Begell House Inc.
Heat Transfer Research
HTR
1064-2285
36
8
2005
Some Specific Features of Heat and Mass Transfer of Gas-Discharge Plasma with a Liquid Electrolytic Cathode
623-629
Kh. K.
Tazmeev
Kama State Polytechnic Institute, Russian Federation
A. Kh.
Tazmeev
Kama State Polytechnic Institute, Russian Federation
A liquid electrolytic cathode is renewable and, therefore, presents a great practical interest. Energy balance on a liquid cathode has been analyzed in the current range 4−16 A at a relatively high current density (∼0.9 A/cm2). The discharge occurred in a diffusion form under the atmospheric pressure without ballast resistance. Power imparted to the discharge unit reached up to 20 kW. The electrolyte represented a table salt solution in distilled water. At room temperature, the electrolyte conductivity made (0.9−2.1)·10−3 ( Ω·cm)−1. It was identified that heat and mass exchange of plasma with the liquid electrolytic cathode substantially depended on the conditions of electrolyte cooling. At high cooling rate, the heat flux comes from the plasma to the liquid cathode whereas at small rate of cooling, all heat from the plasma to the liquid cathode is returned back into the discharge region by the electrolyte vapors. It should be noted that at the least possible rate of cooling of the liquid cathode the heat loss on the cathode is smaller than Joulean heat released inside the electrolyte.
Spatial Simulation of Heat Transfer through Protective Structures in Conditions of Heterogeneous Heat Exchange on the Boundaries
631-639
Genii V.
Kuznetsov
National Research Tomsk Polytechnic University, Institute of Power Engineering, Tomsk,
634050, Russia
Mikhail A.
Sheremet
Department of Theoretical Mechanics, Tomsk State University, 634050, Tomsk, Russia; Institute of Power Engineering, Tomsk Polytechnic University, 634050, Tomsk, Russia
A spatial nonstationary heat conduction problem has been solved for the region, including protective structures and a protected compartment, given locally concentrated sources of heat release and mixed heat exchange with the environment. A finite difference method and a nonuniform difference grid have been used. The obtained results were used to draw a conclusion on the existence of temperature field nonhomogeneity in the sections passing through the heat-release sources.
Application of the "Geometrical-Optical" Asymptotic Method for Accounting the Impacts of a Complex-Shape Boundary of the Random Region on Multidimensional Nonlinear Irregular Thermal Fields
641-653
G. A.
Nesenenko
N. E. Bauman Moscow State Technical University, Moscow, Russia
A method for obtaining approximate analytical solutions of nonlinear boundary-value problems, formulated for multidimensional parabolic equations with a small parameter ε > 0 and the Laplace operator has been proposed and substantiated. Such problems are called singularly perturbed boundary-value problems or irregular boundary-value problems. Regions, in which solutions of the above irregular heat-conduction problems are sought by the proposed method, can have a random shape, and nonlinear boundary conditions can be specified at the boundaries. The approximate solutions are represented by the Poincare asymptotics, containing both powers of a small parameter ε > 0 and powers of respective boundary layer variables. The Poincare asymptotic coefficients depend on the geometrical characteristics of the surface, bounding the region in which the solution is analyzed; in so doing, they do not depend on the small parameter ε > 0. To calculate explicitly the coefficients of asymptotic expansion, a mathematically correct analysis of integral solution representations, written by means of respective Green functions, is used.
Account of the Finite Velocity of Heat Propagation in a Solid Body
655-661
Konstantyn B.
Isaev
I. N. Frantsevich Institute of Problems of Material Sciences, National Academy of Sciences of Ukraine, Kiev, Ukraine
A solution of a one-dimensional hyperbolic nonlinear heat-conduction equation for a pseudo-steady-state mode of heating of a semi-bounded body is obtained within the framework of the relaxation heat flux model which allows for the finiteness of the velocity of heat propagation. The hyperbolic heat-conduction equation accounts for heat sinks (sources). The impact of some factors on the destruction parameters and the temperature field in materials, values of thermal conductivities of which differ by three orders, is demonstrated.
