عنوان مقاله [English]
The first solution to increase the efficiency of spacecraft is to decrease the weight of spacecraft which cause an increase in speed and flight range. Since the body of spacecraft tolerates a specific temperature range, the use of thermal protection systems which are designed to increase the weight of the structure in optimal conditions is essential. In this paper, thermal insulation with heat sink as a body boundary condition is considered in order to lower body temperature. For this purpose, transient thermal conduction equations are written in the curvilinear coordinate system and it is developed for a variety of axially symmetric vehicles geometries. The ablative insulation material is graphite and the effects of pyrolysis layer are ignored. The equations are solved with using discrete finite difference method and governing equations are solved with using alternating direction implicit method (ADI). Then the impact of the heatsink with different thickness on body temperature was investigated. The numerical results were compared with the exact solution results and they can see that their difference is less than 2% at all times. To reduce the body temperature, the concept of the heatsink is used and the results show that the heatsink decrease from 10% to 24% of the body temperature (depending on the thickness of the heatsink).