Induction-Zone Behavior in Different Fuels in Rotating Detonation Engine Combustion

Rotating Detonation Engines (RDEs) have been studied extensively, particularly in recent years, with the motivation coming from the promise of superior propulsive performance in high-speed flight. A significant amount of the research efforts in this area has been based on using hydrogen as the fuel. In general, hydrocarbon fuels such as methane, acetylene, and ethylene, are more difficult to detonate than hydrogen because of their lower flammability. Therefore, it is expected that the induction-zone behavior of different fuels will vary based on their chemical properties and combustion characteristics. The induction-zone in the specific case of a detonation wave refers to the region where the fuel-oxidizer mixture is at a relatively low temperature, which is located after the shock wave, but before the point of thermal runaway, which defines the location of the flame. The objective of this study is to investigate the induction-zone behaviors of different fuels used in a model of the RDE combustor. This knowledge will enable better decisions in fuel selection. A large-eddy simulation solver will be used for the analysis. The characteristics of the induction zone, including its length, temperature, and fuel-oxidizer mixture composition, are expected affect the overall propulsive performance and efficiency of the RDE.