A review of rocket gain technology in the rocket-based combined cycle ejector mode

Rocket-based combined cycle (RBCC) engines are considered one of the primary power solutions for future reusable vehicles, near-space high-speed flight vehicles and other novel types of aerospace vehicles. In recent years, RBCC power has made significant breakthroughs in key research areas, such as mode transition, wide-domain combustion organization and flow channel design. The ejector mode, the most distinctive among the RBCC engine's modes, serves as a bridge between the ground and the ramjet mode. The performance of the ejector mode plays a pivotal role in determining the vehicle's overall design. This paper first reviews publicly reported research progress on the ejector mode in typical RBCC vehicles and analyzes the thrust and specific impulse gain characteristics of the ejector mode in each scheme based on public data. Second, independent research progress on the gain characteristics of the ejector mode in public reports is reviewed, and the thrust and specific impulse gain characteristics achieved are analyzed. Finally, the key technical directions for the development of rocket gain technology are identified, highlighting directions for improving ejector mode performance and promoting the integrated design of ejector mode gain technology with other modes.