Volume 98, №2

OPTIMAL SYNTHESIS OF HEAT EXCHANGE SYSTEMS

A region of physical realizability of two- and multifl ow heat transfer has been constructed in the space of thermodynamic indicators: heat load, energy dissipation, and thermal conductivity coeffi cient. The boundary of this region is achievable in a counterfl ow displacement heat exchanger, provided the conditions placed on the fl ows′ heat capacities are observed. Using the concept of thermodynamic equivalence of a two-fl ow heat exchanger and a multifl ow system, the requirements for an optimal heat exchange system have been formulated. It is shown that the dependencies of the cold and hot fl ows′ temperatures on the heat load in an equivalent heat exchanger constructed using the suggested algorithm determine the total number of two-fl ow cells in the system, their heat loads, the heat transfer coeffi cients, entropy production, and the structure of the contacts. In this case, each hot fl ow in an optimal system can be in contact with several cold ones, and each cold fl ow can contact several hot ones. Cases of fl ow state phase variation have been considered. Limitations placed on the temperatures of all or part of the fl ows at the inlet and outlet of a heat exchange system have been taken into account. An algorithm has been suggested for selecting free parameters of fl ows, their heat capacities, boundary temperatures, and distribution of contact surfaces.
Author:  A. M. Tsirlin
Keywords:  two- and multifl ow heat exchange, heat load, energy dissipation, thermal conductivity coeffi cient, optimal heat exchange system, exergy, entropy
Page:  287

CONCENTRATION OF GERMANIUM ISOTOPES BY A MULTISTAGE SCHEME IN A RECTANGULAR CASCADE

Multistage schemes of germanium isotope concentration in a rectangular cascade with a given number of stages, feed point, fl ow of feeding the stages and the cascade are considered. A computational experiment on the separation of germanium tetrafl uoride in a cascade with large stage separation coeffi cients characteristic of gas centrifuges is carried out. The cascade calculations are performed by varying the cutoff s of partial stage fl ows with minimization of deviations of the calculated fl ows of feeding the stages from the given fl ow. For minimization, the bee colony algorithm is used, which ensures the required accuracy in determining the cascade parameters.
Author:  V. A. Palkin
Keywords:  isotope separation, rectangular cascade, gas centrifuges, germanium isotopes
Page:  302

MODELING OF SHOCK-WAVE LOADING OF GOLD AND GOLD COMPONENT-BEARING ALLOYS UP TO 1000 GPa

Numerical modeling of thermodynamic parameters of shock-wave loading of gold and alloys, containing gold as a component, has been performed using a thermodynamically equilibrium model. The model allows one to take into account the presence of a polymorphic phase transition in the material subjected to shock-wave action, which is essential for reliable modeling of both a pure material and alloys containing this material. Equations of state for two gold phases have been obtained using experimental data. Shock adiabats have been constructed for these phases in the pressure range of 1–1000 GPa. The pressure values on isotherms, as well as the values of heat capacity, entropy, and enthalpy along the gold isobar have been calculated. The results of the modeling have been compared with experimental data and with the results of calculations by other authors. Shock-wave loading of solid and porous gold–lead and gold–germanium alloys has been reliably described. The obtained equations of state can be useful in practical applications and in shock-wave experiments
Author:  K. K. Maevskii
Keywords:  equation of state, shock adiabat, thermodynamic equilibrium, phase transition, alloys, gold
Page:  308

HEAT AND MASS TRANSFER IN THE PROCESS OF RECTIFICATION ACCORDING TO THE INTERNAL ENERGY SAVING THEORY

The internal energy saving theory accounting for a multiple vapor condensation on the fractionating column trays is presented. The heat and mass transfer occurring on the trays is analyzed in terms of the law of thermodynamics. A formula for a quantitative assessment of internal energy saving in rectifi cation with account for various aggregative states of the initial mixture is presented. Using the internal energy saving theory, it has been proven that in supplying a "cold" (without preheating) initial mixture into the fractionating column the heat expenditures on its separation become smaller than the total heat consumption in the column reboiler and in the initial mixture heater. It has been proven that in separation of the initial vapor mixture, in a number of cases, its precondensation in the reboiler is advisable for reducing expenditures.
Author:  M. K. Zakharov, D. B. Pletnev, and E. A. Gubkin
Keywords:  internal energy saving, rectifi cation, condensation, evaporation, liquid–vapor mixture, cold mixture.
Page:  317

