Numerical investigation on flame-stabilization mechanism of supersonic-combustor-based high-temperature CO/H₂ jet

A large-eddy simulation (LES) was performed on two different supersonic combustors based on a high-temperature CO/H₂ jet, and the flame-stabilization mechanism was analyzed. The results showed that for a strut-cavity-based combustor with the high-temperature jet turned on, the jet ignited, and the strut promoted the mixing of the supersonic airflow and fuel. The cavity recirculation zone realized the exchange of energy and momentum between the high-temperature gas and fuel in the shear layer, resulting in a decrease in the chemical timescale—referred to as the flame-stabilization mode of the high-temperature jet and cavity shear-layer ignition. Moreover, in a strut-cavity-based combustor with the high-temperature jet turned off, the strut promoted the mixing process, and the cavity improved the residence time of the fuel, resulting in the flow timescale being larger than that of the reaction—referred to as the flame-stabilization mode of the strut-cavity recirculation-zone flame stabilization. In the strut-based combustor with the high-temperature jet turned on, the rocket jet performed an ignition role in the flame stabilization process— referred to as the flame-stabilization mode for high-temperature jet ignition. When the jet was turned off, the chemical timescale increased rapidly and continued to be larger than the flow timescale, resulting in flameout.