Thermal shock resistance of ultra-high-temperature ceramic thermal protection system

Thermal shock resistance (TSR) of ultra-high temperature ceramic (UHTC) thermal protection system was investigated. The influences of the ratio of the UHTCs' compressive-tensile strength, surface heat flux, convective heat transfer coefficient, and coolant temperature are studied. The failure of the ultra-high-temperature ceramic (UHTC) plate under aerodynamic thermal environments is caused by compressive stress at the upper surface for the lower ratio of the compressive tensile strength and initially by tensile stress inside the plate and then by compressive stress at the upper surface for the higher ratio of the compressive-tensile strength as surface heat flux increases. The thermal upshock resistance of the UHTCs caused by aerodynamic heating can be improved by convective cooling because of the reduced thermal stress near the upper surface, middle plane, and lower surface.