Volume 91, №4
MASS CONDUCTIVITY OF CAPILLARY-POROUS COLLOIDAL MATERIALS SUBJECTED TO CONVECTIVE DRYING
Mass conducting (diffusional) properties of capillary-porous colloidal materials have been studied experimentally in the process of their convective drying depending on the moisture content and temperature of the material using as an example maize grains of three varieties. The physical mechanisms that infl uence the dependence of the mass conductivity coeffi cient of such a material on its moisture content are considered. It is shown that provided there is invariance of the dependence of the local temperature of the material on its local moisture content, the mass conductivity coeffi cient of the material can be determined depending on the moisture content of the latter and on the drying agent temperature, which simplifi es the calculation of the drying kinetics substantially.
Author: S. P. Rudobashta, G. A. Zueva, E. A. Muravleva, and V. M. Dmitriev
Keywords: capillary-porous colloidal material, convective drying, mass conductivity, kinetic calculation
CHARACTERISTIC FEATURES OF SOUND PROPAGATION IN A WARM BUBBLE-LADEN WATER
The propagation of weak disturbances in a water–air bubble medium has been studied under the conditions when in addition to the gas (e.g., air) undissolved in water the bubbles contain steam that can convert into water in the process of mixture motion. The air contained in the bubbles will in this case exert diffusion resistance and infl uence the intensity of phase transitions in the steam–water system. The infl uence of the initial parameters of a two-phase water–bubble mixture (volume content of phases, dispersed phase size, water temperature) on the evolution of harmonic waves in a bubble liquid has been analyzed.
Author: V. Sh. Shagapov, M. N. Galimzyanov, I. I. Vdovenko, and N. S. Khabeev
Keywords: water–air bubble medium, bubbles, phase transition, harmonic waves, phase velocity, damping factor
REGIMES OF HYDRATE FORMATION IN THE PROCESS OF INJECTION OF CARBON DIOXIDE INTO A POROUS MEDIUM SATURATED WITH METHANE AND WATER
The problem on the formation of the hydrate of carbon dioxide in the process of its injection into a porous medium saturated with methane and water, whose initial temperature does not correspond to the thermodynamic conditions of existence of the carbon-dioxide hydrate, was considered. This problem was solved for the case where the hydrate formation takes place at the front interface not coincident with the boundary of displacement of methane by carbon dioxide. It is shown that, in the case where the initial temperature of the porous medium exceeds the equilibrium temperature of hydrate formation, the carbon-dioxide hydrate can be formed in three regimes. Curves separating these regimes depending on the injection pressure, the initial temperature of the medium, and its permeability have been constructed
Author: M. K. Khasanov
Keywords: hydrate formation, porous medium, carbon dioxide, solid gas hydrates, methane, water
COMPUTER SIMULATION OF THE PROCESS OF FILTRATION OF MINE WATERS ON A LAYER OF SAND
Simulation of the technology of removal of highly dispersed solid impurities from industrial effl uents using the sand fi lter has been carried out by the discrete-element method. Calculations of the formation of barrier and cake beds, of the fi lter reaching an operating regime, and of the degree of treatment of the liquid as a function of the size of impurity particles and their percentage in the mixture have been performed. The infl uence of the fi lter wall on the process of treatment of the liquid has been analyzed.
Author: N. N. D′yachenko and E. N. D′yachenko
Keywords: mathematical simulation, filtration, mine waters, adhesive interaction.
MODELING OF THE PROCESS OF ELECTROSTATIC SORPTION ON SUSPENDED PARTICLES OF SOLID-PHASE POWDERS IN AIR SPACE
In the present work, the authors have made a literature analysis of the infl uence of various factors on the adsorbability of harmful substances in air space. A physicomathematical substantiation of the improvement of the sorption capacity due to the presence of a charge on particles of nanostructured sorption compositions has been proposed. The kinetics of sorption as a function of the interaction time and the dispersity of particles of the charged sorbent and neutral particles of the solute has been determined. Experimental and theoretical assessment of the process of coagulation of liquid-phase particles of glycerin with electrostatically charged solid-phase powders of various kinds in a closed volume have been made. The proposed physicomathematical model of electrostatic sorption was tested for adequacy to experimental data on variation in the average volume-surface diameter of electrostatically charged aerosol formations with time.
