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Completed TRL 3 (started at 3, targeting 5)
The Combined Cycle Mode Transition challenge demonstrates autonomous control and establishes performance/operability assessment methodologies for future reusable hypersonic propulsion systems that use turbine engines at slow speeds while transitioning to scramjets for high-speed operations. This challenge addresses the technology barrier of propulsion system mode transition via ground tests.
Besides significantly reducing the risk of mode transition of a Turbine-Based Combined Cycle (TBCC) propulsion system for a potential flight demonstration, HTP will added to the research area as follows:
1) Mode Transition framework: Create a basis of knowledge for transient mode transition characteristics that is structured to guide future TBCC development.
2) TBCC components: Discover critical interaction between the propulsion components of a highly instrumented TBCC research model.
a. Inlet-to-inlet interaction: Understand and document effects of low-speed inlet flowpath changes on the high-speed inlet. Develop methodologies to trade the performance and operability design space for the dual inlets of a TBCC propulsion system.
b. Low-speed inlet / turbine engine: Understand airflow matching and dynamic distortion compatibility between the low-speed flowpath components for performance and operability.
c. High-speed inlet / isolator / Dual-Mode Ramjet (DMRJ): Understand the interplay between the high-speed flowpath components for performance and stability.
3) Autonomous Mode Transition: Researching controllers as a step towards autonomous control of a TBCC propulsion system. For the first time, control will be developed with a relevant mode transition path based on transient data and analytical modeling.
4) Advanced Controls: Exercise state-of-art control algorithms to enhance system response, robustness and noise rejection.
5) Transient validation database: Acquire high quality data for time-accurate analyses and CFD code validation.
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