HEAT AND MASS TRANSFER IN POROUS AND DISPERSED SYSTEMS
PHYSICOCHEMICAL BASES OF AUTONOMOUS MAINTENANCE
OF HUMIDITY AND TEMPERATURE IN CLOSED SPACES
Yu. I. Aristov,b L. L. Vasiliev,a I. S. Glaznev,b
L. G. Gordeeva,b A. S. Zhuravlev,a, M. N. Kovalevaa
An inexpensive adsorption humidistat working in the static and dynamic regimes is proposed. This humidistat
is designed for maintenance of the relative humidity and temperature in a closed space at levels (15–
18%, 20–25oC) necessary for reliable storage of rare books, manuscripts, pictures, and museum valuables
and for their safe transportation in the process of visiting exhibitions. Principles of maintenance of the relative
humidity in a closed space with the use of chemical substances and autonomous thermostatting of this
space are considered. Results of testing of some new moisture buffers under laboratory and real conditions
Keywords: storage of rare books, manuscripts, pictures, and exhibits, humiddistat, microclimate, thermo- and
THERMAL MANAGEMENT OF THE ADSORPTION-BASED
VESSEL FOR HYDROGENEOUS GAS STORAGE
L. L. Vasiliev, L. E. Kanonchik, and V. A. Babenko
Thermal management is a design bottleneck in the creation of rational gas storage sorption systems. Inefficient
heat transfer in a sorption bed is connected with a relatively low thermal conductivity (0.1–0.5 W/(m⋅K))
and an appreciable sorption heat of activated gas storage materials. This work is devoted to the development
of a thermally regulated onboard system of hydrogenous gas (methane and hydrogen) storage with the use of
novel carbon sorbents. A hydrogenous gas storage system based on combined gas adsorption and compression
at moderate pressures (3–6 MPa) and low temperatures (from the temperature of liquid nitrogen of about 77
K to a temperature of 273 K) is suggested.
Keywords: hydrogenous gas, storage vessel, heat pipe, sorbent, carbon fiber, metal hydride, numerical modeling.
FLUID FILTRATION IN A POROUS MEDIUM
WITH WELLS WITH VERTICAL HYDRAULIC
FRACTURE OF THE FORMATION
A. Ya. Davletbaev
Consideration is given to the problem on propagation of a pressure field in a low-permeability porous medium
with two wells that are connected by a technogenic hydraulic fracture. The approximate numerical solution
of this problem is obtained; an analysis of the influence of the above fracture on the system’s
parameters is made; responses of the pressure in a well are modeled. The inverse problem is solved with the
numerical model developed, and the system’s parameters are evaluated from the field data measured in the
process of hydrodynamic investigation by the method of pressure interference testing.
Keywords: technogenic hydraulic fracture, well, filtration, porous medium, low-permeability reservoir, pressure
NUMERICAL METHOD OF SOLVING THE INVERSE
PROBLEM OF WATER–OIL PLUG DISPLACEMENT
FROM AN OIL POOL
Kh. M. Gamzaev
The inverse problem on the recovery of a boundary regime in the process of water–oil plug displacement
from an oil pool by the given law of motion of the boundary between the liquids is considered. Applying the
methods of rectification of fronts and difference approximation, the problem posed is reduced to two difference
problems. A computational algorithm for solving the resulting problems is suggested.
Keywords: oil pool, plug displacement, inverse boundary problem, method of rectification of fronts, difference
ON THE LONGEVITY AND STRENGTH
OF ICE-CONTAINING MATERIALS
A. A. Konovalov
It has been shown that there exist two failure mechanisms (brittle and ductile) of the frozen ground connected
with the phase transition of the ground moisture. For both failure mechanisms, formulas for the longevity and
long-term strength of the ground, including that with variable load and temperature, have been obtained. For
the first time the quantitative expression for the pressure and temperature conditions determining the prevalence
of one of these mechanisms has been obtained.
Keywords: longevity, strength, frozen ground, ice, failure, strain.
