HEAT AND MASS TRANSFER IN DISPERSIVE MEDIA FILTRATION PRESSURE FIELD IN AN INHOMOGENEOUS BED IN CONSTANT DRAINAGE
A. I. Filippov, O. V. Akhmetova,
and I. M. Filippov
UDC 532.546
Based on the modification of the "exact-on-average" method, simple analytical formulas have been found for calculation, in the zero and first asymptotic approximations, of pressure fields in an inhomogeneous anisotropic bed in constant drainage for the case of one-dimensional linear flow. The results of calculations of the fields from the obtained formulas have been given.
Keywords: filtration, pressure fields, inhomogeneous anisotropic bed, asymptotic expansion.
NON-STOKESIAN SEDIMENTATION AS APPLIED TO THE ANALYSIS OF THE INTERACTION OF PARTICLES
IN A SUSPENSION
J. Duecka and L. L. Minkovb UDC 532.582.7:532.584
For the rate of sedimentation of a particle, a simple interpolation formula including the limiting cases of high
and low Reynolds numbers is suggested. It is seen that coarse particles settling by the Newton law entrain
fine fractions of a suspension much more weakly than analogous particles settling according to the Stokes
law. The influence of non-Stokesian sedimentation on the effect of acceleration of particles in a polydisperse
suspension has been analyzed. In particular, it is found that the rate of sedimentation of the finest particles
of a polydisperse suspension is equal to the Stokesian rate for a particle with an effective diameter that depends
on the suspension parameters. An expression for this effective diameter is given.
Keywords: settling of particles, sedimentation rate, polydisperse suspension, entrainment of particles.
MATHEMATICAL MODELING OF THE KINETICS OF DEPOSITION OF PARTICLES DURING THEIR PULSE INTRODUCTION THROUGH THE FREE SURFACE OF A MIXED-MEDIUM PLANE LAYER
A. A. Boger, V. I. Ryazhskikh,
and M. I. Slyusarev
UDC 517.958:531.12
Based on diffusion concepts of transfer of slightly concentrated polydisperse suspensions in the gravity field,
we propose a mathematical model of the kinetics of deposition of such suspensions in a plane layer of a homogeneously
mixed medium through the free surface of which Stokesian particles penetrate according to the
rectangular pulse law.
Keywords: deposition, size distribution of particles, mixing intensity, deposit.
MODELING OF THE PROCESS OF FORMATION AND GROWTH OF TITANIUM DIOXIDE PARTICLES IN THE WORKING ZONE OF A PLASMA-CHEMICAL
REACTOR
S. M. Aul’chenko UDC 532.075.8
Modeling of the formation and growth of titanium dioxide particles in the working zone of a plasma-chemical
reactor is carried out. The influence of a heterogeneous reaction and nucleation process on the size of particles
has been studied. Parametric calculations of the formation and growth of titanium dioxide particles depending
on the magnitude of the flow rate and velocity of titanium tetrachloride jet injection were performed.
Keywords: titanium dioxide, titanium tetrachloride, plasma-chemical reactor, one-velocity multicomponent medium,
quasi-gas-dynamical system of equations, homogeneous and heterogeneous reactions, coagulation.
FORMATION AND INVESTIGATION OF OPTICAL MEDIA CONTAINING GOLD NANOPARTICLES
V. K. Goncharov,a K. V. Kozadaev,a
D. I. Shiman,b and D. V. Shchegrikovicha
UDC 621.373.826.004.14
Consideration has been given to certain aspects of condensation processes occurring in laser-induced erosion
plumes of metals and giving rise to fluxes of metallic nanoparticles. Samples of colloidal solutions of
gold and gold-containing polymer films have been produced as a result of precipitation of nanoobjects
formed in laser erosion of gold into aqueous and polymer-containing media. The experimental samples
formed have been comprehensively investigated using optical spectroscopy and transmission and scanning
electron microscopy.
Keywords: laser synthesis of metal nanoparticles, erosion laser plume, colloidal solution of gold, gold-containing
polymer film, surface plasmon resonance.
