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Thermophysics and Aeromechanics

2001 year, number 4

1.
SKIN FRICTION MEASUREMENTS IN AN INCOMPRESSIBLE TURBULENT BOUNDARY LAYER. PART 1. ADVERSE PRESSURE GRADIENT

V.I. KORNILOV and Yu.A. LITVINENKO*
Institute of Theoretical and Applied Mechanics SB RAS,Novosibirsk, Russia
*Novosibirsk State Technical University, Russia

Abstract >>
Direct and indirect skin friction measurement techniques that are most widely used in practice are reviewed and briefly characterized. A comparative analysis of measurement results is given for some methods used in an incompressible turbulent boundary layer on a flat plate under conditions of a positive (adverse) stream-wise pressure gradient formed on the plate surface and in a gradient-free flow. The degree of efficiency of the above methods is demonstrated, and their application range and the limits are shown. P.475-491



2.
DEVELOPMENT OF DISTURBANCES WITH SIMULTANEOUS OCCURRENCE OF TWO TYPES OF SEPARATION ON WING MODEL

V.V. KOZLOV, B.YU. ZANIN, and I.D. ZVERKOV
Institute of Theoretical and Applied Mechanics SB RAS,Novosibirsk, Russia

Abstract >>
Experimental results of subsonic flow over a straight wing model are described. On the surface near the leading edge a local separation bubble exists, and besides, downstream the separation of turbulent boundary layer in the trailing part of a wing is observed. A three-dimensional vertical structure of flow is noted using visualization. By means of hot-wire measurements the quantitative data on distribution of mean velocity of flow above a wing, as well as on amplitude and frequency spectra of pulsations are obtained. P. 493-498



3.
ON A MECHANISM OF ROTATION OF CONVECTIVE COLUMNS

Yu.A. BEREZIN and V.M. TROFIMOV
Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia

Abstract >>
The distribution of axisymmetric disturbances of the velocity field in a convective column from a source of the momentum moment and/or heat is investigated. A system of differential equations for the amplitude functions of the axial and azimuth velocity, momentum moment, the pressure and density differences is obtained on the basis of the model of turbulence being non-equilibrium with respect to the momentum moments, and the boundary layer and Boussinesq approximations under the assumption on the Gauss distribution of flow parameters in the radial direction. The system of equations is closed within the framework of the Taylor's hypothesis on the relation between the external radial flow and the axial one in the column. The solution was found numerically. The regimes of the azimuth rotation within the column are revealed, which are caused by the redistribution of the momentum moment between the mean flow and the motion of vortices at an intermediate scale with respect to the column size and the scale of pulsations having a zero mean value of the velocity and moment. P. 499-509



4.
HETEROGENEOUS CUTTING DEVICES: ANALYSIS OF PARTICLE ACCELERATION EFFICIENCY

D.S. MIKHATULIN, Yu.V. POLEZHAEV, and D.L. REVIZNIKOV*
Joint Institute for High Temperatures RAS, Moscow, Russia
*Moscow Aviation Institute (Technical University), Russia

Abstract >>
This is a continuation of the study on the gas-dynamic track in a heterogeneous cutting device, which was initiated in [1, 2]. The efficiency parameter for particle acceleration was determined as a ratio of the kinetic energy to energy consumed on particle acceleration. The influence of gas (air and overheated steam) temperature and pressure on intensity and efficiency of particle acceleration was analysed. Recommendations are given about most effective way for creation of heterogeneous flow, which would provide a maximal kinetic energy of particle flux in interaction with the target. P. 511-518



5.
MODELLING OF HYDRODYNAMICS OF HIGH-CONCENTRATION GRANULAR MEDIUM IN POWDER TECHNOLOGY

E.V. ZAITSEVA, Y.N. RYZHIKH, and A.V. SHVAB
Tomsk State University, Russia

Abstract >>
A method is proposed for the computation of gravity flow of a high-concentration granular medium. A model of nonlinearly viscous fluid is used as a granular medium model. A peculiarity of the model for granular medium motion is a more accurate formulation of boundary conditions, which enables us to account for the sliding of particles on rigid surfaces by introducing an empirical coefficient at the determination of vorticity on a wall. The comparison of numerical and experimental data has shown that the consideration of the effect of medium "sliding" on the boundary enables us to describe the granular medium motion with the rheological parameters of the model being close to those of the Newton fluid. The proposed method has been applied for the  analysis of gravity flows in vertical channels in the presence of obstacles of various forms. The prospects for the developed approach at the theoretical investigation of a free-flowing granular medium are confirmed by a comparison with experimental data known in literature. P. 519-528