Author: M. Yu. Stepkina and O. B. Kudryashova
Keywords: disinfection, sorption, nanostructured particles, electrostatic spraying, kinetics of sorption, electrostatic coagulation
INFLUENCE OF CRACKS AND PORES IN COAL O N ITS IMPEDANCE SPECTRA
A model of coal containing coincidentally distributed closed pores and randomly oriented cracks was considered for theoretical substantiation of the experimental curves for the electrochemical impedance of a dry coal with a middle-stage metamorphism. Analytical expressions for the frequency dependences of the real and imaginary parts of the impedance of this coal have been obtained. Hodographs of the impedances of coals with different degrees of cracking have been constructed in the form of two overlapping semicircles in the upper half-plane of the system of axes. It was established that the high-frequency semicircle represents the closed porosity in a coal and the lowfrequency semicircle is due to its cracking. A method of determining the coeffi cients of cracking and closed porosity of coal by its experimental impedance spectra is proposed.
Author: L. I. Stefanovich, É. P. Fel′dman, and A. K. Kirillov
Keywords: coal, metamorphism, electrochemical impedance, impedance spectroscopy, impedance hodograph, cracking, closed porosity
NUMERICAL SOLUTION FOR DETERMINING THE TEMPERATURE AND MOISTURE DISTRIBUTIONS OF RECTANGULAR, CYLINDRICAL, AND SPHERICAL OBJECTS DURING DRYING
A simultaneous heat and mass transfer model for convective drying of moist food materials has been developed. Cartesian, cylindrical, and spherical coordinate systems are taken for the analysis, as food materials dried in industries are of different shapes. The governing transient partial differential equations describing heat and mass transfer are discretized, using the fi nite difference method, and sets of algebraic equations are obtained. The diffusion coeffi cient is a temperature function, and, therefore, the heat and moisture transfer equations are solved simultaneously. A MATLAB computer code is developed to solve them. Transient temperature and moisture profi les during convective drying are estimated. The present results are compared with the existing experimental data, and it is observed that there is good agreement.
Author: G. Arunsandeep and V. P. Chandramohan
Keywords: convective drying, temperature and moisture distributions, fi nite difference method, diffusion coeffi cient, partial differential equations
INFLUENCE OF THE DENSITY OF A FOREST COMBUSTIBLE MATERIAL ON THE SUPPRESSION OF ITS THERMAL DECOMPOSITION BY A LIQUID AEROSOL
Experimental investigations on the characteristic time of suppression of the thermal decomposition of the soil cover of coniferous and foliage forests and on the volume of water required for this purpose have been performed. Experiments were conducted with samples of typical forest combustible materials (birch leaves and spruce needles) of different densities under conditions characteristic of a forest fi re extinguished by a liquid aerosol with the use of modern fi re-extinguishing means. It was established that it makes no sense to increase the volume of water used for suppression of the ignition of a forest combustible material whose density exceeds a defi nite limiting value.
Author: A. O. Zhdanova, G. V. Kuznetsov, and P. A. Strizhak
Keywords: forest combustible material, hotbed of fi re, thermal decomposition, fl ame combustion, suppression of combustion, water, aerosol fl ow
EXPERIMENTAL INVESTIGATION OF THE EFFECT EXERTED BY A NATURAL FIRE ON WOOD MATERIAL
An experimental investigation of ignition of a wood material under the action of the forest fi re front has been carried out in a laboratory to determine the conditions of ignition and combustion. The surface temperatures of samples were measured by means of thermocouples. The dependences have been derived showing the change of the surface temperature of samples exposed to the ground fi re front.