SOME SCIENTIFIC FOUNDATIONS OF MODERN ENERGY-SAVING TECHNOLOGIES OF GAS CLEANING WITH THE USE OF IMMOVABLE, MOVING, AND FLUIDIZED BEDS
A. F. Dolidovich UDC 541.183.26:66.096.5:66.074
Some results of theoretical and experimental investigations on the hydrodynamics of immovable, gravitationally
moving, and fluidized beds of catalysts and adsorbents and the heat and mass transfer in them are presented.
The mechanical, structural, physical, and chemical properties of these catalysts and adsorbents as well
as their adsorption, catalytic, and regeneration characteristics are considered. Correlations for calculating a
number of parameters of the indicated substances are presented, and the schemes and principles of operation
of gas-cleaning systems developed on the basis of the investigations performed are described.
Keywords: adsorbents, catalysts, volatile organic substances, dust, immovable, moving, and fluidized beds, gascleaning
systems.
KINETIC THEORY OF TRANSFER PROCESSES MODELING OF FLOWS IN A MICROCHANNEL BASED ON THE BOLTZMANN LATTICE EQUATION
A. I. Tyrinov, A. A. Avramenko,
B. I. Basok, and B. V. Davydenko
UDC 532.5:536.24
An approach to the analysis of micro- and macroflows with the use of the method of Boltzmann lattices is
considered. The velocity profiles of flows in the entry sections of microchannels under no-slip and slip conditions
on the wall have been obtained. The influence of the Knudsen number on the hydrodynamic entrance
length of a microchannel and its hydrodynamical resistance have been analyzed.
Keywords: hydrodynamics, micro- and macroflows, lattice Boltzmann method, no-slip and slip microchannels.
HYDROLYSIS OF AQUEOUS-ALKALINE SOLUTIONS OF SODIUM BOROHYDRIDE. ASYMPTOTICS OF LOW CONCENTRATIONS OF THE ALKALI
S. I. Shabunya and A. A. Nesteruk UDC 543.637:546.271-386
Distinctive features of modeling the kinetics of the hydrolysis of aqueous-alkaline solutions of sodium borohydride
taking account of the change in the pH of the solutions investigated are described.
Keywords: sodium borohydride, hydrolysis, degree of hydrolysis, hydrolysis constant, kinetics.
ADHESIVE INTERACTION OF ELASTICALLY DEFORMABLE
SPHERICAL PARTICLES
E. N. D’yachenkoa and J. G. Dueckb UDC 537.211:539.61
Two spherical particles that attract each other by van der Waals volume forces and can undergo deformation
as a result of the attraction are considered. Small deformations of such particles can be described by the solution
of the Hertz problem. The deformation of particles, in turn, alters the force of attraction between them.
It has been established that the relationship between the adhesion and elasticity of the indicated particles is
determined by the degree to which these particles deform and that the adhesion force acting between the particles
depends on their elasticity, size, and the Hamaker constants.
Keywords: van der Waals forces, Hertz problem, spherical particles, elasticity, adhesion, attraction and deformation
of particles.
HYDROGASDYNAMICS IN TECHNOLOGICAL PROCESSES ON THE BASICALLY SINGLE-TYPE EXCITATION SOURCE OF RESONANCE IN THE WIND TUNNEL AND IN THE HYDROTURBINE CHANNEL OF A HYDRAULIC POWER PLANT
R. K. Karavosov and A. G. Prozorov UDC 533.6.071.4;621.51:534
We have investigated the spectra of pressure pulsations in the near field of the open working section of the
wind tunnel with a vortex flow behind the tunnel blower formed like the flow behind the hydroturbine of a hydraulic power plant. We have made a comparison between the measurement data for pressure pulsations and the air stream velocity in tunnels of the above type and in tunnels in which a large-scale vortex structure
behind the blower is not formed. It has been established that the large-scale vortex formation in the incompressible medium behind the blade system in the wind tunnel is a source of narrow-band acoustic radiation
capable of exciting resonance self-oscillations in the tunnel channel.
