**CONDENSATION FROM A VAPOR-GAS MIXTURE**

A. P. Kryukov,a V. Yu. Levashov,a

and N. V. Pavlyukevichb

UDC 533.7:536.423

A review of the possible approaches to calculation of vapor condensation from a binary vapor-gas mixture on a surface is presented. Emphasis is paid to justification of the application of molecular-kinetic theory methods for calculation of applied problems. Quantitative estimates for the parameters of the existence in principle of the regimes of one-dimensional stationary condensation are given.

**Keywords: **molecular-kinetic theory, condensation, vapor-gas mixture, noncondensable gas, diffusion, Boltzmann

equation, condensation choking.

**NEW INTEGRAL RELATIONS FOR ANALYTICAL ****SOLUTIONS OF PARABOLIC-TYPE EQUATIONS ****IN NONCYLINDRICAL DOMAINS**

E ′

. M. Kartashov UDC 536.2.001.24

The theory of the method of Green’s functions in solving boundary-value problems of nonstationary heat conduction

in domains with moving boundaries has been developed. A modification of the thermal-potential method for a uniform law of motion of the boundary has been proposed, which leads to integral relations of a new (simplest) form compared to the existing results; this makes it possible to consider numerous particular cases that are of practical interest for many applications. A number of special features of model representations

of nonstationary heat transfer in domains with moving boundaries have been revealed.

**Keywords:** nonstationary heat conduction, thermal potentials, Green’s functions, domains with moving boundaries.

**ELECTRORHEOLOGY: FROM ITS BEGINNING TO THE PRESENT**

E. V. Korobko and A. D. Matsepuro UDC 532.135:531.202

The development of world studies in the field of electrorheology — the division of hydromechanics of liquid structuring in external electric fields — has been considered from the historical aspect. The significant contribution

and the key role of the Belarusian school of scientists founded by A. V. Luikov have been noted.

**CONCERNING THE FORMULATION OF THE IRREVERSIBILITY ****PRINCIPLE IN LOCALLY NONEQUILIBRIUM THERMODYNAMICS**

A. I. Shnip UDC 536.7

It is shown that in the existing locally nonequilibrium thermodynamic theory there are a number of paradoxes that can be interpreted as an indication that the used formulation of the second law of thermodynamics is insufficiently

complete. An additional thermodynamic postulate allowing one to remove these paradoxes and having close analogies in other thermodynamic approaches is suggested.

**Keywords: **thermodynamics, second law, locally nonequilibrium systems, heat conduction with memory, electromagnetic

field, additional thermodynamic postulate.

**NANOCLUSTER INITIATION OF COMBUSTION ****OF OFF-GRADE HYDROCARBON FUELS**

S. V. Alekseenko,a,b S. E′. Pashchenko,b

and V. V. Salomatova,b

UDC 621.311

We have performed large-scale experiments on burning, in the regime of nanocluster pulsating combustion, such off-grade fuels as straw oil, hydrocarbon fuel, exhaust crankcase waste, crude oil, and others on the laboratory prototype of the self-contained burner of the Institute of Thermal Physics, Siberian Branch of the Russian Academy of Sciences. The application of modern diagnostics has made it possible to obtain a large body of information on the features of the physicochemical processes of such combustion in the presence of superheated steam. The experimental and theoretical studies have shown that as a result of the heterogeneouscatalytic

decomposition of water molecules on soot nanoclusters in the mixing zone, high concentrations of the OH radical are formed and that this decomposition can be effective on carbon particles of size 1–5 nm at temperatures characteristic of traditional flares. The generation of an active OH radical leads to a significant

increase in the rates of chemical reactions and a stable high-temperature combustion of "heavy" fuels with

the observance of ecological norms.

Keywords: nanoparticle, cluster, combustion, off-grade fuel, burner.

**FAST PYROLYSIS OF AN ENSEMBLE ****OF BIOMASS PARTICLES IN A FLUIDIZED BED**

O. S. Rabinovich, V. A. Borodulya,

L. M. Vinogradov, and V. V. Korban

UDC 620.0+66:658.567

A combined approach to the modeling of fast pyrolysis of biomass particles in a fluidized bed has been used.