6.
ON FLOW OF A VISCOUS INCOMPRESSIBLE FLUID PAST AN IMPULSIVELY STARTEDSEMI-INFINITE VERTICAL PLATE WITH UNIFORM HEAT FLUX

R. MUTHUCUMARASWAMY and P. GANESAN*
Sri Venkateswara College of Engineering,Sriperumbudur, India
*Department of Mathematics, Anna University, Chennai, India

Abstract >>
An implicit finite-difference technique is employed to derive a solution to the flow of an incompressible viscous fluid past an impulsively started semi-infinite vertical plate with uniform heat flux. Transient and steady-state velocity and temperature profiles, the local and average skin-friction and the Nusselt number are shown graphically. The velocity profiles at small values of time t are shown to agree with theoretical solution of the flow past an impulsively started infinite vertical plate with constant heat flux. The effects of different parameters Pr (the Prandtl number) and Gr (the Grashof number) are studied. The stability and the convergence of the implicit finite-difference scheme are established. P. 529-537



7.
QUASI-DIFFUSIVE METHODS FOR CALCULATION OF RADIANT HEAT TRANSFER AT GENERALIZED STATEMENT OF THE PROBLEM

N.A. RUBTSOV
Kutateladze Institute of Thermophysics SB RAS, Novosibirsk, Russia

Abstract >>
Methodical aspects for development of quasi-diffusive methods are presented for calculation of radiant heat transfer in absorbent, emissive and isotropic scattering gray medium in application to generalized statement of the problem. The heat transfer problem can be reduced to solution of approximate differential equations relative to the flux density of volumetric incident (or semispherical resulting) radiation. In turn, these equations can be reduced to differential equations for determination of the flux densities of volumetric and surface incident radiation with given  generalized characteristics of radiation in volume and on boundaries



8.
IMPACT OF THE RADIANT COMPONENT ON HEAT AND MASS TRANSFER IN THE OIL FILM ON THE CYLINDER OF A DIESEL ENGINE

B.O. LEBEDEV
Novosibirsk State Academy of Water Transport, Russia

Abstract >>
The effect of the radiant component on the process of heating and evaporation of an oil film in Diesel engine was studied. It was demonstrated that this effect is considerable and cannot be neglected in study of heat and mass transfer in the oil film. The research results explain the experimental phenomena of drastic reduction in oil consumption in engines using fuel-water emulsion. P. 555-560



9.
COMPUTATION OF GAS FLOW RATE THROUGH THE PLASMATORCH CHANNEL BY PRESSURE DIFFERENCE

V.A. DOSTOVALOV and B.A. YURYUKOV*
Far-East State Technical University, Vladivostok, Russia
*Institute of the Problems of Material Studies, NAS of Ukraine, Kiev

Abstract >>
he technique is proposed to compute the gas flow rate in a plasmatorch by the difference in pressure over the channel length in those cases when it is impossible to define the flow rate with other methods, for example, in a plasmatorch with atmospheric air suction. The results of calculation of stream parameters in the plasmatorch channel for the laminar and turbulent flow regimes are approximated with simple formulas. A method is suggested to estimate a point of the transition from the laminar to turbulent flow with an electric arc, and a relation for critical Reynolds number is obtained. P. 561-567



10.
ABOUT THE CONFERENCES ON HIGH-POWER GAS AND CHEMICAL LASERS

A.S. BOREISHO
Baltic State Technical University, St. Petersburg, Russia

Abstract >>
The joint international symposia "Gas and Chemical Lasers" (GCL) and "High-Power Lasers" (HPL) are among the regular forums held by SPIE and EOS (The International Society for Optical Engineering and European Optical Society). Usually the national optical society of the host country and corresponding governmental bodies also take part in organization of the current conference. These conferences obtain financial support from European affiliates of research departments of U.S. Air Forces (U.S. Air Force Research Laboratory, Air Force Office of Scientific Research, etc.). P.569-570