Keywords: self-oscillations, acoustic radiation, wind tunnel, vortex structure, blower, hydroturbine, hydroacoustic
resonance, ring vortex, self-excitation, sound level meter.
EXPERIMENTAL AND THEORETICAL STUDIES OF THE INFLUENCE OF PULSE PRESSURE OSCILLATIONS ON THE PROCESSES OF MICROHEMOCIRCULATION
S. N. Bagayev,a V. N. Zakharov,a V. A. Orlov,a
S. V. Panov,a A. V. Fedorov,b V. M. Fomin,b
and T. A. Khmel’b
UDC 532.546
The influence of pulse pressure oscillations on the processes of transcapillary exchange in the hemodynamics
has been investigated by experimental and numerical methods. The active role of microvessel walls in the
mass transfer has been confirmed. On the basis of the generalized nonstationary Starling scheme patterns of
transcapillary exchange with alternation of the filtration and reabsorption processes have been determined.
Flows in the interstitial space have been modeled numerically. It has been established that the presence of
pulsations promotes enhancement of the transcapillary exchange.
Keywords: hemodynamics, transcapillary exchange, experiment, numerical modeling.
EXPERIENCE IN DEPOSITING CARBON COATINGS BY THE GAS-JET METHOD
V. A. Volodin,a A. A. Emel’yanov,b A. K. Rebrov,b
N. I. Timoshenko,b and I. B. Yudinb
UDC 537.534.2
The gas-jet deposition of carbon and diamond-like films on a substrate with precursor gas activation by a hot
wire mesh has been studied experimentally. Several designs of the wire activator for depositing films from a
gaseous mixture of CH4, H2, and Ar have been tested. The carbon structure of obtained films was determined
by Raman spectroscopy.
Keywords: gas-jet deposition, thermal activators, carbon films, Raman spectroscopy.
CONTINUOUS CHEMICAL HF LASER WITH A MODIFIED RADIALLY EXPANDING
NOZZLE UNIT
I. A. Fedorov, Yu. P. Maksimov, V. K. Rebone′,
N. E. Tretiyakov, and A. L. E′tsina
UDC 621.378:535
We have determined experimentally the energy and spectral characteristics of a supersonic continuous
chemical HF laser (oscillator) with a modified radially expanding nozzle unit operating according to the
"nozzle–injector–injector" scheme of mixing reactants based on a new method of obtaining oxidizing gas.
The practical realization of measures to decrease the heat loss and the loss of fluorine atoms, as well as
the optimization of the mode of operation of the modified laser, permitted a 30% increase in its radiation
power compared to the base oscillator equipped with a nozzle unit operating according to the "nozzle–injector"
mixing scheme. Ways of further enhancement of the energy characteristics of the HF laser radiation
are proposed.
Keywords: HF laser, nozzle unit, heat loss, energy and spectral radiation parameters.
DYNAMICS OF INTERACTION OF EROSION PLASMA COUNTERFLOWS
P. P. Khramtsov, O. G. Penyazkov,
V. M. Grishchenko, and I. A. Shikh
UDC 533.9.082.5; 537.523.2
The results of investigation of the dynamics of interaction of two erosion plasma counterflows in a free space
and in a confined volume have been given. It has been shown that the confinement of the interaction region
of the plasma flows makes it possible to increase the bulk energy density and the lifetime of the cumulative
zone.
Keywords: cumulative zone, plasma, erosion plasma accelerator.
DISTINCTIVE FEATURE OF SELF-OSCILLATIONS
(SURGING) OF IMPELLER PUMPS
V. V. Gotsulenkoa and V. N. Gotsulenkob UDC 621.65.001:532.595.7
It has been established experimentally and confirmed analytically that before the stall of a centrifugal impeller pump, self-oscillations (surging) of the pump are set up in the region of ascending cavitation branchings of its monotonically decreasing head characteristic. Beyond this region, the pumping mode of such a pump is absolutely stable. It has been established that changes in the nonstationary operation of a centrifugal impeller pump produced by variation of its wave resistance are diametrically opposite in character in cavitation and cavitation-free modes.
