Carbon/carbon composites are usually used as a thermal protection material in the nose cap and leading edge of hypersonic vehicles. In order to predict the thermal and ablation response of a carbon/carbon model in a hypersonic aerothermal environment, a multiphysical coupling model is established taking into account thermochemical nonequilibrium of a flow field, heat transfer, and ablation of a material. A mesh movement algorithm is implemented to track the ablation recession. The flow field distribution and ablation recession are studied. The results show that the fluid-thermal-ablation coupling model can effectively predict the thermal and ablation response of the material. The temperature and heat flux in the stationary region of the carbon/carbon model change significantly with time. As time goes on, the wall temperature increases and the heat flux decreases. The ablation in the stagnation area is more serious than in the lateral area. The shape of the material changes, and the radius of the leading edge increases after ablation. The fluid-thermal-ablation coupling model can be used to provide reference for the design of a thermal protection system.

The analysis of thermo-structural behaviour is crucial to the nose cap of a hypersonic vehicle under aerothermodynamic loads. Considering chemical nonequilibrium of the flow field, heat transfer, and deformation of the structure, a fluid-thermal-structural coupling model of the typical nose cap was established. The coupling relation between the flow field and nose cap was analyzed. The results show that the fluid-thermal-structural model can effectively predict the response of the nose cap under a hypersonic environment. The highest temperature and the peak of maximum principal stress appear at the front of the nose cap at an initial stage. As time goes on, the highest temperature increases gradually and the peak of maximum principal stress decreases after reaching a certain value. The position of the peak of maximum principal stress gradually moves to the inside of the nose cap and eventually stabilizes. With the increase in the Mach number, the highest temperature and the peak of maximum principal stress of the nose cap increase. The fluid-thermal-structural coupling model can provide guidance for the optimal design of the nose cap of a hypersonic vehicle.