Volume 96, №6

IDENTIFICATION OF MATHEMATICAL MODELS OF HEAT TRANSFER OF HTSC COILS. 2. ALGORITHM FOR SOLVING IHP AND THE RESULTS OF EXPERIMENTAL DATA PROCESSING
The presented work is a continuation of the development of a computational and experimental method for determining the thermophysical characteristics (TPC) of the stator coils of a generator operating with the use of the phenomenon of high-temperature superconductivity (HTSC). The paper considers algorithms for identifying heat transfer models in the composite material of the stator coil winding. Using the discovered thermophysical properties, it is planned to study the electrothermal interaction in a high-temperature superconductor before its transition to a superconducting state. There is a signifi cant variety of methods for solving the problems of identifying mathematical models of heat transfer, in particular, of determining the thermophysical characteristics of composite materials. As a result of the analysis of alternative methods for solving the identifi cation problem, the iterative regularization method is used in this work
Author:  O. M. Alifanov, S. A. Budnik, A. G. Vikulov, A. V. Nenarokomov, D. M. Titov, A. V. Morzhukhina, V. V. Il'in
Keywords:  HTSC coils, inverse heat exchange problems, iterative regularization method, cryogenic processes
Page:  1393

METHOD OF INVERSE PROBLEMS FOR THERMAL DIAGNOSTICS OF THERMOELASTIC STRUCTURES
The application of inverse problems to thermal diagnostics of homogeneous structures is outlined, variational formulations of the problems under study are considered, their solvability is proven, and an iterative solution algorithm is described. The results are applied to the thermal diagnostics of thermoelastic structures, a theorem of existence and uniqueness of the solution to the problem of determining the inhomogeneous thermal characteristics of the medium, which is used to restore the physical and technical image of the diagnosed object, is proved, and the necessary condition for the extremum is formulated in the form of a variational inequality. An example of a numerical solution to the problem under consideration is given and an analysis of the calculation results on the application of the proposed diagnostic technique is given.
Author:  A.M. Pashaev, A. D. Iskenderov,M. A. Musaeva
Keywords:  thermal diagnostics, thermoelasticity, variational method, inverse problems, diagnostics of structures
Page:  1407

DUAL VARIATIONAL MODEL OF THE NONLINEAR HEAT CONDUCTION PROBLEM WITH CONSIDERATION OF SPATIAL NONLOCALITY
The microcontinuum theories have great potential for modeling structure-sensitive materials. Research into the possibilities of using nonlocal thermomechanics in modeling nanodevices and nanoelectromechanical systems, media with a complex internal micro- and nanostructure is of great interest today. Analysis of such models is associated, as a rule, with overcoming certain diffi culties caused by the necessity of numerical solution of integro-diff erential equations. The possibilities of analyzing mathematical models of a continuous medium can be expanded through the use of variational methods. This paper describes the construction of relations for the dual variational model of a stationary nonlinear heat conduction problem with consideration for the nonlocality eff ects. It is shown that the conditions of stationarity of the alternative functional coincide with known similar conditions in the absence of nonlocality. A quantitative analysis was carried out using the example of a problem about a plate that is infi nite in its plane with active internal heat-release sources. Such problems are typical, for example, of the phenomena of a thermal explosion when exothermic chemical reactions occur in the body material or of thermal breakdown of a dielectric layer under the infl uence of electrical potentials. The dual variational formulation of the problem allows one not only to obtain an approximate solution to the problem under consideration, but also to estimate the error of this solution, and, if necessary, to reduce this error by selecting approximating functions
Author:  I. Yu. Savelyeva
Keywords:  spatial nonlocality, dual variational formulation, functional, nonlinear heat conduction problem, heat release, plate
Page:  1416

