HEAT AND MASS TRANSFER IN COMBUSTION PROCESSES
OPTIMUM CHEMICAL REGENERATION OF THE GASES BURNT IN SOLID OXIDE FUEL CELLS
A. P. Baskakov,a Yu. V. Volkova,b,c and N. S. Plotnikovc
UDC 636.7 (075.8)
A simplifi ed method of calculating the concentrations of the components of a thermodynamically equilibrium mixture (a synthesis gas) supplied to the anode channel of a battery of solid oxide fuel cells and the change in these concentrations along the indicated channel is proposed and results of corresponding calculations are presented. The variants of reforming of a natural gas (methane) by air and steam as well as by a part of the exhaust combustion products for obtaining a synthesis gas are considered. The amount of the anode gases that should be returned for the complete chemical regeneration of the gases burnt in the fuel cells was determined. The dependence of the electromotive force of an ideal oxide fuel element (the electric circuit of which is open) on the degree of absorption of oxygen in a thermodynamically equilibrium fuel mixture was calculated.
Keywords: solid oxide fuel cell, chemical regeneration, reforming, electromotive force, anode gas.
NUMERICAL INVESTIGATION OF PHYSICOCHEMICAL PROCESSES OCCURRING DURING WATER EVAPORATION IN THE SURFACE LAYER PORES OF A FOREST COMBUSTIBLE MATERIAL
A. O. Zhdanova, G. V. Kuznetsov, and P. A. Strizhak
A numerical investigation of the physicochemical processes occurring during water evaporation from the pores of the surface layer of a forest combustible material has been carried out. The characteristic features of the suppression of the thermal decomposition reaction of a combustible material with water fi lling fullyits pores and formation of a water fi lm over its surface have been determined. The characteristic times of suppression of thermal decomposition reactions under various environmental conditions and the thickness and kinds of forest combustible material (birch leaves, pine and spruce needles, etc.) have been established.
Keywords: forest combustible material, surface layer, water, fi lm, thermal decomposition, suppression.
National Research Tomsk Polytechnic University, Power Engineering Institute, 30 Lenin Ave., Tomsk, 634050, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 751–758, July– August, 2014. Original article submitted February 17, 2014.
METHODS AND DEVICES FOR FIGHTING NATURAL FIRES WITHIN A NEW CONCEPT OF CONTROL OF NATURAL AND MAN-MADE DISASTERS
A. M. Grishin, V. P. Zima, and D. P. Kasymov
Developments of methods and devices for localization and suppression of natural fi res are presented. These developments have been created with account taken of the knowledge on the frame structure. With them, one can destroy, by relatively small energy actions, the most vulnerable parts of the fi re front: the zones of pyrolysis and
mixing of combustible pyrolysis products with the air oxygen.
Keywords: natural fi re, shock wave, pyrolysis zone, fi re safety, natural and man-made disasters.
Tomsk State University, 36 Lenin Ave., Tomsk, 634050, Russia; email: fi , . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 759–766, July–August, 2014. Original article submitted January 4, 2014.
INFLUENCE OF THE SPATIAL TEMPERATURE DISTRIBUTION IN COAL PARTICLES ON THEIR HEATING AND IGNITION IN A GAS-DISPERSED FLOW
V. I. Timoshenko
The infl uence of nonuniform heating of dry and moisture-saturated coal particles on the time and character of their ignition has been analyzed. The kinetic model of heterogeneous reactions on the particle surface and the equilibrium model of reactions in a gas phase are used. It is shown that a change in the temperature inside a moisture-containing particle can diminish (two and more times) the time of its ignition as compared to an isothermal particle.
Keywords: chemically equilibrium mixture, heterogeneous chemical reactions, phase transition front, movable boundary, water evaporation rate, gas-dispersed fl ows.
Institute of Technical Mechanics, National Academy of Sciences of Ukraine and State Space Agency of Ukraine, 15 I. V. Leshko-Popel' Str., Dnepropetrovsk, 49600, Ukraine; email: . Translated from Inzhenerno- Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 767–771, July–August, 2014. Original article submitted April 30, 2013.
