Coupling simulation of aircraft aerothermodynamics regulated by gradient characteristics of thermal protection structure and its experimental verification

Advanced thermal protection system is an important part for safe flight of high-speed aircraft. With the development of composite material system for thermal protection, functional gradient composite materials with integrated thermal protection/insulation have been gradually applied to realize on-demand customization and collaborative design of thermal protection and thermal insulation properties. A tight coupling computation method for high Mach number aerothermal environment and thermal response of functionally gradient structure was developed for integrated thermal insulation composite structures. High-speed compressible flow/heat transfer coupling simulation of composite thermal structures with functionally gradient materials embedded was carried out under typical conditions. The infrared heating experiment of quartz lamp was carried out by testing functional gradient material with embedded layered temperature sensors. The influence of coupled heat transfer characteristics of composite thermal structures was obtained. The regulation mechanism of structural gradient characteristics on aerodynamic thermal load of aircraft was analyzed. It was found that under the condition of high Mach number air flow, the thermal insulation gradient material can better regulate the heat transport process inside the thermal insulation structure, which can not only prevent the instantaneous surface from exceeding the temperature limit to cause thermal damage, but also achieve uniform changes in the internal temperature of the structure to avoid thermal mismatch.