Journal of Propulsion and Energy ISSN:2734-1887(Print) 2765-0049(Online)

A high-resolution numerical study is carried out to investigate the transient process of the fuel injection, combustion, and the shock-train formation by air-throttling in the isolator of an ethylene-fueled direct-connect scramjet combustor. The transient simulation begins with the supersonic air flow development followed by fuel injection. Air-throttling is then applied at the expansion part of the combustor to provide mass addition to block the flow to subsonic speed. The ignition occurs several milliseconds later when the fuel and air are mixed sufficiently. The pressure buildup by the combustion leads to the shock-train formation in the isolator section that advances to the exit of the facility nozzle. Then, the air- throttling is deactivated, the exhaust process begins and the situation before the air-throttling is restored. Present simulation shows the detailed processes in the dual mode scramjet combustor for better understanding of the operation regimes and characteristics.