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Thermophysics and Aeromechanics

2015 year, number 1

1.
Supersonic flow over paired compression wedges of different sweep installed on the pre–compression surface

Yu.P. Gounko and I.I. Mazhul
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
E-mail: mazhul@itam.nsc.ru, gounko@itam.nsc.ru
Keywords: pre-compression surface, swept compression wedges, supersonic velocities, shock waves, three-dimensional shock-induced separation of boundary layer, side flow spread
Pages: 115

Abstract >>
The results of the numerical modeling of the flow over configurations consisting of two adjacent wedges with swept leading edges located on a flat surface of the pre-compression ramp are presented. The flow around compression wedges with different sweeps of leading edges is considered: zero sweep (χ= 0), positive sweep (χ> 0), and negative sweep (χ< 0). Swept wedges deflect the flows compressed by them either to the sides opposite to the configuration symmetry plane (χ> 0) or, on contrary, one towards another (χ< 0). The computations have been done with solution of the averaged Navier—Stokes equations and with the use of the SSTκ-ωturbulence model at the freestream Mach number = 6. The difference in flow structure is analyzed, which includes, in particular, quasi-conical three-dimensional separations of the turbulent boundary layer on the pre-compression surface, which are induced by shock waves generated by swept wedges. The characteristics of the side flow spread on compression wedges of different sweep are presented.

DOI: http://dx.doi.org/10.1134/S0869864315010011
																								



2.
Evolution of wave packets in supersonic flat-plate boundary layer

A.A. Yatskikh1, Yu.G. Ermolaev2, A.D. Kosinov1,2, and N.V. Semionov2
1Novosibirsk State University, Novosibirsk, Russia
2Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
E-mail: yermol@itam.nsc.ru
Keywords: supersonic boundary layer, wave packet, laminar-turbulent transition
Pages: 1727

Abstract >>
Results of an experimental study of the evolution of short-duration isolated wave packets in flat-plate boundary layer at Mach number M = 2 are reported. The influence of the wave packets on the laminar-turbulent transition onset is examined. Interaction of the wave packets with natural disturbances is studied. The spatio-wave structure of the wave packets is investigated in detail. The spreading angle of the wave pack-ets and their propagation velocities are evaluated.

DOI: http://dx.doi.org/10.1134/S0869864315010023
																								



3.
Structure of turbulent separated flow in the neighborhood of a plate-mounted prism of square section

S.A. Valger1, N.N. Fedorova1,2, and A.V. Fedorov1,2
1Novosibirsk State University of Architecture and Civil Engineering, Novosibirsk, Russia
2Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
E-mail: svetlanavalger@gmail.com
Keywords: wind actions, turbulence, boundary layer, separation, numerical methods, turbulence models
Pages: 2941

Abstract >>
A 3D turbulent separated flow in the neighborhood of a plate-mounted bluff body, a parallelepiped with side length ratio 1:1:2, has been numerically simulated. The 3D structure of the flow in the vicinity of the body was revealed, and the distributions of flow quantities were obtained. Numerical data for the 3D separated flow obtained with the help of several turbulence models were compared to experimental data on the profiles of mean flow velocity and turbulence kinetic energy. It is shown that restriction of the production term for turbulence kinetic energy allows a reduction in turbulence viscosity level and improves the prediction accuracy for separation zones.

DOI: http://dx.doi.org/10.1134/S0869864315010035
																								



4.
A quantitative study of the hydrodiode effect

A.A. Kuraev and A.B. Semenov
Novosibirsk State Technical University, Novosibirsk, Russia
E-mail: andrej.semyon@yandex.ru
Keywords: hydrodiode, flow rate coefficient, oscillations, elastic volume element, inertial pressure
Pages: 4348

Abstract >>
A semi-empirical model of the hydrodiode is considered. The model is based on the balance equation for the liquid flow across a two-membrane hydrodiode. Results of the quantitative study are compared to experimental data.

