Development and characterization of a contoured passive thermal protection system

Present work deals with process refinement, fabrication, and testing of a novel contoured passive thermal protection system (TPS), based on aluminosilicate fiber reinforced silica matrix composite. Taguchi method-based statistical approach was employed to understand the effect of process parameters such as thickness, layer density, stacking sequence and firing temperature on dielectric properties, flexural strength, and bulk density of composites. Analysis of variance was performed to ensure the statistical significance. The developed TPS was characterized for thermal insulation properties by testing under infrared heating conditions. The science behind the insulation characteristics of the TPS was analyzed using FTIR, XRD, and SEM to understand the associated high-temperature phase transitions. Present study has shown that, the back-face temperature exponentially decays with TPS thickness. For TPS having 9 mm thickness, the back-face temperature was found to be below 100°C when the front face was exposed to 1000°C. The insulation index was found to be increasing with increase in temperature and TPS thickness. Improved thermal insulation characteristics of TPS are due to energy consuming processes such as crystalline changes and micro cracks formation.