LOW-TEMPERATURE SYNTHESIS OF NANOPARTICLES IN THE PROCESS OF EVAPORATION OF FEMTOLITER DROPLETS OF A SOLUTION AT A LOW PRESSURE
O. G. Penyazkov, V. I. Saverchenko, and S. P. Fisenko
Results of an X-ray phase analysis of the products of the low-temperature spray pyrolysis of femtoliter droplets of aqueous nickel-chloride solutions are presented. It is shown that the composition of the nanoparticles accumulated on the electrode-substrate in an aerosol reactor depends on the pressure in it and the initial supersaturation of the solution. It was established that marked chemical transformations of the indicated droplets begin at a pressure lower than 80 Torr. The infl uence of the evaporation of droplets from a solution and the nucleation in the supersaturated solution formed on the kinetics of the chemical transformations of these droplets, giving rise to the substances obtained in the experiments, is discussed.
Keywords: supersaturated solution, dissociation, nickel oxide, evaporation, nucleation, diffusion growth.
A. V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, 15 P. Brovka Str., Minsk, 220072, Belarus; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 772–777, July– August, 2014. Original article submitted April 2, 2014.
FREE-MOLECULAR GAS FLOW IN A NARROW (NANOSIZE) CHANNEL
V. V. Levdanskii,a V. I. Roldugin,b V. M. Zhdanov,c and V. Zdimald
We have analyzed a free-molecular gas fl ow in cylindrical channels (capillaries) with impermeable walls for various schemes of the scattering of molecules by channel walls, taking account of the surface diffusion of adsorbed molecules, and a gas fl ow in such channels with allowance for phase transformations on their walls. A substantial infl uence of surface diffusion on the mass transfer in gaseous mixtures in the indicated channels has been revealed. The modifi cation of the phenomenological relations of the nonequilibrium thermodynamics of discontinuous systems is considered. The problem of uniform deposition of thin fi lms on the inner surface of a cylindrical channel is discussed.
Keywords: narrow channels, free-molecular gas fl ow, surface diffusion, gaseous mixture, phase transformations.
aA. V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, 15 P. Brovka Str., Minsk, 220072, Belarus; email; ; bA. N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninskii Ave., Moscow, 119991, Russia; cNational Research Nuclear University "MIFI," 31 Kashirskoe Highway, Moscow, 115409, Russia; dd
NUMERICAL CALCULATION OF THE DYNAMICS OF TEMPERATURE FIELDS THAT DETERMINE THE PHASE COMPOSITION OF POLYCRYSTALLINE IRON DURING ITS EXPOSURE TO A COMPRESSION PLASMA FLOW
V. V. Astashinskii
The results of Stefan problem-based calculations of the distribution of nonstationary temperature fi elds in the surface layer of iron samples exposed to compression plasma fl ows at the given initial and boundary conditions are presented with account for the temperature dependence of the heat capacity and thermal conductivity of a sample. It is shown that on ultrafast heating and cooling (~107 K/s), an iron sample exhibits a modifi ed layer having a nonequilibrium microstructure and containing amorphous and nanocrystalline phases that increase its strength and wear resistance.
Keywords: plasma-induced modifi cation of material, nitriding, crystallization, numerical simulation.
Belarusian State University, 4 Nezavisimost′ Ave., Minsk, 220030, Belarus; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 791–795, July–August, 2014. Original article submitted April 22, 2014.
TEMPERATURE STATE OF A UNIPOLAR GENERATOR DISK
V. S. Zarubin, G. N. Kuvyrkin, and I. Yu. Savel′eva
The steady-state process of heat conduction in the rotating disk of a d.c. unipolar generator has been considered. A mathematical model has been constructed and on the basis of its analysis the features of the radial temperature distribution in the disk have been elucidated and the infl uence on this distribution of the temperature dependence of the electrical resistivity and the heat conductivity coeffi cient of the disk material have been determined. We have established the limiting value of the temperature coeffi cient of electrical resistivity at which the existence of a stable temperature distribution in a disk of hyperbolic profi le under certain boundary conditions becomes impossible. A solution and a numerical example for a linear problem as applied to a disk with a power dependence of its thickness on the radial coordinate are given.
Keywords: d.c. unipolar generator, temperature state of the disk, variational mathematical model.
N. É. Bauman Moscow Technical State University, 5, building 1 2nd Baumanskaya Str., Moscow, 105005, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 796–801, July– August, 2014. Original article submitted February 24, 2014.
