Advancing Exhaust Flow Uniformity, Operational Stability, and Total Pressure Gain of Rotating Detonation Engines for Successful Turbine Integration

Rotating Detonation Combustors (RDCs) have gained significant attention in recent years for their potential for higher fuel efficiency through pressure-gain combustion (PGC). RDC integrated with a gas turbine, offers the potential for increased system efficiency. However, RDC operation involves several non-idealities, generating a shock-laden, highly unsteady exhaust flow field that differs substantially from steady, subsonic flow required at the turbine inlet.This dissertation aims to develop novel RDC designs with tailored inlet and exit geometries for successful turbine integration. Firstly, RDC exit was configured with a convergent nozzle (CN) of varying RDC throat area ratio (ARC = 1.0 to 2.0) to increase the chamber pressure and total pressure gain (TPG). The 100 kHz particle image velocimetry (PIV) at RDC exit showed reductions in flow unsteadiness with increasing exit restriction, although periodic flow oscillations matching the detonation wave frequency persisted even at the highest ARC. Next, RDC equipped with CNs of ARC > 2 showed improvements in exhaust flow uniformity and TPG, but shock reflections from the CN adversely affected the wave stability, eventually leading to detonation failure at ARC > 3.0. A novel Rapid-to-Gradual (RTG) nozzle was developed to overcome shock reflection and wave stability issues. RDCs configured with RTG showed significant improvement in stability, exit flow uniformity, and TPG even at ARC = 5.0. Next, injector stiffness was reduced to further improve the performance of RDC with RTG nozzle. In case of CN, reduced injector stiffness can result in RDC-plenum coupling creating strong longitudinal oscillations that adversely affect the stability of the detonation wave. RTG nozzle greatly increased the stable range of RDC operation without/with stiff injectors, while providing excellent flow uniformity at the exit and TPG approaching TPG to nearly zero. This experimental study has advanced the fundamental understanding making it possible to achieve operational stability, exhaust flow uniformity, and total pressure gain in RDCs for successful turbine integration. The superiority of the RTG nozzle to achieve these outcomes in RDC has been demonstrated.