PHASE TRANSITIONS IN AEROSOLS AND SPREADING OF RESPIRATORY EPIDEMICS

Thermophysical processes infl uencing the spread of respiratory epidemics on drying (or freezing) of an aerosol containing a virus of about 100 nm in size have been identifi ed for the fi rst time. It is shown that suffi ciently rapid drying or freezing of a micron amount of aerosol produced inside a sick person leads to an increase in the Laplace pressure, which mechanically destroys the virus. It has been established that the characteristic time of phase transitions does not exceed 3 ms of a micron amount of aerosol and that the most favorable conditions for the survival of the virus in an aerosol are the air temperature held near zero Celsius and high air humidity, ensuring a suffi ciently long existence of the aerosol and, consequently, of the virus inside it.
Author:  P. S. Grinchuk, S. M. Danilova-Tret′yak, and S. P. Fisenko
Keywords:  aerosol, evaporation, freezing, Laplace pressure, air humidity, air temperature, COVID-19
Page:  326

DYNAMICS AND EVAPORATION OF DROPLETS IN AN ASCENDING CONVECTIVE FLOW OF HEATED AIR

Consideration has been given to the procedure for determining the rate of evaporation of single droplets and their cluster precipitating through a high-temperature zone in a gravitational fi eld with account for a convective ascending gas fl ow. Results are presented of an experimental investigation of the rate of droplets′ evaporation in a convective fl ow: approximation dependences for temperature distribution through the heater height have been obtained for various values of its power output. A physicomathematical model has been developed for free convection inside an open cylindrical tube and gravitational precipitation of droplets in an ascending convective fl ow. An analysis has been made of the eff ects of the droplets′ size and power magnitude of the heat energy supplied to the wall on droplet temperature and mass loss.
Author:  O. V. Matvienko, V. A. Arkhipov, V. I. Romandin, O. I. Daneiko, S. A. Basalaev, and N. N. Zolotorev
Keywords:  single droplet, cluster of droplets, gravitational sedimentation, high-temperature medium, evaporation, experimental investigation, mathematical modeling
Page:  329

EXPERIMENTAL STUDY OF DEFLAGRATION-TO-DETONATION TRANSITION IN n-HEPTANE/OXYGEN MIXTURES

The results of an experimental study of the process of defl agration-to-detonation transition in lean, stoichiometric, and rich n-heptane/oxygen mixtures at an elevated initial temperature of 105o C are presented. The studies were conducted in a heated detonation tube of circular cross section with an internal diameter of 22 mm for the case of low-power spark initiation of combustion. The dependences of the length and time of defl agration-to-detonation transition on the initial pressure and composition of the mixture were established experimentally. Typical "trace" imprints of detonation waves were obtained under various initial conditions, and the characteristic dimensions of the detonation cell were measured.
Author:  P. N. Krivosheyev, E. A. Baranyshin, O. G. Penyazkov
Keywords:  n-heptane/oxygen mixture, fl ame acceleration, defl agration-to-detonation transition, length and time of defl agration-to-detonation transition, detonation cell
Page:  342

RESEARCH ON TORREFACTION OF BIOFUEL AND ITS GASIFICATION IN A SUPERADIABATIC REGIME

The advantages of the biofuel torrefaction method as a promising method of preliminary thermochemical treatment of solid biomass-based fuels for improving their performance characteristics are shown. The results of wood chips and peat torrefaction in a nitrogen atmosphere are presented. During peat torrefaction, a signifi cant eff ect of its self-heating was observed. The obtained samples of torrefi ed biofuel were gasifi ed in a superadiabatic reactor. A comparison analysis of the gasifi cation characteristics for the original (untreated) chips and torrefi ed chips is carried out. Data on the composition of gas-phase gasifi cation products and nitrogen oxide concentration obtained using electrochemical gas analyzers are presented. Using a comparative analysis of the composition of liquid-phase gasifi cation products, the fact of a relatively greater presence of heavier organic components in the condensate during gasifi cation of torrefi ed chips is established by the mass spectrometry method. The data obtained confi rm the potential of the combined use of the methods of torrefaction and gasifi cation of biofuel mixtures in a superadiabatic regime as an energy-effi cient and environmentally friendly method of processing and recycling municipal waste, as well as of forestry, agricultural and industrial production
Author:  N. M. Gorbachev, S. I. Futko, A. V. Vlasov, M. I. Rusakevich, I. A. Koznacheev, D. S. Makarenko, and T. N. Bochko
Keywords:  biomass, biofuel, biomass gasifi cation, biomass torrefaction, pyrolysis and gasifi cation of wood, nitrogen oxides, municipal solid waste, fi ltration combustion, superadiabatic eff ect, thermogravimetric analysis, gas analysis, mass spectrometry
Page:  349

