transfer with respect to the transfer of heat in a smooth channel was obtained. The dependence of the increase in pressure losses on the Reynolds number qualitatively agreeing with the dependence for the channels with sandy roughness is obtained.
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V.N. Mamonov, N.B. Miskiv, A.D. Nazarov, A.F. Serov, V.I. Terekhov
Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
Keywords: Couette-Taylor system, rotating cylinders, energy dissipation, antitorque moment, ribs
Abstract >>
The experimental results on the effect of longitudinal ribs on the antitorque moment for Couette-Taylor flow between two rotating cylinders are presented. The tangential Reynolds number in the experiments was varied by varying the cylinder speed and the working fluid viscosity (water-glycerin solution). The experiments covered laminar, transient and turbulent flow regimes (Re = 200 - 1·105). It is shown that the ribs have an amplifying effect on the drag torque and mechanical energy dissipation only in the region of small Reynolds numbers (Re < 2000) in the laminar regime and in the presence of Taylor vortices in the gap. The intensification effect can reach two and more times and is caused by intensive turbulence of the flow by longitudinal ribs. In the turbulent regime, the heat release intensification is not observed, which is confirmed by the data available in the literature.
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I.S. Tsyryulnikov, S.G. Mironov, T.V. Poplavskaya
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
Keywords: supersonic nonisobaric jets, wave structure, effect of vibrational relaxation
Abstract >>
A nonisobaric supersonic jet of vibrationally excited carbon dioxide exhausting from converging axisymmetric nozzles with the diameter ranging in a wide interval (from 0.03 to 114 mm) is studied experimentally and numerically. Numerical simulations are performed within the framework of the two-temperature approach with the use of the Landau-Teller relaxation equation for each vibrational mode of carbon dioxide molecules. The simulations reveal that vibrational nonequilibrium of molecules affects the gas-dynamic structure of the jets in the temperature range of 300 - 900 K, and this effect is verified experimentally. Vibrational excitation of molecules in the experiment is ensured by means of gas heating. The effect of vibrational nonequilibrium is manifested as reduction of the amplitude of the static pressure in wave structure cells and as reduction of the longitudinal size and number of wave structure cells as compared to the case of an equilibrium supersonic flow. It is shown that the maximum effect of nonequilibrium is observed in jets exhausting from the nozzle with a diameter of ≅ 3 mm.
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N.I. Klochkov1,2, I.D. Zverkov1,3, D.A. Gavrilov4,5
1Novosibirsk State Technical University, Novosibirsk, Russia
2“Aeroflot Technics” Plc, Moscow, Russia
3Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
4Novosibirsk State University, Novosibirsk, Russia
5Informatics College at the NSU, Novosibirsk, Russia
Keywords: composite honeycomb constructions, thermal imaging method for nondestructive inspection, delamination of skin, equipment for nondestructive inspection
Abstract >>
The modern aviation industry has many applications for honeycomb composite panels (HCP). The HCP-manufactured product line becomes more extended. This dictates a need for most effective and inexpensive methods for nondestructive inspection for HCP integrity that can ensure a high level of flight safety. One of promising methods for nondestructive inspection is the thermal technique. This paper presents and analyses the method feasibility of revealing the delamination of outer skin from an HCP filling. This task is performed by numerical simulation and the paper presents a pictorial test with a sample of HCP typical for aircraft engineering. Our results demonstrate how the thermal imaging tools can be used for the fact of skin delamination with account for technical restrictions found in real experiments with a physical sample of HCP.
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O.I. Vishnyakov, P.A. Polivanov, A.A. Sidorenko, A.D. Budovsky
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
Keywords: shock wave/boundary layer interaction, flow separation, electric discharge
Abstract >>
The paper presents the results of experimental study of disturbances generated by an electric discharge. Tthe disturbances occur in the zone of interaction of a shock wave and a boundary layer (the income shock wave has the Mach number М = 1.43). Experiments were carried out in a supersonic wind tunnel with the unit Reynolds number Re1 = 11×106 1/m. The flow velocity was measured using the PIV method and hot wire method. The artificial disturbances are generated by a periodic pulsed electric charge; the charge facility is allocated at the model surface upstream the interaction zone. The discharge time is less than 100 ns: this enables creating a wide-spectrum disturbance inside the boundary layer. The method of phase-synchronous measurement with the ensemble averaging for realization produces the spatial and temporal characteristics of disturbances generated in the interaction zone. The major growth of initial disturbances occurs in the shear layer behind the shock wave/boundary layer interaction zone (here the flow is turbulent).
