Modeling of Thermal Protection Based on Anisotropic Materials with a High Degree of Anisotropy

Abstract

This article describes a theoretically sound method for providing thermal protection for high-speed aircraft structural elements under aerogasdynamic heating conditions. The method involves posing and analytically solving the problem of heat transfer in a blunt nose section made of an anisotropic heat-shielding material with a high degree of anisotropy in one direction (the ratio of the maximum to the minimum component of the thermal conductivity tensor). A new analytical solution is obtained for this problem under conditions of heat exchange with the surrounding high-temperature medium (gasdynamic boundary layer) on the blunt body, in which the principal axis of the thermal conductivity tensor with the largest coefficient is directed along the body, and with the minimum coefficient, in the direction normal to the body surface. A situation arises in which the conductive heat flows from the forward stagnation point of the body and its vicinity, where the maximum heat fluxes are observed, to the tail section, thus significantly cooling the vicinity of the stagnation point. It becomes possible, at the thermal protection design stage, to control the characteristics of the thermal conductivity tensor (its principal components and the orientation of the principal axes relative to the selected coordinate system) to cool the most thermally loaded elements of the air vehicle structure. Numerical results have confirmed the effectiveness of this method of thermal protection for high-speed aircraft.