COMPLEX HEAT EXCHANGE IN THE PROCESS
OF FILTRATION IN A GRANULAR BED
Yu. S. Teplitskii,a E. A. Pitsukha,b and D. G. Belonovicha
Simple generalized equations for calculating the temperature field in a high-temperature ring granular bed,
the critical height of this bed, and its resistance have been obtained on the basis of a heat-exchange model
accounting for the radiative heat transfer.
Keywords: ring granular bed, heat-exchange model, radiative heat transfer, air heater, low-power, boiler.
INVESTIGATION OF FLOWS IN A VORTEX-BED CHAMBER
E. A. Pitsukha,a Yu. S. Teplitskii,b and V. A. Borodulyab
Swirling flows in a vortex chamber of diameter 0.393 m with a granular bed on a gas-distribution grate and
a bottom blow were experimentally investigated. The structure of a swirling flow and the influence of a
granular bed on this flow were determined. Equations for calculating the main characteristics of a swirling
air flow in the indicated chamber with an immovable granular bed and a bottom blow have been derived.
Keywords: vortex-bed chamber, bottom blow, granular bed, gas-distribution grate, tangential velocity, longitudinal
velocity, drag of the chamber.
MODELING AND EXPERIMENTAL INVESTIGATION
OF THE HEAT AND MOISTURE TRANSFER
IN THE PROCESS OF MICROWAVE-CONVECTIVE
DRYING OF VEGETABLE MATERIALS
P. V. Akulich,a A. V. Temruk,b
and A. V. Akulichc
This paper discusses the results of mathematical modeling of the interrelated processes of heat and moisture
transfer in vegetable materials in the process of their convective drying with the use of microwave radiation
and of experimental investigations of the influence of the operating parameters of the process on the drying
dynamics and kinetics.
Keywords: heat and moisture transfer, drying, drying kinetics and dynamics, vegetable materials.
INFLUENCE OF CATALYTICITY OF A POROUS
MEDIUM ON THE CONCENTRATION LIMIT
OF FILTRATION COMBUSTION OF A WATER-ORGANIC
MIXTURE IN A REVERSIBLE FLOW REACTOR
K. V. Dobrego and I. A. Koznacheev
The problem on oxidation purification of water in a reversible flow reactor with the use of a catalyst has
been studied by numerical methods. We have made comparative studies of the concentration limits of mixture
combustion attained in inert and catalytic porous media reactors at varied values of the liquid flow rate, the
reactor length, the heat loss coefficient, and the size of the packed bed. It has been established that the use
of a catalyst leads to an insignificant decrease in the concentration limit: 11.6% against 13.4% (adiabatic
case) and 12.5% against 13.9% (standard insulation).
Keywords: water purification, filtration combustion, modeling.
HEAT AND MASS TRANSFER IN COMBUSTION PROCESSES
FORMATION OF DETONATION IN A PULSE
COMBUSTION CHAMBER WITH A POROUS
Kh. Alhussan,a M. S. Assad,b
O. G. Penyazkov,b and K. L. Sevrukb
A study has been made of the influence of a porous obstacle on deflagration-to-detonation transition in a
pulse combustion chamber of small length. Dependences of the detonation-wave velocity on the distance have
been obtained for two samples of a porous material (steel spheres and a ceramic porous body). It has been
shown that the use of an insert from a porous material leads to a reduction of 40% in the predetonation distance
without changing substantially the structure of the pulse combustion chamber.
Keywords: deflagration-to-detonation transition, porous obstacle, detonation velocity, thrust.
THERMODYNAMIC SUBSTANTIATION OF THE EXISTENCE
OF A PHASE TRANSITION POINT WITH A CHANGE
IN THE STRUCTURE OF THE SOLID-FUEL MIXTURE
GLYCIDYL AZIDE POLYMER/RDX
S. I. Futko
UDC 662.612.2, 662.311.1
With the help of thermodynamic calculations for a wide range of solid-fuel mixtures glycidyl azide polymer
(GAP)/RDX with a component ratio from 100% GAP/0% RDX to 0% GAP/100% RDX we have found a
structural transition point corresponding to a mixture of 60.8 mass % of RDX in GAP at which a sharp
change in the trend of thermodynamic combustion characteristics of these mixtures occurs. The given point is
determined from the condition of equality of molar fractions of C and O atoms in the above mixtures. It is
pressure-independent, corresponds to the minimum point on the curve of the rate of combustion of the mixture
as a function of its composition and to the structural change in the solid-fuel mixture GAP/RDX from amorphous
to polycrystalline, and is a phase transition point.