Author: V. P. Zima and D. P. Kasymov
Keywords: wood, ignition, vegetable combustible materials, thermocouple, physical modeling, combustion site.
MODELING OF THE COMBUSTION OF A METHANE–AIR MIXTURE IN AN ENCLOSED SPHERICAL VOLUME
Results of numerical modeling of the propagation of the combustion front of a methane–air mixture in an enclosed spherical volume with an ignition source at the center have been presented. A mathematical model consists of the mass, momentum, and total-energy equations of the gas with account of the heat conduction and chemical reaction, and also of the mass equations of components of the gas mixture with account of their diffusion and burning. The velocity of advance of the combustion front, the pressure change in the volume with time, and the time of burning of the mixture as functions of the content of methane have been determined. The nonuniformity of the distribution of the gas temperature in the volume space after the burning of the mixture has been shown.
Author: A. Yu. Krainov and K. M. Moiseeva
Keywords: methane–air mixture, spherical volume, rate of combustion, mathematical modeling, Mache effect
FEATURES OF BURNING OF PULVERIZED PEAT FUEL IN A VORTEX BURNER DEVICE
The authors have substantiated the relevance of development and implementation of novel combustion schemes ensuring stabilization of the furnace process due to the burning of the basic pulverized fuel without using additional energy sources and high-reactive fi elds. Distinctive features of burning of pulverized peat fuel in a straight-fl ow vortex burner device have been investigated experimentally. Regimes of stable combustion of peat dust without addition of high-reactive gaseous and liquid fuels have been determined; transient regimes of operation of the burner device have been found, whose analysis enabled the authors to determine the required character of distribution of air when it is fed into the combustion zone. Emission characteristics of burning of peat dust in a swirling fl ow have been investigated; the most effi cient conditions of organization of the combustion process from the viewpoint of ensuring a high combustion effi ciency and minimum emissions of nitric oxides NOx have been determined.
Author: A. S. Mikhailov, Sh. A. Piralishvili, E. G. Stepanov,O. A. Evdokimov, and N. S. Spesivtseva
Keywords: combustion, peat, pulverized burning, swirling fl ow, vortex burner device.
DETERMINING THE PARAMETERS OF THE WORKING GASES USED IN THE PROCESS OF HYPERSONIC METALLIZATION OF STEEL COATINGS
Theoretical and practical investigations of the effect of combustible gas parameters on the thermodynamic characteristics of a two-phase jet have been carried out. The infl uence of the thermal parameters of combustion of alkanes on the quantity of air supplied to cool the metallizer combustion chamber has been studied. The infl uence of the combustible mixture composition on the properties of steel coatings formed has been estimated.
Author: M. A. Belotserkovskii, V. V. Shkurko, A. V. Sosnovskii, and D. I. Trusov
Keywords: gas-thermal spraying, hypersonic metallization, metal coatings, combustible gas
NEW SCHEMES OF DIGITAL SPECKLE PHOTOGRAPHY
This paper presents a review and an analysis of the development of speckle photography from the fi rst experiments performed at the National Physical Laboratory of Great Britain up to the present time. The possibility of diagnosing turbulent and three-dimensional fl ows by the speckle photography methods has been shown. The single-exposure scheme of speckle photography has been analyzed and the possibility of using multiaspect speckle photography in reconstructive tomography of complex three-dimensional fl ows has been shown. Methods based on speckle technologies such as Talbot interferometry, PIV and BOS techniques have been analyzed. Particular consideration is given to the application of new measuring technologies in diagnosing turbulent fl ows and reconstructive tomography of three-dimensional fl ows.
Author: O. G. Penyazkov and N. A. Fomin
Keywords: digital speckle photography, speckle technologies, speckle fi eld, cross-correlation analysis, PIV, BOS, Talbot interferometry
INITIAL STAGE OF THE EFFERVESCING LIQUID OUTFLOW FROM A SEMI-INFINITE CHANNEL. SOLUTION IN THE FORM OF THE RIEMANN WAVE
The theory of Riemann waves used in the present work for describing the initial stage of outfl ow of an effervescing liquid from a tubular channel, and basic equations describing the effervescing liquid fl ow are given. A mathematical model of the outfl ow of an effervescing liquid from a tubular channel in the case of seal failure at one end of the channel has been constructed. Self-similar solutions of the process of outfl ow for the initial stage with insignifi cant forces of hydraulic friction have been obtained.
