Evaluation on maximum flight Mach number of active cooling scramjet

It is an effective measure to use active cooling structure in scramjet's TPS (thermal protection systems) to keep long duration engine operation. According to the severe thermal environment of scramjet, an active cooling structure based on ceramic matrix composite (CMC) was designed. The mathematical models on active cooling structure design were also developed. A factor called coolant mass flow ratio was introduced to analyze the maximum flight Mach number from the aspect of the whole vehicle's TPS. The exit temperature of coolant flowing through the coolant channel was used as an important baseline to evaluate the maximum flight Mach number of active cooling scramjet. Also some important factors including coolant mass flow ratio, flight altitute and combustion equivalence ratio were analyzed to study their influence on maximum flight Mach number. Results show that by enhancing coolant mass flow ratio, reducing flight height properly and increasing combustion equivalence ratio in a certain range, the exit temperature can be reduced and consequently the maximum flight Mach number can be enhanced.