Survey of Rotating Detonation Engines and performance models

This report gives a detailed description of the Rotation Detonation Engine, or RDE. This type of engine has been shown to have a great potential, but issues, in particular regarding very short operation times, have resulted in that the RDE has been looked upon with some skepticism. However, the last years (2015-2019) the RDE has received considerable interest. For example, at the AIAA Propulsion and Energy, 2019, Indianapolis, a large number of the sessions were dedicated to different aspects of this engine. Furthermore, at a visit at University of Cincinnati, the authors of this report were informed that the previous concerns regarding limited run times seemed to have been resolved. Considering the potential of the RDE - reduced fuel consumption/longer range/higher speed - the authors are therefore of the firm belief that this field of research should be a prioritized. To put the RDE in a proper context, the report makes an overview - focusing both on the technology and the status of the research situation around the world for competing engine concepts: turbojet engines, as well as ramjet and scramjet engines. Although propulsion is an extremely complex area, with many issues still not resolved, it is important to be able to quickly form a perception of how the different engine types relate to each other, and where they have their strong and weak sides. The kind of simplified models used in this context will necessarily be using rather severe assumptions and approximations. This report describes how a simplified performance model for turbojet and ramjet engines have been implemented and how the model used for these engine types was extended to also handle scramjet engines. A first step has also been taken to developing a model for performance estimates for engines working with detonative combustion.