Volume 88, №6
NONISOTHERMAL FLOW OF A REACTIVE FLUID WITH SIMULTANEOUS IMPREGNATION OF A POROUS LAYER
Consideration is given to the nonisothermal filling of a plane cavity with a Newtonian chemically reactive fluid with simultaneous impregnation of a porous layer. Flow in the plane cavity is described by noninertial Navier–Stokes equations, and in the porous layer, by the Darcy equation; fl ow in the region adjacent to the boundary between the fluid and the porous layer is defi ned using the Brinkman equation. The viscosity is taken to be dependent on temperature and on the extent to which the chemical reaction proceeds. A single-temperature model is used as the energy equation. Temperature fi elds in the region of a channel and in the porous layer are interrelated by conjugate fourth-kind boundary conditions. An example of determining the maximum allowable molding time is shown.
Author: A. V. Baranov
Keywords: Newtonian fluid, heat transfer, shear flow, impregnation, molding
NONSTATIONARY MASS TRANSFER NEAR THE SURFACE OF A CYLINDRICAL BODY
The problem of nonstationary diffusion of the target component to a phase that is external relative to the surface of a cylindrical body has been formulated and solved analytically. From the found solution the dependences have been obtained for calculating the instantaneous mass transfer coeffi cient and the phase-contact-time mean mass transfer coeffi cient, on the basis of which the process of extraction of technological pollutants from fi brous materials has been analyzed.
Author: S. P. Rudobashta, M. K. Kosheleva, and É. M. Kartashov
Keywords: mass transfer coefficient, diffusion, extraction, fibers
PRESSURE FIELD IN THE PROCESS OF RADIAL FILTRATION IN A NONUNIFORM ORTHOTROPIC STRATUM IN THE ASYMPTOTIC APPROXIMATION
Simple analytical formulas for defi nition of the pressure fi eld, formed in the process of continuous withdrawal of a fluid from a nonuniform anisotropic stratum, in the zero and fi rst approximations on the assumption that the fl uid flow in the stratum is one-dimensional and linear were derived on the basis of the modifi ed asymptotic method exact on average. The results of calculations of the pressure fi elds in such stratums by the formulas obtained are presented.
Author: A. I. Filippov, O. V. Akhmetova, and M. R. Gubaidullin
Keywords: pressure field, filtration, asymptotic method, nonuniform orthotropic stratum
ON NONSTATIONARY PROCESSES OF HEAT TRANSFER IN A BED OF FINELY DISPERSED CAPSULES IN THE PRESENCE OF PHASE TRANSITION
Within the framework of the two-temperature model, the authors have investigated the dynamics of charging and
discharging of a bed of fi nely dispersed spherical capsules. Generalized dependences have been obtained for
calculating the times of charging and discharging of a heat accumulator.
Author: Yu. S. Teplitskii and A. R. Roslik
Keywords: heat accumulator, enthalpy method, two-temperature model, charging, discharging, paraffin
CRITERION OF OCCURRENCE OF FILTRATION CONVECTION OF A MIXTURE WITH ACCOUNT OF EQUILIBRIUM AND NONEQUILIBRIUM ADSORPTION
Convective stability of a binary mixture in a porous medium has been studied with account taken of equilibrium and nonequilibrium adsorption. The regularities of the infl uence of the parameters of equilibrium adsorption and of kinetic coeffi cients in the case of nonequilibrium adsorption on the conditions of occurrence of convection have been established. A comparison of the results with the case of the absence of adsorption has been presented.
Author: M. M. Ramazanov and N. S. Bulgakova
Keywords: filtration convection, adsorption of the components, porous medium
FRONTAL REGIME OF HEAT AND MASS TRANSFER IN A GEOTHERMAL BED
Based on an earlier proposed mathematical model, the conditions for the existence of a frontal regime of steam extraction from a high-temperature bed have been derived. It is shown that unlike the familiar one-dimensional case, in the radial-symmetrical model considered the radius of the region occupied by steam tends to a limiting value, that is, the front of boiling that separates the regions of water and steam practically comes to a stop after a time. A formula has been derived pointing clearly to the dependence of the indicated limiting value of the front radius on the water and steam parameters as well as on the characteristics of the geothermal bed. It is shown that for the steam to occupy a considerable region around the well when the bed is in service, it is necessary that the initial state of water be close to that of steam generation. Otherwise the front of boiling in the considered regime of heat and mass transfer extends from the well only a little.