We used models of different levels: two models of pyrolysis of a single particle — with lumped and distributed parameters — and a model of pyrolysis of an ensemble of biomass particles based on the continuum equations for the gas blown through the bed and the equations of motion for individual particles. We have determined optimal (in terms of the biofuel yield) temperatures of the process for various particle sizes of wood biomass and various values of its moisture.

**Keywords:** fast pyrolysis, biomass, biofuel, pyrolysis kinetics, fluidized bed, computational hydrodynamics.

**CALCULATION OF THE KINETICS OF DRYING ****DISPERSE MATERIALS ON THE BASIS ****OF ANALYTICAL METHODS**

S. P. Rudobashta UDC 621.928.9:66.099.2:66.046

In the context of a systematic approach, the general problem of the kinetics of drying disperse materials is split into two basic levels: the micro- and macrokinetic ones, and in conformity with this, the problems of mathematical modeling of the kinetics of drying on the micro- and macrolevels are considered. The merits and drawbacks of the application of a moving and fixed coordinate systems for calculating the kinetics of drying of disperse materials in continuously operating apparatuses are discussed. A number of kinetic mathematical

models of the process of drying disperse materials in its second period are presented and analyzed.

**Keywords:** kinetics, dispersity, heat and mass transfer, moving and fixed coordinates, inhomogeneity of particles

with respect to their size and time of residence in an apparatus.

**MODELING OF SUPERHEATED-STEAM DRYING ****OF BIOFUEL IN A FLUIDIZED BED**

V. I. Kovenskii, V. A. Borodulya,

Yu. S. Teplitskii, G. I. Pal’chenok,

and D. S. Slizhuk

UDC 677.057.135.2

The drying of a dispersed material in a fluidized bed has been modeled mathematically. The dependence of the bed’s mass, which ensures a prescribed final humidity, on the regime parameters of the fluidized system

has been established. The superheated-steam drying of wood granules in a fluidized bed has been investigated experimentally.

**Keywords:** fluidized bed, biofuel, superheated steam.

**IDENTIFICATION OF MODELS AND PREDICTION ****OF PHYSICAL PROPERTIES OF HIGHLY POROUS**

**
HEAT-SHIELDING MATERIALS**

O. M. Alifanov and V. V. Cherepanov UDC 519.6:535.2:536.3

A complex procedure has been proposed, which allows determining and predicting a significant part of the physical properties of heat-shielding highly porous materials. It is based on the combination of experiment, statistical methods of mathematical modeling, methods of solving the problem of radiation transfer, and methods of identifying mathematical models in solving pertinent inverse problems. Apart from decreasing expenditures,

this approach markedly expands the capabilities of experimental methods. It allows studying and predicting components of the thermal conductivity, energy accommodation coefficient, complex refractive index

and dielectric constant, scattering indicatrix, etc. As an element of the proposed approach, an original method of numerical solution of radiation transfer in a heterogeneous plane layer has been described. The results can

be used for developing new materials and nondestructive methods of control and diagnostics, designing thermal-

protection systems, etc.

**Keywords:** highly porous materials, thermal experiments, methodology, thermal physical properties, determination

and prediction, radiation transfer, integral equation, functional minimization, conjugate-gradient method,

stabilization.

**PROBLEMS OF SIMULATING TORNADO-LIKE HEAT ****TRANSFER IN TURBULENT FLOW PAST A DIMPLED ****RELIEF ON A NARROW CHANNEL WALL**

S. A. Isaeva and A. I. Leontievb UDC 532.517.2:4:536.24

This paper analyzes the state of the art of numerical and partly physical simulation of convective heat transfer in the vicinity of dimpled reliefs on one of the walls of narrow plane-parallel channels. We show that there is a mismatch and spread of the results of these investigations, their conclusions lack substantiation, and there are "white spots" in the problems under consideration and in the methods of their investigation. Several physical experiments have been analyzed, and the correlation between the calculated predictions and measurement data has been discussed. In conclusion, the thermohydraulic characteristics of various dimpled reliefs are compared, and the advantage of oval dimples over spherical ones is demonstrated.