INFLUENCE OF ELECTROMAGNETIC WAVES ON THE TEMPERATURE FIELD OF FROZEN BIOLOGICAL OBJECTS IN ARCTIC CONDITIONS
Today, it can be considered established that the thermal scheme of the human body consists of a "core", which includes the brain, internal organs of the chest and abdominal cavities, and a "shell" consisting of skin, hypodermic matrices, and superfi cial muscles. The goal of the work is to design a device for slow noncontact defrosting of a limb that has received a cold injury and previously was thermally insulated from the external environment. Measurements were made of the temperature of the muscle tissue of a biological object frostbitten under experimental conditions that was previously placed in a heat-insulating material with subsequent noncontact heating with low-power microwaves. Since the heat-insulating material is ratio transparent for the microwave range, the heating eff ect will act directly on the sample under study.
Author:  A. S. Andreev, S. O. Semenov, R. Z. Alekseev, E. S. Lukin, M. V. Fedorov
Keywords:  muscle tissue, hypothermia, thermometry, low temperatures, cold injury, frostbite
Page:  1427

FREE VIBRATIONS OF A THREE-LAYER PLATE EXCITED BY A HEAT FLUX
The eff ect of a heat fl ux of constant intensity on a circular three-layer plate, thermally insulated along the contour and lower surface, is considered. A solution of the problem of thermal conductivity of the plate with thicknessaveraged thermophysical parameters of materials is presented. The nonstationary temperature fi eld is nonuniform over the thickness of the plate. It is shown that on instantaneous drop, the heat fl ux can cause sagging and free vibrations of the three-layer plate. The kinematics of the plate package obeys the broken line hypothesis. After applying a load, the normal in thin load-bearing layers does not change its length and remains perpendicular to the middle surface of the layer. In a relatively thick fi ller, the deformed normal retains its length and straightness, but is rotated by a small additional angle, i.e., the shift is taken into account. The formulation of the corresponding initial boundary-value problem is given. The equations of motion were obtained using the variational method with account for the transverse forces of inertia. The boundary pivot conditions are accepted on the contour of the plate. Radial movements in the layers are expressed through three sought functions: plate sagging, shear, and radial movement of the middle plane of the fi ller. It is shown that these sought functions satisfy the inhomogeneous system of three diff erential equations. To solve the system, the method of series expansion in the constructed fundamental system of eigenorthonormal functions was used. A transcendental equation is written out to obtain the corresponding eigenvalues. A numerical parametric analysis of the solution was carried out depending on the geometric and thermophysical characteristics of the layer materials and the time of exposure to the heat fl ux
Author:  É. I. Starovoitov, Yu. M. Pleskachevskii, D. V. Leonenko, D. V. Tarlakovskii
Keywords:  nonstationary temperature fi eld, three-layer circular plate, free vibrations
Page:  1432

CALCULATION OF SEDIMENT FORMATION ON FINNED HEAT EXCHANGER TUBES ON CONDENSATION OF A VAPOR–GAS MIXTURE WITH SOLID PARTICLES
A mathematical model of the process of deposition of solid particles on the outer surface of tubes of a fi nned heat exchanger on condensation of a vapor–gas mixture containing particles has been developed. The model is based on determining the temperature fi eld in a round fi n from a given distribution of sediment thickness. The proposed model makes it possible to evaluate the infl uence of design and thermal parameters on the heat fl ux removed by a round fi n to a cylindrical tube. The infl uence of changes in such parameters as the fi n thickness and thermal conductivity of the sediment layer on heat transfer was assessed
Author:  A. V. Dmitriev, N. D. Yakimov, V. V. Khar′kov, G. R. Badretdinova
Keywords:  fi nned tubes, round fi n, sediment formation
Page:  1443