Author: A. B. Alkhasov, M. M. Ramazanov, and D. A. Alkhasova
Keywords: steam generation in a bed, heat and mass transfer, fl ow regimes, radial model, analytical solution
EVAPORATION AND CONDENSATION OF MOISTURE IN A MOLE-PLOWED SOIL
Consideration is given to temperature waves, traveling in a soil from its surface, with account for phase transitions of moisture and for the influence exerted by mole passages made by a special technology. It is pointed out that evaporation and condensation, rather than a fl ux of soil air, introduce noticeable corrections into the distribution of the soil layer temperature. An analysis of the problem and evaluating solutions are given and a technique of calculation of the moisture condensed in mole passages and in the rooty layer of soil is suggested. Weather data for Yuzhno-Sukhokumsk are used. The results are applicable to the climatic conditions of the Prikaspiiskaya (NearCaspian) semidesert.
Author: M. G. Alishaev
Keywords: air, moisture content, evaporation, condensation, mole passage, soil, filtration, temperature, traveling wave.
MATHEMATICAL MODEL OF A THERMOSTATING COATING WITH A THERMOELECTRIC MODULE
On the basis of a variational formulation of the problem of stationary heat conduction in a heterogeneous solid, a mathematical model of a fragment of a fl at heat-insulating layer containing a thermoelectric module has been constructed. This model has been used to establish conditions under which, when fulfi lled, the heat-insulating layer can serve as a thermostating coating for an object with a given fi xed temperature under convective-radiative heat exchange on the outer surface of the fragment under consideration. The results of the qualitative analysis of the proposed model are presented.
Author: V. S. Zarubin, G. N. Kuvyrkin, and I. Yu. Savel′eva
Keywords: heat insulation, thermostating Peltier effect, thermoelectric module
INFLUENCE OF MICROWAVES ON THE THERMAL CONDITIONS OF A "POLYMER–SEMICONDUCTOR–COMPOSITE" SYSTEM
A numerical analysis of the influence of microwaves on the thermal conditions of elements of electronic equipment (EE) has been carried out. Investigations have shown that the temperature fi eld of the ″polymer–semiconductor– composite″ system under the action of microwaves is nonuniform. It has been established that under rather typical operating conditions with increasing electric fi eld intensity there is a considerable increase (from 362 to 387 K) in the maximum temperature of the modeled object. Such a strong infl uence of microwaves on the thermal conditions of the ″polymer–semiconductor–composite″ system is comparable to the increase in the ambient temperature by 20 K or the increase in the heat release of the internal source by 30%.
Author: V. G. Kuznetsov and E. V. Kravchenko
Keywords: radio emission, microwave heating, unstable thermal conditions, computational modeling, finite difference method
METHOD OF BOUNDARY CHARACTERISTICS
A new integral method based on the system of identical equalities of 2n-multiple integrals of the desired temperature function and the corresponding boundary characteristics is presented. This method was used for the approximate solution of problems of a semi-bounded space and a lengthy plate with fi rst-kind boundary conditions. The results obtained show that the integral method of boundary characteristics surpasses the analogous integral methods by several orders of magnitude in accuracy and convergence of approximate solutions. The solutions constructed with this method are exact in essence because the errors in determining parameters in a wide range of their values comprise hundredths and ten-thousands of a percent
Author: V. A. Kot
Keywords: heat-condition equation, boundary characteristics, disturbance front, heat-balance integral, identical equality, integral method
ENGINEERING APPROACH TO THE DETERMINATION OF THE RADIATION FIELD OF A POLYETHYLENETEREPHTHALATE (PET) MEDIUM UNDER RADIANT HEATING
An engineering approach to the determination of the radiation fi eld of the PET medium under radiant heating is proposed. Instead of the reverse counting procedure for determining the radiation intensity in the negative direction, we make a correction that has a superposition character and can be determined through the refl ection coeffi cient at the boundary and the already determined radiation fi eld in the positive direction inverted in the coordinate direction. The structure of the given approach provides a reasonable balance between the adequacy of calculations and the computational resource consumption and permits estimating quickly the necessary machine time expenditures.
Author: D. É. Sidorov, A. E. Kolosov, O. V. Pogorelyi, and A. A. Gur′eva
Keywords: polyethyleneterephthalate (PET), radiant heating, semitransparent medium, radiation field, numerical calculation.