HEAT CONDUCTION OF WALLS WITH A MONOTONE TEMPERATURE CHANGE. ASYMPTOTICS AND QUASI-STATIONARITY
O. V. Korshunov
Systematizing the partial solutions of the nonstationarity heat conduction problem of a fl at wall in comparison with the general asymptotic solution of this problem, we have found the transverse temperature distributions with any monotone change in the ambient conditions and elucidated the heat conduction properties of the wall under these conditions. The asymptotic solution is given by semiconvergent series and defi nite integrals and has been investigated for power time dependences with an exponent of 0–2, which has enabled us to justify the concept of quasi-stationarity of the thermal parameters of the wall and obtain asymptotic errors and corrections defi ning the deviations of these parameters from their stationary values. The features of the average heat fl ows most resistant to thermal disturbances as to both time and amplitude have been considered.
Keywords: heat conduction of a fl at wall, variable boundary conditions, asymptotic dependences, quasi-stationarity, heat fl ow density.
Joint Institute of High Temperatures, Russian Academy of Sciences, 13 Izhorskaya Str., Moscow, 125412, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 802–813, July–August, 2014. Original article submitted April 24, 2012.
OPTIMUM CONTROL OF HEAT SUPPLY OF A BUILDING. 1. FORMULATION OF THE PROBLEM AND BASIC FORMULAS
K. O. Sabdenov, T. M. Baitasov, and M. Erzada
The problem of optimization of the heat supply of a building in the mixing of the heat-transfer agent from the feed and return pipelines has been formulated. The optimality criterion of the heat supply is maintaining the indoor temperature at the level of a value comfortable for man. An analysis of the process of heat supply has been made in the presence of the lateral pipeline and in its absence in the hydraulic system of the heat point alike. Necessary computational formulas for analysis of the optimality of heat supply have been proposed.
Keywords: optimization of heat supply, heat point, heating system of a building, mixing of the heat-transfer agent, optimum mixing coeffi cient.
L. N. Gumilev Eurasian National University, 2 Mirzoyan Str., Astana, 010008, Republic of Kazakhstan; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 814–821, July–August, 2014. Original article submitted February 4, 2014.
OPTIMUM CONTROL OF HEAT SUPPLY OF A BUILDING.
2. ANALYSIS AND RESULTS
K. O. Sabdenov, T. M. Baitasov, and M. Erzada
The temperature regime inside a building has been calculated. It has been established that the presence of a lateral pipeline at the heat point ensures such a value of the mixing coeffi cient at which a constant comfortable temperature of 24oC is attained. When this pipeline is absent, the comfortable temperature may not be attained at any values of the mixing coeffi cient. Consideration has been given to the problem on determination of the optimum dependence of the average velocity of the heat-transfer agent in the heating system on the mixing coeffi cient. The notion of an ideal temperature chart has been introduced.
Keywords: optimization of heat supply, heat point, system of heating of a building, mixing of the heat-transfer agent, optimum mixing coeffi cient, temperature chart.
L. N. Gumilev Eurasian National University, 2 Mirzoyan Str., Astana, 010008, Republic of Kazakhstan; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 822–827, July–August, 2014. Original article submitted February 4, 2014.
APPLICATION OF HEAT-TRANSFER CALCULATIONS AND COMPUTATIONAL FLUID MECHANICS TO THE DESIGN OF PROTECTIVE CLOTHING
I. Cherunova,a N. Kornev,b G. Jacobi,b I. Treshchun,b A. Gross,b J. Turnow,b S. Schreier,b and M. Paschenb
Three examples of use of computational fl uid dynamics for designing clothing protecting a human body from high and low temperatures with an incident air fl ow and without it are presented. The internal thermodynamics of a human body and the interaction of it with the surroundings were investigated. The inner and outer problems were considered separately with their own boundary conditions.
Keywords: human thermodynamics, conjugate heat transfer, computational fl uid dynamics, clothing design.
aDon State Technical University, 147 Shevchenko Str., Shakhty, 346500, Russia; e-mail: ; bUniversity of Rostock, 2 A. Einstein Str., Rostock, 18059, Germany; e-mail: . Published in Inzhenerno- Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 829–837, July–August, 2014. Original article submitted April 2, 2014.
