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2021 year, number 2
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V.S. Zakharov1,2,3, O.V. Guskov1,2, A.N. Prokhorov1,2, V.N. Berezhnoy4
1Baranov Central Institute of Aviation Motors, Moscow, Russia
2Moscow Institute of Physics and Technology, Dolgoprudny, Russia
3Bauman Moscow State Technical University
4Scientific Testing Center of the Space-Rocket Industry, Peresvet, Russia
Keywords: high-rise stand tests, supersonic nozzle, gas-dynamics tube, turbulence model
Abstract >>
The influence due to the shape of the expanding part of supersonic nozzles on the gas-dynamic structures formed in the ducts of high-altitude rocket and aerodynamic test benches has been studied. The research was carried out using the means of computational gas dynamics with the example of a model gas-dynamics tube with three replaceable supersonic nozzles having identical throat and outlet-section diameters. For confirming the adequacy of the models and methods used, the calculated values were compared to experimental ones. To this end, a model setup was developed, manufactured, and tested. Air with ambient temperature was used as the working medium. Another goal of the study was to compare the calculations performed with the use of different turbulence models.
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V.I. Kornilov1, E.A. Shkvar2,3
1Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
2Zhejiang Normal University, Jinhua, China
3Institute of Hydromechanics NASU, Kiev, Ukraine
Keywords: airfoil, turbulent boundary layer, distributed mass transfer, lift force, drag force, lift-to-drag ratio
Abstract >>
The efficiency of stationary air blowing/suction into the turbulent boundary layer of the NACA 0012 airfoil through permeable sections located at the adjacent sides of the wing in the vicinity of its trailing edge is studied numerically and experimentally. The flow rates in these sections are varied in the intervals 0 ¸ 9.33×10-4 and 0 ¸ 8.48×10-4, respectively. The studies are carried out at the Reynolds number Re c = 0.7×106 in the range of angles of attack a = - 6 ¸ 6º. The efficiency of the control method is estimated from the results of measurements using the original method proposed by Jones, based on traversing the wake behind the airfoil, and a modification of this method, as well as by using the results of numerical simulations. The necessity of the Jones formula modification is demonstrated to be particularly important in the case with individual suction and blowing because mass transfer through the surface changes the momentum transferred from the undisturbed external flow to the boundary layer.
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D. Zheng1,2, X. Wang1, Q. Yuan1
a:2:{s:4:"TYPE";s:4:"HTML";s:4:"TEXT";s:105:"1Xi’an Jiaotong University, Xi’an, China
2University of Toronto, Toronto, Canada";}
Keywords: film cooling, upstream ramps, compound angles, adiabatic cooling effectiveness
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This paper presents a numerical investigation on the concept for improving film cooling performance by placing a ramp upstream the film hole with compound angle. Eight cases with different geometry models are investigated, including the compound angles of 15°, 30°, 45° and the distances between the upstream ramps and film holes (upstream distances) of 5 mm, 10 mm, and 15 mm. The effect of compound angle and upstream distance on film cooling performance is studied. The cases of film cooling on a flat plate, film cooling with compound angle, and film cooling with an upstream ramp are also presented as a contrast. The film cooling performance is evaluated at the density ratio of 0.97 with the blowing ratios ranging from 1.0 to 2.0. Results obtained show that the film cooling performance with compound angle is greatly improved by the upstream ramp, especially in the region downstream the film hole. Both the entrainment of coolant and modified kidney vortices are observed in the case of the novel geometry. The film cooling performance is greatly improved by the dual effect of coolant entrainment and modified kidney vortices. In addition, the film cooling performance is influenced by compound angle and upstream distance. With the increase of compound angle, the lateral adiabatic cooling effectiveness rises. With the increase of the upstream distance, the lateral adiabatic cooling effectiveness goes down.
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P. I. Geshev
Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
Keywords: falling liquid film, turbulence, intermittency, damping, gas flow friction, heat transfer and film thickness
Abstract >>
A model for calculating the thickness and heat transfer of a turbulent film moving under the action of gravity and the shear stress of friction of a gas flow is constructed. The aim of this work is to supplement the previously proposed simple model of turbulent viscosity using a cubic law of damping in a viscous sublayer and a logarithmic asymptotic velocity far from the wall with additional linear damping near the free surface and to take into account the damping of turbulent transfer caused by intermittency of turbulence in flowing wave films of liquid.