ENHANCEMENT OF THE PROCESSES OF TRANSFER OF HEAT IN A DIABATIC FRACTIONATING COLUMN
Raising energy effi ciency in the course of heat- and mass-transfer processes in column fractionating apparatuses is one topical problem of applied science and industry. Consideration has been given to a method of raising energy effi ciency during the rectifi cation of liquid mixtures due to the diabatization of the columns, that consists in installing built-in heat exchangers. The aim of the research is to determine thermal characteristics of the fl ow with the classical method of enhancement of heat transfer: fi nning the tubes externally. A mathematical description of the condensation of ascending vapor on the horizontal surface of fi nned tubes was developed. As a result of the research, the authors have determined heat outputs, temperatures of the heat-transfer agent at exit from a tubular dephlegmator, fl ow rates of cooling water, heat-transfer coeffi cients, linear coeffi cients of heat transfer, and thermal resistances of heat transfer with fi nned and smooth dephlegmator tubes on each tray in the rectifying section of the fractionating column. Results of theoretical investigations have shown that enhancing the processes of transfer of heat when the exterior tube surface is fi nned made it possible to increase heat fl uxes in the dephlegmators to 3.74 times. It has been shown that the use of heat-transfer enhancers in the form of fi nning on the outside of dephlegmator tubes allows equalizing thermal heat-transfer resistances. It has been established that the investigated structure of a tubular dephlegmator with fi nned tubes makes it possible to raise the Murphree effi ciency of the valve tray by 7.7%.
Author:  I. N. Madysheva, A. O. Mayasova
Keywords:  diabatic rectifi cation, fi nning of tubes, heat transfer, thermal resistance
Page:  1451

DUAL SERIES EQUATIONS TO SOLVE THE LAPLACE EQUATION WITH MIXED BOUNDARY CONDITIONS
A solution of the Laplace equation in cylindrical coordinates is presented for a bounded cylinder with the known height and radius which is subject to inhomogeneous mixed boundary conditions of the third and second kinds on the surface. On the other surface, unmixed boundary conditions of the fi rst or second kind are given. Through separation of variables, the Hankel integral transform, and the dual series equations, the solution of the mixed problem is reduced to solving the Fredholm integral equation of the second kind
Author:  N. A. Hoshan
Keywords:  dual series equations, mixed boundary conditions
Page:  1460

CONDITIONS OF INITIATION OF DETONATION IN A STOICHIOMETRIC HYDROGEN–AIR MIXTURE BY A STREAMER DISCHARGE
A numerical simulation of the conditions for the direct initiation of detonation in the region of a combustible mixture, in which its critical energy is minimum, has been performed using a streamer microwave discharge for the source of detonation initiation. The calculations were conducted on the basis of the model of the two-dimensional detonation in a combustible mixture, fl owing in a cylindrical channel, with the use of the system of gas-dynamics and chemicalkinetics equations. The process of detonation initiation was considered as applied to a stoichiometric hydrogen–air mixture fl owing in a cylindrical channel at diff erent initial pressures. The requirements for the source of initiation of detonation in a combustible mixture were investigated with respect to the attainment of its critical parameters in practice
Author:  P. V. Bulat, K. N. Volkov, L. P. Grachev, I. I. Esakov, A. A. Ravaev
Keywords:  combustible mixture, streamer discharge, initiation of detonation
Page:  1468

EXPERIMENTAL AND THEORETICAL STUDY OF GRANULATED CHARGE COMBUSTION IN A CLOSED VOLUME
An experimental and theoretical study of the combustion of granulated charges consisting of pyroxylin powders in a manometric bomb of constant volume is presented. A comparison was made of the experimentally measured dependence of pressure increase in a manometric bomb with calculations according to thermodynamic model of combustion of a gunpowder sample in a manometric bomb using the empirical law of the dependence of the burning rate on pressure and a conjugate model of unsteady combustion of gunpowder. The unsteady rate of burning of pyroxylin powder, due to the high rate of pressure growth in the manometric bomb, diff ers from the quasi-stationary speed. This diff erence depends on the rate of pressure growth and on its absolute value and decreases with increasing pressure
Author:  A. N. Ishchenko, A. Yu. Krainov, K. S. Rogaev, A. S. D'yachkovskii, E. Yu. Stepanov
Keywords:  manometric bomb, powder, unsteady combustion, numerical simulation
Page:  1474