POLYCYCLIC AROMATIC HYDROCARBONS IN EMISSIONS OF THE INTERNAL COMBUSTION SPARK-IGNITION ENGINE

A quantitative analysis of the concentrations of 16 compounds of the class of polycyclic aromatic hydrocarbons in the combustion products emitted into the atmosphere by an internal combustion piston engine was performed using the chromatograph mass spectroscopy method. The most common commercial gasolines AI-92, AI-95, and AI-98 were used as fuel. The eff ect of the octane number of gasoline on the release of polycyclic aromatic hydrocarbons was studied during engine operation in idle, high speed, load, and cold (warm-up) start, as well as in the transient mode of multiple sharp increase in speed from nmin = 750 _min^–1 to n_max = 5600 _min^–1 and back. To capture polycyclic aromatic hydrocarbons in the fl ow of engine exhaust gases, a setup was devised whose operation principle is based on aspiration of gases through sorbents with a well-developed surface. It is shown that the emission of most polycyclic aromatic hydrocarbons during engine running in the main modes of vehicle operation is many times greater (for individual compounds, for example, benzo(a)pyrene and benz(a)anthracene, tens or even hundreds of times) than the reference value established by the World Health Organization and the European Environment Agency for atmospheric air in populated areas. With an increase in the octane number of gasoline, the concentration of highly carcinogenic polycyclic aromatic hydrocarbons (benzo(a)pyrene and benz(a)anthracene) in exhaust gases decreases, but remains within the limits threatening the human life and health.
Author:  M. S. Assad, V. V. Pisarev, and A. N. Oznobishin
Keywords:  polycyclic aromatic hydrocarbons, carcinogenicity, internal combustion engine, gasoline, octane number
Page:  362

THERMAL PARAMETERS OF A RADIATOR WITH A THREE-DIMENSIONAL LATTICE ORDERED STRUCTURE UNDER FREE-CONVECTION CONDITIONS

Results of computational and experimental studies of the thermal parameters of radiators based on a three-dimensional lattice ordered structure under the conditions of free air convection have been presented. To ensure visualization of the qualitative pattern, and also to confi rm the reliability of quantitative results of the study, the authors have carried out thermal imaging investigations enabling them to determine the general pattern of distribution of thermal parameters over the radiator height. The obtained results of physical and mathematical modeling show a satisfactory agreement between the calculations of thermal state of heat-liberating element (HLE) No. 2 and the data obtained in experimental studies in the range of heat loads from 2 to 20 W. For the case of HLE No. 1, certain deviations are observed that can point to the presence of the stagnation zone at the center of the radiator, which contributes to the reduction in the infl uence of free convection as the dominant mechanism of heat transfer
Author:  A. A. Lopatin, R. A. Gabdullina, A. R. Biktagirova, A. A. Terent′ev, A. A. Saetgaraev, and O. V. Lopatina
Keywords:  radiator with a three-dimensional lattice structure, heat transfer, eff ective conductivity, three-dimensional lattice structures
Page:  373

CHARACTERISTIC PROPERTIES OF THE THERMAL FIELD IN AN IDLE WELL WITH AN INDUCTION HEATER IN THE PRESENCE OF BEHIND-CASING FLUID MOVEMENT

The characteristic properties of the fi elds of local fl uid velocity and temperature of an idle well (in the absence of fl uid motion in the borehole) have been investigated under the conditions of local induction heating of a metal pipe (casing string, or pipe) in the presence of behind-casing fl uid movement, viz., vertical fl uid fl ow passing over the pipe on the outside, on the basis of a numerical solution of the Navier–Stokes equation in the Oberbeck–Boussinesq approximation in the Ansys Fluent engineering package. It has been established that in the absence of behind-casing fl uid movement, the region of disturbance of temperature and local fl uid velocity fi elds in which a vortex motion is formed due to natural heat convection does not exceed 1.5 m above the heating area. If there is fl uid movement, the size of the perturbed region displays a multiple vertical increase, which results from the casing pipe′s warmup above the area of induction impact due to heat exchange with an ascending fl ow in the casing string borehole annulus. The sensitivity of the temperature of the inner casing pipe surface and the borehole fl uid temperature to the presence of behind-casing fl uid movement has been demonstrated. Qualitative and quantitative criteria indicating the presence of behind-casing fl uid movement above the induction heating area have been suggested. A comparison has been made of the results of numerical calculations with the experimental data obtained using a laboratory setup.
Author:  F. F. Davletshin, R. Z. Akchurin, A. Sh. Ramazanov, R. A. Valiullin, R. F. Sharafutdinov, and I. V. Kanafin
Keywords:  induction heating, temperature, fresh-water horizons, idle well, behind-casing fl uid movement, natural heat convection
Page:  385

INVESTIGATIONS OF CHARACTERISTIC PROPERTIES OF THE COOLANT FLOW AT THE INLET TO A CASSETTE FUEL ASSEMBLY OF A RITM-200 REACTOR OF A LOW-POWER NUCLEAR PLANT

