Begell House Inc.
Heat Transfer Research
HTR
1064-2285
28
7-8
1997
Optimization of Diffusers in Aerohydrodynamic Systems
414-420
10.1615/HeatTransRes.v28.i7-8.10
Alfred I.
Nakorchevskii
Institute of Engineering Thermophysics of the Academy of Sciences of Ukraine Kiev, Ukraine
K. N.
Starosila
Institute of Technical Thermal Physics National Academy of Sciences of Ukraine Kiev, Ukraine
One-dimensional equations are obtained that determine the energy loss in a diffuser with a curved generating line. The solution is found to the problem of finding the minimal length of a diffuser providing the maximal recovered pressure in the outlet cross-section at a given expansion ratio. A variational boundary problem is considered with the aim of the determination of the diffuser shape providing the minimal energy loss. The generating line of such a diffuser has a weak convexity followed by a weak concavity. A comparison is performed between the computational data on the most popular types of curvilinear diffusers.
Energy Balance of Taylor-Gortler Vortices
421-425
10.1615/HeatTransRes.v28.i7-8.20
A. A.
Avramenko
Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
S. G.
Kobzar'
Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
Artem
Khalatov
Institute of Engineering Thermophysics of NAS of Ukraine
An energy equation for Taylor-Gortler vortices has been derived, which describes the balance of the mechanical energy in a curvilinear boundary layer in the vicinity of a concave surface. The equation is qualitatively compared with the equation of the kinematical energy of turbulence, and the effect of various factors on the formation and degeneracy of Taylor-Gortler vortices is established.
Systems Approach and Search for Integral Properties of Thermal Systems in Heat Engineering
426-437
10.1615/HeatTransRes.v28.i7-8.30
L. A.
Kozdoba
Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
The main concepts of the systems approach are presented. The theory of groups (complexes), which can determine the integral properties of thermal systems used in heat engineering, is considered.
Friction and Heat Transfer During Injection into a Near-Sonic High-Temperature Gas Flow in a Channel
438-445
10.1615/HeatTransRes.v28.i7-8.40
A. A.
Vasil'yev
Engineering Thermophysics Institute, Ukrainian Academy of Sciences, Kiev
O. I.
Didenko
Institute of Technical Thermal Physics, National Academy of Sciences of Ukraine Kiev, Ukraine
V. F.
Vishnyak
Institute of Engineering Thermophysics National Academy of Sciences of Ukraine Kiev
V. N.
Panchenko
Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine Kiev
The results of the numerical study of the effect of injection, its intensity and distribution on the resistance and heat transfer in near-sonic high-temperature laminar and turbulent gas flow in a flat channel are presented. It is shown that with an approach to the flow crisis, the injection reduces heat transfer coefficients and, at the same time, considerably increases the friction coefficient.
Efficiency of a Chemically Neutral Multicomponent Vapor-Gas-Liquid-Solid Wall-Protective Screen. Part. 1. General Statements. Equilibrium Screen
446-459
10.1615/HeatTransRes.v28.i7-8.50
V. M.
Repukhov
Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
A mathematical model of a chemically neutral multicomponent vapor-gas-liquid-solid wall-protective screen, both equilibrium and nonequilibrium, is constructed with due regard for phase transformations. The approximate analytical solution of the problem is obtained for all the screen regions in the form of the unified equation of temperature efficiency of the screen both in the general case and in the case of partial or complete analogy of heat and mass transfer or under the assumption of the similar profiles of the total temperature and vapor mass content of screen components. It is shown that two latter models are almost identical and agree quite well with the experiment. The solutions obtained are analyzed and the methods for computing thermal efficiency of the protective screen are given.
