HEAT AND MASS TRANSFER IN DISPERSE AND POROUS MEDIA
ON THE HYDRODYNAMICS OF AN INHOMOGENEOUS FLUIDIZED BED WITH VERTICAL ORGANIZATION OF THE OVER-BED SPACE
E. A. Pitsukha,a Yu. S. Teplitskii,b and V. A. Borodulyab
An experimental investigation of the hydrodynamics of the vortex space over a fl uidized bed in a chamber of diameter 0.393 m has been carried out. The existence of two regimes associated with the size of the outlet hole has been established: the regime of a swirling air fl ow without a noticeable sweeping of particles from the bed and the regime with particle entrainment from the bed.
Keywords: bubbling (fl uidized) bed, over-bed space, hydrodynamics, cyclone–grate-fi red chamber, particle entrainment.
a"Beloozersk Power Mechanical Plant" Joint Stock Company, 1 Zavodskaya Str., Beloozersk, 225215, Belarus; email: ; bA. 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. 5, pp. 981–984, September–October, 2014. Original article submitted March 26, 2014.
NUMERICAL SIMULATION OF FLOWS IN A CYCLONE CHAMBER WITH DIFFERENT CONDITIONS OF AIR INLET AND OUTLET
E. A. Pitsukha
A numerical investigation of fl ows in a cyclone chamber has been carried out at the fraction of bottom blast φ = 0–0.5, at the values of the dimensionless pinch diameter dout/D = 0.7 with different locations and confi gurations of nozzles for air intake. In the simulation of swirling fl ows, the well-known k–ε and k–ω turbulence models, as well as the laminar fl ow model, were used. A satisfactory agreement between the results of numerical simulation and experimental data at dout/D = 0.5–0.7 is obtained. For a chamber with a relative pinch diameter dout/D = 0.3 the calculated fl ow parameters differ substantially from experimental values.
Keywords: cyclone chamber, turbulence model, computational grid, tangential velocity, longitudinal velocity, bottom blast, total pressure.
"Beloozersk Power Mechanical Plant" Joint Stock Company, 1 Zavodskaya Str., Beloozersk, 225215, Belarus; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 985–992, September–October, 2014. Original article submitted May 2, 2014.
INVESTIGATION OF THE VIBROFLUIDIZED BED BETWEEN TWO WALLS WITH THE USE OF MATHEMATICAL MODELING
E. S. Kamenetskii,a G. I. Sverdlik,b N. S. Orlova, and I. V. Tryapitsynba
To describe the motion of the vibrofl uidized bed of a granular material between two walls, we have modifi ed the two-liquid model based on the Darcy law and the hydrodynamic granular gas model. On the basis of the results of modeling we have investigated the infl uence of thickness of the packed bed of the material, the distance between the walls, as well as of the vibration amplitude and frequency of the walls on the particle distribution between them.
Keywords: two-liquid model, Darcy law, hydrodynamic model of granular gas, vibrofl uidization, numerical calculation, coarse particles, fine particles.
aSouth Mathematical Institute, Vladikavkaz Science Center of the Russian Academy of Sciences and Government of the Republic of South Osetia-Alania, 22 Markus Str., Vladikavkaz, 362027, Russia; email: ; bNorth-Caucasus Mining-Metallurgical Institute, 44 Nikolaev Str., Vladikavkaz, 362021, Russia. Translated from Inzhenerno- Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 993–999, September–October, 2014. Original article submitted April 16, 2014..
INFLUENCE OF VIBROWAVE ACTION ON THE CHARACTER OF PRESSURE DISTRIBUTION IN THE FORMATION WITH ALLOWANCE FOR THE DYNAMIC COUPLING OF THE SYSTEM "FORMATION–WELL"
É. M. Abbasov and N. A. Agaeva
The infl uence of elastic waves in the wellhead on the character of change in the bottom-hole pressure has been studied based on theoretical investigations. An analytical expression for the bottom-hole pressure has been obtained with allowance for the dynamic coupling of the system "formation–well."