Results of investigations into the coolant fl ow at the cassette fuel assembly (FA) inlet of the RITM-200 reactor at a small nuclear power plant are presented. The goal of the investigation is an experimental determination of the eff ects of the elements of the FA inlet portion design on the coolant hydrodynamics in the active segment of the fuel element cluster and the development of recommendations on optimizing the design of certain elements of the FA inlet portion. To achieve this, experiments were carried out on a scaled model simulating the geometry of the FA inlet fl ow path from the choke fl ange to the second spacer grid in the fuel element cluster. The experiments were conducted using the pneumometric method. The fl ow velocity was measured through the entire cross section of the experimental model. The characteristic properties of the coolant fl ow were visualized with axial velocity cartograms (collation maps) in cross sections of the experimental model. The experimental data have been used in hydraulic profi ling of the FA inlet portion and also in substantiating the thermotechnical reliability of new cassette cores. An experimental database has been used in validation of the LOGOS CFD-program and also for clarifi cation of thermohydraulic core design procedures.
Author:  S. M. Dmitriev, T. D. Demkina, A. A. Dobrov, D. V. Doronkov, D. S. Doronkova, A. N. Pronin, and A. V. Ryazanov
Keywords:  nuclear reactor, fi ssile core, fuel assembly, inlet, fuel element bundle, diff user, absorption grid, spacer grid, axial velocity, coolant, hydrodynamics
Page:  398

INCREASING THE POWER OF THE α-TYPE STIRLING ENGINE BY CHANGING MUTUAL ORIENTATION OF COMPRESSION AND EXPANSION CYLINDERS

The power of a V-shaped α-type Stirling engine can be increased greatly by decreasing the angle Δψ between the cylinders of the heater and cooler. This occurs due to the tendency to zero of the phase diff erence between the oscillations of their pistons. Together with the decrease in the angle Δψ, the coeffi cient of hydraulic resistance of the regenerator KΣ also decreases. An increase in the angle Δψ leads to the appearance of a critical value of KΣ, when the engine stops working.
Author:  K. O. Sabdenov
Keywords:  α-type Stirling engine, heater, cooler, regenerator, isothermal approximation
Page:  409

CFD STUDY OF THE AIR FLOW AND HEAT TRANSFER IN A LOUVERED FINNED HEAT EXCHANGER FOR VEHICLES

The air fl ow and the heat transfer in louver fi ns were simulated using the CFD method. The results of the CFD calculations on the air pressure drop in the air fl ow and on its outlet temperature were compared with the experimental data, obtained for the air velocities 1.5, 2.5, 3.5, and 4.5 m/s. In all these cases, the errors in determining the pressure drop in the air fl ow and in its outlet temperature were within 10%. The infl uence of the louver angle, the fi n pitch, and the louver pitch on the rate of heat transfer in the air fl ow and on the pressure drop in it were investigated.  
Author:  Xiaohu Jiaoa and Runze Yanga
Keywords:  louver fi n, laminar fl ow, numerical simulation
Page:  419

SIMULATION OF THE INTENSIFICATION OF CONVECTIVE HEAT TRANSFER BY NANOFLUIDS WITH CARBON NANOTUBES

The intensifi acation of convective heat transfer by nanofl uids based on isopropyl alcohol and ethylene glycol with carbon nanotubes in a cylindrical channel with a heat fl ow of constant density at the channel wall was investigated. It was established experimentally that the indicated nanofl uids are pseudoelastic and, therefore, their rheology is well defi ned by the model of a power-law fl uid. It is shown that the velocity of fl ow of such a nanofl uid in the region of the channel wall is increased, and the velocity profi le of this fl ow is fl attened. The indicated eff ect enhances with increase in the concentration of carbon nanotubes in the nanofl uid. It was established that the deformation of the velocity profi le of the nanofl uid leads to an increase in its heat transfer coeffi cient, which is one of the mechanisms of intensifi cation of convective heat transfer by nanofl uids with carbon nanotubes. The increase in the heat transfer coeffi cient of a nanofl uid, as compared to that of its base fl uid, is especially large for the nanofl uids with singlewalled carbon nanotubes. In the case of their concentration 0.25% in a nanofl uid based on isopropyl alcohol, the heat transfer by the nanofl uid is larger by 2.7 times that the heat transfer by its base fl uid, and the coeffi cient of thermohydraulic effi ciency of the nanofl uid fl ow at small Reynolds numbers can reach 3.5.
Author:  V. Ya. Rudyak, D. V. Guzei, and A. V. Minakov
Keywords:  nanofl uid, thermohydraulic effi ciency, heat transfer, carbon nanotubes
Page:  427

FORECASTING THE INCREASE IN ANOMALOUS INTENSIFICATION OF HEAT EXCHANGE ON A SURFACE WITH AN INCLINED GROOVE USING NUMERICAL OPTIMIZATION METHODS

