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Thermophysics and Aeromechanics

2019 year, number 1

Methods for determining the equivalent aerodynamic damping of reentry vehicle models tested in a setup with free oscillations

E.A. Chasovnikov1, S.A. Chasovnikov2
1Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
2Voevodskii Institute of Chemical Kinetics and Combustion SB RAS, Novosibirsk, Russia
Keywords: модель спускаемого аппарата, свободные колебания, эквивалентное аэродинамическое демпфирование, reentry vehicle model, free oscillations, equivalent aerodynamic damping

Abstract >>
Two methods are developed for determining the equivalent aerodynamic damping of reentry vehicle models. In the first method, the equivalent aerodynamic damping is determined on the basis of the experimental envelopes of the transitional process for the angle of attack changing with time; in the second method, all experimental points of the transitional process are involved. Both methods are found to produce similar results. The adequacy of the methods is verified by an example of a reentry vehicle model, which demonstrates that the predicted transitional processes for the angle of attack changing with time are in good agreement with the experimental data.

Improvement of the take-off and landing characteristics of wing using an ejector pump

A.V. Voevodin, A.A. Kornyakov, A.S. Petrov, D.A. Petrov, G.G. Sudakov
Zhukovsky Central Aerohydrodynamic Institute, Zhukovsky, Russia
Keywords: струйный насос, эжектор, крыло, отсос, выдув, управление обтеканием, численные и экспериментальные исследования, jet pump, ejector, wing, gas suction, jet blowing, flow control, numerical and experimental studies

Abstract >>
The effectiveness of use of an ejector pump for controlling the flow around a wing under take-off and landing conditions of flight is investigated. The proposed device permits organization of simultaneous suction of boundary layer through a slot on the upper surface of the wing and gas blowing in the vicinity of the trailing edge of wing through a flat slot-type diffuser; the latter makes it possible to effectively implement the principle of wing-flow control using gas suction and jet blowing. The design of the ejector pump makes it possible to obtain values of suction and blowing velocities of order 50-100 m/s. The paper proposes a mathematical model of the flow around the wing airfoil taking into account the operation of the ejector pump, and presents results of a computational study of aerodynamic characteristics of one- and three-element wing airfoil under landing conditions. It is shown that the simultaneous use of suction and blowing improves the flight characteristics of the mechanized airfoil more effectively in comparison with the separate use of these means.

Numerical modeling of the pressure distribution on the axisymmetric body surface at the supersonic freestream interaction with a transversely blown gas jet

V.A. Kislovskiy, V.I. Zvegintsev
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
Keywords: сверхзвуковое обтекание, выдув, газоструйные течения, аэродинамические силы, распределение давления, supersonic flow, blowing, gas-jet flows, aerodynamic forces, pressure distribution

Abstract >>
The results of numerical investigation of the interaction of a supersonic free stream with the Mach number of 3.85 with a transverse gas jet blown from the surface of an axisymmetric model located at zero angle of attack with respect to the flow are presented. The numerical modeling was conducted using the averaged Navier-Stokes equations employing the k-w SST turbulence model. The investigation of the influence of the gas jet blowing on pressure redistribution over the axisymmetric model surface and on the formation of an additional transverse force and moment has also been conducted. The shift of the blowing orifice along the model length leads to a significant variation of arising forces and moments. A fundamental difference in the distribution of pressures over the surface at the jet blowing from the axisymmetric body and from a flat plate is shown.

Peculiarities of the rise of structured formations at the boundary of the change of the regimes “diffusion-concentration convection” at an isothermal mixing of a binary mixture equally diluted by the third component

V.N. Kossov1,2, O.V. Fedorenko2, D.B. Zhakebaev3, A.P. Kizbaev3
1Abai Kazakh National Pedagogical University, Almaty, Kazakhstan
2Scientific and Research Institute of Experimental and Theoretical Physics KNU, Almaty, Kazakhstan
3Al-Farabi Kazakh National University, Almaty, Kazakhstan
Keywords: диффузия, конвекция, давление, концентрация, неустойчивость, diffusion, convection, pressure, concentration, instability

Abstract >>
The peculiarities of the change of the regimes “diffusion-gravitational concentration convection” have been studied numerically. It is shown that at a certain mixture composition and pressure, substantially nonlinear distributions of the concentrations of components arise at the expense of the difference in the diffusion coefficients of components, which lead to the corresponding distribution of the gaseous mixture density. This is a reason for the formation of structured formations and the rise of convective instability in the mixtures under study. The time of the rise of convective flows and of the mean velocity of the components transfer has been estimated. Obtained results are compared with experimental data.