Keywords: filtration, pressure, formation, vibrowave action, differential equation, Bessel function, period, fluid.
Scientifi c-Research and Design Institute "Neftegaz," 88a Zardabi Ave., Baku, Az1012, Azerbaijan; email: aelhan@ mail.ru. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1000–1010, September–October, 2014. Original article submitted Mach 30, 2014.
BAROTHERMAL EFFECT IN GASES IN AN ISOLATED SEAM
A. I. Filippov, P. N. Mikhailov, and N. A. Spiridonova
An analytical solution of the problem on a temperature fi eld occurring during gas fi ltration in a porous seam has
been obtained in barotropic approximation. The dependences of temperature distribution in a gaseous seam on its
permeability and on the baric compressibility of the gas have been investigated.
Keywords: barothermal effect, temperature field, permeability of a gaseous seam, baric compressibility of a gas.
Institute of Applied Investigations of the Republic of Bashkortostan, 68 Odesskaya Str., Sterlitamak, 453103, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1011–1016, September–October, 2014. Original article submitted April 4, 2014.
DETERMINATION OF FILTRATION PROPERTIES OF A DEFORMABLE POROUS-FRACTURED BED FROM THE RESULTS OF HYDRODYNAMIC INVESTIGATIONS OF HORIZONTAL WELLS
A. I. Abdullin,a R. Sh. Mardanov,b P. E. Morozov,a M. N. Shamsiev,a,b and M. Kh. Khairullina
A computational algorithm has been proposed for interpretation of results of hydrodynamic investigations of horizontal wells in unsteady regimes of fi ltration in deformable porous-fractured beds. The proposed approach makes it possible to evaluate the dependence of the permeability coeffi cient of fractures on pressure. A study has been made of the dynamics of change in the bottom-hole pressure after bringing a horizontal well into production and shutting it down in the nonlinear elastic regime of fi ltration of the fl uid in a porous-fractured bed.
Keywords: barothermal effect, temperature field, permeability of a gaseous seam, baric compressibility of a gas.
aInstitute of Mechanics and Mechanical Engineering, Kazan Scientifi c Center of the Russian Academy of Sciences, 2/31 Lobachevskii Str., Kazan, 420111, Russia; bKazan (Volga region) Federal University, 18 Kremlevskaya Str., Kazan, 420008, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1017– 1021, September–October, 2014. Original article submitted March 6, 2014.
HEAT AND MASS TRANSFER IN COMBUSTION PROCESSES
NUMERICAL MODELING OF THE IGNITION OF HYDROGEN–OXYGEN MIXTURES
UNDER NONEQUILIBRIUM CONDITIONS
G. Ya. Gerasimov and O. P. Shatalov
UDC 541.126:127; 536.46
A numerical study has been made of the intensifi cation of combustion in hydrogen-oxygen mixtures with a low-temperature nonequilibrium plasma, when the concentration of the active particles in the mixture (atoms, radicals, ions, and excited particles) is much higher than their equilibrium concentrations. Primary emphasis has been placed on the infl uence of higher-than-average concentrations of electronically excited O2(a 1Δg) molecules and O( 1Δ) atoms on the acceleration of the process of ignition. Electron-beam irradiation of the fuel mixture and the action of a high-voltage nanosecond discharge on it were selected for comparison of the effi ciency of different types of plasma initiation of combustion.
Keywords: combustion, excited oxygen, kinetic mechanism, induction time, electron-beam irradiation, gas discharge.
Institute of Mechanics of M. V. Lomonosov Moscow State University, 1 Michurin Ave., Moscow, 119192, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1022–1028, September– October, 2014. Original article submitted December 5, 2013.