Efficiency of a Chemically Neutral Multicomponent Vapor-Gas-Liquid-Solid Wall-Protective Screen. Part. 2. Nonequilibrium Screen
460-475
10.1615/HeatTransRes.v28.i7-8.60
V. M.
Repukhov
Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
A mathematical model of a chemically neutral multicomponent vapor-gas-liquid-solid wall-protective screen, both equilibrium and nonequilibrium, is constructed with due regard for phase transformations. The approximate analytical solution of the problem is obtained for all the screen regions in the form of the unified equation of temperature efficiency of the screen both in the general case and in the case of partial or complete analogy of heat and mass transfer or under the assumption of similar profiles of the total temperature and vapor mass content of the screen components. It is shown that two latter models are almost identical and agree quite well with the experiment. The solutions obtained are analyzed and the methods for calculating thermal efficiency of the protective screen are given.
Effect of Dimension and Roughness of a Heating Surface on the Characteristics of Individual Vapor Bubbles
476-480
10.1615/HeatTransRes.v28.i7-8.70
G. R.
Kudritskii
Institute of Technical Thermophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
The results of the experimental study of the effect of the dimension and roughness of a heating surface on the mechanism of growth and detachment of individual vapor bubbles are presented. It is shown that growth of vapor bubbles depends mainly on the dimensions of the maximum zone of the bubble contact with the heating surface.
Calculation of Critical Thermal Loads under Extreme Intensities of Mass Forces
481-483
10.1615/HeatTransRes.v28.i7-8.80
Yu. B.
Zudin
Moscow Power University, Moscow, Russia
The computational relationship obtained earlier for the critical density of a thermal flux is compared with the experimental values of the critical thermal loads obtained at the extreme (very high or very low) intensities of mass forces.
Energy Efficiency Technologies for Pectin-Containing Products
484-489
10.1615/HeatTransRes.v28.i7-8.90
R. Sh.
Vainberg
Institute of Engineering Thermophysics National Academy of Sciences of Ukraine Kiev
S. A.
Bogdanov
Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine Kiev
N. D.
Butskii
Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine Kiev
An experimental investigation into the kinetics of extraction and demethoxylation of pectin is discussed. Energy saving technologies for the existent production of pectin containing preparations are sought on the way of using different acid-alkali interaction of raw materials and reagents, optimization of the grain-size composition of raw materials, and utilization of the waste of apple-to-pabular-powder processing. It has been established that the acid-alkali interaction of components saves up to 30 tons of conditional fuel per ton of low-methoxylated pectin.
Variation of the Medium State in a Hypobaric Storehouse
490-493
10.1615/HeatTransRes.v28.i7-8.100
E.
Pisarev
Institute of Engineering Heat Physics, National Academy of Sciences of Ukraine Kiev, Ukraine
The processes of fluid mixing in an agricultural food storehouse with a ventilating air flow were analyzed for variable pressure, temperature, and relative humidity using Iddiagrams of humid air. At a reduced pressure in the storehouse, of the medium parameters are prone to considerable variations.
Heat Flux Transducers in Studies of Heat-resistant Properties of Materials: on the Correctness of Readings
494-498
10.1615/HeatTransRes.v28.i7-8.110
T. G.
Grishchenko
Institute of Energy Saving, National Academy of Sciences of Ukraine Kiev
L. V.
Dekesha
Institute of Energy Saving National Academy of Sciences of Ukraine Kiev
T. V.
Mendeleeva
Institute of Energy Saving, National Academy of Sciences of Ukraine Kiev, Ukraine
This paper presents a calculation an estimated profile of the temperature field in a short bounded cylinder. We prove that, under certain conditions, it can deviate from the one-dimensional axial distribution.
Precision Setup for Fluid Pump Efficiency Testing
499-502
10.1615/HeatTransRes.v28.i7-8.120
Yu. D.
Zozulyak
Institute of Applied Mechanics and Mathematics National Academy of Sciences of Ukraine Lvov, Ukraine
Yu. L.