The article considers the forecasting of the increase in anomalous intensifi cation of heat exchange on a surface with inclined grooves using numerical optimization methods. It was shown previously that anomalous intensifi cation of separated fl ow and of heat exchange in inclined grooves with hemispherical ends is observed during the movement of water- and air-heat-carriers in structured channels. Optimization of the groove shape in plan allows increasing the eff ect of anomalous intensifi cation of heat emission from a heated structured surface. The optimization was carried out using a multi-objective genetic algorithm within the framework of numerical modeling based on the solution of the full Reynolds-averaged Navier–Stokes equations. A teardrop shape of an inclined groove is proposed which allows a signifi cant increase in the intensity of heat exchange near a heated structured surface.
Author:  S. A. Isaev, A. E. Usachov, O. A. Sapunov, D. V. Nikushchenko
Keywords:  heat exchange, intensifi cation, numerical modeling, optimization, turbulence
Page:  439

GENERALIZATION OF THE PRANDTL MODEL OF SLOPE FLOWS TO THE CASE OF THE PRESENCE OF A HEAVY HEAT-GENERATING IMPURITY IN THE ENVIRONMENT

The Prandtl slope fl ow model is generalized to the case where on the inclined lower boundary there is a homogeneous stationary source of a heavy heat-generating impurity, the mass and heat release of which make a signifi cant contribution to the density of the medium. A stationary analytical solution is obtained for the velocity of the resulting slope fl ows, temperature deviations, and impurity distribution. The model can describe, for example, some features of the dynamics of atmospheric fl ows caused by aerosol that absorb solar radiation.
Author:  L. Kh. Ingel′
Keywords:  slope fl ows, Prandtl model, heavy impurity, heat-generating impurity, aerosol in the atmosphere
Page:  448

ENHANCED BIOCONVECTION ADJACENT TO PERMEABLE CYLINDER IN HYBRID NANOFLUIDS: BACTERIA DISTRIBUTION AND PHYSICAL FEATURES UNDER MAGNETIC FIELD INFLUENCE

The presence of motile bacteria within hybrid nanofl uids induces the phenomenon of bioconvection. The hybrid nanofl uid was subjected to the presence and distribution analysis of Bacillus cereus, Bacillus brevis, Salmonella typhimurium, and Pseudomonas fl uorescens. This study explains the theoretical analysis of a hybrid fl uid with nanoparticles and gyrotactic microorganisms subjected to induced magnetic fi eld in three dimensions. Using the group technique, the governing system of equations has been simplifi ed to a set of ordinary diff erential equations (ODEs). The present study was motivated by an investigation into the eff ects of several parameters. The Prandtl number Pr, magnetic parameter M, inclination angle γ, shape factor n, permeability coeffi cient kp, diff usion coeffi cient of microorganism Dn, Brownian motion coeffi cient DB, thermophoresis diff usion coeffi cient DT, and concentration diff erence δc are examples of such parameters. For diff erent fl ow regulating parameters, the modifi cation of physical quantities, such as temperature, velocity, nanoparticle characteristics, and the density of motile microorganisms, is observed with precise physical features
Author:  Samah M. Mabrouk, Ehsan H. Nasr, Abd Elnaby Kabeel, Ahmed S. Rashed
Keywords:  bioconvection, hybrid fl uid, Brownian motion coeffi cient
Page:  454

ANALYSIS OF BIOCONVECTIVE FLOW OF VISCOELASTIC FLUID PAST AN ELONGATING AND CONVECTIVELY HEATED SURFACE IN A NON-DARCIAN POROUS REGIME

This study examines a laminar, magnetohydrodynamic bioconvective fl ow of an incompressible, time-independent viscoelastic fl uid with gyrotactic motile microorganisms across an elongating and convectively heated surface in a non-Darcian porous regime. The eff ects of activation energy and heat sink are considered in concentration and energy equations. Governing equations are transformed into a nondimensional form by applying proper similarity variables. Here, use is made of MATLAB-bvp4c code to solve the transformed equations. Impact of various physical parameters on the profi les of the density of motile microorganisms, velocity, concentration, and temperature are detected graphically. It is shown that the velocity profi le is reduced with increase in the parameter and bioconvection Rayleigh number. Activation energy diminishes the concentration profi le but amplifi es the density profi le of motile microorganisms.
Author:  Utpal Jyoti Das, Indushri Patgiri, and Jubi Begum
Keywords:  magnetohydrodynamics, viscoelastic fl uid, heat sink, bioconvection, activation energy
Page:  468

