STUDY OF THE THERMAL STATE OF A PYROLYTIC GRAPHITE PLATE BASED ON AN ANALYTICAL SOLUTION.

Graphite and graphite-containing materials having a high degree of anisotropy are widely used for thermal protection. When modelling the thermal state of products, made of anisotropic materials, it is necessary to take into account many factors and the presence of mixed derivatives significantly complicates the solution for the problems of anisotropic thermal conductivity. This paper examines the thermal state of a pyrolytic graphite plate in the presence of heat transfer at its free boundaries on the basis of an analytical solution of the second initial-boundary value problem of anisotropic thermal conductivity with general anisotropy (off-diagonal components of the thermal conductivity tensor are not equal to zero). This solution makes it possible to analyse qualitatively and quantitatively the thermal state of bodies, made of materials with a high degree of anisotropy, in particular, pyrolytic graphite. The analysis of the influence of the thermal conductivity tensor principal axes orientation on the temperature fields of plate corners has been carried out, as well as the degree of anisotropy -- the ratio of the maximal principal component of the thermal conductivity tensor to the minimum. It is shown that even a thin layer of pyrolytic graphite makes it possible to control heat fluxes only due to the orientation of the main axes of the thermal conductivity tensor during high-intensity heating of various structural elements. [ABSTRACT FROM AUTHOR]