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K.Yu. Litvintsev1, A.A. Dekterev1, V.D. Meshkova2, S.A. Filimonov1
1Kutateladze Institute of Thermophysics RAS SB, Novosibirsk, Russia
2Siberian Federal University, Krasnoyarsk, Russia
Keywords: urban environment, radiation, heat transfer, wind regime
Abstract >>
In the present paper, a computational study of the influence of solar and thermal radiation on the formation of wind and temperature conditions in urban environment is carried out using the example of a region of Krasnoyarsk in winter. For calculations, a developed microscale mathematical model of urban atmosphere was used. The calculation results showed that the presence of radiation in the daytime leads to an increase in temperature and average speed of wind, as well as to the formation of an unsteady wind regime in the urban environment.
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S.P. Aktershev, S.V. Alekseenko, A.V. Bobylev
Kutateladze Institute of Thermophysics RAS SB, Novosibirsk, Russia
Keywords: rivulet flow, steady-state traveling nonlinear waves, theoretical model
Abstract >>
Nonlinear waves in a rectilinear rivulet flowing down a vertical plate are investigated on the basis of the developed semi-analytical model. The characteristics of nonlinear quasi-two-dimensional steady-state traveling waves are obtained numerically. Another wave family (the family of double-humped waves), branching off from the first family by doubling the spatial period, is found for small values of the wave number. It is shown that steady-state traveling waves do not exist in a certain narrow range of the excitation frequency, but a pulsating wave mode is realized.
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Yu.Yu. Puzina, A.P. Kryukov
Moscow Power Engineering Institute, Moscow, Russia
Keywords: experiment, superfluid helium, interfacial surface oscillations, channel, dynamics equation
Abstract >>
The paper considers experimental data on the dynamics of superfluid helium in a U-shaped cylindrical channel. An experimental cell and a methodology for investigations, parameter measuring and obtained data processing are described. When a heat flux is applied near the heater, vapor can appear, and the interfacial surface executes regular oscillations of macroscopic amplitude with a constant frequency. The dependences of the interfacial surface position and the corresponding parameters on time are given. The obtained experimental results are interpreted based on the earlier obtained analytical solution.
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A.A. Chernov1,2, M.N. Davydov1,3, S.I. Lezhnin1,2
1Novosibirsk State University, Novosibirsk, Russia
2Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
3Lavrentyev Institute of Hydrodynamics SB RAS, Novosibirsk, Russia
Keywords: gas bubble, magmatic melt, decompression, barodiffusion, boundary value problem with a moving boundary, numerical simulation
Abstract >>
The effect of barodiffusion on the dynamics of gas bubble growth in a highly viscous, gas-saturated magmatic melt undergoing rapid decompression is studied. A mathematical model of the process, which represents a joint dynamic and diffusion problem, is proposed. It is shown that as the bubble grows, a diffusive boundary layer is formed around it, leading to the appearance of a large viscosity gradient in the melt and, as a consequence, to a large pressure gradient. A semi-analytical solution of the problem based on the existence of a quasi-stationary state for the bubble growth process is found. It is shown that the effect of barodiffusion is significant at the initial and transient stages of the process. Its influence decreases with time and disappears completely at the stage of diffusion.
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V.I. Zvegintsev, S.V. Lukashevich
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
Keywords: unsteady gas-dynamic processes, vacuum vessel, filling, pressure increase, quasi-stationarity
Abstract >>
Based on the hypothesis of quasi-stationarity, relations were obtained for calculating the unsteady process of filling a vacuum vessel. As a criterion for the completion of the filling process, the admissible degree of pressure increase in the vacuum vessel is adopted. An analysis was made of the possibilities of increasing the duration of the filling process for a vacuum vessel of a given volume.