MECHANISM FOR INCREASING THE PRESSURE IN AN OIL WELL BY A COMBUSTIBLE OXIDIZING LIQUID MIXTURE
G. V. Melik-Gaikazov
UDC 536.46 + 622.276.6
A method of estimating the pressure pulse arising in a deep oil well as a result of the thermal explosion of a combustible oxidizing liquid mixture in it is presented. It was established that less than 10% of this mixture is expended for the formation of a pressure pulse in this well. The conditions under which a tubing string positioned in such a well experiences a plastic bending and its walls are crumpled were determined. The maximum admissible difference between the pressures at the walls of this tube were calculated, and axial compression loads were related to critical forces of different orders. It is shown that, when the indicated tube is submerged in the liquid in the well, its resistance to a short-time axial compression load increases.
Keywords: ammonium nitrate, hydraulic shock, combustible oxidizing liquid mixture, vibrations of a liquid column, oil well, axial compression of a tube.
N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, 4 Kosygin Str., Moscow, 119991, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1029–1036, September– October, 2014. Original article submitted January 21, 2014.
NUMERICAL INVESTIGATION OF THE FORMATION OF A CONVECTIVE COLUMN AND A FIRE TORNADO BY FOREST FIRES
A. M. Grishina and O. V. Matvienkoa,b
Computational modeling of the formation of a convective column by forest fi res has been carried out. It has been established that in the case of an unstable atmosphere stratifi cation the basic factor infl uencing the thermal column formation is the intensifi cation of the processes of turbulent mixing and that at a stable atmosphere stratifi cation
a more signifi cant factor determining the convective column formation is the action of the buoyancy force. It has been shown that a swirling fl ow in the convective column is formed due to the appearance of a tangential velocity component as a consequence of the local circulation arising against the background of large-scale motion owing to
the thermal and orographic inhomogeneities of the underlying surface.
Keywords: forest fi res, tornado, convective column, heat exchange, turbulence, mathematical modeling.
aTomsk State University, 36 Lenin Ave., Tomsk, 634050, Russia; bTomsk State Architecture-Civil Engineering University, 2 Solyanaya Sq., Tomsk, 634003, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 602–606, September–October, 2014. Original article submitted March 26, 2014.
MECHANOCHEMICAL TREATMENT, FEATURES OF THE STRUCTURE AND PROPERTIES, AND REACTIVITY OF SHS SYSTEMS BASED ON NATURAL MATERIALS
3. INFLUENCE OF MECHANOCHEMICAL TREATMENT AND MODIFICATION OF OXIDE
MATERIALS ON THE TECHNOLOGICAL COMBUSTION
UDC 546.07 + 541.17 + 621.762
Z. A. Mansurov, N. N. Mofa, B. S. Sadykov, and V. I. Antonyuk
We have investigated the laws of technological combustion of (SiO2 + Al) and (SiO2 + CaSiO3 + Al) systems with the combustion reaction activated by preliminary mechanochemical treatment of the charge components with various modifying additives containing bound water, carbon, and amino groups. It has been shown that modifying the charge components in the regime of mechanochemical treatment leads to a change in the induction period of ignition, the combustion kinetics, and the thermodynamic characteristics of the process, which promotes intensifi cation of the development of redox reactions and more complete conversion of the charge mixture components.
Keywords: mechanochemistry, quartz, wollastonite, modifi cation, SH-synthesis, composites.
Institute for Combustion Problems, 172 Bogenbaibatyr, Almaty, Kazakhstan; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp.1051–1059, September–October, 2014. Original article submitted May 12, 2014.
MODELING AND NUMERICAL INVESTIGATION OF THE PROCESS OF VAPOR-OXYGEN GASIFICATION OF SOLID FUELS IN A VERTICAL FLOW REACTOR UNDER PRESSURE
B. B. RokhmanUDC 532.529:532.517.4
With the use of the developed model, detailed information has been obtained on the working process in a fl ow reactor with single- and two-stage schemes of vapor-oxygen gasifi cation of coals under a pressure of 3 MPa. The dependence of the ratios of mass fl ow rates O2/coal and H2O/coal on the type of fuel has been established and their optimal values for the "Shell" process have been found. At a given consumption ratio of gas coal and brown coal of brand B1, the optimum diameters of particles providing minimum combustible loss of the carbon mixture have been determined. It has been found that the content of methane in the syngas in the case of two-stage gasifi cation is much higher than in the case of single-stage gasifi cation.