SIMULATION OF CONVECTIVE HEAT EXCHANGE IN THE ELECTRICALLY CONDUCTING LIQUID IN A SPHERICAL CAVITY. ALGORITHM OF SOLUTION
An algorithm is proposed for calculating the convective heat exchange in a spherical cavity modeling the liquid core of the Earth with account for the internal heat sources and the Joule dissipation in the electrically conducting liquid in it.
Author: S. V. Solov′ev
Keywords: convective heat exchange, magnetic hydrodynamics, Joule dissipation, spherical cavity
SIMULATION OF THE KINETICS OF GROWTH OF IRON NANOPARTICLES IN THE PROCESS OF CHEMICAL VAPOR DEPOSITION OF HYDROCARBONS WITH INJECTION OF FERROCENE FOR THE SYNTHESIS OF CARBON-NANOTUBE ARRAYS
A kinetic model of growth of iron nanoparticles in the process of synthesis of carbon-nanotube arrays in an injectiontype reactor of chemical vapor deposition, in which iron nanoparticles are formed as a result of the coalescence of iron atoms representing products of the thermal decomposition of a mixture of ferrocene with xylene, has been developed. It is shown that the formation of iron nanoparticles in the indicated reactor is very nonequilibrium in character. The parametric dependences of the monodisperse distributions of iron nanoparticles by their diameter, number density, and volume fraction on the fl ow rate of nitrogen, the temperature of the high-temperature region in the reactor, and the concentration of ferrocene in xylene have been obtained. The calculations performed have shown that the diameter of the iron nanoparticles formed increases monotonically with increase in the temperature of the chemical vapor deposition of hydrocarbons and the concentration of ferrocene in xylene and, quite the reverse, decreases monotonically with increase in the rate of the nitrogen fl ow. The calculated and experimental diameters of the iron nanoparticles formed at mass fractions of ferrocene in xylene of 0.5–10% were compared. The model proposed can be used for calculating the synthesis of carbon nanotubes in a chemical-vapor-deposition reactor of the injection type.
Author: S. I. Futko, B. G. Shulitskii, V. A. Labunov, and E. M. Ermolaeva
Keywords: chemical vapor deposition, injection-type CVD reactor, carbon nanotubes, iron nanoparticles, coalescence, nanotube array, heterogeneous catalysis, transition metals, metallorganic materials, ferrocene, hydrocarbons, xylene
ISOTHERMAL DEPOSITION OF DROPLETS AND NANOPARTICLES FROM THE INCIDENT GAS JET ONTO A SUBSTRATE
By computational-hydrodynamics methods the authors have investigated the fi eld of the gas velocity in the fl ow developed after the turn of the gas jet near the substrate. Consideration has been given to the problem on deposition of charged micron-size droplets from radial fl ow above the substrate by the action of the external electrostatic fi eld. A study has been made of the infl uence of Brownian diffusion on the nanoparticle deposition from the laminar radial fl ow above the substrate. The authors have introduced similarity numbers for these problems and have determined their infl uence on the effi ciency of deposition.
Author: Yu. A. Stankevich and S. P. Fisenko
Keywords: computational gasdynamics, laminar fl ow, electrostatic deposition, Brownian diffusion
SYNTHESIS OF CARBON NANOSTRUCTURES ON NICKEL NANOPOWDERS PRODUCED BY THE METHOD OF ELECTRIC EXPLOSION OF CONDUCTORS
The authors present the results of experiments on the synthesis of carbon nanostructures by the method of thermal chemical gas-phase deposition with the use of nickel nanopowders produced by the method of electric explosion of conductors and utilized as the catalysts. To study the process of origination and growth of individual carbon nanostructures, the authors conducted experiments not only on nanopowders, but also on separated clusters. Experiments were conducted at different temperatures (200–700oC) and pressures (100–400 mbar) to determine optimum conditions and the lower temperature boundary for carbon-nanostructure synthesis. The experiments have shown that the lower boundary of synthesis for nanopowders is a temperature of 325oC. For the separated powders, as for the nanopowders, stable growth of carbon nanostructures was observed at 350oC, but at pressures lower than 300 mbar. Unlike the carbon nanostructures produced on nanopowders, carbon nanostructures on separated powders exhibit a strong dependence of their origination and growth on temperature and pressure. Results of the Raman spectroscopy and of the x-ray structural analysis have shown that carbon nanostructures grown at 325oC and 300 mbar have the highest purity.