Author: F. R. Khuzina, M. S. Salieva, V. A. Krasil′nikov, and A. R. Nabiullin
Keywords: effervescing liquid, self-similar solutions, hydraulic friction
INTENSIFICATION OF HEAT EXCHANGE IN LAMINAR VORTEX AIR FLOW IN A NARROW CHANNEL WITH A ROW OF INCLINED OVAL TRENCHES
With the use of multiblock computational technologies, the laminar fl ow and heat exchange in the modules arranged in a row at regular intervals in a plane-parallel channel, at the centers of which oval trenches oriented at an angle of 45o to the fl ow are positioned, were calculated at Re = 103 . On the basis of the calculation data obtained, it was established that an increase in the maximum velocity of the fl ow in such a channel by one and a half times leads to the intensifi cation of the heat exchange in it and an increase in the heat transfer from the surface region on its wall with an inclined trench by 80% with an increase in the hydraulic losses by 25%, as compared to those of an analogous smooth channel.
Author: S. A. Isaev, A. I. Leont′ev, O. O. Mil′man, A. G. Sudakov, A. E. Usachov, and M. E. Gul′tsovа
Keywords: intensifi cation of heat exchange, laminar air fl ow, narrow channel, inclined oval trenches, single-row package, periodicity, VP2/3 package.
NUMERICAL AND EXPERIMENTAL INVESTIGATIONS OF DISTURBED PRESSURES IN THE VICINITY OF A TANDEM WING CONFIGURATION
This paper presents the results of numerical calculations and experiments in the form of distributions of disturbed pressures generated by the tandem confi guration of a schematized model of a supersonic passenger airplane on the control surface in the disturbed region. The numerical solution of the problem on the fl ow over a geometrical model was carried out and the necessary measurements were made in experiments at a Mach number of the free stream M = 2.03 and an angle of attack α = 3.5o . It has been shown that the pressure distribution over the azimuth coordinate has a spatial character. Comparison of numerical calculations with the results of the experiment has shown their good agreement in the part of the profi le where shock waves from the nose and from the forward and the rear wings are present. Because of the design features of the model–holder coupling, the trailing shock wave and the wake were not modeled in the experiment.
Author: V. F. Volkov, T. A. Kiseleva, and V. G. Chirkashenko
Keywords: supersonic fl ow, shock wave, sonic boom, tandem confi guration, monoplane
FREE CONVECTIVE FLOW, HEAT AND MASS TRANSFER IN A MICROPOLAR FLUID OVER A SHRINKING SHEET IN THE PRESENCE OF A HEAT SOURCE
The paper considers a free convective fl ow of a micropolar fl uid in the presence of a heat source/sink over a shrinking sheet. Similarity transformations are used to reduce the governing coupled nonlinear partial differential equations, namely, the momentum and concentration equations, as well as the nonhomogeneous heat equation, to a set of nonlinear ordinary differential equations. Their numerical solution is obtained by the Runge–Kutta fourth-order method accompanied by the shooting technique. The effects of various physical parameters characterizing the fl ow are studied. The validation of the present results by the earlier published ones is performed in a particular case, and good agreement is obtained.
Author: S. R. Mishra, J. Mohanty, and J. K. Das
Keywords: micropolar fl uid, free convection, shrinking sheet, heat and mass transfer, Runge–Kutta method
NUMERICAL MODELING OF THE THERMAL STATE OF A METAL–CONCRETE CONTAINER WITH SPENT NUCLEAR FUEL DURING ITS TRANSPORTATION
In the work, the authors have presented the procedure and have given results of numerical modeling of the thermal state of a metal–concrete container with spent nuclear fuel during its transportation in a special car. Maximum temperatures of fuel-element sheaths have been determined for several versions of loading of the container with fuel including spent nuclear fuel, with short storage periods.