Keywords: vapor-oxygen gasifi cation, vertical fl ow reactor, coal, pyrolysis, binary mixture, syngas, particle, polydispersion, heterogeneous and homogeneous reactions.
Institute of Carbon Energy Technologies, National Academy of Sciences of Ukraine, 19 Andreevskaya Str., Kiev, 04070, Ukraine; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1060– 1071, September–October, 2014. Original article submitted April 18, 2014.
HEAT CONDUCTION AND HEAT TRANSFER IN TECHNOLOGICAL PROCESSES
ANALYTICAL SOLUTIONS OF HYPERBOLIC HEAT-CONDUCTION MODELS
É. M. Kartashov
An analytical method for solution of hyperbolic transfer models has been developed which includes new integral relations in terms of Green′s function and boundary functions of the problem of temporal and spatial inhomogeneities. A series of illustrated examples has been considered.
Keywords: transfer models, method of Green′s functions, heat-conduction equation.
M. V. Lomonosov Moscow State Academy of Fine Chemical Technology, 82 Vernadskii Ave., Moscow, 119571, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1072–1081, September–October, 2014. Original article submitted June 16, 2014.
ANALYTICAL METHODS OF PARAMETRIC OPTIMIZATION IN INVERSE HEAT-CONDUCTION PROBLEMS WITH INTERNAL HEAT RELEASE
A. N. Diligenskaya and É. Ya. Rapoport
Consideration is given to inverse heat-conduction problems on identifi cation of the strength of internal heat sources or the law of their spatial distribution. The problems have been formulated in an extremum statement as problems of optimum control over an object with distributed parameters when the set of control actions is limited to the class of continuous and continuously differentiable functions. On the basis of parametrization of control actions, the problem is reduced to an unsmooth problem of mathematical programming for the solution of which we use a special method taking account of the alternance properties of the sought optimum solutions.
Keywords: inverse heat-conduction problem, special problems of mathematical programming, parametric optimization, alternance method.
Federal State Budget-Funded Educational Institution of Higher Vocational Training "Samara State Technical University," 244 Molodogvardeiskaya Str., Samara, 443100, Russia; email: , . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1082–1089, September–October, 2014. Original article
submitted April 15, 2014.
METHODS OF INVESTIGATING THE LIMITING POSSIBILITIES OF STRUCTURE-INHOMOGENEOUS THERMOSTABILIZING
E. L. Gusev
The problems of optimal design of structure-inhomogeneous thermostabilizing constructions have been investigated. Variational problems of the optimal design of structure-inhomogeneous thermostabilizing constructions have been formulated. The parameters determining the hysicomechanical and geometric structures of the construction were varied. The quality functional in the variational problem determines the level of decrease in the temperature field intensity. On the basis of the necessary optimality conditions in the variational formulation asound structure of layerinhomogeneous constructions realizing the limiting possibilities for lowering the intensity level of the temperature
fi eld has been investigated.
Keywords: thermostabilizing constructions, internal symmetry, temperature waves, quality functional, temperature wave damping decrement, multivalued mapping, setting on points of parameter control.
Institute for 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. 5, pp. 1090–1095, September–October, 2014. Original article submitted April 15, 2014.
NUMERICAL INVESTIGATION OF THERMAL-PROTECTION CHARACTERISTICS
OF STRUCTURAL SANDWICH PANELS
M. N. Danilov and N. N. Fedorova
Results of numerical investigation of thermal-protection characteristics of structural sandwich panels with the ANSYS software system have been presented. Calculation results have been compared to the corresponding specifi cations.
Keywords: sandwich panel, enclosing structure, finite-element method, thermal protection, dew point.