Author: G. Partizan, B. Z. Mansurov, B. S. Medyanova, B. A. Aliev, and Xin Jiang
Keywords: carbon nanostructure, nanopowders, nickel, thermal chemical deposition, gas phase
CONTROL OF THE SYNTHESIS OF SUBMICRON TITANIUM DIOXIDE PARTICLES IN A CONTINUOUS PLASMA-CHEMICAL REACTOR
A simulation of the formation and growth of titanium dioxide particles in the working zone of a plasma-chemical reactor has been performed. The possibility of use of the premixing of reagents (titanium tetrachloride and oxygen) outside the reactor for increasing the yield of the fi nal product was investigated. Calculations of the formation and growth of titanium dioxide particles were performed for different values of parameters of the physical and mathematical model of the process.
Author: S. M. Aul′chenko and E. V. Kartaev
Keywords: titanium dioxide, plasma-chemical reactor, quasi-gasdynamic system of equations, homogeneous and heterogeneous reactions, nucleation, coagulation
HEAT TRANSFER BETWEEN A PLASMA JET AND A METAL SURFACE IN A CUT CAVITY
Investigations are presented of the formation of a plasma jet and of the current-density and heat-fl ux distributions in the process of metal cutting along the cut cavity with direct and reverse polarities of the plasmatron connection. The study of the specifi c features of heat transfer of the arc with the surface of the cut cavity was carried out on the basis of the developed plasma unit which makes it possible to model the technological process of separating metal cutting. A sectional cut model is proposed which can be used to work out and optimize the methods of determination of cutting parameters.
Author: A. N. Veremeichik, M. I. Sazonov, V. M. Khvisevich, and D. L. Tsyganova,
Keywords: metal cutting, plasmatron, electric arc
PLASMACHEMICAL PROCESSING OF MEDICOBIOLOGICAL WASTES
The process of processing medicinal wastes by plasma methods has been investigated. Thermodynamic calculations of the processing of wastes have been performed using bones of animal origin as an example. Experimental investigations were carried out in a plasma chamber furnace equipped with an electric arc plasmatron of power 30 kW
Author: V. E. Messerle, A. L. Mossé, A. N. Nikonchuk, and A. B. Ustimenko
Keywords: medicobiologic wastes, plasma methods, thermodynamic calculations, plasma chamber furnace
IONIZATION OF AIR IN A RANQUE–HILSCH VORTEX TUBE AND THE METHOD OF OBTAINING UNI- AND BIPOLAR IONIZATION
Results of investigations on determining the principles of ionization in a Ranque–Hilsch vortex tube have been given. The existing principles of ionization and the possibilities for them to occur in a Ranque–Hilsch vortex tube have been considered. Conclusions based on an analysis of ionization methods have been drawn. With the aim of establishing processes occurring in the vortex tube, the authors have developed a procedure, have identifi ed the goal and objectives of testing, have created a test bench, and have conducted experimental investigations on the physical prototype of a vortex tube. Testing results have been given in the form of plots. An analysis of the results has been made, and conclusions have been drawn. On the basis of the conducted investigations, the authors have proposed a novel method of ionization of air and control over the parameters of uni- and bipolar ionization. A diagram of the device developed for air ionization has been presented.
Author: K. V. Lebedinskii, N. E. Kurnosov, A. A. Nikolotov, and D. P. Alekseev
Keywords: ionization, vortex tube, balloelectric effect, magnetic field.
SIMULATION OF NON-NEWTONIAN EMULSION FLOWS IN MICROCHANNELS
Simulation of emulsion flows in differently shaped microchannels to reproduce the choking of such flows as a result of the effect of dynamic blocking has been made. A model of a highly concentrated emulsion as a structure of tightly packed deformed droplets surrounded by elastic shells is considered. The motion of liquid was determined by the method of the lattice Boltzmann equations together with the immersed boundary method. The infl uence of the nonNewtonian properties and of elastic turbulence of the indicated emulsion, as well as of the elasticity of the shells of its droplets and of the interaction of these shells on the emulsion motion in a microchannel, has been investigated. It is shown that the flow of this emulsion can be slowed down substantially only due to the mutual attraction of the shells of its droplets.