Author: Yu. E. Karyakin, V. M. Kuzin, A. A. Pletnev, and E. D. Fedorovich
Keywords: metal–concrete container, spent nuclear fuel, thermal calculation, numerical modeling.
INFLUENCE OF THERMAL ACTION ON THE EFFECT OF INCREASING THE CARRYING CAPACITY OF ROTATING DISKS WITH THIN HIGH-MODULUS COATINGS
Based on the general concepts of the linear theory of unbound thermoelasticity, the problems on calculating the temperature fi elds and mechanical behavior of rotating disks with strengthening coatings have been formulated. A single numerical method has been developed for integrating the posed thermal conductivity and thermoelasticity problems, and concrete calculations of the carrying capacity of layered disks were performed. It has been established that the presence of defi nite temperature fi elds in a layered disk may hinder its strengthening of the disk surface covered with a thin high-modulus coating of thickness 0.1–0.6 mm that sharply strengthens the disk at the temperature of its natural state
Author: A. P. Yankovskii
Keywords: rotating disk, rigid coating, strengthening, loss of strength, carrying capacity, unbound thermoelasticity, thermal action
GENERALIZED SOLUTION OF THE MIXED HEAT-CONDUCTION PROBLEM BY THE WEIGHTED TEMPERATURE METHOD
On the basis of the weighted temperature method, an algorithm of generalized solution of boundary-value problems on the heat conduction in bodies canonical in shape with boundary conditions of general form has been constructed. It is shown that this problem is equivalent, in the limit, to the infi nite system of identities including n-fold integral operators for the temperature function, initial and boundary conditions, and internal heat source as well as an additional boundary function (the temperature at one of the boundary points or its derivative with respect to the coordinate of this point). High approximation accuracy of the approach proposed is demonstrated by the example of solving a number of boundary-value problems on nonstationary heat conduction with nonsymmetric and mixed boundary conditions.
Author: V. A. Kot
Keywords: boundary-value problem, nonstationary heat conduction, analytical methods, approximation, weighted temperature method
UNITIZED POWER AND HEAT GENERATING STEAM–GAS PLANT
This paper considers the prospects of creating steam–gas thermoelectric plants for power supply to microdistricts and towns remote from centralized power plants. We propose a new type of thermoelectric plants with a waste heat boiler of medium steam parameters and an afterburner section located between its evaporation stages. It has been shown that fuel afterburning increases electric and thermal power and the specifi c electric power production at heat consumption.
Author: V. V. Biryuk, E. A. Larin, M. Yu. Livshits, L. P. Shelud′ko, and A. A. Shimanov
Keywords: decentralized heat supply, thermoelectric plant, steam–gas plant, steam-generating capacity
RHEOLOGICAL PROPERTIES OF HYDROCARBON SYSTEMS WITH A HIGH CONTENT OF RESINS AND ASPHALTENES
The physicochemical properties of the investigated hydrocarbon media — oils and high-boiling fractions — are presented. Based on the rheological characteristics, the type of fl uids has been determined in accordance with the Newton law, as well as the presence of viscosity anomaly of the investigated media at various temperatures. The values of the oil thixotropy energy, as well as of the viscous fl ow activation energy of the studied systems, have been obtained. Phase transition of high-boiling fractions at 60o C has been revealed. The dependences of the viscous fl ow entropy of investigated hydrocarbon media on increase in the temperature from 10 to 140o C have been obtained. The dependences of the frequency of jumps of hydrocarbon system molecules on viscosity have been obtained for the fi rst time.
Author: A. A. Boitsova and N. K. Kondrasheva
Keywords: rheology, multicomponent hydrocarbon medium, high-boiling fraction, oil, structural-mechanical properties, viscous fl ow activation entropy, frequency of molecule jumps, hysteresis loop, thixotropy energy, phase transition.
