Dynamic Characteristics of Combustion Mode Transitions in a Strut-Based Scramjet Combustor Model

The first results of the dynamic characteristics of combustion mode transition in a liquid-fueled strut-based scramjet combustor to support real hypersonic flight dynamics and control system design is presented. Combustion experiments were performed under the incoming airflow conditions and inflow Mach number. Three different combustion modes with respect to equivalence ratio are observed and evaluated, namely, two kinds of ramjet-mode operation and a scramjet-mode operation according to the number of thermal choking points. Time-domain dynamic characteristics of combustion mode transition are presented and discussed as the fuel rate changes over time in the form of ramp. Differing greatly from the phenomena of static features of each combustion mode, two novel mode transitions appear. The hysteresis effect on the combustion mode transition, fuel schedule, and engine thrust must all be considered for control system design of the vehicle.