Author: I. V. Malanichev and F. G. Akhmadiev
Keywords: emulsion, effect of dynamic blocking, computational hydrodynamics, method of the lattice Boltzmann equations, method of immersed boundary
HYDRODYNAMIC ASPECTS OF THE TOMS EFFECT
The physicomathematical model of migration of polymers in a liquid turbulent fl ow in a pipe is based on a comparison of forces transverse to the motion of the mainstream fl ow: the Saffman, Magnus, and turbophoresis forces. It has been shown that the polymer particles are grouped near a certain boundary within the limits of the boundary layer. On this basis, the authors have made assumptions on the mechanism of suppression of turbulent pulsations and decrease in the viscous friction near the wall, which makes up the Toms effect. The proposed model satisfi es, at least, qualitatively, various actually observed manifestations of the effect.
Author: S. A. Strel′nikova, G. V. Tkachenko, and B. A. Uryukov
Keywords: turbulent flow in pipelines, polymer additives, Toms effect, Magnus effect, Saffman force
TURBULENT BOUNDARY LAYER ON A FINELY PERFORATED SURFACE UNDER CONDITIONS OF AIR INJECTION AT THE EXPENSE OF EXTERNAL FLOW RESOURCES
The characteristics of an incompressible turbulent boundary layer on a fl at plate with air blown in though a fi nely perforated surface from an external confi ned fl ow through an input device, located on the "idle" side of the plate, have been investigated experimentally and numerically. A stable decrease in the local values of the coeffi cient of surface friction along the plate length that attains 85% at the end of the perforated portion is shown. The experimental and calculated data obtained point to the possibility of modeling, under earth conditions, the process of controlling a turbulent boundary layer with air injection by using the resources of an external confi ned fl ow.
Author: V. I. Kornilov, A. V. Boiko, and I. N. Kavun
Keywords: turbulent boundary layer, flat plate, finely perforated surface, blowing-in (injection), input device, friction
MAGNETOHYDRODYNAMIC PHENOMENA AND HEAT TRANSFER NEAR A ROTATING DISK
We propose an approach that permits constructing an analytical solution of the problem of flow and heat transfer in a viscous compressible conducting medium near an infi nite dielectric disk rotating in a homogeneous magnetic field. The influence of the magnetic fi eld on the process of heat transfer near the disk surface has been investigated. It has been shown that Joule energy dissipation prevails over viscous dissipation at moderate magnetic fi elds.
Author: V. D. Borisevich and E. P. Potanin
Keywords: rotating disk, boundary layer, conducting gas, flow and heat transfer
INFLUENCE OF THE GEOMETRIC PARAMETER ON THE REGIMES OF NATURAL CONVECTION AND THERMAL SURFACE RADIATION IN A CLOSED PARALLELEPIPED
We have performed a numerical analysis of the stationary regimes of thermogravitational convection and thermal surface radiation in a closed differentially heated parallelepiped. The mathematical model formulated in dimensionless natural velocity–pressure–temperature variables was realized numerically in the control volume approach. Analysis of the radiative heat exchange was carried out on the basis of the surface radiation approach with the use of the balance method in the Polyak variant. We have obtained three-dimensional temperature and velocity fi elds, as well as dependences for the mean Nusselt number refl ecting the infl uence of the geometric parameter, the Rayleigh number, and the reduced emissive factor of the walls on the fl ow structure and the heat transfer.
Author: S. G. Martyushev, I. V. Miroshnichenko, and M. A. Sheremetb,
Keywords: natural convection, thermal surface radiation, diathermal medium, parallelepiped, control volume approach
PRESSURE DISTRIBUTION IN THE ANNULUS BETWEEN ROTATING COAXIAL CYLINDERS AT LARGE SHEAR STRESSES
Results of an experimental study of the excess pressure distribution in the annulus between the inner rotating and the outer immovable coaxial cylinders at large shear stresses are reported.
Author: V. D. Tyutyuma
Keywords: isentropic model of momentum transfer, equations of motion, viscous compressible medium, fl ow in the annulus between rotating cylinders, pressure distribution
COMMENTS ON THE PAPER "UNSTEADY RADIATIVE-CONVECTIVE BOUNDARY-LAYER FLOW OF A CASSON FLUID WITH VARIABLE THERMAL CONDUCTIVITY" BY M. GNANESWARA REDDY
The comments on the recently published paper by M. Gnaneswara Reddy are presented. It is shown that the similarity transformations made in the paper are not correct.
