Parametric numerical analysis of regenerative cooling in hydrogen fueled scramjet engines

•3-D coupled model of hydrogen coolant is introduced and validated through experiments.•Small flow area can largely reduce the wall temperature but increase the pressure drop significantly.•The optimal channel aspect ratio is a relatively large value and it become larger with smaller flow area.•Decreasing fin thickness can reduce the wall temperature significantly without large pressure drop increase.•Low inlet coolant temperature will cause local heat transfer deterioration and it should be avoided.

Efficient cooling technologies are required in hydrogen fueled scramjet engines because of its rather large heat load and relatively small coolant mass flow rate. Regenerative cooling is the most promising way to cool the scramjet engine. To study the thermal behavior inside the cooling channels of the regenerative cooling system at different channel sizes and to find the optimum design parameters, 3-D model of coolant flow in terms of the fuel real properties is built and validated through experiments. The effects of flow area, channel aspect ratio, fin thickness and coolant inlet temperature on cooling performances were explored. The simulation results indicate that a small flow area can largely reduce the wall temperature, but the pressure drop will be increased significantly at the same time. For the given cases, the wall temperature keeps decreasing when the channel aspect ratio increase from 1 to 8, but there exist an optimal channel aspect ratio at a relatively large value. The optimal channel aspect ratio become larger when the flow area becomes smaller. Decreasing fin thickness can reduce the wall temperature significantly without bringing large increase of pressure drop. Low inlet coolant temperature will cause local heat transfer deterioration and it should be avoided to guarantee the engine will not burn out.