Sizing optimization of lightweight multilayer thermal protection structures for hypersonic aircraft

In the context of hypersonic aircraft design, the major issue of the thermal protection system (TPS) is to obtain the optimal thickness of the insulation layers due to intense aerodynamic heating during re-entering earth's atmosphere. In this study, an idea combining a transient heat transfer model and an efficient optimization model is introduced for multi-layer insulation of TPS. The TPS geometric dimensions in the thickness direction are particularly considered as the design variables and the objective function is the mass of the thermal protection structure with the limitation of the extreme temperatures of the hypersonic vehicle structure. In order to decrease the computational complexity, the Globally Convergent Method of Moving Asymptotes (GCMMA) method is specially used to search the optimal solution. The results show that the usage of multilayer insulation materials for the TPS can save more than 25% weight compared to a single-layer TPS. The detailed analysis and comparison indicate the advantages of the presented optimization model.