Keywords: self-oscillations, surging, pump stall, cavitation branchings, cavitation-free pump operation.
ANALYSIS OF THE REGIMES OF CONTROLLING TRANSIENT PROCESSES IN PIPELINES
K. R. Aidazadea and D. A. Asadovab UDC 622.692.42
This paper considers the problem of optimal control of the process of going from one stable regime to another
in piping the hydrocarbon raw material. We have investigated the influence of the transient period on
the dissipation factor of the system, the length of the part of the pipeline, and the difference between the parameters
of the initial and final stable regimes with account for the technological limitations set on the control
actions and phase variables. The dependence of the optimal transient period on the class and range of
permissible control functions, the process parameter, and its initial and final regimes has been analyzed.
Keywords: pipeline, control actions, stable regime, dissipation factor.
HEAT AND MASS TRANSFER IN COMBUSTION PROCESSES ON THE PROBLEM OF DECREASING SELF-OSCILLATIONS OF VIBRATING COMBUSTION
V. V. Gotsulenko and V. N. Gotsulenko UDC 629.7:533.6.001
It has been shown that the self-oscillation amplitude can be decreased by changing the parameters weakening
its mechanisms, which can be used for controlling this nonstationary phenomenon.
Keywords: self-oscillations, limiting cycle, amplitude control, vibrating combustion.
CONDITIONS AND DELAY TIME OF IGNITION OF IRON MICROPARTICLES IN OXYGEN
V. V. Leshchevich,a O. G. Penyazkov,a A. V. Fedorov,b
A. V. Shul’gin,b and J.-C. Rostaingc
UDC 662.612.32
Experiments on autoignition and combustion of iron microparticles in oxygen have been conducted. The parameters
of the gas medium were created using a rapid-compression machine. Investigations have been carried
out on powders with particle size from 20 to 125 μm at an oxygen pressure of to 28 MPa and a
temperature from 650 to 1100 K. The ignition delay was measured by recording radiation from the lateral
wall of the combustion chamber and determining the pressure on the end wall. Autoignition conditions have
been represented as the dependences of the oxygen density and pressure at the end of the compression stroke
on the temperature and the particle size. A point semiempirical mathematical model making it possible to satisfactorily
describe experimental data on the dependence of the delay time of ignition of a microparticle fill
on the oxygen temperature has been proposed.
Keywords: fine metal particles, rapid-compression machine, till, ignition-delay time, mathematical modeling.
ANALYSIS OF MOMENTUM CHARACTERISTICS OF THE MINIENGINE OF A MICROELECTROMECHANICAL SYSTEM OPERATING ON A SOLID MIXED PROPELLANT
S. I. Futkoa, V. P. Bondarenko,b
and L. N. Dolgiib
UDC 662.612.2,662.311.1
A self-consistent problem relating combustion parameters of a solid propellant in a miniengine of the microelectromechanical
system to the engine’s structural characteristics is solved. The dependence of the pressure
in the combustion chamber of this engine on the combustion rate of the propellant in it and the engine’s
outlet diameter is determined. Recommendations are formulated for the choice of the composition of a mixed
solid propellant based on glycidyl azide polymer doped with nitramines and for the geometry of the combustion
chamber of the above miniengine, which provide the required values of its total momentum and the propulsive
force.
Keywords: microelectromechanical system, solid-propellant rocket mini-engine, combustion of a solid mixed
propellant, glycidyl azide polymer, nitramines, propulsion momentum.