DYNAMICS OF PRESSURE FIELDS IN THE FORMATION AND IN THE HF FRACTURE DURING NATURAL OSCILLATIONS OF THE LIQUID COLUMN IN THE WELL
The problem of natural oscillations of a column of liquid in a vertical well, which arose as a result of a sharp closure of the well, was studied. A mathematical model of the process of natural oscillations of a column of liquid in a well connected to the formation through the permeable walls of an open area and a hydraulic fracture is constructed. The dynamics of fi ltration pressure fi elds in a formation and in a hydraulic fracture near the wellbore zone is considered. The infl uence of formation permeability, hydraulic fracture conductivity and of the well length on the nature and depth of penetration of fi ltration pressure disturbances during natural oscillations of the liquid column in the well was analyzed. It has been established that this method of well diagnostics is quite informative and allows one to obtain information about the formation characteristics of a hydraulic fracture and the formation zone adjacent to the well.
Author:  V. Sh. Shagapov, G. R. Rafi kova, Z. Z. Mamaeva
Keywords:  well, oil, hydraulic shock, natural oscillations of liquid, hydraulic fracture, fi ltration disturbances
Page:  1481

NUMERICAL MODELING OF THE INFLUENCE OF THE FACTORS OF IMPERFECTION OF PERFORATION ON VELOCITY FIELDS IN AN OIL AND GAS STRATUM
A study has been made of the pressure and velocity fi elds of fi ltration fl ows appearing in extracting hydrocarbons from sands penetrated imperfectly. The problem on the pressure fi eld has been presented in which account is taken of two factors of imperfection of perforation: the fi rst is in the presence of a virgin portion in the perforation interval, and the second is caused by the noncoincidence of the perforation interval with the boundaries of a permeable saturated stratum. A fi nite-diff erence program has been created for calculating velocity and pressure fi elds in a stratum with imperfect penetration. Numerical experiment demonstrates that the infl ow from imperfectly penetrated layers of a homogeneous isotropic stratum is not uniform, and the modulus of the horizontal velocity components peaks on the boundaries of penetrated layers
Author:  A. I. Filippov, O. V. Akhmetova, M. R. Gubaidullin
Keywords:  fi ltration, imperfect penetration, two-dimensional fl ow, fi nite-diff erence program, pressure fi eld, velocity fi eld
Page:  1490

MODELING THE PROCESS OF GAS FILTRATION IN A CONJUGATED BED–WELL SYSTEM WITH ACCOUNT FOR BED DEFORMATION
A model of the process of gas motion in a bed–well system is constructed with account for bed deformation. The boundary-value problem of nonstationary motion of gas has been solved. Analytical expressions are obtained allowing one to determine the dynamics of the wellhead pressure and fl ow rate of gas. Numerical calculations were carried out at practical values of the system parameters
Author:  N. R. Abdullaeva
Keywords:  pressure, gas fi ltration, Laplace transform, diff erential equation, deformation
Page:  1498

SIMULATION OF THE INDICATOR LIQUID FLOW IN A FORMATION WITH HYDRAULIC FRACTURING
The results of modeling the fi ltration of an indicator liquid (aqueous solution of an indicator) in a hydraulically fractured low-permeability formation with account for diff usion and convective mass transfer through the side walls of the fracture are presented. Simulation of fi ltration–diff usion processes is of great importance for the implementation of tracer studies in oil production, as well as for some processes of hydrogeology and ecology (control of the injection of industrial waste into formations), chemical and membrane technologies. The problem is solved using the Laplace integral transform method. An analysis of the obtained solutions was carried out, which makes it possible to determine the main qualitative characteristic features of the diff usion and fi ltration processes under consideration
Author:  I. L. Khabibullin, R. Z. Khasanova
Keywords:  aqueous solution of indicator, solution margin, diff usion, fi ltration, Laplace transform method, indicator concentration
Page:  1508