THEORETICAL PRINCIPLES OF DETERMINING THE LONGITUDINAL THERMAL CONDUCTIVITY OF THIN-WALLED STRUCTURAL ELEMENTS FROM COMPOSITE MATERIALS
S. V. Reznik, V. P. Timoshenko, P. V. Prosuntsov, and L. V. Mial′
We propose a method for determining the longitudinal thermal conductivity of thin-walled structural elements from composite materials involving the formation in the sample of the investigated material of a nonstationary temperature fi eld whose gradient coincides with the direction of the reinforcement plane. We have made estimates of the infl uence of the main methodological errors of the proposed method on the determination accuracy of the thermal conductivity of the material.
Keywords: thermal conductivity, thin-walled structural elements, composite materials, reinforcement plane.
N. É. Bauman Moscow State Technical University, 5 2nd Baumanskaya Str., Moscow, 105005, Russia; email: pavel. . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 838–844, July–August, 2014. Original article submitted March 26, 2014.
THERMAL CHARACTERISTICS OF AIR IN THE PROBLEM OF HYPERSONIC MOTION OF BODIES IN THE EARTH’S ATMOSPHERE
K. Alhussan, D. O. Morozov, Yu. A. Stankevich, L. K. Stanchits, and K. L. Stepanov
The thermal properties of hot air needed for describing the hypersonic motion of bodies in the Earth’s atmosphere have been considered. Such motion, as is known, is accompanied by the propagation of strong shock waves analogous to waves generated by powerful explosions. Calculations have been made and data banks have been created for the equations of state and thermal characteristics of air in the temperature and density ranges corresponding to velocities of motion of bodies of up to 10 km/s at altitudes of 0–100 km. The formulation of the problem of hypersonic motion in the absence of thermodynamic equilibrium is discussed.
Keywords: equations of state, thermodynamic functions, dissociation, ionization, kinetic processes.
A. V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, 15 P. Brovka Str., Minsk, 220072, Belarus; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 845– 852, July–August, 2014. Original article submitted April 7, 2014.
ESTIMATION OF SYSTEMATIC ERRORS OF THE MULTIMODEL METHOD FOR NONDESTRUCTIVE DETERMINATION OF THE THERMOPHYSICAL PROPERTIES OF SOLID MATERIALS
N. P. Zhukov, N. F. Mainikova, I. V. Rogov, and A. O. Antonov
We have considered the results of the analysis and estimation of systematic errors involved in the multimodel method for determining the thermophysical properties of solid materials. We have analytically obtained the condition that determines the upper limit of the reliably determinable thermal conductivity of the materials under study.
Keywords: solid materials, thermal analysis, thermophysical properties, nondestructive method, systematic errors.
Tambov State Technical University, 106 Sovetskaya Str., Tambov, 392000, Russia; email: teplotekhnika@nnn. tstu.ru. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 853–859, July–August, 2014. Original article submitted November 22, 2013.
METHOD OF DETERMINING THE FILTRATION PROPERTIES OF OIL-BEARING CROPS IN THE PROCESS OF THEIR PRESSING BY THE EXAMPLE OF RAPE-OIL EXTRUSION
E. V. Slavnova and I. A. Petrovb
A method of determining the change in the fi ltration properties of oil-bearing crops in the process of their pressing by repeated dynamic loading is proposed. The use of this method is demonstrated by the example of rape-oil extrusion. It was established that the change in the mass concentration of the oil in a rape mix from 0.45 to 0.23 leads to a decrease in the permeability of the mix by 101.5–102 times depending on the pressure applied to it. It is shown that the dependence of the permeability of this mix on the pressure applied to it is nonmonotone in character.
Keywords: permeability, plastically deformable porous medium, fi ltration, extrusion of oil.
aInstitute of Mechanics of Continua, Ural Branch of the Russian Academy of Sciences, 1 Acad. Korolev Str., Perm′, 614013, Russia; email: ; bPerm′ National Research Polytechnic University; 29 Komsomol′skii Ave., Perm′, 614000, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 860– 864, July–August, 2014. Original article submitted January 23, 2014.
