【摘要】 本文着眼于超燃冲压发动机燃烧室面临的热防护问题，构建了三维主被动复合热防护多物理场耦合模型，融合超临界压力下碳氢燃料流动传热特性与结构力学响应，既考虑燃料在冷却通道内的对流换热主动降温机制，又纳入被动层的隔热导热换热规律，实现了对复合热防护系统复杂传热-力学行为的数值计算。探究了主被动热防护层沿厚度方向和轴向方向的温度梯度分布规律，揭示了高温环境下两层结构的热膨胀演化特性及分界面间隙的形成与分布机制。研究表明，被动热防护层的隔热性能承担了更多的热载荷；而主被动层材料在导热系数、热膨胀系数上的固有差异，叠加沿层厚方向和轴向方向的非均匀温度场，导致两层结构产生异步热变形，最终在交界面形成局部接触间隙。更多还原

【Abstract】 This paper focuses on the thermal protection issues faced by scramjet combustors, constructing a three-dimensional multi-physics coupling model for active-passive composite thermal protection. It integrates the flow and heat transfer characteristics of hydrocarbon fuels under supercritical pressure with structural mechanical responses, considering both the active cooling mechanism of convective heat transfer of fuels in cooling channels and the heat insulation and conduction laws of the passive layer, thereby realizing numerical calculations of the complex heat transfer-mechanical behaviors of the composite thermal protection system. The study explores the temperature gradient distribution laws of the active and passive thermal protection layers along the thickness and axial directions, and reveals the thermal expansion evolution characteristics of the two-layer structure in high-temperature environments as well as the formation and distribution mechanism of interface gaps. Research shows that the thermal insulation performance of the passive thermal protection layer bears more thermal load; however, the inherent differences in thermal conductivity and thermal expansion coefficient between the active and passive layer materials, combined with the non-uniform temperature fields along the layer thickness and axial directions, lead to asynchronous thermal deformation of the two-layer structure, ultimately forming local contact gaps at the interface.更多还原