11.
PRESSURE RECOVERY SYSTEMS FOR HIGH-POWER GAS AND CHEMICAL LASERS

A.S. BOREISHO, I.A. KISELEV, A.E. ORLOV, A.V. SAVIN, V.P. SHALIMOV, V.M. MALKOV*, and V.M. KHAILOV**
Baltic State Technical University, St. Petersburg, Russia
*Institute of Theoretical and Applied Mechanics SB RAS,Novosibirsk,Russia
**Central Institute of Aviation Motors, Moscow, Russia

Abstract >>
Several concepts and scheme solutions are discussed for pressure recovery systems (PRS) in application to specific technical problems. The main features of the diffuser, ejector and steam-gas generator are considered. The specific design schemes for PRS on the base of aviation gas turbine engines were analysed with application to HF(DF)- and COIL-lasers; the workable variants were picked up. Analysis confirmed the opportunity for development of a PRS for a high-power gas chemical laser with modern technologies. The problem of sound suppressing for a stationary and mobile variants of PRS was considered. P. 571-587



12.
ON THE CHOICE OF WORKING PARAMETERS FOR THE SYSTEM OF PRESSURE RECOVERY OF SUPERSONIC CHEMICAL LASERS

V.M. MALKOV, A.S. BOREISHO*, A.V. SAVIN*, I.A. KISELEV*, and A.E. ORLOV*
Institute of Theoretical and Applied Mechanics SB RAS,Novosibirsk, Russia
*Baltic State Technical University, St. Petersburg, Russia

Abstract >>
Here we consider the problems of a reasonable choice of working parameters for supersonic diffuser (SD) and ejector (EJ), used by the systems of pressure recovery (PRS) of continuous chemical lasers (CCL). The matching condition for SD and EJ parameters was analysed at their merger into a single system. Data presented are mainly attributed to the case of HF(DF) continuous chemical lasers. P. 589-600



13.
NUMERICAL SIMULATION OF GAS DYNAMIC PROCESSES IN PRESSURE RECOVERY SYSTEMS OF SUPERSONIC CHEMICAL LASERS

A.S. BOREISHO, A.V. SAVIN, V.M. MALKOV*, A.A. IGNATIEV**, and A.V. FEDOTOV**
Baltic State Technical University, St. Petersburg, Russia
*Institute of Theoretical and Applied Mechanics SB RAS,Novosibirsk, Russia
**Institute of High Performance Computing and Data Bases, St. Petersburg, Russia

Abstract >>
The start processes and stationary flow in the diffuser of the laboratory HF/DF laser are investigated on the basis of the computer simulation technology using the non-stationary three-dimensional Navier



14.
THE TEST METHODS FOR PRESSURE RECOVERY SYSTEMS OF HF/DF LASERS

A.S. BOREISHO, A.F. LEONOV, I.A. KISELEV, A.E. ORLOV, A.V. SAVIN,and V.M. MALKOV*
Baltic State Technical University, St. Petersburg, Russia
*Institute of Theoretical and Applied Mechanics SB RAS,Novosibirsk, Russia

Abstract >>
The laser-free test methods for the pressure recovery system (PRS) of the HF/DF Continuous Chemical Laser (CCL) are discussed. The method of physical modelling of the HF/DF-CCL flow using a generator of a model gas (GMG) is suggested here. Some scheme and construction solutions as well as a brief technical description of such a system are presented in this paper. Test results for the PRS with GMG are compared with data of actual tests for PRS with DF-CCL. P. 609-617



15.
HYDRODYNAMICS IN CLOSED-FLOW CO2 LASERS

A.I. IVANCHENKO, A.M. ORISHICH, and A.P. GOLYSHEV
Institute of Theoretical and Applied Mechanics SB RAS, Novosibirsk, Russia

Abstract >>
By means of hydrodynamic and thermodynamic calculations, it is shown that the ignition of a discharge in a closed-flow