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O.Yu. Tsvelodub1,2, D.G. Arkhipov1,2, I.S. Vozhakov1,2
1Novosibirsk State University, Novosibirsk, Russia
2Kutateladze Institute of Thermophysics SB RAS
Keywords: thin liquid film, turbulent gas flow, turbulent viscosity, Boussinesq hypothesis, evolution equation, periodic perturbations
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The problem of the joint flow of a turbulent gas stream and a vertically falling wavy liquid film is considered. Tangential and normal stresses on the interfaces are calculated. The components of the Reynolds stress tensor are determined within the framework of the Boussinesq hypothesis. For the case of small Reynolds numbers of a liquid, the problem is reduced to a nonlinear integro-differential equation for the deviation of the layer thickness from the unperturbed level. A numerical study of the evolution of periodic perturbations is carried out. Several typical scenarios of their development are presented
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A.A. Safronov1, A.A. Koroteev2, N.I. Filatov1, N.V. Bondareva2
1Keldysh Research Center, Moscow, Russia, Moscow, Russia
2Moscow Aviation Institute, Moscow, Russia, Moscow, Russia
Keywords: capillary breakup, dispersion of liquids, capillary waves in a jet, wave process
Abstract >>
The work describes regularities of the formation of waves in a jet of a viscous liquid, initiated by a sudden rupture of the jet. The possibility of the existence of fast growing disturbances in a viscous jet is established. The cyclic regularity of the dependence of the distance between the formed droplets on their number is observed. It is justified that he decisive role in the formation of growing fast waves is played by effects caused by the action of the force of viscous friction.
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O.N. Kashinsky, A.S. Kurdyumov
Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
Keywords: film cooling, upstream ramps, compound angles, adiabatic cooling effectiveness
Abstract >>
The flow with movement of single slugs in an annular channel was studied. The shear stress on both walls of the annular channel was measured using the electrodiffusion method. The averaged wall shear stress distributions along the channel length during gas slug motion are presented for different regimes. A significant difference in the values of shear stress on the inner and outer walls of the channel is shown.
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I.N. Zhizhimontov1,2, A.B. Shabarov1, S.V. Stepanov1,2
1Tyumen State University, Tyumen, Russia
2Tyumen Petroleum Research Center
Keywords: thermophysics, physical and mathematical model, heat and mass transfer, filtration, horizontal wells, natural coordinates, thermal recovery method, high viscosity oil, HVO
Abstract >>
The paper presents the description and results for computational-and-parametric study for the simulation of heat and mass transfer for an water-oil mixture produced from a set of horizontal wells (at the example of high viscosity oil field). The purpose is the theoretical and numerical study of heat and mass transfer for water-oil mixtures with a focus on a set of scientific and production problems in the field of analyzing the development of hydrocarbon reserves in high-viscosity oil fields. The research objects are rocks and natural formations saturated with a multiphase fluid. For computational domain grid construction, the authors proposed and tested a new approach for constructing a dynamic grid in a natural semi-fixed coordinate system. According to this approach, the streamlines and isopotential lines are obtained from an analytical solution based on the complex variable theory. The paper offers a physical and mathematical model of unsteady heat and mass transfer for water-oil mixtures occurring in a system of parallel horizontal wells. The physical and mathematical model and the calculation method are implemented in a computer code complex. The computational and parametric study was carried out and the most general patterns of the oil recovery factor were identified depending on the reservoir geometry and the interwell distance, well operation modes, the hot agent temperature, and the reservoir properties. The study demonstrated a relation of the ultimate oil recovery with the innovative dimensionless parameter. Namely, a growth of this parameter combining the geometry parameters, porosity, permeability, and initial oil saturation of formation corresponds to a logarithmic growth in the oil recovery factor.
