Design and thermomechanical performance study of active-passive coupled thermal protection structures for hypersonic glide vehicles

During the re-entry phase, hypersonic glide vehicles have to withstand extreme heat flux and complex aerodynamic loads simultaneously, while traditional thermal protection structures struggle to synergistically optimize thermal insulation efficiency, deformation compatibility and thermomechanical performance. This paper designs an active-passive synergistic thermal protection structure integrating passive thermal insulation and impact resistance, active channel heat control and other functions. An integrated protection system adapted to the fluid-thermal-mechanical multi-physics coupling environment is constructed via a layered configuration of rigid ceramic insulation tiles, strain isolation pads and other components. A three-dimensional transient multi-physics coupling numerical model is established to systematically analyze the influence mechanisms of four key geometric parameters including insulation tile thickness and channel shape. The results show that aviation kerosene as the cooling medium can improve the thermal protection efficiency of the structure from 59% to 71%; reducing the size of insulation tiles under high-pressure loads mitigates stress concentration and enhances the safety margin; an increase in the number of flow channels alleviates thermal stress and strengthens the cooling effect; the trapezoidal channel configuration features small deformation and uniform stress distribution, achieving the optimal comprehensive performance. Through the synergistic coupling of each functional layer, the structure realizes the integrated improvement of thermal protection efficiency and structural safety, and provides important theoretical support for the optimal design of thermal protection systems for hypersonic vehicles.