Novosibirsk State University of Architecture and Civil Engineering, 113 Leningradskaya Str., Novosibirsk, 630008, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1196–1105, September–October, 2014. Original article submitted March 14, 2014.
HEAT AND MASS TRANSFER IN A WETTED THERMAL INSULATION OF HOT WATER PIPES OPERATING UNDER FLOODING CONDITIONS
V. Yu. Polovnikov and E. V. Gubina
We present the results of numerical simulation of the thermal regimes of hot water pipes under flooding conditions with account for evaporation and diffusion of steam in a wetted thermal insulation. The extents of heat losses by hot water pipes under these conditions have been revealed. The contributions of evaporation and steam diffusion effects to the total heat losses are shown. The necessity of taking into account the nonstationarity of transfer processes and of the values of volume fractions of moisture and steam in the structure of a wetted thermal insulation layer in modeling thermal regimes of hot water pipes under fl ooding conditions has been proven.
Keywords: hot water-supply systems, heat losses, hot water pipe, wetting of insulation, flooding.
National Research Tomsk Polytechnic University, 30 Lenin Ave., Tomsk, 634050, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1106–1112, September–October, 2014. Original article submitted July 17, 2014.
INVESTIGATION OF THE CONVECTIVE-RADIANT DRYING OF INDUSTRIAL FABRICS BY THE REGULAR-REGIME METHOD
A. I. Ol′shanskii and S. V. Zhernosek
Equations defi ning the kinetics of drying of fabrics have been derived and a method of graphical-analytical representation of the drying process has been developed. The mechanism of the change in the heat fl ows in the process of drying of industrial fabrics was determined.
Keywords: convective-radiant drying, industrial fabric, rates of heating of a moist body and removal of moisture
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. 5, pp. 1113–1122, September–October, 2014. Original
article submitted April 3, 2014.
WELDING WITH MICROJET COOLING AS A METHOD OF IMPROVING THE PLASTIC PROPERTIES OF WELDS
D. Hadryśa and J. Piwnikb
The goal of this paper is to provide a new welding technology based on microjet cooling just after the welding and to investigate the possibilities of improving the plastic properties of welds. This is possible because in this case the welds have a benefi cial structure with a high amount of acicular ferrite (AF) in a weld metal deposit (WMD). A very high percentage of AF in the WMD (55–75%) cannot be obtained by an ordinary welding method (basic electrodes, MIG/ MAG (Metal Inert/Active Gas), and TIG (Tungsten Inert Gas)). Welding with microjet cooling is very promising and capable of industrial application, mainly due to the signifi cant improvement of weld quality and reduction of costs.
Keywords: welding with microjet cooling, acicular ferrite, plastic properties.
aSchool of Labour Safety Managament in Katowice WSZOP, Bankowa Str., 8, 40-007 Katowice, Poland; email: dhadrys @wszop.edu.pl; bBialystok University of Technology, Mechanical Faculty, Wiejska Str., 45c, 16-351 Białystok, Poland. Published in Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1123–1128, September–October, 2014. Original
article submitted April 4, 2014.
TRANSFER PROCESSES IN RHEOLOGICAL MEDIA
MATHEMATICAL SIMULATION OF A SWIRLING VISCOPLASTIC FLUID FLOW
IN A CYLINDRICAL CHANNEL
O. V. Matvienko,a,b V. P. Bazuev,b and N. K. Dul′zonb
The paper describes the results of investigations of a swirling viscoplastic fl uid fl ow in a cylindrical channel. It has been established that on increase in the limit shear stress and plastic viscosity, the effect of swirling on the flow structure becomes less expressed: the depth of the axial velocity dip decreases to its complete disappearance, with the hydrodynamic flow stabilization being observed over a smaller distance from the channel inlet. It is shown that at the same Rossby number the recirculation intensity increase with decreasing limit shear stress and plastic viscosity.