CALCULATION OF THE PHASE EQUILIBRIUM OF A HYDROCARBON MIXTURE WITH REGARD FOR THE CAPILLARY PRESSURE JUMP IN IT BY THE EXAMPLE OF THE ASTRAKHAN FIELD
The infl uence of a capillary pressure jump in a porous medium on the equilibrium between its liquid and gas phases, defi ned by the Peng–Robinson equation of state, was investigated. A numerical analysis of the phase diagrams of a gas–condensate mixture, constructed in gas-pressure and liquid-pressure coordinates for diff erent capillary pressure jumps in the mixture, has been performed. The boundary of the two-phase region of such a mixture was determined as a domain of its existence in the two-phase state. The calculations were not associated with a concrete porous medium, and they were based on the condition of phase equilibrium of such a medium at diff erent capillary pressure jumps in it.
Author:  M. I. Raikovskii, A. Yu. Dem'yanov, O. Yu. Dinariev, D. V. Rudenko
Keywords:  capillary pressure jump, saturation, phase equilibrium, gas–condensate mixture, free energy
Page:  1516

FORMATION OF GAS HYDRATE IN A POROUS MEDIUM WITH ARRHENIUS-TYPE KINETICS
The authors have presented a theoretical model of the process of hydrate formation in a porous medium on injection of gas into it in the case where the hydrate-formation kinetics is described by the Arrhenius law. It has been established that in the case of a phase-transition boundary impermeable to the gas fl ow hydrate formation is implemented mainly at constant pressure. It has been shown that on injection of the gas with a temperature equal to the initial temperature in the stratum, the entire water in its pores goes into a gas-hydrate state
Author:  I. K. Gimaltdinov, M. V. Stolpovskii, E. Yu. Kochanova
Keywords:  gas hydrate, porous stratum, methane, injection, temperature
Page:  1527

OFF-NORMAL INCIDENCE OF A SOUND WAVE ON THE BOUNDARY "BUBBLE LIQUID–POROUS MEDIUM SATURATED WITH BUBBLE LIQUID"
A theoretical study has been made of the refl ection and refraction of a harmonic sound wave on the boundary "bubble liquid–porous medium saturated with bubble liquid." It has been established that in the case of incidence of such a wave on the indicated boundary at a certain angle, the total internal refl ection of a transverse wave occurs. Conditions have been determined with which the refl ection of the wave as that from a rigid wall occurs
Author:  I. K. Gimaltdinov, L. F. Sitdikova, A. A. Gimaltdinova
Keywords:  sound wave, refl ection and transmission coeffi cient, total internal refl ection
Page:  1534

MATHEMATICAL MODELING OF THE SEPARATION OF A MIXTURE OF NITROGEN AND OXYGEN USING A SELECTIVE MEMBRANE
A mathematical model is presented for the process of separating air into nitrogen and oxygen in a membrane installation, in which separation occurs in dynamics on the inside and outside of a tubular porous membrane. Using numerical modeling of the said process, a distribution has been obtained for nitrogen concentration after passage through the membrane. It has been established that the permeability of the membrane tubes has a signifi cant eff ect on the quality of the bleed gas and the installation ramp-up time
Author:  M. A. Anisimova, A. Ya. Gil′manov, A. V. Kuznetsov, A. P. Shevelev
Keywords:  separation, gas mixture, mechanics, selective membranes, permeability, mass conservation law, Darcy′s law
Page:  1542

MATHEMATICAL SIMULATION OF ELECTRIC BAROMEMBRANE SEPARATION OF POTASSIUM SULFATE SOLUTION IN A FLAT-CHAMBER APPARATUS
A combined approach is suggested to the mathematical simulation of electric baromembrane separation of potassium sulfate solution with varying transmembrane pressure and a fi xed value of current density, which consists of using material balance equations for the solvent, dissolved substance, and empirical dependences for kinetic coeffi cients. A static mathematical model of the process of electric baromembrane separation of potassium sulfate solution in a fl at-chamber apparatus with permeate outfl ow through two semi-permeable walls has been developed, which makes it possible to calculate the target indicators of the electric baromembrane system (volumetric fl ow rate and total salt content of the dissolved substance in the retentate)
Author:  S. V. Kovalev, P. Lua, I. S. Sedoplatov, D. I. Kobelev, O. A. Kovaleva
Keywords:  electric baromembrane separation, mathematical model, potassium sulfate
Page:  1549