WETTING POWER OF DEMULSIFIERS FOR HIGH-VISCOSITY AND HEAVY OILS OF KAZAKHSTAN
The authors give experimental data on the dynamics of wetting of a hydrocarbon surface with surfactant solution and on the velocity of motion of the liquid front through solid components of the oil (resins, asphaltenes, and paraffi ns) treated with hydrocarbon compounds.
Author: R. Kh. Salakhov, R. F. Khamidullin, Z. A. Mansurov, D. U. Bodykov, and M. A. Seitzhanova
Keywords: high-viscosity oil, surfactant, wetting power, demulsifi er, aggregative stability.
CONTROLLING CHARGED-PARTICLE FLUXES IN THE EROSIVE LASER PLASMA OF A GRAPHITE TARGET IN VACUUM
Parameters of the erosive laser plasma of a graphite target on exposure to Nd3+:YAG-laser pulses with a wavelength λ = 1064 nm and a pulse duration τ ~ 20 ns have been investigated. Two zones of glow have been found. One zone is quiescent and is located at the target surface at the site of exposure to laser radiation. The other glow zone moves opposite to a laser beam with a velocity of ~10 km/s. A method to control charged-particle fl uxes in the erosive laser torch has been proposed.
Author: V. K. Goncharov, M. V. Puzyrev, and V. Yu. Stupakevich
Keywords: erosive laser plasma, graphite target, electric double layer.
CONTROLLING THE SIZE AND PHASE COMPOSITION OF SUBMICRON TITANIUM-DIOXIDE PARTICLES SYNTHESIZED IN A FLOW-TYPE PLASMA CHEMICAL REACTOR
The authors have modeled a number of operating regimes of a fl ow-type plasma chemical reactor that differ in one parameter. This made it possible to qualitatively and quantitatively assess the infl uence of these regimes on the gasdynamic structure of fl ow in the reactor, which determines the size and the phase composition of synthesized particles.
Author: S. M. Aul′chenko and E. V. Kartaev
Keywords: titanium dioxide, plasma chemical reactor, quasigasdynamic system of equations, homogeneous and heterogeneous reactions, nucleation, coagulation
CALCULATION OF FILTRATION CHARACTERISTICS OF POROUS MEDIA BY THEIR DIGITIZED IMAGES WITH THE USE OF LATTICE BOLTZMANN EQUATIONS
We have investigated the features of using STR and MTR models of lattice Boltzmann equations for calculating the fi ltration characteristics of porous media with the use of their digital images. The results of calculations performed on the basis of these models were compared with the results of analytical calculations made with the use of stationary Navier–Stokes equations and continuity equations. Calculations of the laminar fl ow in a pipe with the use of the MTR model had a much higher accuracy as compared to analogous calculations by the SRT model and showed independence of the relaxation parameter. It has been established that for fl uid fl ow in pore channels the MRT model and the Navier–Stokes equations give comparable results, whereas in using the SRT model the numerical solution depends on the relaxation parameter.
Author: T. R. Zakirov, A. A. Galeev, E. O. Statsenko, and L. I. Khaidarova
Keywords: mathematical modeling, lattice Boltzmann equations, x-ray microtomography, porous media.
THERMAL AND THERMOPHYSICAL PROPERTIES OF THE RADIOACTIVE GRAPHITE–INERT GAS SYSTEM IN HEATING. COMPUTER EXPERIMENT
Consideration has been given to the capabilities of the TERRA software system for modeling thermodynamically the heating of a radioactive graphite–inert gas system in a nuclear reactor. As a result of such modeling, the authors have determined processes occurring in the reactor with the involvement of Eu, Pu, and U actinoids during the heating of the radioactive graphite–argon system at pressures of 105 and 106 Pa, and also equilibrium constants of chemical reactions and the infl uence of pressure on them. The thermophysical properties of the system have been studied, and the infl uence of pressure on its specifi c volume, the heat capacity, and the molar mass of a gas phase and the weight fraction of a condensed phase has been established.