Keywords: solid mixed fuel, solid fuel combustion, mathematical modeling, solid-fuel rocket engines, technologies
of microelectromechanical systems, microthruster, glycidyl azide polymer, nitramines, RDX, rate of combustion,
amorphous structure, polycrystalline structure.
MATHEMATICAL SIMULATION OF THE COMBUSTION
OF A PEAT BED. INFLUENCE OF STEAM CONDENSATION
N. N. Gnezdilov, I. M. Kozlov, and K. V. Dobrego
A model of the pyrolysis and combustion of a porous medium in the absence of forced convection is suggested.
Substantial differences between this statement of the problem and filtration combustion of gases in
inert porous media are considered. The influence of the condensation of steam contained in the products of
pyrolysis on gas filtration and the temperature field close by the combustion site is shown.
Keywords: filtration, combustion, heterophase medium, peat.
DISTINCTIVE FEATURES OF BURNING OF A SOLID BIOFUEL
IN A CYCLONE-BED FURNACE
E. A. Pitsukha,a Yu. S. Teplitskii,b and V. A. Borodulyab
A study has been made of the distinctive features of burning of a solid biofuel (wood, peat) in a cyclone-bed
furnace. The limiting values of the moisture of wood chips as received and of the mass content of milled peat
in the chip–milled peat mixture, at which the regime of its combustion is unstable, have been found. The temperature,
velocity, and pressure distribution in the indicated furnace have been established. The dependences
of the concentration of carbon and nitrogen monoxides on the excess air in exhaust gases in burning lump
wood and crushed peat briquettes have been established.
Keywords: cyclone-bed furnace, air-heater boiler, combustion chamber, afterburner section, bottom blowing,
tangential blowing, excess air, carbon monoxide, nitrogen monoxide, temperature in the furnace, moisture of the
fuel as received.
IMPROVEMENT OF THE SERVICE PROPERTIES
OF ELASTOMER COMPOSITIONS BY INTRODUCTION
OF CARBON NANOMATERIALS
K. V. Vishnevskii,a Zh. S. Shashok,a N. R. Prokopchuk,a
A. V. Krauklis,b and S. A. Zhdanokb
The influence of a carbon nanomaterial obtained in a high-voltage discharge plasma on the endurance of
elastomer compositions has been investigated for the first time. The results of these investigations agree with
those obtained in determining the parameters of the vulcanization kinetics, conventional tensile strength, relative
breaking elongation, and resistance to thermal aging and swelling in liquid hydrocarbon media of highly
filled rubbers based on butadiene-nitrile caoutchoucs. To verify the assumed mechanism underlying the action
of a carbon nanomaterial on elastomer compositions, the parameters of their vulcanizing network have been
determined using the method of equilibrium swelling. It is shown that the introduction of a carbon nanomaterial
into polar caoutchouc-based rubber allows one to substantially improve its service characteristics and
Keywords: endurance, activation energy of thermal-oxidation dehydration, service characteristics, butadiene-nitrile
caoutchouc, rubber, carbon nanomaterials, nanotubes, nanofibers.
SIZE EFFECTS DURING PHASE
TRANSFORMATIONS IN NANOOBJECTS
V. Levdanskii,a J. Smolik,b and V. Zdimalb
The joint influence of size effects connected with physicochemical processes both on the surface of nanoobjects
and in their volume on the phase transformations taking place in them has been investigated theoretically.
The joint manifestation of the surface and volume size effects has been analyzed using as an example
the growth of silicon nanowhiskers.
Keywords: size effects, nanoobjects, phase transitions, nanowhiskers.
