EXPERIMENTAL SUBSTANTIATION OF THE POSSIBILITY OF IMPROVEMENT OF THE OUT-OF-PLANE THERMOPHYSICAL PROPERTIES OF A HYBRID STRUCTURE OF A RADIATION HEAT EXCHANGER

The prospective program of the deployment of a manned lunar base has revealed the need for developing a new elemental composition for a thermal control system (TCS). For a TCS radiation heat exchanger (RHE), to reduce the mass and to improve the reliability of operation under the conditions of the lunar surface, it is suggested that an RHE radiant duralumin panel with heat pipes be replaced with a high-conductivity radiant panel of hybrid structure on the basis of pyrolytic graphite. A hybrid panel has a substantial anisotropy of thermophysical properties. The thermal conductivity along the panel plane exceeds the cross-field thermal conductivity almost one hundred times. To improve the out-of-plane thermophysical properties of a hybrid panel, it is suggested that the panel be pierced with metal elements. The presented paper is devoted to determining the thermophysical properties of a graphite- based anisotropic hybrid structure pierced with metal elements perpendicular to the plane. To determine the thermal diffusivity and thermal conductivity of the samples, use was made of an unsteady laser flash method. Approximations have been obtained for the temperature dependences of in-plane and out-of-plane thermal diffusivity and thermal conductivity of a hybrid pyrolytic graphite structure for the temperature range of 256–372 K.

Author:  A. E. Belyavskii, N. S. Kudryavtseva
Keywords:  anisotropic hybrid structure, thermal conductivity, thermal diffusivity, laser flash method, radiation heat exchanger
Page:  1152