Author: N. M. Barbin, T. S. Kolbin, D. I. Terent′ev, S. G. Alekseev, and I. A. Kaibichev
Keywords: thermodynamic modeling, equilibrium constants, radioactive graphite, radionuclides, heating
DETERMINATION OF THE THERMOPHYSICAL CHARACTERISTICS OF LIQUIDS BY THE LASER-BURST METHOD
From the results of mathematical modeling of heat-conduction processes under conditions corresponding to experiments on determination of the thermophysical characteristics of liquids by the laser-burst method, the authors have substantiated possible ranges of variation in basic factors. The authors have established the values of the heat fl uxes and of the thicknesses of liquid layers that ensure minimum errors in determining the thermal diffusivity of the liquid when the surface of a measurement cell is exposed to a laser burst of fi nite duration.
Author: M. D. Kats and I. M. Kats
Keywords: laser-burst method, thermal diffusivity of the liquid, layer thickness, heat fl ux, methodological errors, heat-conduction equations, numerical solution
EXPERIMENTAL INVESTIGATION OF THE CONTACT HEAT RESISTANCE IN THE THREADED JOINT ZONE OF CONTACT SURFACES
For the fi rst time the range of values has been determined experimentally of the absolute contact heat resistance in the zone of the threaded joint of two parts of cylindrical form from aluminum alloy with a thread length exceeding its diameter by a factor of more than 3 with the transferred heat fl ux varied over the range from 4.5 to 78.5 W. It has been shown that the contact heat resistance is infl uenced by the value of the transferred heat fl ux, the presence of a heat conducting medium in the contact zone, and the conditions of tightening the thread for contact heat resistance. It has been established that in a threaded joint of length 53 mm having a diameter of 14 mm and a thread pitch of 0.5 mm without using a heat conducting medium in the contact zone, as the heat fl ux increases from 4.5 to 78.5 W, the value of the contact heat resistance without tightening of the thread decreases from 0.35 to 0.18o C/W. Tightening of the thread up to the stop leads to an insignifi cant decrease in the value of the contact heat resistance. At the same time the injection into the contact zone of the threaded joint of the heat conducting paste KPT-8 decreases the heat resistance of the contact by a factor of 2.2 at the minimal transferred heat fl ux (4.5 W) and by a factor of 1.6 at the maximal heat fl ux (78.5 W).
Author: Yu. E. Nikolaenko and A. S. Postol
Keywords: contact heat exchange, heat resistance, threaded joint, heat pipe, light emitting module.
INVESTIGATIONS OF THE SONIC BOOM PROBLEM AT THE INSTITUTE OF THEORETICAL AND APPLIED MECHANICS, SIBERIAN BRANCH OF THE RUSSIAN ACADEMY OF SCIENCES
This paper is a review of the series of investigations carried out at the S. A. Khristianovich Institute of Theoretical and Applied Mechanics (ITAM, Siberian Branch of the Russian Academy of Sciences (RAS)) aimed at solving the sonic boom problem. It has been shown, with the example of fl ow over a body of revolution at Mach number M = 2, that a decrease in the fl ow temperature near the body leads to a change in the fl ow structure in the region of the formation of a hanging shock wave and a decrease (by 12%) in the sonic boom intensity on the ground. The results are presented of investigations of the infl uence of the relative position and geometrical shape of confi guration elements of a supersonic passenger airplane on the sonic boom parameters at long distances from the disturbance source. The prospective aspect of the supersonic passenger airplane providing the minimum level of sonic boom in cruising fl ight has been determined. The scheme (IZS method) for measuring in the experiment disturbed pressure profi les at a given distance from the investigated model has been described.
Author: V. M. Fomin, V. F. Volkov, T. A. Kiseleva and V. F. Chirkashenko
Keywords: supersonic fl ow, sonic boom, cryogenic action, monoplane, tandem wing confi guration, engine nacelle.