HEAT AND MASS TRANSFER IN DISPERSE AND POROUS MEDIA
ESTIMATION OF THE DISCHARGE OF A HORIZONTAL WELL IN THE PROCESS OF MINING A SUPERVISCOUS-OIL POOL BY THE METHOD OF STEAM-ASSISTED GRAVITY DRAINAGE
M. Kh. Khairullin, P. E. Morozov, M. N. Shamsiev, and A. E. Abdullin
An analytical model for estimating the discharge of a horizontal well in the process of mining deposits of superviscous oils and natural bitumens by the method of steam-assisted gravity drainage has been developed. The results of calculations carried out using this model are in good agreement with the corresponding data of experiments
on the physical simulation of the process of steam-assisted gravity drainage. The infl uence of the fi ltration capacity and the linear sizes of an oil pool on the discharge of a horizontal well in it was investigated.
Keywords: steam-assisted gravity drainage, superviscous oil, steam chamber, horizontal well, fl ow rate of oil.
Institute of Mechanics and Machine Building of the Kazan′ Scientifi c Center, Russian Academy of Sciences, 2/31 Lobachevskii Str., Kazan′, 420111, Republic of Tatarstan. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 865–870, July–August, 2014. Original article submitted December 21, 2013.
MODELING THE FORMATION OF HYDRATES IN GAS WELLS IN THEIR THERMAL INTERACTION WITH ROCKS
É. A. Bondarev, I. I. Rozhin, and K. K. Argunova
Consideration is given to a conjugate problem of heat exchange between the imperfect gas in a well and the environment (rocks). This problem is reduced to solution of differential equations describing nonisothermal gas fl ow in the well and the propagation of heat in the rocks. The dependence of the coeffi cient of heat exchange of the gas with the hydrate layer on the time-varying fl ow area is taken account of in aquasistationary mathematical model of formation (dissociation) of hydrates in the gas well. It is shown that in the conjugate formulation of the problem, the time of formation of hydrate plugs grows substantially in contrast to the case where the rock temperature is assumed to be constant.
Keywords: formation of hydrates, imperfect gas, permafrost rocks, conjugate problem.
Institute of Oil and Gas Problems, Siberian Branch of the Russian Academy of Sciences, 1 Oktyabr′skaya Str., Yakutsk, 677980, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 871–878, July–August, 2014. Original article submitted February 3, 2014.
ACOUSTO-CONVECTIVE DRYING OF PINE NUTS
UDC 532.72; 669.015.23
A. A. Zhilin and A. V. Fedorov
An experimental investigation of the process of drying pine nut grains has been carried out by three methods: acousto-convective, thermoconvective, and thermal. A qualitative and a quantitative comparison of the dynamics of the processes of moisture extraction from the nut grains for the considered drying methods have been made. To elucidate the mechanism of moisture extraction from the pine nut grains, we carried out a separate investigation of the process of drying the nut shell and the kernel. The obtained experimental data on the acousto-convective drying of nuts are well described by the relaxation model, the data on the thermoconvective drying are well described by the bilinear law, and the data on the thermal drying are well described by the combined method consisting of three time steps characterized by different kinetic regimes of drying.
Keywords: acousto-convective drying, thermoconvective drying, thermal drying, pine nut drying, drying of the pine nut shell, relaxation model.
S. A. Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch of the Russian Academy of Sciences, 4/1 Institutskaya Str., Novosibirsk, 630090, Russia; email: , . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 879–886, July–August, 2014. Original article submitted February 19, 2014.
STUDY OF THE HEAT TRANSFER IN THE PROCESS OF DRYING OF MOIST MATERIALS FROM EXPERIMENTAL DATA ON MOISTURE TRANSFER
A. I. Ol′shanskii
Heat transfer in the process of drying of moist materials has been calculated from the experimental data on moisture transfer. Equations for computation of the average temperature of the materials, the heat fl uxes in them, and the time of their drying in the second period have been presented. Numerical values of the drying parameters obtained by calculation from the formulas have been compared to the corresponding experimental data.
Keywords: moist material, mean-integral temperature, moisture content, rate of heating of a body, drying time.
Vitebsk State Technological University, 72 Moskovskii Ave., Vitebsk, 210035, Republic of Belarus; email: zs_85@ mail.ru. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 887–897, July–August, 2014. Original article submitted January 13, 2014.