Keywords: rheology, viscoplastic fluid, swirling flows, computational hydrodynamics.
aTomsk State University, 36 Lenin Ave., Tomsk, 634050, Russia; bTomsk State Architecture and Civil Engineering University, 2 Solyanaya Sq., Tomsk, 634003, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1129–1137, September–October, 2014. Original article submitted February 18, 2014.
TWO-TEMPERATURE AND RHEOLOGICAL EFFECTS IN A VISCOELASTIC ISOTROPIC MATERIAL WITH TEMPERATURE-DEPENDENT PROPERTIES
M. K. Mondal and B. Mukhopadhyay
The influence of the temperature difference in a viscoelastic solid body with a spherical cavity and its rheological properties on the mechanical properties of this body was investigated in the Laplace transform domain with the use of the Lord–Shulman and Green–Lindsay heat-conduction equations.
Keywords: thermoviscoelastic material, spherical cavity, rheological properties, vector-matrix differential equation, relaxation function.
Department of Mathematics, Bengal Engineering and Science University, Shibpur, P.O. Botanic Garden, Howrash, 711103, West Bengal, India; email: . Published in Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1138–1148, September–October, 2014 Original article submitted April 5, 2013.
HYDRODYNAMICS IN TECHNOLOGICAL PROCESSES
DETERMINATION OF THE BOUNDARY PARAMETERS OF THE THERMAL CRISIS OF THE VORTEX-SOURCE COMBINATION AT ENERGY INPUT
UDC 533.6 + 535.211
A. N. Kucherov
We have investigated the flow regions of the vortex-source combination with a constant pressure established due to the specially chosen intensity distribution of the energy exchange sources (heat input and heat removal) in the space of similarity parameters initial coordinate (temperature)–gas circulation–length of the energy exchange zone. Regions in which a thermal crisis is realized and steady fl ow choking occurs have been determined. We have constructed boundaries of the thermal crisis regions in the following cases of vortex-source combination outfl ow: into a vacuum, from a rarefi ed space, into a submerged space or from a submerged space.
Keywords: gas, source, out flow, vortex-source combination, energy input, circulation, flow rate, pressure, Mach number, flow choking, thermal crisis, heat removal.
Prof. N. E. Zhukovskii Central Aerohydrodynamic Institute, 1 Zhukovskii Str., Zhukovskii, Moscow Region, 140180, Russia; email: , . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1149–1159, September–October, 2014. Original articles submitted January 29, 2014.
FLOW OF A HIGHLY VISCOUS FLUID IN A FINE INJECTOR
S. K. Betyaev
Under consideration is the scheme of a creeping fl ow in a plane or a circular injector-channel through the side surface of which a working liquid is injected.
Keywords: injector, creeping fl ow, injection.
Zhukovskii, 140181, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1160–1163, September–October, 2014. Original article submitted November 21, 2012.
FORCED CONVECTION IN A STRATIFIED ROTATING MEDIUM UNDER THE INFLUENCE OF VORTEX SHEARING STRESS
ON THE SURFACE
L. Kh. Ingel′
The response of a semi-infi nite stratifi ed rotating medium to the action of an inhomogeneous vortex shearing stress on a horizontal surface is investigated analytically in a linear approximation. The previously unexplored region of the values of governing parameters is considered. It has been established that in the first approximation the indicated response represents a geostrophic vortex penetrating into a stably stratifi ed medium to depths of the order of the horizontal scale of the shearing stress inhomogeneity and that the amplitude of the originating thermal perturbation is proportional to this scale and to the angular rotational velocity of the medium and inversely proportional to the
coeffi cient of its viscosity.
Keywords: rotating stratifi ed medium, inhomogeneous shearing stress, response, forced convection, linear
approximation, analytical solution.
"Taifun" Scientifi c-Production Association, 4 Pobeda Str., Obninsk, Kaluzhskaya Region, 249038, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1164–1168, September–October, 2014. Original article submitted March 17, 2014.