DOI: http://dx.doi.org/10.1134/S0869864315010047
																								



5.
Hydrodynamics and heat transfer in a laminar flow of viscoelastic fluid in a flat slot channel

D.V. Ananyev, G.R. Halitova, and E.K. Vachagina
Research Center for Power Engineering Problems, Kazan Scientific Center of RAS, Kazan, Russia
E-mail: Dima211083@yandex.ru
Keywords: hydrodynamics, heat transfer, flat slot channel, laminar flow, mathematical modeling, Phan-ThienTanner model, viscoelastic fluid
Pages: 4960

Abstract >>
Results of the numerical study of hydrodynamics and heat transfer in a laminar flow of viscoelastic fluid in a flat slot channel are presented in the present paper. The model of nonlinear viscoelastic fluid of Phan-ThienTanner is used to describe the viscoelastic properties of fluid. The solution to the stated problem by software package COMSOL Multiphysics is considered. The method of solution is verified, and results are compared with data of the other authors. It is determined that in the flow of viscoelastic fluid in a flat slot channel, the maximal contribution of heating due to dissipation is approximately 78 %.

DOI: http://dx.doi.org/10.1134/S0869864315010059
																								



6.
Numerical modeling of gas-liquid flows in mini- and microchannels

D.V. Guzei1, A.V. Minakov1,2, M.I. Pryazhnikov1, and A.A. Dekterev1,2
1Siberian Federal University, Krasnoyarsk, Russia
2Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
E-mail: gudimas@yandex.ru
Keywords: two-phase flows, microchannels, VOF method, SIMPLEC algorithm, control volume method
Pages: 6171

Abstract >>
The paper presents the results of testing a methodology for calculating two-phase flows in mini- and microchannels. The numerical methodology is based on the known fluid-in-cell method (VOF method) and the CSF procedure to account for surface tension forces. Solutions of several test problems of two-phase flow in microchannels, including the water-oil emulsion flow and gas-liquid flow in microchannels of the T-type and the stationary slug flow in a circular minichannel, were considered with the aid of this technique. Comparisons of numerical results with experimental data were carried out. A good agreement between the results was obtained.

DOI: http://dx.doi.org/10.1134/S0869864315010060
																								



7.
The approximate kinetic analysis of strong condensation

Yu.B. Zudin
National Research Centre Kurchatov Institute, Moscow, Russia
E-mail: yzudin@gmail.com
Keywords: kinetic analysis, strong condensation, Knudsen layer, condensation flux, mixing surface, analytical solution
Pages: 7384

Abstract >>
The approximate kinetic analysis was carried out for the problem of strong condensation based on conservation equations for molecular fluxes of mass, momentum, and energy within the Knudsen layer. The closing relation was the condition for conservation of condensation flux between the Knudsen layer boundary and the mixing layer. Approximate analytical solution of the problem was obtained in the form of pressure ratio vs. temperature ratio (Mach number as a parameter). The analytical solution demonstrates a good agreement with available simulation data.

DOI: http://dx.doi.org/10.1134/S0869864315010072
																								



8.
Attainable superheating of the oxygen-nitrogen-helium solutions

A.M. Kaverin, V.N. Andbaeva, and V.G. Baidakov
Institute of Thermophysics UrB RAS, Ekaterinburg, Russia
E-mail: kav@itp.uran.ru
Keywords: solutions, spontaneous boiling-up, homogeneous nucleation, additive approximation, surface tension
Pages: 8594

Abstract >>
Method of measuring the lifetime of the superheated liquid was used to determine temperatures of the limit superheating of the solution of oxygen-nitrogen-helium. The method of calculating the properties of this solution (temperature of limit superheating, saturated vapor pressure, and density) based on the data on the properties of solutions of oxygen-helium and nitrogen-helium was proposed. The surface tension of the solution of oxygen-nitrogen-helium was determined in a special experiment.

