Influence of the flow mode and flow distribution on heat transfer performance in a jet-regeneration composite cooling system

This study aims to address the severe thermal challenges of scramjet engines during higher Mach number flights. For this purpose, this work proposes a jet-regeneration channel composite cooling technology. Then, it numerically investigates the heat transfer performance of supercritical n-decane under different flow patterns and composite cooling flow distribution. The results show that, among the three flow patterns, the combined jet-crossflow cooling performs the best. Using supercritical n-decane as the cooling medium, the optimal ratio under a single jet is 87. 5% of the total flow rate for the crossflow and 12. 5% for the jet flow. However, for multiple jets (with 2 and 3 jet numbers), the optimal ratio is 75% of the total flow rate for crossflow and 25% for jet flow. Moreover, a comparative study of the combined cooling heat transfer performance of supercritical n-decane and ambient air demonstrates that, although ambient air has better cooling effects, its heat transfer uniformity is poor. The temperature unevenness of the supercritical n-decane composite cooling performs poorer, resulting in better overall heat transfer performance. The results of this study provide a basis for selecting flow media and rational distribution of flow in the composite cooling system.