Justin Smet

Development of future hypersonic aircrafts has been of great interest for a variety of different military and civil uses globally. These aircrafts have potential uses from hypersonic air travel, to space exploration, to other applications. These aircrafts typically have immense drag forces on them and utilize high power combustion engines to propel the vehicle. Rocket engines can serve this purpose but need to bring oxidizer which makes the cost extremely high. In contrast, air-breathing propulsion system directly obtains oxidizer from the air, and hence becomes the only economic option for vast deployment of hypersonic aircrafts. The typical air-breathing propulsion engine for hypersonic aircrafts is the supersonic combustion ramjet (scramjet). Scramjets work through compressing the intake hypersonic air flows to supersonic through shock waves all without moving parts, and burning fuel at supersonic conditions. Under such conditions, ignition and flame stabilization is very difficult. Due to the extremely high cost of scramjet experiments, Computational Fluid Dynamics (CFD) is essential in analyzing and designing scramjet engines. This computational research aims to simulate a scramjet engine which utilizes two ethylene injections into the flow field which are set up as a jet in cross-flow configuration. One of these injectors is located in a cavity flameholder, which creates relatively low speed eddys to extend the residence times and prevents the flame from being blown out. Chemical Explosive Mode Analysis (CEMA) is used to analyze the simulation data to understand the underlying mechanisms for ignition and flame stabilization under such a harsh supersonic condition.