DOI: http://dx.doi.org/10.1134/S0869864315010084
																								



9.
Electric-arc steam plasma generator

A.S. Anshakov1,2, E.K. Urbakh1, S.I. Radko2, A.E. Urbakh1, and V.A. Faleev1
1Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia
2Novosibirsk State Technical University, Novosibirsk, Russia
E-mail: anshakov@itp.nsc.ru
Keywords: steam, plasmatorch, composite electrode, volt-ampere characteristics, heat fluxes, electrode erosion, thermal calculation
Pages: 95104

Abstract >>
Investigation results on the arc plasmatorch for water-steam heating are presented. The construction arrangement of steam plasma generator with copper electrodes of the stepped geometry was firstly implemented. The energy characteristics of plasmatorch and erosion of electrodes reflect the features of their behavior at arc glow in the plasma-forming environment of steam. The results of numerical study of the thermal state of the composite copper-steel electrodes had a significant influence on optimization of anode water-cooling aimed at improvement of its operation life.

DOI: http://dx.doi.org/10.1134/S0869864315010096
																								



10.
Modelling of heat transfer in composite bodies reinforced with tubes with incompressible liquid coolant moving in laminar regime

A.P. Yankovskii
Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
E-mail: nemirov@itam.nsc.ru
Keywords: thermal conductivity, composites, reinforcement with tubes, liquid coolant, heat and mass transfer, structural model
Pages: 105126

Abstract >>
The equations were obtained for description of heat transfer in composite bodies with reinforcement with a set of smooth tubes with pumping of incompressible liquid coolant. The appropriate boundary-value problem of heat transfer was formulated with the following qualitative analysis. The steady temperature fields in cylindrical shells with spiral-shaped tube reinforcement (with liquid coolant flow) were simulated. The influence on the temperature fields from the side of reinforcement geometry parameters, flow direction and velocity, tubes cross sections was studied. It was found that these characteristics allow significant variation of temperature field in its gradients within the composite item: this open ways for effective control of temperature fields.

DOI: http://dx.doi.org/10.1134/S0869864315010102
																								



11.
Modifying structure and properties of nickel alloys by nanostructured composite powders

A.N. Cherepanov1, V.E. Ovcharenko2,3, G. Liu4, and L. Cao4
1Khristianovich Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia
2Institute of Strength Physics and Materials Science SB RAS, Tomsk, Russia
3National Research Tomsk Polytechnic University, Tomsk, Russia
4Beijing Institute of Aeronautical Materials, Beijing, China
E-mail: ancher@itam.nsc.ru
Keywords: heat-resistant alloy, nanopowders, grain structure, carbide phase, intermetallics, heat resistance, mechanical properties
Pages: 127132

Abstract >>
The article presents the results of an experimental study of the influence of powder nanomodifiers of refractory compounds on the mechanical properties, macro–and microstructure of heat-resistant alloys ZhS6K and Inconel 718. It is shown that the introduction of nanomodifiers into the melt leads to the refinement of the alloy structure: the average grain size decreases 1.52 times, and their morphology becomes similar to equiaxial at significant reduction of the particle size in the carbide phase. The service life of ZhS6K alloy under cyclic loading at 600 ºC increases 2.7 times, and at 975ºC by 40 %, and relative elongation increases more than twice. The mechanical properties of Inconel 718 significantly increase: long-term strength at 650º increases 1.52 times, and the number of cycles before the collapse at 482º grows more than three times. It has been found out that addition of nanomodifiers to the melt, in alloys, forms clusters of particles of refractory compounds at borders and joints of the formed grain structure that may help slowing down the processes of recrystallization (prevents the increase in the size of the contacting grains by their associations) and stabilizes the strength properties of the alloys at higher temperatures.

DOI: http://dx.doi.org/10.1134/S0869864315010114
																								



12.
In memory of Albert P. Baskakov

Editorial Board
Siberian Branch of the RAS, Novosibirsk, Russia
Pages: 133134

Abstract >>
The prominent scientist in the field of heat and power engineering, Honorary Professor of the Ural Federal University, Honored Scientist of the RSFSR Albert P. Baskakov passed away on January 21, 2015.

DOI: http://dx.doi.org/10.1134/S0869864315010126