Trajectory-based flow-thermal-structural coupling analysis for hypersonic vehicles

This study investigates the flow-thermal-structural coupling phenomena in hypersonic vehicles, where extreme temperature and pressure conditions induce complex thermochemical nonequilibrium effects in the surrounding flow field. These effects pose significant challenges in accurately predicting aerodynamic thermal loads. Additionally, aerodynamic heating substantially influences the structural mechanical responses of hypersonic vehicles, making precise thermal environment predictions crucial, particularly given their structural complexity. To address these challenges, this study employs a two-temperature model to establish the governing equations for hypersonic flow. The experimental data from a Mach 6.47 flow around a circular tube are reproduced to achieve high-fidelity thermal field distributions. Structural heat conduction and mechanical response equations are incorporated using a loosely coupled method based on timescale analysis, enabling simulations of the circular tube's mechanical behavior. The results exhibit strong agreement with experimental data, validating the accuracy of the proposed approach. Building on these findings, a flow-thermal-structural coupling strategy tailored to flight trajectory characteristics is developed and applied to a representative trajectory of an X-51A-like vehicle. This method effectively captures flow field dynamics, surface heat flux, and pressure distributions across different vehicle regions. Moreover, it provides a detailed analysis of thermal stress, strain, and stress interactions between the skin and framework, offering critical theoretical insights for the design and development of hypersonic vehicles.