Designing an ultra-high-performance Rotating Detonation Rocket Engine (RDRE) is challenging due to the lack of in-depth understanding of many key mixing and combustion processes. The design of ultra-high-performance RDRE injectors requires improved understanding of how the injector design affects its response and performance under the highly unsteady and impulsive detonation environment. These injectors must be optimized for (i) the ability to improve and control gaseous and liquid injector diodicity, while also minimizing the forward direction injector pressure drop to improve overall system performance, (ii) the ability to optimize the relative injector response and recovery of the fuel and oxidizer to achieve the desired mixture ratio and minimize deflagration losses, and (iii) the ability to control the mixing rate to ensure reliable detonation at the ideal lift-off position. The proposed research effort will develop ultra-high-performance injector solutions that meet these requirements. The Phase II overall goals are twofold: (1) design, test, and evaluate high diodicity single-element monophase and multi-element multiphase injectors in cold flow and hot-fire RDE experiments, with the CFD design optimization driving some of the injector concepts, and (2) initiating the development of a design methodology that is supported by CFD optimization and experimental validation. These steps will guide the transition and development beyond Phase II for infusion into more relevant and practical systems. The outcomes of the effort will lead to the development of validated accurate rules and tools that can be used for designing ultra-high-performance RDRE injectors. The expansion of scientific knowledge regarding injector design, detonation combustion, and global performance will provide NASA an experimental dataset to anchor future modeling and simulations.

The proposed work seeks to modernize the injector technology for RDEs for rocket applications. This includes design methodology, manufacturing, and hardware designs capable of providing high injector diodicity at reduced injector pressure drops. Detailed designs and measurements of the injector behavior will be compared to numerical simulations, and multidisciplinary design optimization will produce optimized injector designs that will be evaluated in an RDE test rig. This will benefit new technologies in air-breathing and rocket propulsion.

Non-NASA applications of the proposed efforts include ultra-high-performance injector technology for RDE applications, enabling the infusion of pressure gain and combustion size benefits into practical systems. Commercial applications include air-breathing propulsion, missiles, stationary power generation.