**Keywords: **tornado-like enhancement, heat transfer, hydraulic losses, turbulence, dimpled relief in a channel,

Menter model.

**PROBLEMS OF SIMULATING TORNADO-LIKE HEAT ****TRANSFER IN TURBULENT FLOW PAST A DIMPLED**

**
RELIEF ON A NARROW CHANNEL WALL**

S. A. Isaeva and A. I. Leontievb UDC 532.517.2:4:536.24

This paper analyzes the state of the art of numerical and partly physical simulation of convective heat transfer in the vicinity of dimpled reliefs on one of the walls of narrow plane-parallel channels. We show that

there is a mismatch and spread of the results of these investigations, their conclusions lack substantiation, and there are "white spots" in the problems under consideration and in the methods of their investigation.

Several physical experiments have been analyzed, and the correlation between the calculated predictions and measurement data has been discussed. In conclusion, the thermohydraulic characteristics of various dimpled reliefs are compared, and the advantage of oval dimples over spherical ones is demonstrated.

**Keywords:** tornado-like enhancement, heat transfer, hydraulic losses, turbulence, dimpled relief in a channel,

Menter model.

**MODELING OF THE FORMATION ****OF A VAPOR CLOUD IN A WIND ****FLOW WITH INTENSE EVAPORATION**

O. V. Golub,a G. V. Kotov,a

and S. P. Fisenkob

UDC 614.878+536.2

The stationary problem on formation of a vapor cloud as a result of evaporation above a liquefied-gas spillage under the action of the wind has been considered. It has been shown that the cloud parameters are influenced by the wind velocity, the degree of turbulence of the incident flow, and the geometric dimensions of the spillage. The results of numerical two-dimensional and three-dimensional calculations of the equation of convective diffusion with allowance for the wind-velocity profile have been presented. The effect of the Knudsen

layer above the evaporating liquid on the cloud formation is discussed.

**Keywords: **layer, turbulent diffusion coefficient, roughness size, atmospheric pressure, air temperature.

**CURRENT STATUS OF THE PROBLEM OF HEAT ****PUMPS AND REFRIGERATING DEVICES**

L. L. Vasiliev UDC 621.57

In connection with the limited energy reserves in the Republic of Belarus, it is expedient to use sorption heat pumps and refrigerators in heating and refrigeration supply systems. Such heat engines possess a unique capability of utilizing the heat of low-temperature energy sources: water ponds, groundwater, and waste water and steam in combination with traditional heaters of rooms (boilers, furnaces, etc.). Adsorption reversible heat pumps developed at the A. V. Luikov Heat and Mass Transfer Institute of the National Academy of Sciences of Belarus make it possible to obtain 20 to 30 kW ⁄ m3 of thermal energy and up to 5 kW ⁄ m3 of cold. Such heat pumps save up to 15–20% of primary energy (fuel) for production of electricity, heat, and cold.

**Keywords: **heat pumps, sorbents, secondary energy resources, evaporators, condensers.

**DEVELOPMENT OF THE THEORY AND METHODS ****FOR CALCULATING THE DYNAMICS OF SORPTION**

**
AND DESORPTION**

N. I. Nikitenko, Yu. F. Snezhkin,

and N. N. Sorokovaya

UDC 532.516:536.24

A system of equations of heat and mass transfer, phase transformations, and deformation of porous bodies in sorption and desorption are derived and substantiated. Formulas for the area of contact between a liquid and

gas in a unit volume of a porous body, for the intensity of phase transition, heat of phase transformations, equilibrium partial vapor pressure, and for the thickness of adsorbate layer on the surfaces of capillaries with

allowance for the influence of adsorption forces are presented. The results of a comparison between calculated and experimental data are given.

**Keywords:** heat and mass transfer, phase transformations, deformation, contact area of phases, thickness of adsorbate

layer.

