The study of convective heat exchange of structured, inhomogeneous element serving as a heat-insulating layer for the skin of aircraft products

Аuthors

Maskaykin V. A.^*, Makhrov V. P.^**

*e-mail: vladimir.maskaykin@mail.ru
**e-mail: v_machrov@rambler.ru

Abstract

The presented article considers the heat exchange in various types of combinations of materials to ensure thermal protection. The purpose of such kinds of combinations of materials studying consists in obtaining such type of its structure, which meets the thermal insulation requirements for implementing in the structures operating under extremely low or high temperatures.

As the result of the convective thermal exchange study with the selected elements, it was revealed that interchangeability of the thermal exchange processes of material among themselves is characteristic for thermal insulation enhancing. The results demonstrate the element with layered combination of materials has high thermal insulation index. Interaction of materials with the opposite thermal conductivity characteristics, peculiar to the elements under consideration with layered combination of materials, is necessary to keep a positive temperature of the element. Presumably, the retention of temperature is stipulated by the fact that a material with high thermal insulation indices does not allow the next layer of material cooling (the material with low thermal conductivity). A material with low thermal conductivity indices in its turn transfers heat to a material with high thermal insulation indices due to its high thermal conductivity characteristics.

Unlike an element with a layered combination of materials, an element with a structured combination of materials has low thermal insulation indices due to the «discontinuity» of the heat exchange process. As the result, a summation of the processes of materials heat transfer occurs, depending on their thermal conductivity characteristics.

According to the obtained results of the study on convective heat transfer of the considered thermal insulation elements, it can be assumed that the introduction of an element with a solid material as a heat-insulating layer for the skin of aircraft products is unacceptable. When considering elements, which involve two or more different materials in the heat exchange process, the most effective element for the insulating skin layer is the element with a layered combination of materials.

Keywords:

thermal insulation, non-stationary thermal conductivity, thermal insulation materials, structuring of materials, convective heat transfer

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