Conditions for a Thermal Explosion in the Plate under Convective-Radiation Heat Transfer

Author(s):  
V.S. Zarubin ◽  
G.N. Kuvyrkin ◽  
I.Yu. Savelyeva ◽  
A.V. Zhuravsky

The processes of obtaining and storing energy-saturated substances are characterized by energy release in their volume. The intensity of this energy release increases with increasing temperature. The stability of the stationary temperature state of a solid with a temperature-dependent intensity of volumetric energy release is directly related to the conditions of heat transfer of this body with the environment. If the heat energy released in the volume of the body can no longer be diverted into the environment, the steady temperature state of the body becomes impossible. The paper studies the conditions for a thermal explosion in a solid in the form of a plate with a temperature-dependent coefficient of thermal conductivity and convective-radiation heat transfer on its surfaces. The statement of the nonlinear problem of steady-state thermal conductivity in the plate is represented by a system of integral relations. The limits of integration of the integrals included in these relations are the desired functions and parameters which determine the temperature state of the plate. A quantitative analysis of these relationships makes it possible to establish the influence of the parameters which determine the intensity of heat transfer and the dependence of the thermal conductivity of the plate material on the conditions for a thermal explosion with an arbitrary law of variation with temperature of the volumetric power of the energy release in the plate. The results of such an analysis are presented in the framework of a one-parameter model of the stationary theory of thermal explosion

1976 ◽  
Vol 19 (134) ◽  
pp. 973-979 ◽  
Author(s):  
Masaaki KURIYAMA ◽  
Kozo KATAYAMA ◽  
Yoshiyuki TAKUMA ◽  
Yasushi HASEGAWA

2017 ◽  
Vol 4 (3) ◽  
pp. 269-272
Author(s):  
P. Kloc ◽  
V. Aubrecht ◽  
M. Bartlová

Mean absorption coefficients (MACs) offer great potential for fast numerical calculation of radiation heat transfer. They are based on replacing complex absorption coefficient spectrum by a handful of frequency bands with a single, temperature dependent value assigned to each band. Accuracy of radiation transfer calculation thus depends on the accurate interpretation of the mean value inside each frequency band as well as on the proper band distribution. Yet finding optimal band distribution is not an easy task often requiring numerical optimization process. This contribution focuses on the parameters of such optimization process, namely selection of an objective function and its effect on the optimal band distribution. It demonstrates, that improper objective functions can produce physically unreasonable artifacts in the calculation of radiation heat transfer. Optimal formulation of the objective function is proposed in this contribution.


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