INVESTIGATION INTO A FLOW OF A POLYMER–BITUMEN BINDER, DESCRIBED BY THE CROSS MODEL, IN A CYLINDRICAL PIPE

Mathematical modeling of a fl ow of polymer–bitumen binder in a cylindrical pipe has been carried out. Oxidized BND 70/100 grade butadiene–styrene copolymer-modifi ed bitumens have been selected for investigations. The results of investigations have shown that the rheological properties of the binding substances under consideration can be described with the Cross model. At low shear rates, the spatial structure formed as a result of modifying bitumen with a polymer remains unchanged, and the fl ow is characterized by high eff ective viscosity values. At high shear rates, the process of spatial structure breakdown becomes intense and is accompanied by viscosity decrease. With increase in temperature the binder passes from a gel state to a liquid state. With increase in the average fl ow rate the formation of a dynamic boundary layer and the fl ow stabilization occur at large distances from the inlet. The eff ective viscosity values in the near-axial zone increase downstream. With hydrodynamic stabilization in the nearaxial region a high-viscosity fl ow zone is formed. In the pre-axial fl ow zone, the eff ective viscosity assumes maximum values, while near the wall, it takes minimum values.
Author:  O. V. Matvienko, N. S. Firsanova, O. A. Skvortsova, and I. S. Cherkasov
Keywords:  rheology, road construction, bitumen binders, SBS-polymer, viscosity, non-Newtonian liquid, Cross model.
Page:  479

COALESCENSE OF DROPLETS IN HIGH-VISCOSITY RHEOLOGICAL LIQUIDS

A step-by-step analysis of the coalescence of normal liquid droplets in a non-Newtonian viscoplastic oil emulsion has been performed. This analysis made it possible to reveal the mechanism and essence of the indicated phenomenon and to construct an algorithm and formulas for calculating the maximum stable size of liquid droplets, their specifi c energy dissipation, the frequency of collisions of droplets, and the thinning of the interphase fi lm of the non-Newtonian liquid between two droplets. It is shown that, in the case of collision of a non-Newtonian liquid droplet with a normal liquid droplet, the non-Newtonian liquid layers on the normal liquid droplet with formation of an adsorption layer on its surface. Analytical solution of the diff usion equation made it possible to obtain expressions for calculating the frequency of collisions of droplets in the non-Newtonian liquid as a function of its parameters and, as a result of the solution of the equations of hydrodynamics, the expression for calculating the thickness of the interphase nonNewtonian liquid fi lm between two droplets has been obtained.
Author:  G. I. Kelbaliyev, S. R. Rasulov, M. R. Manafov, F. R. Shykhiyeva, and N. A. Abdullayev
Keywords:  non-Newtonian liquid, droplets, coalescence, energy dissipation, diff usion, interphase fi lm, frequency of collisions, rate of shear, eff ective viscosity, crude oil emulsions
Page:  492

ON THE FORMATION OF A GRADIENT-VELOCITY FIELD IN STATIONARY FLOWS OF VISCOUS AND BINGHAM FLUIDS

This article is devoted to considering the problems of formation of a gradient-velocity fi eld in stationary cylindrical fl ows of viscous and visco-plastic fl uids. Based on the analysis of a new physical model of fl ow, it was found that in the transverse direction in the fl ows of viscous and Bingham fl uids, a gradient of static pressure is created, which generates a fi eld of Bernoulli forces directed from the periphery of the fl ow to its axis. A characteristic feature in the formation of the pressure and velocity gradient during the fl ow of viscous and Bingham fl uids is shown. It is noted that in sight the use of a new fl ow model can contribute to the creation of more effi cient technologies in extraction and transportation of multiphase heterogeneous systems
Author:  G. G. Ismayilov, E. Kh. Iskandarov, and F. B. Ismayilova
Keywords:  pressure gradient, velocity gradient, viscous fl uid, Bingham fl uid, rheology, shear stress, multiphase
Page:  503

MODELING THE PROCESS OF DEVELOPMENT OF GAS CONDENSATE DEPOSITS WITH REGARD TO THERMODYNAMIC NONEQUILIBRIUM

Calculation schemes for modeling processes with nonequilibrium phase transformations in the course of development of hydrocarbon fi elds are proposed and characteristic indicators of the development of real gas condensate fi elds are estimated on their basis. It is established that nonequilibrium eff ects lead to signifi cant deviations of the values of actual system parameters (liquid phase fraction and condensate content in the formation gas) from their values estimated for equilibrium states, as a result of which the condensate recovery factor determined with regard to the nonequilibrium state of the system diff ers signifi cantly from its estimate for the equilibrium state. A method for calculating the interphase fl ow intensity is introduced, which allows adapting a nonequilibrium thermodynamic model to actual data with regard to the degree of phase behavior deviation from equilibrium and to the dependence of the rate of relaxation of phase compositions on pressure changes.
Author:  Kh. A. Feizullaev, M. S. Khalilov, B. Kh. Feizullaev and A. A. Damirov
Keywords:  thermodynamically nonequilibrium state, two-phase multicomponent fi ltration, mole fractions of the liquid phase, condensate contents in formation gas, condensate recovery factor.
Page:  509

