Ignition Transient in an Ethylene Fueled Scramjet Engine with Air Throttling Part II: Ignition and Flame Development

摘要

The analysis in Part I of this study is extended to explore the ignition transient and subsequent flame development under flow conditions with and without air throttling. In the present work, gaseous ethylene is injected into the chamber upstream of the cavity flameholder. Immediately after a steady ethylene/air flow is established in the combustor, a hot-spot igniter is employed to simulate the spark ignition at the bottom of the cavity. Various processes involved in the ignition transient and flame development are studied in detail under conditions with and without air throttling. The effects of the throttling air flow on ignition enhancement and flameholding are analyzed. Air throttling generates a pre- combustion shock train in the isolator. The resultant decrease in the flow velocity and increases in the temperature and pressure in the combustor section improve the ignition characteristics and the flame stabilization process. The predicted combustor performance and flow distributions agree well with experimental measurements.