The dynamics of a cylindrical zone of turbulent mixing in a longitudinal shear flow of a linearly stratified medium

N.P. Moshkin1, A.V. Fomina2, and G.G. Chernykh3,4
1Lavrentyev Institute of Hydrodynamics SB RAS, Novosibirsk, Russia
2Novokuznetsk Institute KemSU, Novokuznetsk, Russia
3Institute of Computational Technologies SB RAS, Novosibirsk, Russia
4Novosibirsk State University, Novosibirsk, Russia
Keywords: stratified fluid, cylindrical zone of turbulent mixing, longitudinal horizontally uniform shear flow, numerical simulation

Abstract >>
A numerical model has been constructed and the investigation of the dynamics of a cylindrical localized region of turbulent disturbances in a longitudinal horizontally ho-mogeneous shear flow of a linearly stratified fluid has been carried out. Computation-al results have shown a considerable generation of turbulence energy at the expense of shear flow gradients. It was also found that the shear flow affects weakly the inter-nal waves generated at the evolution of the turbulent mixing zone.

Using two-layer compliant coatings to control turbulent boundary layer

B.M. Kulik1, A.V. Boiko2,3, I. Lee4
1Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
2Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
3Tyumen State University, Tyumen, Russia
4Pusan National University, Pusan, Korea
Keywords: податливое покрытие, многослойность, вязкоупругие свойства, комплексная податливость, турбулентное течение, снижение гидродинамического трения, compliant coating, multilayering, viscoelastic properties, complex compliance, turbulent flow, reduction of hydrodynamic friction

Abstract >>
Experiments on the effect of two-layer compliant coatings on the surface friction of a flat plate at flow velocities of up to 16 m/s carried out in a water tunnel are described. To document the properties of the coatings, the dynamic viscoelastic properties of used rubbers were measured in the frequency range approximately corresponding to the frequency range of wall pressure oscillations at current flow velocities. The data on characteristics of the viscoelastic properties of coatings and experimental data on interaction of coatings with the flow form a database required to test various theories and semi-empirical models for predicting the effectiveness of such interaction.

Simulating the regimes of oblique detonation waves arising at detonation initiation by a small-diameter projectile

I.A. Bedarev1, V.M. Temerbekov1,2, A.V. Fedorov1,2
1Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
2Novosibirsk State Technical University, Novosibirsk, Russia
Keywords: детонация, сверхзвуковой поток, численное моделирование, частица, детонационная ячейка, detonation, supersonic flow, numerical simulation, particle, detonation cell

Abstract >>
Initiating detonation in a reactive hydrogen-oxygen mixture by a spherical projectile of small diameter, flying with velocity exceeding the Chapman-Jouguet one, has been studied numerically. The mathematical model is based on the given kinetic scheme for the description of chemical reactions. At verification of the computational algorithm, the flow regimes and the detonation cell size were compared for numerical and experimental data. The agreement between the calculated and the experimental flow patterns and the quantitative correspondence of the modes of existence of inclined detonation waves have been obtained.

Model of solid fuel rocket engine: thermal emission characteristics from a plume calculated with account for temperature and speed non-equilibrium between gas and particle flows

V.A. Kuzmin, I.A. Zagrai, E.I. Maratkanova
Vyatka State University, Kirov, Russia
Keywords: тепловое излучение, гетерогенные продукты сгорания, факел, модельный ракетный двигатель на твердом топливе, скоростная неравновесность, температурная неравновесность, характеристики излучения, степень черноты, вычислительный эксперимент, thermal radiation, heterogeneous combustion products, plume, model solid-fuel rocket engine, speed non-equilibrium, temperature non-equilibrium, emission characteristics, emissivity factor, computational experiment

Abstract >>
The paper presents a method for study of thermal emission characteristics from heterogeneous combustion products in a plume of a model solid-fuel rocket engine. Simulation experiments found the influence of speed and temperature types of non-equilibrium on spectral and integral densities of radiation energy flux and emissivity factors. The values of non-equilibrium were determined at different critical nozzle cross sections and at different average sizes of particle. It was found that the speed non-equilibrium has a minor influence within the gas emission bands; meanwhile it is stronger for transparency bands of gas phase. The non-equilibrium in temperature is the main factor in calculating the emission characteristics of the flow, while the speed delay of particles relative the gas flow is manifested stronger at this background.

