Thermal analysis of a high-efficiency internally-cooled strut injector for scramjet engine

Adding fuel strut in scramjet combustor is an effective solution to improve fuel-air mixing and combustion efficiency. However, strut injector suffers from extreme aerodynamic heat, thereby needing high-efficiency cooling method to ensure its thermal safety. This study presented a numerical demonstration of an internally-cooled strut injector based on coiled and miniature-sized cooling configuration that could operate under low coolant mass flow rate of 10 g/s, while more than three times of coolant was needed for another two control cases of previous designs. The heat transfer coefficient and heatflux on the leading edge of present-designed strut were the maximum of the three struts. The non-uniform distribution of pressure in the manifold caused the deviations in the mass flow and pressure drop in the subsequent paired channels. Friction head loss and local resistance loss was separately responsible for 72.3% and 27.7% of total pressure drop. However, as the mass flow increased, the expense of pressure drop outstripped the merit of heat transfer improvement.