HYDRODYNAMICS IN TECHNOLOGICAL PROCESSES
COMPUTATIONAL MODELING OF FREE CONVECTION BETWEEN COAXIAL CYLINDERS ON THE BASIS OF A PRECONDITIONED FORM OF NAVIER–STOKES EQUATIONS
K. N. Volkova and A. G. Karpenkob
We have performed computational modeling of the free-convective fl ow in the gap between two coaxial cylinders on the basis of complete Navier–Stokes equations from the viewpoint of the compressible gas model. To stabilize numerical calculations of the viscous compressible gas at small Mach numbers, we used the preconditioning method based on the application of physical variables and the dual time stepping method. We have investigated the fl ow structure in the gap between the cylinders and the heat-transfer characteristics on the surface of the outer and inner cylinders at various Rayleigh numbers.
Keywords: free convection, cylinder, computational modeling, preconditioning.
aKingston University, SW15 3DW, London, Great Britain; email: ; bSt. Petersburg State University, 35 Universitetskii Ave., Peterhof, St. Petersburg, 198504, Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 898–903, July–August, 2014. Original article submitted January 29, 2014.
MODELING OF REDUCTION IN THE DRAG AND OF CESSATION OF THE ACTION OF AN ALTERNATING TRANSVERSE FORCE ON A CIRCULAR CYLINDER DUE TO THE THROTTLING EFFECT
S. A. Isaev,a A. G. Sudakov,b Yu. V. Zhukova, and A. E. Usachovdc
An analysis of the physical processes in unsteady fl ow past a circular cylinder surrounded by a sheath with ports for bleeding of the medium has been made by a factorized fi nite-volume method on the basis of numerical solution of Navier–Stokes equations closed with the Menter sheer-stress-transfer model. It has been shown that such arrangement of a circular cylinder ensures stabilization of the wake of the cylinder, and also the reduction in its drag and cessation of the action of an alternating transverse force at Reynolds numbers higher than 105.
Keywords: separating fl ow, circular cylinder surrounded by a sheath with ports for bleeding of the medium, drag, lift, numerical modeling, pressure-correction procedure, Rhee–Chou approach, multiblock computational technologies, Menter sheer-stress model.
aSt. Petersburg State University of Civil Aviation, 38 Pilotov Str., St. Petersburg, 196210, Russia; email: isaev3612@ yandex.ru; bBattery Company "Riegel," 38 Prof. Popov Str., St. Petersburg, 197376, Russia; cA. V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, 15 P. Brovka Str., Minsk, 220072, Belarus; dBranch of the Federal State Unitary Enterprise TsAGI (Central Aerohydrodynamics Institute) "Moscow Complex," 17 Radio Str., Moscow, 107005, Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 904–907, July–August, 2014. Original article submitted March 26, 2014.
HEAT TRANSFER AND FORMATION OF TURBULENCE IN AN INTERNAL SWIRLING FLUID FLOW AT LOW REYNOLDS NUMBERS
O. V. Matvienko
Results of investigations of the structure of swirling fl uid fl ow in a channel, and also of the parameters of turbulence of the fl ow and heat transfer in it at low Reynolds numbers, have been presented. It has been established that a moderate swirl of the fl ow at the channel wall under the action of a centrifugal force gives rise to turbulent disturbances in this fl ow region and that the formation of turbulent pulsations of the fl uid in the vicinity of the channel axis is hindered by the initiation of reverse fl ows and by the conservatism of the action of the centrifugal force on the parameters of turbulence of the fl uid. It has been shown that heat transfer in the swirling fl uid fl ow depends on the integral intensity of the swirl and on the mode of organization of the rotation of the fl uid. It has been established that the heat transfer of the fl ow with a constant swirl angle is higher than that of the fl ow swirled by the law of revolution of a rigid body.
Keywords: swirling flow, turbulence, heat transfer, computational hydrodynamics.
Tomsk State University of Architecture and Civil Engineering, 2 Solyanaya Sq., Tomsk, 634003, Russia; Tomsk State University, 36 Lenin Ave., Tomsk, 634050, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 908–918, July–August, 2014. Original article submitted January 30, 2014.
