Flow and heat transfer of hydrocarbon fuel in the double-layer regenerative cooling channels

Hypersonic air-breathing propulsion (>Mach 5) based on scramjet offers new solutions to both the military strike platform and the civil transportation. However, the hypersonic flight seriously challenges the engine thermal protection. One of the key problems is the tricky flow and thermal behaviors of hydrocarbon fuel in regenerative cooling channels under the complex thermal boundaries and channel geometry, which may cause heat transfer deterioration and structure over-temperature. To improve the cooling design, the double-layer regenerative cooling channels are focused and compared with the traditional single-layer channels. The flow and thermal behaviors of hydrocarbon fuel under different cooling configurations are numerically studied. Cooling performance of double-layer channels is superior than single-layer channels. T_w,max falls by 295.2 K/17.7%. Gravity direction and magnitude show negligible influence on the heat transfer. Regarding channel height ratio, H ₁/H ₂ = 1.1/1 achieves optimal cooling performance in present conditions. Double-layer-channel scheme presents high practicability in scramjet cooling.