An analysis tool of the rocket-based combined cycle engine and its application in the two-stage-to-orbit mission

Abstract

The rocket-based combined cycle (RBCC) engine is believed to be an ideal propulsion system for the space round trip mission in the future. The mission planning process is limited because there is no available performance data on the RBCC engine. This paper proposed a thermodynamic analysis tool of the RBCC engine. Working over a wide speed range, this tool divides the engine’s working process into four modes, namely the ejector, the ramjet, the scramjet and the pure rocket modes. The results are validated by data in the previously published literatures. Based on this tool, the equal-dynamic pressure trajectory analysis is implemented for the first stage of a two-stage-to-orbit vehicle equipped with an RBCC propulsion system. The influences of the launch weight and the engine size of the vehicle on the acceleration performance are studied. The dynamic pressure of the designed trajectory is also in the scope of this work. The results show that a lighter launch weight, a larger engine size and a larger designed dynamic pressure are positive for the fast acceleration process with lower fuel consumption. In addition, a long distance transportation mission requires different design conditions with that in the fast acceleration mission.