NANOSTRUCTURES OF AIVBVI COMPOUNDS
FOR THERMOELECTRIC CONVERSIONS
D. M. Freik, L. I. Mezhylovskaya, I. K. Yurchishin,
Yu. V. Lysyuk, and A. I. Tkachuk
UDC 53.072.001.57; 537.222.2
On the basis of the theoretical model of a quantum well with infinitely high walls the dependences of the
thermoelectric parameters of nanostructures of lead chalcogenides PbTe, PbSe, and PbS on their thickness
have been investigated. It has been found that the Seebeck coefficient of such structures changes nonmonotonically
with the width of the corresponding quantum well. Comparison has been made between the theoretical
and experimental dependences of the Seebeck coefficient of the above nanostructures on their thickness for
the oscillation period of these dependences, and the Fermi energy for such structures has been determined. It
has been shown that the minimum width of the quantum well at which the first energy level of the considered
nanostructures coincides with the Fermi level is equal to the oscillation period of their Seebeck coefficient.
Keywords: nanostructure, quantum-dimensional effects, lead chalcogenides.
HEAT CONDUCTION AND HEAT TRANSFER IN TECHNOLOGICAL PROCESSES
NEW MODEL REPRESENTATIONS OF DYNAMIC
THERMOVISCOELASTICITY IN THE PROBLEM
OF HEAT SHOCK
E . M. Kartashov
A theory of dynamic thermoviscoelasticity in the problem on heat shock has been developed. New integral relations
for dynamic thermoviscoelasticity have been obtained on the basis of the determining dynamic-thermoelasticity
equations and the Maxwell and Kelvin linear rheological models. The expressions obtained can
be used in different scientific and technological practical applications.
Keywords: heat shock, dynamic thermoviscoelasticity of a solid body, heat action.
NUMERICAL MODEL OF THE TEMPERATURE
CONDITIONS OF THE HORIZONTAL GROUND
B. I. Basok, B. V. Davydenko, and A. A. Lunina
A numerical method for solving the problem of heat transfer in the ground mass with a horizontal ground
collector embedded in it is proposed. Using calculations on an acting ground heat exchanger of the type of
a ground–heat transfer medium of a heat-pumping plant as an example, we have determined the operating
temperature conditions of the above collector.
Keywords: ground collector, horizontal ground heat exchanger, heat-pumping plant.
SOLUTION OF NONSTATIONARY PROBLEMS OF CONTACT
MELTING IN BINARY EUTECTIC SYSTEMS WITHOUT
MUTUAL SOLUBILITY IN THE SOLID STATE
M. K. Zhekamukhov and F. B. Zholaeva
UDC 541.123.7; 669.017.3
The criteria of quasi-stationarity of the processes of diffusion of atoms in the liquid interlayer formed during
contact melting of solid bodies in an eutectic system have been established. The conditions of phase transformation
of the crystals that form the eutectic pair have been formulated with account for their densities. It is
shown that the boundaries of phase transformation of these crystals move by the parabolic law under the conditions
of the quasi-stationary nature of diffusion processes in a melt.
Keywords: contact melting, binary eutectic systems, diffusion of atoms in a melt, liquid interlayer.
HYDROGASDYNAMICS IN TECHNOLOGICAL PROCESSES
CRISIS OF A VORTICITY SOURCE DURING HEAT
SUPPLY WITH REGARD TO THE REAL PROPERTIES
OF A DIATOMIC GAS
A. N. Kucherov
On the example of a diatomic gas consisting of a mixture of nitrogen and oxygen (air), the characteristics of
energy-consuming vorticity source flow were investigated, with the dependence of heat capacity on temperature
being taken into account. The statement of this problem undergoes a change if account is taken of the
dependence of heat capacity and adiabatic index on temperature in the range from several hundred to several
thousand degrees Kelvin (a calorically nonideal gas). The phenomenon of a thermal crisis, that is, choking of
a stationary flow on attainment of unity by the radial component of the Mach number, was studied. The characteristic
dimensions of the heating region and the characteristic time of heating have been determined. Estimations
of the error incurred in a model of an ideal gas with constant heat capacity and adiabatic index
have been made. The dependences of the characteristics of the vorticity source on the gas circulation and
flow rate, as well as on the position of the energy supply region and its extension were investigated.
Keywords: vorticity source, heat capacity of a diatomic gas, circulation, flow rate, energy supply, Mach number,
LOCALIZATION OF THE POINTS OF LEAKAGE
IN AN OIL MAIN PIPELINE UNDER NONSTATIONARY
K. R. Aida-zadea,b and E. R. Ashrafovab
Within the framework of the theory of optimal control, problems on the localization of the points of oil leakage
from a transport pipeline system and on the determination of the rate of these leakages were investigated.