PRODUCTION STIMULATION BY CONTROLLING THE PROPERTIES OF CLAY MINERALS DURING OIL DISPLACEMENT BY WATER IN CLAY RESERVOIRS

A technological method of alternate application of fresh and brine waters for intensifi cation of involvement of residual oil reserves in development during oil displacement in clay reservoirs and a hydrodynamic model of predictive assessment of real mechanisms of the indicated intensifi cation are proposed. An increase in oil production with the use of the proposed method as a result of ensuring blocking of watered zones by regulating clay content of the rock and water fl ow direction to less developed (slightly-low-permeable) sections of the reservoir is established.
Author:  S. V. Aghalarova
Keywords:  clay reservoir, oil recovery factors, brine water, fresh water, surface tension
Page:  515

KINETICS OF DEHYDRATION OF VEGETABLE MATERIALS IN A VIBROFLUIDIZED BED WITH NONSTATIONARY RADIATIVE-CONVECTIVE ENERGY SUPPLY

The authors have given the results of numerical modeling and experimental study of the kinetics of dehydration, shrinkage of particles, and heat and mass transfer in a vibrofl uidized bed of materials of vegetable origin with the example of particles of carrots and celery root with convective and radiative-convective supplies of energy. A comparison has been made of the calculation results and experimental data. A change in the qualitative indices of the product depending on the regime of processing has been established. The contribution of infrared radiation and of the convective heat fl ux has been determined. The possibility of enhancing the process of dehydration and reducing its duration in the vibrofl uidized bed with radiative-convective stepwise in time energy supply has been shown.
Author:  P. V. Akulich, D. S. Slizhuk, and A. N. Nikitenko
Keywords:  heat and mass transfer in a dispersed layer, radiative-convective drying, drying of vegetable materials
Page:  522

MATHEMATICAL MODEL OF THE PROCESS OF MULTISTAGE FRAGMENTATION OF DROPLETS IN AN ULTRASONIC FIELD

Consideration is given to the problem of creation of fi ne aerosols by a novel method consisting in the droplets of a liquid breaking up in a series of antinodes of a powerful ultrasonic fi eld. This makes it possible to obtain an aerosol cloud with a droplet size under 50 μm with a high effi ciency at relatively low energy expenditures. A mathematical model of multistage spraying of droplets in an acoustic fi eld has been proposed, which is based on the energy approach with hydrodynamic criteria, with the Weber number and the acoustic Bond number being basic ones. Critical conditions have been determined for the breakup of droplets, and also their limiting dimension. Possible mechanisms of disintegration of droplets, as they pass successively through the antinodes of the ultrasonic fi eld, have been described depending on the initial size of the droplets and the velocity of their motion, the surface tension of the liquid in the droplets, and acoustic pressure. From the results of measurements of the dispersion parameters of the aerosol obtained in the process of multistage spraying of the liquid in the acoustic fi eld, free parameters of the mathematical model of the process have been determined.
Author:  Olga B. Kudryashova, Andrey V. Shalunov, Viktor A. Nesterov, and Sergey A. Terentiev
Keywords:  aerosol, fragmentation of droplets, ultrasonic fi eld, mathematical model
Page:  533

ANALYSIS OF THE POSSIBILITY OF DEVELOPING VISCOUS AND HIGH-VISCOSITY OIL FIELDS THAT IS ACCOMPANIED BY ATTENDANT COMPLICATIONS WITH THE TECHNOLOGY OF CYCLIC STEAM STIMULATION OF THE BOTTOM-HOLE FORMATION ZONE

Consideration has been given to the possibility of using the technology of cyclic steam stimulation (CSS) of the bottom-hole formation zone with various attendant complications, such as the low permeability of the formation, the use of CSS in horizontal, subhorizontal, and inclined directional wells and in combination with the hydraulic fracturing of the formation, the high viscosity of oil, and the stratifi ed inhomogeneity and compartmentalization of the formation. This issue is particularly relevant in view of the ever-increasing interest of subsoil users in developing fi elds of viscous and high-viscosity oil with described complications. Using the analytical integral model that is based on thermal balance and is modifi ed for solution of the optimization problem of use of CSS on horizontal wells, the authors have calculated the optimum time intervals of implementation of all the three CSS steps. In the course of numerical experiment, the optimum number of CSS cycles was established which allows the maximum eff ect from the use of this technology on the described model formation. Also, the numerical modeling has shown that the excessively high and excessively low number of CSS cycles has a negative eff ect on the effi ciency of this technology.
Author:  A. O. Fedorov, A. Ya. Gil′manov, and A. P. Shevelev
Keywords:  cyclic steam stimulation of the bottom-hole formation zone, horizontal wells, hydraulic fracturing of the formation, viscous oil, low-permeability formations, hard-to-extract oil reserves, engineering problems of production of high-viscosity oil
Page:  543