HEAT CONDUCTION AND HEAT TRANSFER IN TECHNOLOGICAL PROCESSES
RADIATIVE-CONDUCTIVE HEAT TRANSFER IN A SEMITRANSPARENT COMPOSITE
WITH MICROSPHERICAL PARTICLES
A. L. Burka and A. A. Emel’yanov UDC 536.244
A mathematical model for calculating the temperature field in a semitransparent composite material that includes
a polymethyl methacrylate matrix and quartz microspheres is suggested. In calculating the optical
properties of the composite material, use was made of the optical properties of the matrix and of the interacting
quartz microspheres at different filling factors which characterize the volume concentration of particles
in the matrix. Allowance for the interaction between the composite components is made following the Maxwell–
Garnett approximation. Data on the complex refractive index of the composite were used for calculating
the coefficients of absorption, scattering, and attenuation of packed particles by the Mie theory. The temperature
fields in a layer of the material are found from solving the boundary-value problem for the energy equation
and a system of radiation transfer equations with the use of these coefficients.
Keywords: composite, filling factor, refractive index, coefficients of absorption and scattering, permittivity, temperature.
CALCULATION OF THE PROCESS OF VACUUM DRYING OF A METAL-CONCRETE CONTAINER WITH SPENT NUCLEAR FUEL
Yu. E. Karyakin,a S. A. Lavrent’ev,b N. V. Pavlyukevich,c
A. A. Pletnev,d and E. D. Fedorovichd
UDC 621.039.743
An algorithm and results of calculation of the process of vacuum drying of a metal-concrete container intended
for long-term "dry" storage of spent nuclear fuel are presented. A calculated substantiation of the initial
amount of moisture in the container is given.
Keywords: nuclear fuel, "dry" storage, metal-concrete container, vacuum drying, capillary effect.
INFLUENCE OF COOLING CONDITIONS ON THE LOCAL PARAMETERS OF HEAT AND MASS TRANSFER IN CONDENSATION HEAT-UTILIZATION UNITS
V. A. Borodulya, V. L. Malevich,
and A. E. Sinkevich
UDC 621.182/.184:536.24
Based on the earlier developed model of calculation of the local parameters of heat and mass transfer in deep cooling of flue gases (a vapor-gas mixture) in a bundle of tubes of a condensation heat-utilization unit, the distribution of the parameters of a condensing vapor-gas mixture both along the length of the tubes and in the depth of the tube bundle in a crossflow under various cooling conditions corresponding to the working parameters of heat-utilization units at industrial thermoelectric plants (TEP) and in boiler houses has been
obtained. A comparison of the calculated values of the heating efficiency of the indicated heat-utilization unit with the results of tests of the condensation heat-utilization unit at the Ul’yanovsk TEP-3 (Russia) has demonstrated their satisfactory agreement.
Keywords: heat and mass transfer, condensation, heat utilization.
NUMERICAL SIMULATION OF WELDING DISTORTION IN THIN PLATES
A. H. Monfared UDC 669.1
A three-dimensional model based on the finite-element method is developed to simulate the temperature
field and stress distribution in the welding and heat-affected zones during fusion welding of thin plates.
The governing equations are solved using the SYSWELD program commercial code. The model’s predictions
are tested and verified against the experiments. Angular distortion and longitudinal bending are measured,
the results are compared with those obtained from the mathematical model, and a relatively good
agreement between them is found. The verified model is used to evaluate the effects of various parameters
on the temperature and stress distributions in the welding and heat-affected zones of a thin austenitic stainless
steel plate.
Keywords: welding, three-dimensional finite element simulation, distortion.
DETERMINATION OF THERMOPHYSICAL PROPERTIES DETERMINATION OF HEAT TRANSFER COEFFICIENTS DURING SOLIDIFICATION OF A CASTING IN A JET
CRYSTALLIZER
V. T. Borukhov,a G. M. Zayats,a
V. Yu. Stetsenko,b and R. V. Konovalovb
UDC 519.6 + 669.715
The problem of determining heat transfer coefficients in thermal processes described by nonlinear initial boundary-value problems for heat conduction equations in a cylindrical coordinate system is considered subject to axial symmetry. An algorithm is suggested and program means are created for identifying heat transfer coefficients. A computational experiment on determining heat transfer coefficients for the AK12 alloy is carried
out, and recommendations for selecting numerical calculation parameters have been developed.
