Experimental and analytical evaluation of an aerospace thermal protection system: Carbon monolith ablator

A porous carbon material with a three-dimensional (3D) networked structure (carbon monolith) was prepared as a substrate for an ablator, which is a thermal protection system (TPS) for re-entry vehicles. A carbon monolith ablator (CMA) was fabricated by impregnating acrylic resin into the carbon monolith. To evaluate the thermal insulation effect of the CMA, arc wind tunnel tests for the carbon monolith and CMA were conducted to simulate atmospheric re-entry. The results indicated that the surface temperature of the CMA was lower than that of the carbon monolith, and the decomposition of the acrylic resin was effective in preventing an increase in surface temperature, as the decomposition of the resin is an endothermic process. Thermal conduction and stress analyses using the finite element method revealed that the tensile stress that evolved during exposure reached those of typical porous carbon materials, and tensile stress relaxation was required to apply the CMA as a TPS.