CORRELATION ANALYSIS OF THE INFLUENCE OF SUBSTITUENTS ON THE DENSITY OF ORGANOMETALLIC COMPOUNDS

Literature data on the density of 25 series of boron, aluminum, silicon, germanium, tin, lead, phosphorus, and arsenic compounds forming weak intermolecular complexes have been analyzed using the correlation-analysis method. During the formulation of a weak complex, an excess charge appears at the reactive site of such a compound, which in turn induces a dipole in the substituent of the compound, with the result that the ion–dipole interaction (polarization eff ect) occurs. It was shown for the fi rst time that the density of the indicated compounds depends not only on the classical inductive, resonance, and steric eff ects of the substituents, but also on the polarization eff ect whose contribution may amount to as much as 54%.
Author:  N. A. Khamaletdinova, O. V. Kuznetsova, and A. N. Egorochkin
Keywords:  organometallic compounds, density, classical electronic eff ects, polarization eff ect.
Page:  551

PERIODICITY OF THE EMISSIVITY OF FOURTH PERIOD METALS IN THE REGION OF MELTING TEMPERATURES

The article presents the results of assessing the fulfi llment of the periodicity of the emissivity of metals of the fourth period of the periodic table in the region of melting temperatures. The calculations used experimental arrays of numerical values of the emissivity of metals obtained personally by the authors and materials from open sources. An example of the relationship between the melting point of a metal and the magnitude of the relative jump in the emissivity of the solid–liquid phase transition is considered. A comparison of the relative jump in the emissivity of the phase transition to the atomic number in the periodic table is carried out. The obtained isotherms of the thermal dependences of the averaged temperatures of the experimental data to the atomic number of the element in the periodic table are analyzed. A stable correlation is established between the emissivity, melting point, and the position of the element in the periodic table. A conclusion is made about a complex structural dependence of the periodicity of the relative jump in emissivity on the melting temperature, and the mechanisms of disordering of the crystal lattice of metals during the transition from the solid to the liquid state are discussed. Common features in the behavior of thermophysical characteristics of metals of the fourth period of the periodic table have been identifi ed.
Author:  D. V. Kosenkov and V. V. Sagadeev
Keywords:  periodic table, metals, emissivity, solid and liquid phases, phase transition
Page:  560

ALTERNATIVE IMPLEMENTATION OF THE METHOD OF MAGNETORHEOLOGICAL CONTROL OF THE MAGNETIC SUSCEPTIBILITY OF A PARTICLE

It has been established that a new magnetorheological method of controlling the magnetic susceptibility of a single ferromagnetic particle moving vertically downwards in a liquid in a vessel located between the poles-hemispheres of a magnetometer above the enter-to-center line of the poles provides an eff ect on the particle in addition to the gravitational impact of the magnetic force directed downwards. In this case, the particle velocity becomes undesirably high, and the time it takes to pass through the magnetometer′s executive zone to be very small. Taking into account these circumstances, which complicate the execution of experiments, it is recommended to place the vessel with liquid in another, symmetrical, part of the interpolar region — between the same poles-hemispheres, but below their center-to-center line. Then, because of the purposefully changed direction of the magnetic force to the opposite and correspondingly changed direction of the particle′s movement (upward), the particle′s velocity within the similar execution zone will decrease signifi cantly (and favorably for performing experiments), and the time of this movement will increase. Expressions have been obtained for determining the magnetic susceptibility of a particle performing such a movement.
Author:  D. A. Sandulyak, A. A. Sandulyak, M. N. Polismakova, V. A. Ershova, A. V. Sandulyak, and A. S. Kharin
Keywords:  single particle, magnetic susceptibility, magnetorheological method, executive zone, constancy of magnetic force factor
Page:  565

CHARACTERISTICS OF A LOWERED-PRESSURE, HIGH-FREQUENCY INDUCTIVE JET CHARGE IN PROCESSES OF MODIFICATION OF PRODUCTS

The parameters of a lowered-pressure high-frequency inductive discharge, which should be taken into account in the modifi cation of products diff erent in physical nature, were investigated. The distributions of temperature, of the velocity of plasma movement, of the strength of the magnetic fi eld, and of the density of the ion current in the jet of such a discharge are presented. It is shown that a higher temperature and a smaller temperature gradient in the jet of this discharge are attained at a pressure of 66.5 Pa in it. A separate investigation of the distribution of the temperature in the discharge jet in the presence of a material treated with it has been performed. The contribution of the implantation of ions into a material to the heating of the material in the process of its treatment in the jet of a high-frequency inductive discharge of lowered pressure was estimated.
Author:  I. Sh. Abdullin, I. K. Nekrasov, F. R. Sagitova, and S. V. Mironov
Keywords:  plasma modifi cation, high-frequency inductive discharge, fl ow of low-energy ions, modifi cation of materials
Page:  569

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