NONLINEAR MAGNETOHYDRODYNAMIC RADIATING FLOW OVER AN INFINITE VERTICAL PLATE IN A SATURATED POROUS MEDIUM:
LAPLACE AND NUMERICAL APPROACHES
A. Sahin,a K. Karabi,b and Z. Joaquinc
A buoyancy-induced unsteady hydromagnetic thermal convection fl ow in a semi-infi nite porous medium adjacent to an infinite vertical plate moving uniformly in the presence of a strong thermal radiation was investigated. The temperature of this flow was assumed to be very high to ensure that the radiative heat transfer was signifi cant,
which makes the problem highly nonlinear even in the case of differential approximation for the radiative heat flux. A system of nonlinear partial differential equations describing an unsteady fl ow of an MHD Newtonian fluid was normalized and solved using the Laplace transform technique and an implicit fi nite-difference scheme of the Crank– Nicolson type. The solutions obtained by the analytical and numerical methods are in excellent agreement. It was established that an increase in the porosity of the medium or in the magnetic fi eld signifi cantly decreases the shear stress in the case of air fl ow. As the radiation increases, the rate of heat transfer increases progressively in both the cases of air and water flows.
Keywords: Laplace transform technique, industrial aerodynamics, chemical engineering, Crank–Nicolson method, thermal-conduction, porous regime, nonlinear MHD fl ow, impulsively started plate, implicit fi nite-difference scheme.
aDepartment of Mathematics & Computing, Rajiv Gandhi University, Rono Hills-791112, Itanagar, Arunachal Pradesh, India; email: ; bDepartment of Mathematics, Gauhati University, Guwahati-781014, Assam, India; email: ; cThermal Engineering and Fluids Department, Technical University of Cartagena, Campus Muralla del Mar, 30202 Cartagena, Spain; email: . Published in Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 4, pp. 1169–1182, July–August, 2014. Original article submitted January 28, 2013.
UNSTEADY HEAT AND MASS TRANSFER MHD FLOW OF A CHEMICALLY REACTING FLUID PAST AN IMPULSIVELY STARTED VERTICAL
PLATE WITH RADIATION
M. Gnaneswara Reddy
The object of this study is to investigate thermal radiation in an unsteady fl ow of a viscous incompressible chemically reacting hydromagnetic fl uid past an impulsively started vertical plate with heat and mass transfer. The fluid is a gray, absorbing-emitting, and nonscattering medium, and the Rosseland approximation is used to describe the radiative heat fl ux in the energy equation. The governing equations are solved using an implicit fi nite difference scheme of the Crank–Nicolson type. Numerical results for the transient velocity, temperature, concentration, local as well as average skin frictions, and the rate of heat and mass transfer are shown graphically.
Keywords: MHD, heat transfer, radiation, fi nite difference scheme, vertical plate.
Dept. of Mathematics, Acharya Nagarjuna University Ongole Campus — 523 001, A.P., India; email: . Published in Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1183–1189, September–October, 2014. Original article submitted April 16, 2013.
CARBON NANOMATERIALS: SURFACE STRUCTURE AND MORPHOLOGY
Z. A. Mansurov,a T. A. Shabanova,b N. N. Mofa,a and V. A. Glagolevb
We propose a classifi cation of individual nanoparticles on the basis of the form of the surface and the internal architectural packing for investigations carried out with the help of transmission electron microscopy. The investigated samples contain individual nanoparticles of seven kinds in different ratios: rounded, tubular, fi brous, fi lm, "veil,"
"active" particles and "particles with regular geometric contours." The classifi cation was made on the basis of an analysis of the results of investigations of the surfaces and internal architectural packing of carbon particles obtained in different physiochemical processes (carbonization, carburizing, arc discharge, mechanochemical
treatment, plasma chemistry, and in carbon-containing fl ames). For the source materials, we used waste of farming products and widely distributed mineral raw materials.