ABOUT THE THERMOMECHANICS OF THE HEAT-RELEASING GRANULAR BED
The laws governing the thermomechanics of a granular bed in the case of nonuniform distribution of heat release have been studied. The bifurcation of a stationary solution of the equation of motion of gas with account for the temperature dependence of gas viscosity is described. The dependences of the critical pressure and critical gas fl ow rate on the determining factors have been established
Author:  Yu. S. Teplitskii, E. A. Pitsukha, A. R. Roslik
Keywords:  granular bed, chocking of gas fl ow, nonuniform heat release, viscous inertial mode of fl ow, bifurcation
Page:  1557

MOISTURE CONDENSATION IN MOLE PASSAGES IN SUMMER
The processes of heat and moisture transfer in mole plowed undersoil are modeled taking into account the phase transitions of water and steam. The annual and daily temperature fl uctuations over the depth of the soil layer and ground have been studied. Estimates of moisture condensation onto the inner surface of the soil and mole passage are proposed. The velocities of atmospheric air movement in mole passages and its fl ow rates in laminar and turbulent modes of fl ow are determined. Moisture condensation from the soil air into the root layer at night and in the morning was found. It has been established that under natural conditions the mass of the condensate fallen in mole passages is insuffi cient to signifi cantly increase the moisture content of soil, but the presence of mole passages in the soil has a positive eff ect on its productivity. It is shown that the use of such passages in semideserts improves the feeding of saigas and other wild animals
Author:  M. G. Alishaev
Keywords:  soil, moisture, evaporation, condensation, temperature, transfer, mole passages, crop-producing power
Page:  1565

AN EXAMPLE OF AN EXACT SOLUTION OF A NONSTATIONARY PROBLEM OF TWO-COMPONENT CONVECTION
An example of an exact analytical solution of a convection problem involving the buoyancy depending on two substances diff using at diff erent rates is given. The development of convection from instantaneous vertically homogeneous sources of these substances in a homogeneous medium in a gravity fi eld is considered. A slowly diff using substance distributed in a smaller area has a stronger eff ect on the velocity gradients of emerging convective currents and thereby determines the development of convection to a greater extent, which is possible even with a relatively small contribution of this substance to the total buoyancy of the medium. In a situation, in which the total buoyancy introduced into the medium is equal to zero (positive and negative buoyancies of two substances compensate each other), origination of a nonzero, on the average, vertical fl ow is possible
Author:  L. Kh. Ingel′
Keywords:  two-component convection, diff erential diff usion, nonstationary problem, analytical solution
Page:  1572

HEAT TRANSFER AND HYDRAULIC LOSSES OF TUBE BUNDLES WITH VORTEX GENERATORS INDENTED ON THEIR SURFACE
Using the methods of computational fl uid dynamics, an investigation has been conducted into convective heat transfer by a bundle of tubes with heat transfer enhancers in the form of a system of spherical dimples made on their outer surface. The presence of enhancers changes the structure of the fl ow and turbulizes it in the vicinity of dimples, which can lead to a reduction in the length of the wake behind the tube bundle and to a decrease in hydraulic losses due to this. Prospects are shown for the use of enhancers to raise the thermal and aerodynamic effi ciency of tube bundles at their various arrangements.
Author:  I. A. Popov, Yu. V. Zhukova, T. A. Baranova, R. T. Kadyrov,a G. S. Marshalova, A. D. Chornyi
Keywords:  convective heat transfer, turbulent fl ow regime, heat transfer enhancement, thermal and aerodynamic effi ciency, computational hydraulic gas dynamics
Page:  1576

