Abstract:

Jet propulsion technology based on the Brayton thermodynamic cycle has matured to the point that continuing investment on research and development (R&D) results in diminishing marginal returns.  In contrast, rotating detonation engine (RDE) provides an alternative combustor concept that can potentially revolutionize the future propulsion and power systems. In an RDE, a detonation wave propagates circumferentially along an annular chamber, setting up cyclic intake and rapid heat release processes that can simplify the engine component design and scaling issues. Also, potential gains in operating range as well as fuel economy over the existing propulsion systems make the RDE concept a very interesting R&D topic for propulsion scientists and engineers.  In this seminar, the status of RDE research at the University of Maryland, USA, will be presented which includes (i) a two-dimensional model development work using the method of characteristics (MOC) technique, and (ii) an experimental study visualizing the fundamental structure of unwrapped RDE flowfield. The 2-D MOC approach provides a numerically efficient model that may be suitable for large parametric studies for design optimization and performance estimation. The model is capable of modeling the curved oblique shock wave, exit swirl, counter-flow, detonation inclination, and varying pressure along the inflow boundary. For experimental study, fundamental behavior of detonation wave propagating across an array of reactant jets inside a linear open channel was investigated. Various propellant combinations, including hydrogen-air, hydrogen-oxygen, ethylene-air, and ethylene-oxygen, have been tested in this experimental setup to provide better understanding of incomplete mixing and partial confinement effects. The experimental results highlight the possible effects of non-uniform premixing on stability of wave propagation and injection recovery processes. The results also suggest that the mixing between the fuel and the oxidizer as well as the mixing between the fresh reactants and the previous cycle products should play a critical role on RDE combustor processes.

Brief Biograph:

Professor Yu is a tenured faculty at the University of Maryland, College Park, Maryland, USA, where he has taught since 1999.  His research interests are in the general areas of propulsion, combustion, and hypersonics.  Some of his pioneering research contributions include the work on liquid-fueled active combustion control, cavity-based supersonic mixing enhancement, and convective-acoustic combustion instability.  He has advised 11 Ph.D. and 22 M.S. theses in those areas.  His work has resulted in over 200 publications in technical journals, books and conferences, as well as producing nine U.S. patents and four conference best paper awards. He currently directs the University of Maryland Hypersonic Center of Testing Excellence as well as the Advanced Propulsion Research Lab.  He is a fellow of American Society of Mechanical Engineers (ASME).

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