Numerical Study of Combined Heat Transfer in Initial Sections of High-Temperature Outlet Channels and Nozzles with Variable and Strong Injection
663-676
S. G.
Rudenko
Academician V. P. Glushko "Energomash" Scientific and Industrial Amalgamation, Khimki, Moscow Region, Russia
Numerical solution of two-dimensional equations of combined heat transfer in the compressible boundary layer approximation for a uniform radiating and absorbing gas (hydrogen with addition of lithium), given the spectral dependence of the absorption coefficients and actual properties of the working body, has been used as the basis for investigation of combined heat transfer in the initial areas of high-temperature outlet channels and nozzles (using as examples nuclear missile engines (NME) and nuclear power plants (NPP) with a gas-phase reactor) in variable and strong injection for laminar and turbulent modes of flow. It has been shown that intense injection results in a significant reduction of heat fluxes to the wall and is an effective means for protection of walls against high heat fluxes, especially convective ones. Also, the effect of radiation on the formation of temperature profiles and on heat fluxes has been studied. Recommendations on the application of simpler computing techniques are given.
Computer Modeling of Physical Processes Occurring in Laser-Plasma Spraying of Diamond-Type Films
677-689
G. S.
Romanov
A. V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, Minsk, Belarus
A. S.
Smetannikov
A. V. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, Minsk, Belarus
Yu. A.
Stankevich
Laboratory of Dispersed Systems - Laboratory of Radiative Gas Dynamics - Heat and Mass Transfer Institute, 220072 Minsk, Belarus
L. K.
Stanchits
Laboratory of Dispersed Systems - Laboratory of Radiative Gas Dynamics - Heat and Mass Transfer Institute, 220072 Minsk, Belarus
K. L.
Stepanov
Laboratory of Dispersed Systems - Laboratory of Radiative Gas Dynamics - Heat & Mass Transfer Institute, National Academy of Sciences, 15 P.Brovka Str., 220072 Minsk, Belarus
Physical and mathematical models of the dynamics of heating and evaporation of a carbon target have been developed. The dynamics of the erosion torch and its interaction with the substrate under the impact of nanosecond laser pulses on the graphite target have been modeled. The impact of thermodynamic and optical characteristics of the graphite target on the dynamics of heating and evaporation has been investigated.
Mathematical Modeling of Heat Transfer in Enhancement of the Heating Processes of Solid Bodies
691-696
V. B.
Veselovskii
Dnepropetrovsk National University, Ukraine
The results of investigation of the solid body surface heating by intense heat fluxes are presented. A mathematical model for the process has been developed. Calculations and experimental investigations of the thermal inertia impact on the energy concentration in a random body layer have been made. Heating process accelerations and creation and conservation of a zone with high temperature gradients, which conditions the decrease of energy consumption in body destruction energy intensity, have been identified.
Heat and Mass Transfer in the Model of a Vortex Plasmachemical Reactor
697-702
V. N.
Kharchenko
Moscow State University of Forestry, Russian Federation
V. N.
Zverev
Moscow State University of Forestry, Russian Federation
Special features of heat and mass transfer and thermophysical parameters in an experimental model of a vortex plasmachemical reactor-centrifuge with crossed electrical and magnetic fields at pulsed gas discharges with a power of 1−10 MW have been discussed. The calculated dependences are in agreement with the experimental data.
Modern Approach to the Account of Contact Thermal Resistances in Power Plants
703-711
S. Yu.
Mesnyankin
Moscow Aviation Institute (State Technical University), Moscow, Russia
Known works on contact heat conduction are summarized and systematized. Nodes in which contact thermal resistance plays an important role are classified. Basic factors, affecting the heat transfer process in a contact zone, are formulated. Results of the generalized research of the existing analytical relations are considered using the theory of fuzzy sets; regions of preferred use of different regularities are formulated. Formulas for more accurate calculation of contact thermal resistance for flat and cylindrical surfaces are derived.
Modeling Heat Accumulation-Discharge in an Unbounded Soil Mass
713-731
Alfred I.
Nakorchevskii
Institute of Engineering Thermophysics of the Academy of Sciences of Ukraine Kiev, Ukraine
B. I.
Basok
Institute of Technical Thermophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
T. G.
Belyaeva
Institute of Engineering Thermophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
An integral method for solving the problems of unsteady heat conduction, which allowed mathematical modeling of the dynamics of heat accumulation-discharge in the unbounded soil mass by individual heat exchangers and a set of them vertically located in the soil, has been proposed. The impact of long-term work interruptions, typical of solar power engineering, has been analyzed. The need for process control has been established. The parameters are substantially improved when the heat exchangers in the system are located in clusters. An example of calculation of heat supply for a populated center of 6000 people has been presented.
Author Index
733-735
Tables of Contents
737-742