INFLUENCE OF THE COMPRESSIBILITY OF AN AXISYMMETRIC FLOW AROUND A CYLINDER WITH COAXIAL DISKS OF OPTIMUM ARRANGEMENT FOR ITS FRONTAL RESISTANCE AT TRANSSONIC FLOW VELOCITIES
A numerical investigation of the infl uence of the compressibility of the air fl owing around a disk–cylinder–disk set with an outward-projecting disk of diameter 0.4 and a clearance between this disk and the cylinder of 0.98, close to the optimum one as to the profi le drag for the movement with a transonic velocity at Mach numbers of 0–2, on the circulation air fl ow in the clearance and on the frontal resistance of the set has been performed. The adequacy of the numerical estimates made was substantiated by their comparison with the corresponding results of experiments in a wind tunnel. It was established that in the transonic Mach number range 0.7–0.8, the structure of a vortex in the clearance between the outward-projecting disk and the front edge of the cylinder is rearranged. Because of this, unlike the axisymmetric fl ow of air around a disk–cylinder–disk set optimum for an incompressible medium, normal and oblique shocks are not formed over the shear layer of the detached fl ow in the indicated clearance, and, at M = 0.9, a lambda-like shock is formed over the side surface of the cylinder. The wave drag of a disk–cylinder–disk set, optimum for transonic velocities, increases at a smaller rate with increase in the Mach number and appear to be smaller by almost two times compared to the wave drag of a disk–cylinder–disk set optimum for the deep subsonic velocities
Author:  S. A. Isaev, D. V. Nikushchenko, A. G. Sudakov, N. V. Tryaskin, L. P. Yunakov
Keywords:  compressibility, cylinder with disks, detached axisymmetric fl ow, vortex structures, frontal resistance, numerical simulation
Page:  1593

STRUCTURE OF THE AIR FLOW IN THE CYLINDER OF ENGINES WITH INLET PIPELINES OF VARIOUS CONFIGURATIONS
Results are presented of an experimental investigation into the structure of a steady-state air fl ow in a cylinder of reciprocating internal combustion engines with intake systems of various designs when it is fi lled through a poppet valve on the basis of the method of thermal visualization imaging. It has been established that cross profi ling of cylinder inlet pipes has a substantial eff ect on the structure of the fl ow in it. It is shown that the use of square and triangular pipes makes it possible to obtain a more uniform fl ow distribution through the cylinder volume compared to pipes of other confi gurations, which ensures a more complete combustion of the fuel–air mixture and, accordingly, an improvement of technical-economic and environmental performance of a piston engine
Author:  L. V. Plotnikov
Keywords:  internal combustion engine, cylinder, intake system, profi led pipes, steady fl ow, experimental investigations
Page:  1604

LAMINAR BOUNDARY LAYER IN TWO-DIMENSIONAL DETACHED FLOWS
A new approach to the calculation of the laminar boundary layer in a two-dimensional detached fl uid fl ow with the use of two or three integral relations representing the velocity profi le of this fl ow in the form of a defi nite-degree polynomial is proposed. The initial problem on the indicated layer is defi ned by the system of two or three ordinary diff erential equations. The Howart, Tani, and Görtler fl ows with a decreasing velocity and the fl ows whose velocity initially increases and then decreases (the Curle fl ow, the transverse fl ow around a circular cylinder, and the fl ow around a sphere) were considered. A comparative analysis of the results of calculations of these fl ows has shown that the approach proposed allows one to practically exactly determine the point of separation of the boundary layer in them
Author:  V. A. Kot
Keywords:  boundary layer, two-dimensional detached fl ows, polynomial solution, integral methods
Page:  1610

