Effect of Fluid-Solid-Thermal Coupling on the Performance of S-Duct in Hypersonic Inlet

This article studies the effects of multi-field coupling on the S-duct by a self-developed fluid-solid-thermal bi-directional coupling code. The flow field inside the S-duct is complex with various vortices as the airflow turns. The results indicate that the total pressure recovery coefficient and the total pressure distortion index (DI) change rapidly at the beginning and reach a steady state at about 100s. The σ decreases by 12%, and the DI increases by 2% compared to the starting point. Structural deformation, size of separation zone, and wall temperature changes over time, and stabilizes around 100 s. The deformation mainly occurs at the outlet, with a maximum displacement of 3.65 mm for up-warping and 4.60 mm for expansion. The values of the total pressure recovery coefficient with S-ducts of bias distance with 20, 40, and 60 mm drop by 2.5%, 8.6%, and 12.1%, and the values of the total pressure distortion index increases with S-ducts of bias distance with 20, 40, and 60 mm increase by 10.8%, 15.1%, and 1.7%. The S-duct with a larger aspect ratio has larger separation zones and a smaller total pressure recovery coefficient.