Numerical investigation on the regulation of coolant heat sink by micro-ribs in transpiration- regenerative composite cooling

High-Mach scramjet engines face extreme thermal loads that single cooling methods cannot withstand. Existing transpiration-regenerative composite cooling has the problem of inaccurate coolant flow distribution, limiting its thermal protection performance. This paper proposes a novel micro-rib integrated transpiration-regenerative composite cooling structure, aiming to provide a novel technical solution to address the unmet cooling demand in hypersonic combustors. The micro-ribs on the porous plate have dual effects on cooling performance: although they inhibit coolant supply at the front end (0 ≤ s/L ≤ 0.12), they effectively reduce the plate temperature by enhancing turbulent heat transfer. Results show the micro-ribs structure reduces the temperature standard deviation of the porous plate upper and lower surfaces by 29.8 K and 5 K respectively compared with single regenerative cooling. Front ribbed arrangement achieves the optimal cooling-pressure loss balance. The heat transfer coefficient first rises then falls with increasing rib height, peaking at an aspect ratio of 1. This study provides guidance for high-efficiency scramjet thermal protection design.