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R.A. Khairulin, R.N. Abdullaev, S.V. Stankus, A.B. Meshalkin
Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
Keywords: gamma method, density, thermal expansion, melt, lithium fluoride, potassium fluoride
Abstract >>
The density of liquid mixtures of lithium and potassium fluorides with a content of 51.2 and 71.1 mol % LiF was measured using gamma-ray attenuation technique in the temperature range from liquidus to 1000-1190 K. For a mixture of near-eutectic composition (51.2 mol % LiF), the relative density change during the solid-liquid phase transition and the density in the solid state near the melting point were directly determined for the first time. The concentration dependences of the molar volume and volumetric coefficient of thermal expansion for the LiF-KF liquid system were plotted on the basis of the experimental and literature data. The obtained dependences were found to be close to the concentration dependences of the corresponding volumetric properties for ideal solutions.
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I.N. Ganiev1, R.S. Shonazarov2, A. Elmurod3, U.N. Faizulloev4, A.G. Safarov5
1Institute of Chemistry named after V.I. Nikitin NAS of Tajikistan, Dushanbe, Tajikistan
2Bokhtar State University named after Nosir Khusrav, Bokhtar, Tajikistan
3Dangara State University, Dangara, Tajikistan
4National Research Technological University (NUST) “MISiS” in Dushanbe, Dushanbe, Tajikistan
5Physical-Technical Institute named after S.U. Umarov NAS of Tajikistan, Dushanbe, Tajikistan
Keywords: aluminum alloy AlCu4,5Mg1, calcium, “cooling” mode, heat capacity, enthalpy, entropy, Gibbs energy
Abstract >>
The cooling rates of the studied alloy samples were determined in the "cooling" mode, by constructing thermograms of cooling alloys and their subsequent differentiation. Considering the heat capacity of the standard (Al brand A5N) and the cooling rates of the samples and the standard, the temperature dependence of the heat capacity of the aluminum alloy AlCu4,5Mg1 doped with calcium was calculated. Computer processing of the results served to obtain a polynomial of the temperature dependence of the heat capacity of alloys in the form of a four-term equation with the correlation coefficient R ≤ 0.999. It has been found that the heat capacity, enthalpy, and entropy of the alloys increase with increasing temperature, while the value of the Gibbs energy decreases. Additions of calcium in the range of 0.05 -1.0 wt. % reduce the heat capacity, heat transfer coefficient, enthalpy and entropy of the AlCu4,5Mg1 aluminum alloy, and the Gibbs energy has an inverse relationship.
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S. Sabzpoushan1,2, M.R. Morad3
1University of Freiburg, Freiburg, Germany
2Sharif University of Technology
3Sharif University of Technology, Tehran, Iran
Keywords: solar-driven Brayton heat engine, cycle efficiency, regenerative cycle, radiative loss, heat transfer nonlinearity
Abstract >>
In endoreversible cycles, irreversibility is considered only between the systems and their surroundings. In this paper, the modelling of heat interaction with a solar regenerative Brayton cycle is studied with regard to various fidelities based on the first and second laws of thermodynamics. The effect of linearity and nonlinearity related to the both convective and radiative heat interactions with the hot and cold reservoirs as well as radiation losses of the solar Brayton cycle have been studied, which is complementary to similar attempts for Carnot cycle. Total efficiencies are compared between various implemented models. The effect of temperature of six critical sections of the whole engine on the collector efficiency, cycle thermal efficiency and the system total efficiency has been studied. Besides, a comparison is done for a real example to show the importance of considering the nonlinearities for calculating thermal efficiency of a closed-loop Brayton cycle at different hot source temperatures, as well. These would help more efficient analysis of the emerging power cycles that can accelerate progress toward low-carbon power production.
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V.E. Messerle1,2,3,4, O. A. Lavrichshev3, A. B. Ustimenko5,3,4
1Institute of Combustion Problems, Almaty, Kazakhstan
2Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
3Al-Farabi Kazakh National University, Almaty, Kazakhstan
4LLP SDTC “Zhalyn”, Almaty, Kazakhstan
5Institute of Combustion Problems Almaty, Kazakhstan
Keywords: ash-and-slag waste, oil refinery waste, plasma processing, gasification, synthesis gas, thermodynamic calculation, experiment
Abstract >>
The results of thermodynamic calculations and experimental studies on plasma processing of ash-and-slag waste and oil refinery waste with production of fuel gas and inert mineral material are presented. The calculated and experimental data on plasma-chemical processing of oil refinery waste are compared
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Abstract >>
On July 30, 2023, the famous scientist in the field of physical gas dynamics, dynamics of rarefied gases and thermal physics, Academician of the Russian Academy of Sciences, Professor Alexei K. Rebrov turned 90 years of age.
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