**INFLUENCE OF FOREIGN ADSORBABLE ****GASES ON THE FORMATION OF CLUSTERS**

**
IN VAPOR–GAS SYSTEMS**

V. V. Levdanskii,a J. Smolik,b

and P. Moravecb

UDC 541.182

The influence of a foreign adsorbable gas on homogeneous and heterogeneous nucleation is investigated theoretically.

**Keywords: **adsorbable gas, phase transitions, nucleation.

**FORMATION AND CONVERSION OF CARBON ****NANOSTRUCTURES UNDER RADIATION**

G. Ya. Gerasimov UDC 541.15

Consideration has been given to the current status of research on the use of radiation techniques for synthesizing new carbon nanomaterials based on fullerenes, carbon nanotubes, and graphene sheets and their derivatives,

which are promising for practical application due to their unique properties. An analysis has been made of the existing experimental and theoretical works on studying different processes induced by the action of radiation on carbon nanostructures (melting of cross-linking carbon nanotubes and formation of molecular junctions between them, polymerization of fullerene layers, formation of new structures, radiation chemistry of fullerenes, and others).

**Keywords:** carbon nanostructures, radiation, fullerenes, carbon nanotubes, graphene sheets, electron beam, ion

beams.

**THERMAL PROPERTIES OF SEMICONDUCTOR ZINC OXIDE ****NANOSTRUCTURES**

Kh. T. Igamberdiev,a,b Sh. U. Yuldashev,a,b

S. S. Kurbanov,a,b T. W. Kang,a

P. K. Khabibullaev,b Sh. M. Rakhimova,b

V. O. Pelenovich,b and A. G. Shashkovc

UDC 536.2

A combination of two methods — laser modulation and 3ω — has been used to determine the heat capacity,

heat conductivity, and heat diffusivity of zinc oxide nanostructures. A significant difference between the thermal parameters of zinc oxide nanostructures grown by different technological methods has been revealed. It has been shown that the relatively low heat conductivity and heat diffusivity values of oxide zinc nanostructures are due to both the internal defects and the contact resistance between the film and its base — the substrate.

**Keywords: **diluted magnetic semiconductors, zinc oxide, nanostructure, heat conductivity, heat diffusivity, heat

capacity, contact heat resistance.

**DISTINCTIVE FEATURES OF OPERATION ****OF AN INTERNAL COMBUSTION ENGINE ****RUNNING ON HYDROGEN-CONTAINING FUELS**

M. S. Assad and O. G. Penyazkov UDC 536.46:533.6:621.4

Experimental investigations have been carried out on an internal combustion engine with hydrogen added to the hydrocarbon fuel, i.e., gasoline. The possibility of improving the energy and environmental indices in the

case of hydrogen feed to the engine’s air path has been shown. It has been established that increase in the fraction of hydrogen in the fuel mixture causes the operating process of the engine to improve, with the result

that the flow rate of gasoline as a function of the H2 fraction decreases by nearly 70%. Considerable reduction in the content of CO, CO2, and CH (of approximately 5–60% depending on the amount of the added

H2) is observed. However, adding hydrogen to the fuel-air mixture leads to an increase in the content of nitric oxides in the combustion products because of the growth in the velocity of propagation of the flame and

increase in the combustion temperature.

**Keywords: **hydrogen, operating process of an internal combustion engine, combustion products, fuel flow rate, elasticity of discharge, power of an engine, excess-oxidant coefficient.

**HEAT TRANSFER IN BOILING OF LIQUID ****IN A FILM MOVING UNDER GRAVITY**

I. I. Gogonin UDC 536.2.423.1

Experimental data on heat transfer in boiling in a film of liquid moving under gravity have been processed

in dimensionless coordinates. A comparison between the data on heat transfer during boiling in a film with

the data on heat transfer in pool boiling is carried out, which makes it possible to more accurately estimate

the influence of the film flow velocity and spray entrainment on heat transfer in film boiling.

**Keywords:** film flow, boiling heat transfer.