The research of effective thermal conductivity coefficient effect on the temperature field of reflector

Contemporary satellite communications require the large-dimensioned antennas with high precision of the reflecting surface. They shall be light, robust and temperature resistant. The unevenness of the temperature field in an antenna can result in the temperature deformations of the reflecting surface and deterioration of the transmitted signal. The temperature influence on antennas and reflectors shall be determined during the design phase. This research examines the reflector accommodated on the telecommunication satellite which operates on the geostationary orbit. The reflector is a three-ply sandwich panel which consists of two skins and a honeycomb core. The heat-transfer properties of the reflector sandwich panel as well as carbon fiber composites and honeycomb core can vary significantly. For the purpose of the most accurate calculations during the temperature analysis phase an engineer has to find the anisotropic thermal conductivity coefficient of the carbon fiber composites and honeycomb core by applying the mathematical simulation. The heat-transfer properties of such materials are often unknown during the temperature analysis phase. The necessity to determine the properties of the reflector materials is confirmed by performed calculations. The basic equations for thermal equilibrium of the spacecraft and its components were reviewed. The thermal mathematical model was developed for the reflector with overall dimensions of 3.6 m x 2 m. The estimate of the reflector materials conductivity and heat-transfer coefficient effect on the maximum and minimum diurnal temperatures and maximum temperature difference was made. The significant influence of the conductivity and heat-transfer coefficients on temperature difference in the reflector was shown.