HYDRODYNAMIC AND DIFFUSION PROBLEMS IN THE THEORY OF NONSTATIONARY DIFFUSOPHORESIS OF SPHERICAL PARTICLES
V. E. Efremov and M. K. Kuz′min
The theory of the nonstationary diffusiophoresis of a large spherical solid particle in a viscous gaseous medium is beginning to be constructed. Hydrodynamic and diffusion problems are divided into stationary and strictly nonstationary parts. The solution of the stationary parts of these problems has yielded the fi nal formula for determining the stationary component of the diffusiophoretic velocity of the particle considered. A corresponding formula in the space of Laplace images has been obtained for determining the nonstationary component of the diffusiophoretic velocity of this particle.
Keywords: nonstationary diffusiophoresis, spherical particles, hydrodynamic problem, diffusion problem.
Moscow State Regional University, 10a Radio Str., Moscow, 105005, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 919–928, July–August, 2014. Original article submitted January 21, 2014.
FREE CONVECTION FLOW OF DISSIPATIVE FLUID FROM NONISOTHERMAL VERTICAL CONE
Bapuji Pullepu and P. Sambath
The effects of viscous dissipation with transient laminar free convection from a nonisothermal vertical cone at a wall surface temperature varying as a power function of the distance from the apex are considered. The fl uid is assumed to be viscous and incompressible. The nondimensional governing equations of the fl ow are unsteady, coupled, and nonlinear partial differential equations, which are solved with the use of an effi cient, accurate, and unconditionally stable fi nite difference scheme of the Crank–Nicolson type. The velocity and temperature profi les are obtained and analyzed to reveal the effect of viscous dissipation at various values of the Prandtl number and the exponent in the power law variation of the surface temperature. The local as well as average skin friction and Nusselt number are presented and analyzed. The present results are compared with available ones from the literature and are found to be in good agreement.
Keywords: fi nite difference method, natural convection, nonuniform surface temperature, unsteady fl ow, vertical cone, viscous dissipation.
Department of Mathematics, SRM University, Kattankulathur, TN, India-603203; email: . Published in Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 929–938, July–August, 2014. Original article submitted February 18, 2013; revision submitted March 10, 2014.
SIMILARITY SOLUTIONS FOR THE FLOW BEHIND AN EXPONENTIAL SHOCK IN A ROTATING NONIDEAL GAS WITH HEAT CONDUCTION AND RADIATION HEAT FLUXES
K. K. Singh and B. Nath
A self-similar solution for the propagation of a shock wave driven by a cylindrical piston moving according to exponential temporal law in a nonideal rotating gas with heat conduction and radiation heat fl uxes is investigated. The density and angular velocity of the ambient medium are assumed to be constant. Heat conduction is expressed in terms of the Fourier law, and radiation is considered to be of diffusion type for an optically thick gray gas model. The thermal conductivity and absorption coeffi cient are assumed to vary with temperature and density. Similarity solutions are obtained, and the effects of variations in the heat transfer parameters and gas nonidealness on the fl ow variables in the region behind the shock are investigated.
Keywords: similarity solutions, nonideal gas, rotating medium, exponential shock wave, heat transfer effects.
Department of Mathematics, North-Eastern Hill University, Shillong-793022, India; email: . Original article submitted March 14, 2013. Published in Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 939–948, July– August, 2014. Original article submitted March 14, 2013.
TRANSFER PROCESSES IN RHEOLOGICAL MEDIA
METHOD OF DETERMINING THE THERMOVISCOELASTIC PARAMETERS OF POLYMERS AND ELASTOMERS
UDC 669.041; 539.3
S. V. Shil′ko,a D. A. Chernous,a and S. V. Paninb
A method of determining the thermoviscoelastic parameters of polymers and elastomers based on the identifi cation of the deformation model by experimental dependences of the shear modulus and loss-angle tangent on temperature is suggested. The method is tested with polyethylene terephthalate in the temperature range from –100 to +100oC.
Keywords: thermoviscoelastic parameters, deformation model, polymers, elastomers, relaxation characteristics.
aA. V. Belyi Institute of the Mechanics of Metal-Polymer Systems, National Academy of Sciences of Belarus, 32a Kirov Str., Gomel′, 246050, Belarus; email: ; bInstitute of Strength Physics and Material Science, Siberian Branch of the Russian Academy of Sciences, 2/4 Akademicheskii Ave., Tomsk, 634021, Russia; email: svp@ispms. tsc.ru. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 949–952, July–August, 2014. Original article submitted February 4, 2014..