CALCULATION OF THE THERMAL PROPERTIES OF AMORPHOUS AND CRYSTALLINE SUBSTANCES
An improved classical theory of the nucleation of crystals in a disordered medium with conservation of the spherical shape of the growing crystals is presented. The counteractions of the matrix of such a medium to the growth of crystals in it as well as the changes in this medium with change in its temperature and with time, calculated by a simple thermodynamic model of a two-phase system, are demonstrated. The coeffi cients of thermal expansion of a number of metals and the heat capacities of them at temperatures falling within a wide range were calculated. The temperature and time dependences of the volume fraction of the crystalline phase in a metal were constructed using the indicated thermodynamic model, and they were in good agreement with the experimental ones. It is shown that the changes in the volume of a metal, caused by its heating or cooling, are defi ned correctly by this model and that the indicated changes are determined by the dependences of the thermal volume expansion of the metal on its temperature and the volume fraction of the ordering phase in it. It was established that the thermodynamic model of a two-phase system can be used for the defi nition of the temperature dependence of the heat capacities of metals experiencing diff erent phase transitions
Author:  S. V. Terekhov
Keywords:  amorphous alloys, crystallization, smeared phase transition, thermodynamic model, heat capacity
Page:  1631

COMPARATIVE ANALYSIS OF THE RESISTANCE OF ROCKY SOIL BARRIERS TO PENETRATION BY STRIKERS WITH CONICAL AND OGIVAL NOSES
Based on the local interaction theory, a comparative analysis has been made of the force of resistance in penetration of rocky soil barriers by nondeformable strikers with conical and ogival noses. Normal stresses on the surface of the striker nose contacting the barrier were assumed in the form of a quadratic dependence on a striker velocity that is normal to the vector component surface, while tangential stresses were determined on the basis of the dry friction law. In conducting the analysis, use was made of the nose shape coeffi cients describing the contribution to the total force of resistance by the summands depending on the striker velocity raised to zero, fi rst, and second powers. For strikers with an ogival nose, an assessment was made of a possible infl uence on the resistance force exerted by the eff ect of the barrier material separation from the nose surface.
Author:  S. V. Fedorov, V. A. Veldanov, I. A. Bolotina, A. V. Dyukov, T. A. Gushchina
Keywords:  high-velocity penetration, rocky soil barrier, nondeformable striker, conical nose, ogival nose, force of resistance
Page:  1640

BLOCK DIAGRAM OF APCS OF INSTALLATIONS FOR WET-HEAT PROCESSING OF GRAIN PRODUCTS
Remote control of electric motors of mechanism drives from a control panel in automatic, semi-automatic, and manual modes of operation, as well as local start and stop of electric motors for repair or removal of automatic locking are considered. The instrumentation and automatic devices used must provide blocking, control, and signaling of the operation of electrical equipment, levels of product fi lling of bunkers and heat and mass exchangers, temperature of the drying agent, moisture content of the dried material, indication of the position of valves and slide gates, operation of the furnace and the condition of its fuel- and air-supply systems
Author:  P. M. Matyakubova, P. R. Ismatullaev, N. I. Avezova, M. M. Makhmudzhonov
Keywords:  control systems, remote control, heat and mass exchange, wet-heat processing, ignition device, mathematical model
Page:  1652

PLANE WAVE REFLECTION IN A MEMORY-DEPENDENT NONLOCAL MAGNETOTHERMOELASTIC ELECTRICALLY CONDUCTING TRICLINIC SOLID HALF-SPACE
In this paper, the memory-dependent nonlocal magnetothermoelasticity theory is used for the refl ection problem in a magnetized electrically conducting thermo-triclinic solid half-space. The velocity equation is derived by formulating and solving the governing equations for a triclinic magnetothermoelastic medium according to the memory-dependent derivative nonlocalized thermoelasticity. Three quasi-plane waves, namely, quasi-longitudinal displacement (qP), quasi-thermal (qT), and quasi-shear vertical (qSV) waves, propagate in the medium according to the plane-wave solution. The wave velocities are calculated. For the incidence of a coupled quasi-plane wave, the equations for the refl ection coeffi cient and energy ratio are derived. These characteristics are presented graphically. 
Author:  A. K. Yadava, E. Schnack
Keywords:  memory-dependent derivative (MDD), nonlocality, kernel, magnetic fi eld, refl ection coeffi cient, energy ratio, triclinic half-space
Page:  1658

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