Keywords: heat transfer coefficient, jet crystallizer, identification, regularization, distributed dynamic system.
MULTIMODEL METHOD OF NONDESTRUCTIVE DETERMINATION OF THE THERMOPHYSICAL PROPERTIES OF SOLID MATERIALS
N. P. Zhukov, N. F. Mainikova,
I. V. Rogov, and E. V. Pudovkina
UDC 536.2.08
A multidimensional method of nondestructive determination of the thermophysical properties of solid materials
subjected to thermal action from a circular plane heat source of constant power is considered.
Keywords: solid materials, thermophysical properties, thermogram, mathematical model.
PHOTOEMISSION MEASUREMENTS OF TEMPERATURE IN PULSED LASER HEATING OF VARIOUS MATERIALS
K. N. Kasparov, G. D. Ivlev,
L. I. Belozerova, and E. I. Gatskevich
UDC 536.46
The possibilities for the photoemission method of measuring the temperature of various materials heated by
millisecond laser pulses have been investigated. The temperature of graphite, tungsten, tantalum, silicon
plates, and silicon dioxide films was determined experimentally with a time resolution of 1 μs within the
range 1200–2900 K.
Keywords: temperature measurement, photoemission method, speed of response, laser irradiation.
MISCELLANEA
USE OF NONLINEAR EFFECTS IN ENGINEERING
Rs. I. Nigmatulin, V. V. Politov,
and K. A. Keivsar
UDC 530.182, 53.06
The results of investigations into the use of effects produced with hydrodynamic oscillators for solution of certain
engineering problems have been presented.
Keywords: nonlinear wave mechanics, amplitude-frequency characteristic, resonator, ultrafiltration, emulsion,
suspension.
EFFECTS OF MASS TRANSFER ON FLOW PAST AN IMPULSIVELY STARTED INFINITE VERTICAL PLATE WITH NEWTONIAN HEATING AND CHEMICAL
REACTION
V. Rajesh UDC 536.25
An exact solution to the problem of flow due to the impulsive motion of an infinite vertical plate in its own
plane in the presence of i) species concentration, ii) Newtonian heating at the plate, and iii) first-order
chemical reaction has been derived by the Laplace transform technique. The influence of various parameters
entering into the problem on the velocity field and skin friction for both air and water in the cases of both
cooling and heating of the plate is discussed.
Keywords: natural convection, incompressible fluid, heat and mass transfer, Newtonian heating, chemical
reaction.
ELECTROMAGNETIC EFFECTS ON RAYLEIGH SURFACE WAVE PROPAGATION IN A HOMOGENEOUS ISOTROPIC THERMO-MICROSTRETCH ELASTIC HALF-SPACE
S. Shaw and B. Mukhopadhyay UDC 536.21
This paper deals with the problem of electromagnetic effect on the propagation of Rayleigh surface waves in
a homogeneous, isotropic, thermally-conducting microstretch elastic half-space. In this context, the generalized
theory of thermoelasticity is considered. The governing equations for the Rayleigh surface waves in the cases
of insulated as well as isothermal boundaries are derived. In the presence of the magnetic effect, the analytical
expressions for the displacement, microrotation, microstretch, and temperature changes are obtained. The
changes in the phase velocity, microrotation, and path of particles for aluminum epoxy material are presented
graphically.
Keywords: Rayleigh surface wave, electromagnetic effect, microrotation, microstretch.
SUBSTANTIATION OF THE RANK MEASURE AS AN EFFICIENT STATISTIC FOR ESTIMATING PARAMETERS OF DISTRIBUTION OF ARBITRARY FORM
E. V. Chernukho UDC 519.23:53.089.6
A formal substantiation (using only theoretical-statistics tools) of the rank measure as the basis of an efficient
algorithm for estimation of any parameters of an arbitrary probability distribution has been proposed. The estimation
efficiency is maximum for distributions of any form. Going beyond the scope of the canons of mathematical
statistics is the generalization of the concept "median."
Keywords: rank measure, estimation of parameters, repetitive experiment, generalized median.