Keywords: synthesis, nanoindividuals, classifi cation, surface and internal architectural packing of particles.
aInstitute for Combustion Problems, 172 Bogenbai batyr Str., Almaty, 050012, Kazakhstan; bK. I. Satpaev Institute of Geological Sciences, 69 Kabanbai batyr Str., Almaty, 050010, Kazakhstan; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1190–1198, September–October, 2014. Original article submitted April 26, 2014.
INFLUENCE OF SIZE EFFECTS ON THE FORMATION OF AEROSOL NANOPARTICLES
IN SUPERSATURATED VAPOR CONDENSATION
V. V. Levdanskii,a J. Smolik,b and V. Zdimalb
The infl uence of size effects on the formation of aerosol nanoparticles in supersaturated vapor condensation has been studied theoretically. Problems connected with the nucleation and nanoparticle growth rates are considered.
Keywords: aerosol, nanoparticles, size effects, condensation.
aA. V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, 15 P. Brovka Str., Minsk, 220072, Belarus; email: ; bInstitute of Chemical Process Fundamentals AS CR, Prague. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1199–1204, September–October, 2014. Original article submitted March 10, 2014.
TEMPERATURE AND CONCENTRATION DEPENDENCES OF THERMAL-DIFFUSION
SEPARATION IN TERNARY GAS SYSTEMS
A. F. Bogatyrev, O. A. Makeenkova, and M. A. Nezovitina
Thermal-diffusion separation in two ternary and six binary gas systems containing H2–CO–CO2 and H2–CH4–Ar has been measured. The measurements were perfumed at three values of the temperature of a cold region of the gas and fi ve values of a hot region of it at a pressure of 0.1 MPa and with different compositions of the mixture.
Separation values measured and computed from the earlier formula have been compared. It has been shown that, for the ternary and binary systems, experimental data are in good agreement with calculated ones.
Keywords: gas system, thermal-diffusion separation, binary and ternary systems, method of calculation of thermaldiffusion separation, thermal-diffusion constant.
National Research University "Moscow Power-Engineering Institute," 1 Énergeticheskii proezd, Smolensk, 214013, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1205–1214, September–October, 2014. Original article submitted February 24, 2014.
INFLUENCE OF A DEFECT BETWEEN CLOSELY-SPACED DISKS
ON THEIR MUTUAL CAPACITANCE
A. G. Kolpakova and S. I. Rakinb
The infl uence of a hollow between closely-spaced disks on their mutual capacitance was investigated. It was established
that the mutual capacitance of neighboring bodies of a heavily compounded composite material determines their heat-conduction and electrical-conduction properties. It is shown that a hollow between the indicated bodies can be used as a model of a defect of their matrix.
Keywords: mutual capacitance of a pair of disks, energy localization, defects.
aSiberian State University of Telecommunications and Information Science, 86 Kirov Str., Novosibirsk, 630102, Russia; email: ; bSiberian State University of Railway Communications, 191 Dusya Koval′chuk Str., 630049, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1215–1220, September– October, 2014. Original article submitted March 10, 2014.
DETERMINATION OF HOT ROLLED SHEET PARAMETERS UNDER THE ACTION OF DESTABILIZING FACTORS
B. T. Budai and N. V. Kasatkin
It has been established experimentally that longitudinal and lateral defects of rolled sheets as well as their high temperature are destabilizing factors decreasing the measurement effi ciency of sheet parameters due to the decrease in the signal-to-background ratio. The analytical dependence of this ratio on the meter parameters, as well as on the defects and temperature of rolled sheets, has been found. It has been shown that the application of this dependence makes it possible to measure with high accuracy the parameters of hot rolled sheets with various defects in a wide range of temperatures.
Keywords: rolled sheets, photodetectors, wavelength, optical method.
Ural Federal University named after the fi rst President of Russia B. N. Yeltsin, 21 Mir Str., Ekaterinburg, 620002, Russia; email: . Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 87, No. 5, pp. 1221–1225, September–October, 2014. Original article submitted December 30, 2013.