Numerical investigation on heat sink utilization mechanism of directional transpiration-regenerative composite cooling in cavity structure

Scramjet cavity, a core structure for supersonic flame stabilization, faces extreme thermal loads. Existing cooling methods for this component present inherent bottlenecks: uneven coolant distribution, overtemperature in high-heat-flux zones, and redundant cooling in low-heat-flux regions. This work presents the first application of a directional transpiration-regenerative composite cooling scheme to the scramjet cavity structure, providing a novel approach to enhance temperature uniformity and eliminate local hot spots. A numerical model for directional composite cooling system applied to scramjet cavity is established. The thermal protection mechanism of directional composite cooling is elucidated, and the regulation laws of directional angle and segmented porosity on coolant heat sink are systematically investigated. Results show that directional composite cooling yields a 520 K reduction in the peak aft wall temperature and a 327 K reduction in extreme temperature difference compared with single regenerative cooling. Within the 4°∼28° range of the directional angle, the aft wall cooling performance improves monotonically with increasing directional angle. The segmented porosity optimization further reduces the peak and average temperatures by 88 K and 66 K, respectively.