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
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.
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.
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
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.
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
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.
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.
K.-X. Liu1, C.-A. Ai1, X.-R. Wang1, X.-F. Cai1, Y. Wang2
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Keywords: система быстрого предварительного охлаждения, коэффициент теплообмена, шероховатость стенки, число диссипации энтранса, rapid precooler, heat transfer coefficient, wall roughness, entransy dissipation number
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.
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
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.
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
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).
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.
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.