Experimental investigation of structure and heat transfer in cellular flame of rich and lean propane-butane-air mixtures

B.F. Boyarshinov, S.Yu. Fedorov, R.Kh. Abdrakhmanov
Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
Keywords: ячеистое пламя, бесконтактные измерения PIV, метод CARS, метод балансов, cellular flame, Particle Image Velocimetry (PIV), Coherent anti-Stokes Raman Scattering (CARS), balance method

Abstract >>
We studied a lean propane-butane-air mixture ascending through a round hole of 10-mm diameter, covered by a brass mesh as a single element of the multicellular flame. Gas temperature was measured by the CARS method (Coherent anti-Stokes Raman Scattering) with original software for spectra processing. The vertical and horizontal velocity components were measured by the PIV method (Particle Image Velocimetry). Distributions of heat release intensity and heat fluxes, which cannot be obtained in direct measurements, were estimated using balance relationships in the energy equation. The results were compared with the data obtained for the rich mixture flame in experiments with the same burner. Convective and molecular heat fluxes were considered separately. It was shown that when the rich air mixture with propane-butane burns, the heat flux caused by thermal conductivity reach a maximum at the center of the heat-release zone. Their intensity is substantially lower in comparison with the convective fluxes behind the flame front, which in turn are almost twice as weak as the convective flux in the flame of a lean mixture. The maximal intensities of heat release in the flame of a rich mixture are lower than in the lean one.

On the numerical simulation of thermal decomposition of hydrocarbon mixtures in channels of cooling systems of high-speed vehicles. Optimization of the fuel composition

P.D. Toktaliev1,2, I.O. Galitskiy1, S.I. Martynenko1,2, A.V. Volokhov1, E.S. Amosova1, V.M. Volokhov1, L.S. Yanovskiy1,2
1Institute of Problems of Chemical Physics of RAS, Chernogolovka, Moscow Region, Russia
2Central Institute of Aviation Motors named after P.I. Baranov, Moscow, Russia
Keywords: топливо, система охлаждения, оптимизация, fuel, cooling system, optimization

Abstract >>
A mathematical model of physical and chemical processes in a turbulent flow of mixtures of alkanes with the number of carbon atoms 0 < C < 9 in heated channels has been developed. The Navier-Stokes equations were used to describe the turbulent transfer, and a detailed kinetic mechanism served to describe the thermal decomposition of hydrocarbons. A detailed description of the developed model and the results of its verification based on experimental data is given. In the present paper, the model is used to numerically study the conjugate heat transfer in a plane heated channel of the cooling system of advanced ramjet aircraft engines on endothermic hydrocarbon fuels. A two-criterion optimization of the initial composition of endothermic hydrocarbon fuel was performed to obtain the maximum endo-thermic effect and energy content of the resulting hydrocarbon fuel mixture, further fed into the combustion chamber of the engine. The limitations in the optimization are the maximum permissible temperature of the heated channel walls (the condition of thermal resistance of the structure) and the maximum acceptable degree of decomposition of the hydrocarbon mixture, in excess of which the intensive formation of solid deposits begins on the washed channel walls.

Influence of parameters of superheated steam on combustion of liquid hydrocarbons

S.V. Alekseenko1, I.S. Anufriev1,2, S.S. Arsentyev1,3, S. Vigriyanov1, E.P. Kopyev1, O.V. Sharypov1
1Kutatelazde Institute of Thermophysics SB RAS, Novosibirsk, Russia
2Novosibirsk State Technical University, Novosibirsk, Russia
3Novosibirsk State University, Novosibirsk, Russia
Keywords: горелочное устройство, жидкое топливо, струя перегретого водяного пара, состав продуктов, калориметрические измерения

Abstract >>
The main characteristics of liquid hydrocarbon combustion in a jet of superheated steam were studied. The influence of main physical parameters of steam flow on combustion parameters (temperature distribution in flame, generated heat power, combustion products composition) were measured for the original burner apparatus.

Features of the vapor formation process near a wall with a gas-droplet film cooling

V.I. Terekhov, N.E. Shishkin
Kutateladze Institute of Thermophysics SB RAS, Novosibirk, Russia
Keywords: концентрация пара, газокапельные струи, параметр вдува, жидкие пленки, канал с адиабатическими стенками, vapor concentration, gas-droplet jets, ejection coefficient, liquid films, channel with adiabatic walls

Abstract >>
On the basis of available experimental data, we have performed an analytical study of the concentration of saturated vapor over a liquid film formed from droplets being deposited onto the wall of an adiabatic channel under gas-droplet film cooling. The analysis was carried out by varying the main parameters of the mixing jets, namely, the ejection coefficient, the concentration of the liquid, and the main-flow temperature. An approximating dependence for the concentration of saturated vapor in the presence of the liquid film is obtained, and the effect due to the flow non-isothermality is taken into account.