KINETIC THEORY OF TRANSFER PROCESSES
ANALYTICAL SOLUTION OF THE COUETTE FLOW PROBLEM FOR ARBITRARY VALUES OF THE KNUDSEN NUMBER
S. V. Gulakova and V. N. Popov
An analytical (in the form of the Neumann series) solution of the Couette fl ow problem has been constructed with the use of the kinetic approach. For the basic equation the Williams equation was used, and for the boundary condition on the channel walls the mirror-diffuse model was applied. With account for the constructed distribution function the value of the gas mass fl ow per unit width of the channel through its upper half has been calculated and a viscous stress tensor component other than zero has been found. A comparison with analogous results obtained by numerical methods has been made.
Keywords: kinetic Boltzmann equation, model kinetic equations, exact analytical solutions, gas fl ow in channels, Couette flow.
M. V. Lomonosov North (Arctic) Federal University, 17 North Dvina Quay, Arkhangel′sk, 163002, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 953–960, July–August, 2014. Original article submitted March 2, 2014.
TECHNOLOGY COMPUTER-AIDED DESIGN AND STUDY OF PROTOTYPES OF A SILICON ZENER DIODE
UDC 621.382.049.77.001.63; 621.382.049.77.001.66
N. L. Dudar,a V. M. Borzdov,b and A. S. Turtsevicha
A technology for manufacture of a silicon Zener diode with a stabilizing voltage of 6.5 V has been proposed. The resistivity of the substrate and the regime of phosphorus diffusion into the substrate have been determined, which ensure required values of the stabilizing voltage under room-temperature conditions and at two boundary temperatures: –55 and 150oC. Modeling data have been compared to experimental results.
Keywords: Zener diode, stabilizing voltage, technology computer-aided design, technological route, diffusion doping.
aJoint Stock Company (JSC) "INTEGRAL," 12 Korzhenevskii Str., Minsk, 220108, Republic of Belarus; email: ; bBelarusianState University, 4 Nezavisimost′ Ave., Minsk, 220030, Republic of Belarus; email: offi ce@ bms.by. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 961–965, July–August, 2014. Original article submitted February 14, 2011.
CORRECTION OF THE SHEAR-STRESS-TRANSFER MODEL WITH ACCOUNT OF THE CURVATURE OF STREAMLINES IN CALCULATING SEPARATED FLOWS OF AN INCOMPRESSIBLE VISCOUS FLUID
S. A. Isaev,a P. A. Baranov,b Yu. V. Zhukova,c A. E. Usachov,d and V. B. Kharchenkoe
The necessity of correcting differential semiempirical turbulence models to calculate circulating fl ows of an incompressible viscous fl uid is discussed. Approaches to taking account of the infl uence of the curvature of streamlines on turbulence characteristics arereviewed. Experience gained in modeling numerically twodimensional separated fl ows in a square and a cylindrical cavity on the wall of a plane-parallel channel is analyzed; an additional semiempirical constant in the expression for vortex viscosity of a modifi ed shear-stress-transfer model is substantiated.
Keywords: separated fl ows, incompressible viscous fl uid, turbulence, cavity, multiblock grids, turbulence models,
Reynolds-averaged nonsteady Navier–Stokes equations, Mentershear-stress-transfer model, correction for the
aSt. Petersburg State University of Civil Aviation, 38 Pilotov Str., St. Petersburg, 196210, Russia; email: ; bBattery Company "Riegel," 38 Prof. Popov Str., St. Petersburg, 197376, Russia; cA. V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, 15 P. Brovka Str., Minsk, 220072, Belarus; email: ; dBranch of the Federal State Unitary Enterprise TsAGI (Central Aerohydrodynamics Institute) "Moscow Complex," 17 Radio Str., Moscow, 107005, Russia; eSt. Petersburg University of Architecture and Civil Engineering, 4 2ndKrasnoarmeiskaya Str., St. Petersburg, 190005, Russia. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 966–979, July–August, 2014. Original article submitted April 7, 2014.
VOLUME 87, NUMBER 4