What is it about?
The mathematical model for describing combined conductive-radiative heat transfer in a dielectric layer, which emits, absorbs, and scatters IR radiation both in its volume and on the boundary, has been considered. A nonlinear stationary boundary-value problem for coupled heat and radiation transfer equations for the layer, which exchanges by energy with external medium by convection and radiation, has been formulated. In the case of optically thick layer, when its thickness is much more of photon-free path, the problem becomes a singularly perturbed one. In the inverse case of optically thin layer, the problem is regularly perturbed, and it becomes a regular (unperturbed) one, when the layer’s thickness is of order of several photon-free paths. An iterative method for solving of the unperturbed problem has been developed and its convergence has been tested numerically. With the use of the method, the temperature field and radiation fluxes have been studied. The model and method can be used for development of noncontact methods for temperature testing in dielectrics and for nondestructive determination of its radiation properties on the base of the data obtained by remote measuring of IR radiation emitted by the layer.
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Why is it important?
With the use of the developed method the temperature field and distribution of radiation intensity in the layer have been studied. The obtained numerical results exhibit substantial dependence of the IR radiation, emitted by the layer into the external medium, on the temperature field in the layer and on its radiative properties.
Perspectives
The method, in aggregate with the known diffusion approximation, can be used to implement an approach for solving of singularly perturbed problems and for quantitative analysis of the problem for conductive-radiative heat transfer in optically thick layer. Such approaches, consisting in considering of the singularly perturbed problem in the interior of domain and in the boundary layer separately with consequent joining of the two obtained solutions. The method of temperature field and distribution of radiation intensity in the layer have been studied. The obtained numerical results exhibit substantial dependence of the IR radiation, emitted by the layer into the external medium, on the temperature field in the layer and on its radiative properties. This makes possible to expect that developed model and method can be used to formulate and solve inverse problems for noncontact temperature testing in dielectrics and for nondestructive determination of its radiation properties (volumetric and surface) on the base of the data obtained by measuring of IR radiation emitted by the layer.
Yurii Boichuk
Pidstryhach Institute for Applied Problems of Mechanics and Mathematics
Read the Original
This page is a summary of: An Iterative Method for Solving of Coupled Equations for Conductive-Radiative Heat Transfer in Dielectric Layers, Advances in Mathematical Physics, January 2017, Hindawi Publishing Corporation,
DOI: 10.1155/2017/9139135.
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