Analytical formulas for the gradient of the functional that determines the deviation of oil flow conditions at
the given points of a pipeline section from the calculated ones were obtained. These formulas allow one to
use numerical methods of first-order optimization for solving the problem posed. Some results of numerical
experiments are given.
Keywords: optimal control, point of leakage, leakage rate, gradient of a functional, lumped source.
SEMIEMPIRICAL METHOD FOR ESTIMATING
THE NOISE OF A PROPELLER
V. F. Samokhin
A semiempirical method for estimating the noise of a propeller on the basis of the Lighthill analogy is proposed.
The main relations of the computational model for the acoustic-radiation power have been obtained
from a dimensional analysis of the general solution of the inhomogeneous wave equation for the pulsed
acoustic radiation from a propeller. A comparison of the calculation and experimental data on the acousticradiation
power and the one-third octave spectra of the sound pressure of four- and eight-blade AV-72 and
SV-24 propellers is presented.
Keywords: aircraft noise, propeller noise, airplanes.
NUMERICAL MODELING OF ELECTRO-VORTICAL
FLOWS IN A CONFINED VOLUME
O. V. Kazak and A. N. Semko
The electro-vortical flow of a metal melt in a confined volume has been investigated for various electromagnetic
and hydrodynamic regimes. The melt motion was described by magnetic hydrodynamic equations for an
incompressible isothermal fluid. A strategy for solving the problem with the use of standard packages of applied
programs has been developed. The laminar flow of the melt at small Reynolds numbers, for which there
is a known solution, as well as the turbulent flow, for which there are experimental data, have been calculated.
In calculating the turbulent flow, various turbulence models were used. It has been shown that the
k–ε and k–ω models describe satisfactorily the electro-vortical flow of the melt and agree well with experimental
data. The good agreement between the results of calculations made with the use of various methods
and packages of applied programs, as well as between theoretical and experimental data, point to the reliability
of the developed methods and approaches and the validity of the obtained results.
Keywords: Lorentz force, turbulent electro-vortical flow, numerical simulation.
MAGNETOGASDYNAMIC SHOCK WAVES
IN A NONIDEAL GAS WITH HEAT CONDUCTION
AND RADIATION HEAT FLUX
K. K. Singh and B. Nath
The purpose of this study is to obtain a self-similar solution of the problem of propagation of a magnetogasdynamic
shock wave in a nonideal gas with heat conduction and radiation heat flux in the presence of a spatially
decreasing azimuthal magnetic field strength. The initial density of the medium is assumed to be
constant. The heat conduction is expressed in terms of Fourier’s law, and the radiation is considered to be
of a diffusion type for an optically thick gray gas model. The thermal conductivity and absorption coefficients
are assumed to vary with temperature and density. The shock is assumed to be driven by a piston moving
with a variable velocity. Similarity solutions are obtained, and the effects of variation of the gas nonidealness
parameter and Alfven–Mach number on the flow field behind the shock are investigated.
Keywords: shock wave, magnetogasdynamics, nonideal gas, self-similar flow, heat transfer effects.
TRANSFER PROCESSES IN LOW-TEMPERATURE PLASMA
ADIABATIC EXPANSION OF CLUSTERING CARBON PLASMA.
N. I. Alekseev,a,b B. I. Reznikov,a B. G. Zhukova,
S. V. Bobashev,a and K. V. Tverdokhlebova
UDC 532.525, 537.523
Self-consistent calculation of the stationary problem on radially symmetric adiabatic expansion of low-intensity
carbon plasma has been performed. The initial conditions for plasma expansion correspond to the conditions
of the outlet cross-section of the electromagnetic rail plasma accelerator — the railgun. In the course of solving
the problem, we determine the temperature, pressure, and concentration of plasma components, as well as
of carbon clusters, beginning from the moment at which the clusterization becomes substantial. It has been
shown that a small part of the flow of carbon atoms (less than 1%) is subjected to clusterization in a wide
range of conditions, and the process of clusterization itself proceeds in a narrow three-dimensional layer. Beyond
this layer the percentage of carbon atoms transforming to clusters remains almost the same, and the
rate of decrease in the temperature with the coordinate drops considerably as compared to the rate before the
beginning of clusterization. The results of the calculation have been compared with the results of the essentially
similar calculation of the carbon clusterization under the conditions of a fullerene arc.