Levashov
Institute of Applied Mechanics and Mathematics, National Academy of Sciences of Ukraine Lvov, Ukraine
V. T.
Novatsky
Institute of Applied Mechanics and Mathematics, National Academy of Sciences of Ukraine Lvov, Ukraine
A modified thermodynamic method for testing the efficiency of centrifugal pumps on large pipelines is suggested. This method is used to develop an experimental test setup for pump efficiency measurements accurate to within 0.5%.
Rotating Regenerators of Low-Potential Heat Energy of Gas Emissions
503-509
10.1615/HeatTransRes.v28.i7-8.130
L. B.
Zimin
Institute of Engineering Thermophysics National Academy of Sciences of Ukraine Kiev
Recuperation of the heat energy of gas emissions from boilers and low-power ovens are considered. New designs of self-regulating no-drive regenerators are suggested in which the rotation of the rotor is proportional to the intensity of heat transfer. The calculation method was modified in order to estimate the efficiency of phase transformations of checker material.
Experimental Studies of Boiling Incipience in Flow through a Contracting-Diverging Nozzle
510-513
10.1615/HeatTransRes.v28.i7-8.140
A. A.
Dolinsky
Institute of Technical Thermophysics, National Academy of Sciences of Ukraine, Kiev
Borys I.
Basok
Head of the Department of Thermophysical Basics of Energy-Saving Technologies, Institute of Engineering Thermophysics National Academy of Sciences of Ukraine ul.
Bulakhovs'koho, 2a, Kyiv, 03164, Ukraine
Alfred I.
Nakorchevskii
Institute of Engineering Thermophysics of the Academy of Sciences of Ukraine Kiev, Ukraine
The hydrodynamics of a boiling superheated water flow ejected into a negative pressure through a contracting-diverging nozzle was studied. Pressure profiles along the nozzle and the flow characteristics of the vapor and liquid phases of the flow were obtained.
Effect of Flow Turbulization on the Losses of Streamlined
514-524
10.1615/HeatTransRes.v28.i7-8.150
E. P.
Dyban
Institute of Technical Thermophysics, National Academy of Sciences of Ukraine Kiev, Ukraine
Eleonora Ya.
Epik
Institute of Engineering Thermophysics of National Academy of Sciences of Ukraine (IET NASU), 2a Zhelyabov Str., 03057, Kyiv, Ukraine
Tatyana T.
Suprun
Institute of Technical Thermophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
L. E.
Yushina
Institute of Technical Thermophysics of the National Academy of Sciences of Ukraine, Kiev, Ukraine
A. G.
Frenkel
Institute of Technical Heat Physics National Academy of Sciences of Ukraine Kiev, Ukraine
Yu. A.
Yakovlev
Institute of Technical Heat Physics National Academy of Sciences of Ukraine Kiev, Ukraine
The effect of flow turbulence on the losses of two arrays of streamlined airfoils was investigated. Turbulence was generated by a pre-selected louvers R12x3 and R6x1.5 with known laws of turbulence degeneration. These louvers were certified by our institute. Experiments were conducted at the test bench of the Progress design establishment in the mean speed range 35−80 m/s, from initial (freestream) turbulence of 0.7% (natural level) to 3.03% with a characteristic vortex size of 3.7−5.85 mm. For an array of airfoils A with a relatively thin rear edge, it was demonstrated that an increase of initial turbulence increases the airfoil losses up to 5%, whereas, for an array of airfoils B with a thicker edge, the airfoil losses remained almost invariable. In both cases, the drag loss increased by about 7%, whereas the edge loss remained invariable (array of airfoils A) or decreased with the growth of initial turbulence (array of airfoils B). Experimental data were compared with a theory developed in the Institute. Similarity equations were derived for calculations of airfoil losses for the studied array of airfoils A and also for drag losses and edge losses for the array of airfoils B, valid under the conditions of the experiments.