Author: P. M. Patil
Keywords: similarity solution, unsteady boundary layer, Casson fluid, variable thermal conductivity, thermal radiation, stretching surface
ELECTROMAGNETIC EFFECTS ON WAVE PROPAGATION IN AN ISOTROPIC MICROPOLAR PLATE
The generalized theory of thermoelasticity is applied to study the propagation of plane harmonic waves in an infi nitely long, isotropic, micropolar plate in the presence of a uniform magnetic fi eld. The present analysis also includes the thermal relaxation time, electric displacement current, and the coupling of heat transfer and microrotation of the material. To determine the effect of the presence of thermal as well as magnetic fi elds on the phase velocity, two potential functions are used, and more general dispersive relations are obtained for symmetric and antisymmetric modes. The results for the cases of coupled thermoelasticity, magnetoelasticity, micropolar thermoelasticity, and classical micropolar elasticity as special cases are derived. The changes in the phase velocity and attenuation coeffi cient with the wave number are shown graphically.
Author: S. Shaw and B. Mukhopadhyay
Keywords: thermoelasticity, micropolar plate, plane harmonic waves, micropolar thermoelasticity, magnetoelasticity, symmetric mode, antisymmetric mode
ERRORS IN DETERMINING THE THERMOPHYSICAL CHARACTERISTICS OF HETEROGENEOUS HIGH-ENERGY MATERIALS BY THE LASER-PULSE METHOD
An analysis has been carried out with respect to the errors incurred in the determination of the thermophysical characteristics of the high-energy heterogeneous material "aluminum–ammonium perchlorate–butyl rubber" and associated with the radiation transfer of energy in the heated layer under conditions corresponding to the realization of the laser-pulse method in the course of action of a fi nite-length collimated laser pulse on the material surface. The infl uence of the radiation absorption process on the magnitude of this error has been established
Author: M. D. Kats and I. M. Kats
Keywords: heterogeneous material, thermophysical characteristics, laser-pulse method, systematic errors, numerical solution, coefficient of radiation absorption
NANOMATERIALS IN PROTON EXCHANGE FUEL CELLS
The present paper considers the state of the art of investigations on the use of nanomaterials in the technology of preparing proton exchange fuel cells. This technology has great prospects for use in transport facilities, as well as in stationary and portable electronic devices. The unique properties of nanostructures permit creating new effective catalysts, polymer membranes, and hydrogen storage systems — key elements of the above technology, which upgrades markedly the effi ciency of energy conversion in devices created on its basis and decreases their cost.
Author: G. Ya. Gerasimov
Keywords: fuel cells, proton exchange membranes, nanomaterials, carbon nanostructures, electrochemical reaction, catalysts, hydrogen storage systems
ANALYTICAL ESTIMATION OF VELOCITY AND TEMPERATURE FIELDS IN A CIRCULAR PIPE ON THE BASIS OF STOCHASTIC EQUATIONS AND EQUIVALENCE OF MEASURES
A stream of nonisothermalNewtonian liquid in a circular smooth pipe is considered on the basis of systems of stochastic equations and of the physical law of equivalence of measures between laminar and turbulent motions. Analytical expressions were previously obtained for isothermal fl ows for the fi rst and second critical Reynolds numbers, critical point, indices of velocity profi les, second-order correlation moments, correlation functions, and spectral functions depending on the parameters of initial turbulence. Analytical expressions, obtained with the use of the earlier derived formulas for the critical Reynolds numbers and the critical points, are presented for the indices of velocity and temperature profi les as functions of the initial turbulence parameters as well as of the Eckert and Prandtl numbers.
Author: A.V. Dmitrenko
Keywords: equivalence of measures, stochastic equations, turbulence
OPTIMIZATION OF THE SLOT SUCTION OF AIR FROM A CIRCULAR VORTEX CELL ON A THICK NACA0022 AIRFOIL WITH A MAXIMUM LIFT–DRAG RATIO
On the basis of multiblock computational technologies and the Menter model of shear-stress transfer modifi ed with account of the curvature of streamlines, the optimum position of a slot for air suction on the leeward side of the contour of a vortex cell built in a thick NACA0022 airfoil was determined for the purpose of increasing its lift–drag ratio to a maximum value in a nondisturbed air fl ow at a Mach number of 0.05 and an angle of attack of 7o .
Author: S. A. Isaev, E. I. Kalinin, A. G. Sudakov, and V. B. Kharchenko
Keywords: lift-drag ratio, thick airfoil, vortex cell, slot suction, turbulence