Optimal design and numerical analysis of the rapid precooler

K.-X. Liu1, C.-A. Ai1, X.-R. Wang1, X.-F. Cai1, Y. Wang2
1Xi’an Research Institute of Hi-Tech, Xi’an, China
2National University of Defense Technology, Changsha, China
Keywords: система быстрого предварительного охлаждения, коэффициент теплообмена, шероховатость стенки, число диссипации энтранса, rapid precooler, heat transfer coefficient, wall roughness, entransy dissipation number

Abstract >>
Under the background of highly compact heat exchanger design core for the hypersonic aerospace precooled engine, a rapid precooler is designed and its performance is simulated under the high-altitude background. To this end, firstly, according to the known parameter range, a plate tube-fin rapid precooler unit with the optimal parameters is designed by using the genetic algorithm to find the minimum of the objective function-entransy dissipation number. Then introducing the roughness viscosity coefficient into the improved finite volume method, the effect of rapid heat transfer enhancement is obvious. The fin design can improve the heat transfer efficiency of the heat exchanger unit by 46.5 %. Finally, the rapid precooler is designed based on the unit. The performance simulation results indicate that the average temperature has decreased by 735 K for less than 1.5 ms hot air flowing through the rapid precooler at a high speed. The purpose of rapid heat transfer enhancement is achieved. Also we explore the influence of different hot air velocity and coolant velocity on rapid precooler and investigate the influence of scale effect on heat transfer performance.

Effect of gas flow velocity on convection in a horizontal evaporating liquid layer

Yu.V. Lyulin1,2, A.S. Kreta2, O.A. Kabov2,3
1Skolkovo Institute of Science and Technology, Moscow, Russia
2Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
3Novosibirsk State University, Novosibirsk, Russia
Keywords: конвекция, термокапиллярная граница раздела, двухфазные течения, испарение, PIV-метод, convection, thermocapillary interface, two-phase flows, evaporation, PIV-method

Abstract >>
The structure of convective flows in a horizontal evaporating layer of liquid (ethanol) was studied experimentally depending on the velocity of gas (air) flowing near the interface. Using the PIV method, we measured distribution of the two-dimensional velocity field and visualized the convective flows in a liquid layer. The existence of a vortex flow structure in an evaporating liquid layer, when the interface moves towards the gas flow, was proved.

Simulation of production of hollow silica particles in a plasma flow. Part 1. Dynamics of motion and heating of porous particles

V.A. Arkhipov1, S.S. Bondarchuk2,3, V.V. Shekhovtsov4, O.G. Volokitin4, A.S. Anshakov5, V.I. Kuzmin6
1Tomsk State University, Tomsk, Russia
2Institute for Problems of Chemical and Energetic Technologies SB RAS, Biysk, Russia
3Tomsk State Pedagogic University, Tomsk, Russia
4Tomsk State University of Architecture and Building, Tomsk, Russia
5Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
6Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
Keywords: электроплазменная установка, низкотемпературная плазма, пористые частицы, кремнезем, полые микросферы, скорость частиц, нагрев, плавление и испарение частиц, математическое моделирование, electric plasma setup, low temperature plasma, porous particles, silica, hollow microspheres, particle velocity, particle heating, melting and evaporation, simulation

Abstract >>
The paper presents simulation results for the dynamics of motion, heating, and melting of porous silica particles by electro-plasma technology during production of hollow silica microspheres. With the use of available analytical and numerical solutions of equations of motion and energy for particle flow, we analyze the laws of evolution of particle parameters in the plasma flow for the case of particle diameter varying in the range D = (250-350) mm and for porosity in the range П = (0-0.6).

80th Anniversary of Vladimir V. Salomatov

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30 December, 2018 is the 80th anniversary of the chief researcher of the Institute of Thermophysics SB RAS, Doctor of Technical Sciences, full member of the International Energy Academy, Professor Vladimir V. Salomatov.

In memoriam of Albert F. Kurbatskii

Abstract >>
On December 24, 2018, the well-known scientist in the field of fluid and gas mechanics, honored scientist of the Russian Federation, doctor of physical and mathematical sciences, Professor Albert F. Kurbatskii passed away.