An Acoustic Study of Heat Transfer in Quenched Specimens
525-528
10.1615/HeatTransRes.v28.i7-8.160
A. A.
Moskalenko
Institute of Technical Thermophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
N. I.
Kobasko
Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine, Kiev
O. V.
Tolmachyova
Institute of Technical Thermophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
We present an experimental analysis of cooling rates and intensity profiles of sound signals emitted in cooling of a 20-mm diameter silver ball in water containing an insignificant amount of retrograde-solubility polymer. A fact of multiple periodic change of film boiling has been established, which proves the hypothesis about the periodic occurrence and disappearance of a heat insulating film on the quenched metal surface.
Phase Composition of Water Transported in Drying of Porous Materials
529-535
10.1615/HeatTransRes.v28.i7-8.170
I.
Gamayunov
Tver State Technical University, Tver', Russia
The mechanism of water transport and phase composition in drying of porous bodies are revealed using radioactive tracers.
Gas Screen in Components of Gas Turbine Engines
536-542
10.1615/HeatTransRes.v28.i7-8.180
Artem
Khalatov
Institute of Engineering Thermophysics of NAS of Ukraine
I. S.
Varganov
Institute of Technical Thermal Physics, National Academy of Sciences of Ukraine, Kiev, Ukraine
The analytical problem of the interaction of an injected stream and the main flow under the condition of the changes in their momentum is solved for the exhaust nozzles of gas-turbine engines. The formula obtained allows one to determine the relative and absolute flow rates necessary not only for the control of the critical cross-sectional areas of the nozzles, but also for the flame stabilization in the combustion chambers of gas turbine engines. The comparative analysis of the calculated and experimental data showed their satisfactory agreement.
Modeling of Heat and Mass Transfer Processes in Heatproof Coatings of Blades of Gas Turbine Engines
543-550
10.1615/HeatTransRes.v28.i7-8.190
P. G.
Krukovskiy
Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
Ye. S.
Kartavova
Institute of Engineering Thermophysics, Ukrainian National Academy of Sciences, Ukraine
A new method for determining the mass transfer characteristics and the service life of composite coatings protecting against high-temperature gas corrosion is suggested. The method is based on the mathematical model of heat and mass transfer processes in composite protective coatings and in blades, the identification of the parameters of the mathematical model by solving the inverse problems using the data of the short-duration experimental measurements. The method allows one to predict the corrosion state of the surface layers of composite protective coatings and thus also the service life of the blades of gas-turbine engines.
The Generalized Calculation Method for Hydraulic Resistance of Cyclone Type Dust Collectors
551-556
10.1615/HeatTransRes.v28.i7-8.200
S. I.
Priemov
Institute of Technical Thermal Physics, National Academy of Sciences of Ukraine, Kiev, Ukraine
The new calculation method is proposed to determine the hydraulic resistance of the cyclone type dust collectors having the mixed shape involving the elements of cylinder and cone. The method is based on the kinematical scaling criterion for the internal curled flows, i.e., on the parameter characterizing the magnitude of flow curling. The performance of 13 the most widely used cyclone dust collectors is analyzed. It is shown that the accuracy of calculations using this method developed in the Institute of Technical Thermal Physics is by a factor of five or more higher than the accuracy of currently available calculation techniques.
The Choice of Turbulence Model and the Simulation of Ingot Casting and Solidification
557-563
10.1615/HeatTransRes.v28.i7-8.210
V. V.
Belousov
Donetsk State University, Donetsk, Ukraine
F. V.
Nedopekin
Donetsk State University, Donetsk, Ukraine
Based on the numerical implementation of the mathematical model taking into account the natural and forced convection within the enclosure, three schemes for the closure of turbulence are analyzed: the Prandtl mixing path model, the single-parameter k model, and the two-parameter k-ε model. It is shown that the k-ε model provides a more comprehensive description of the effect of flows in the process of steel casting to the ingot mold. For the calculations in the design problems for the regions of a rather simple shape, the implementation of the single-parameter model is proposed. The effect of the Rayleigh number on the turbulent character of the melt flow is studied.