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S.P. Rusin
Joint Institute for High Temperatures RAS, Moscow, Russia
Keywords: instrumental accuracy, temperature, multiwave thermometry
Abstract >>
The instrumental accuracy of determining the model temperatures by the data of radiance temperature measurements at two and three experimental points is analyzed using model examples, when neither thermodynamic temperature nor emissivity of the sighting site is known. The instrumental accuracy of determining the desired temperature is estimated depending on the choice of a spectral window in the thermal radiation spectrum. It is shown that moving the spectral window to the long-wavelength region of the radiation spectrum can deteriorate the instrumental accuracy of measuring the desired temperature by several times.
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V.E. Messerle1,2,3, S.A. Bolegenova4, A.S. Askarova1,5, S.A. Bolegenova1,5, V.Yu. Maximov1, A.O. Nugymanova1
1Al-Farabi Kazakh National University, Almaty, Kazakhstan
2Research Institute Experimental and Theoretical Physics, Novosibirsk, Russia
3Kutateladze Institute of Thermophysics SB RAS
4Research Institute Experimental and Theoretical Physics, Almaty, Kazakhstan
5Research Institute Experimental and Theoretical Physics
Keywords: heat and mass transfer, numerical simulation, distributions for velocity, temperature, and concentration, staged combustion
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The paper describes a study of the influence of Overfire Air (OFA) technology on heat and mass transfer parameters for a furnace chamber in the BKZ-75 boiler at the Shakhtinsk power plant (Kazakhstan); this plant is fueled with Karaganda high-ash coal. The computer simulation methods were applied for studying different air supply regimes through the air injectors operating in OFA design with different contributions: 0 (reference variant), 5, 10, 15, 18, and 20 %. The computer simulation of in furnace processes offers the distribution for total velocity vector, tem-pertaure field, NO2 concentration field for the entire furnace and the exit zone. The study demonstrated that the operation with air injection at 18 % of OFA is optimal for combustion of high-ash coal. This operation mode offers a higher tempertaure at the flame core and a gradual tempertaure reduction at the chamber outlet; the latter feature is significant for chemistry of combustion products. The boiler under this operation mode offers a reduction of nitrogen oxide NO2 emissions from the furnace.
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V.A. Kuzmin1, I.A. Zagrai1, I.A. Desiatkov2
1Vyatka State University, Kirov, Russia
2SC VyatkaTorf, Kirov, Russia
Keywords: emission characteristics, temperature, furnace gases, steam boiler, peat, emissivity factor, pyrometry, temperature non-equilibrium
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For the conditions of flame combustion of the milled peat with natural gas support flaring, the spectral radiation energy flux densities and emissivity factors of furnace gases are calculated for a situation of a furnace in BKZ-210-140F steam boiler. From the analysis of emission characteristics, a strategy was determined and a pyrometer set was selected for measuring the furnace gas temperature. For these pyrometers distributed over the furnace height, the temperature of the furnace gases was registered depending on the emissivity factor assigned for the pyrometers. The calculated spectral values of emissivity factor and pyrometer experimental functions give the furnace gas temperature for different spectral ranges. The study demonstrated a maximum temperature non-equilibrium about 850 K between the gaseous phase and the condensed particles for the zone of flame root (near the burners).
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H. Semai, A. Bouhdjar
Center of the Development of Renewable Energies, Alger, Algeria
Keywords: turbulent flow, natural convection, heat transfer, solar chimney power plant
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The work studies the turbulent fluid flow under the effect of natural convection within a solar chimney power plant (SCPP). This study is carried out by numerical simulation using the Saturne code coupled to the Syrthes code. Geometric modifications were brought upon the chimney outlet. Divergent shape with different exit sections was set at the tower outlet. The study is undertaken for two types of solar chimney power plant. In the first configuration, only soil below the collector is considered as a storage system. In the second one, the storage system is composed of the soil and a 10 cm thick tub filled with water, covering the entire surface of the collector. The boundary conditions will be defined according to meteorological data, for a typical day available on the site of Adrar, Algeria. The results allow us to focus on the storage system influence on the SCPP performance and their operation duration after sunset and to determine the geometric modification effect on the plant energy efficiency.
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Abstract >>
On April 13, 2021, Professor Vladimir B. Kurzin, Doctor of Physics and Mathematics, became 90 years of age.
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