Keywords: railtron, rail accelerator, plasma jet, carbon clusters.
DRIFT MODEL OF A GLOW DISCHARGE WITH ACCOUNT
FOR THE NONLOCAL VALUE OF THE ELECTRIC FIELD
STRENGTH IN THE IONIZATION SOURCE
A. I. Saifutdinov and B. A. Timerkaev
A drift model of a glow discharge is proposed, which takes account of the nonlocal dependence of the ionization
source on the electric field strength. The problem is reduced to solving a nonlinear differential equation
of second order for the strength squared using the Newton–Kantorovich quasilinearization method.
Keywords: glow discharge, cathode region, cathode layer, negative glow, Faraday dark space, ionization
source, nonlocality of ionization processes, Newton–Kantorovich quasilinearization process.
IN ACTUAL GASEOUS SYSTEMS
A. F. Bogatyrev and M. A. Nezovitina
Interdiffusion coefficients of ten gaseous pairs have been measured as functions of pressure at different temperatures.
The measurements were performed by the two-bulb and stationary flow methods. The data obtained
have been compared to the results of calculation from the formulas of rigorous and elementary kinetic theories.
It has been shown that calculation from the formula obtained within the framework of the elementary kinetic
theory is consistent with experiment within the experimental error.
Keywords: gases, interdiffusion coefficient, experiment, molecular-kinetic theory.
SOME STATISTICAL CHARACTERISTICS
OF THE ROUGH SURFACE OF HUMAN SKIN
V. V. Barun and A. P. Ivanov
UDC 535.016, 535.311, 535.36, 57.012.3, 612.79
The statistical properties of the skin surface have been described with the use of two approaches. The first
approach is based on the probabilistic description of the skin topology at a given distribution density of
rough surface heights and its correlation function. The Gaussian and quasi-periodic surfaces, whose parameters
were estimated from the literature data, have been considered. The second approach is based on the application
of the directional distribution function of microsurfaces of the skin. In the approximation of
geometric optics, the shadowing effects of surface relief elements, as applied to the human skin, have been investigated.
The changes in the probability density of heights and slopes of parts of the surface irradiated with
a directed beam due to the shadow regions have been estimated. The influence of shadowings on the electromagnetic-
field-quadratic photometric characteristics of the scattered light has been investigated. The results
obtained are of interest for solving direct and inverse problems of biomedical optics — for analyzing the radiation
fields in the biotissue and recovering its parameters by optical methods.
Keywords: skin, rough surface, reflection of light, probability density, correlation function, shadow, luminous
PLANE WAVES IN A TRANSVERSELY ISOTROPIC
ROTATING MAGNETOTHERMOELASTIC MEDIUM
Baljeet Singha and Anand Kumar Yadavb
The governing equations for a transversely isotropic rotating magnetothermoelastic medium are solved, giving
a cubic velocity equation, which is indicative of three plane waves. Some limiting cases are considered: in the
absence of anisotropy, rotation, and thermal and magnetic effects. The effects of the anisotropy, rotation, thermal
and magnetic parameters on the speeds of plane waves are shown graphically.
Keywords: anisotropic thermoelasticity, rotation, magnetic field, plane waves.
STUDY OF PLASTIC DEFORMATION OF THE SURFACE
OF AN Ni2MnGa SINGLE CRYSTAL BY THE INDENTATION
O. M. Ostrikov,a A. L. Sozinov,b and A. V. Sorokab
Distinctive features of plastic deformation of a magnetic Ni2MnGa alloy are studied by the method of local
dosed deformation. It is found that the martensite phase of an Ni2MnGa single crystals is susceptible to mechanical
twinning. Here twins represent thin lenses formed away from the imprint of the indenter.
Keywords: magnetic alloy with shape memory, plastic deformation, Ni2MnGa, Heusler alloy, twinning, indentation,