Close-Coupled Fuel Injector/Flameholder Concept Featuring Direct Fuel Injection Into Flameholder Wake

Close-coupled fuel injector/flameholders used in modern augmentors face difficult challenges in static stability due to higher airflow velocities and higher levels of vitiation than past augmentors. In addition, close-coupled fuel injection schemes typically employ jet-in-crossflow methods to adequately penetrate and mix the fuel with the mainstream, but have difficulty providing sufficient fuel to the flameholder wake to anchor the flame. In this SBIR program, CFDRC proposes to develop a novel fuel injection concept that injects a small percentage (~10%) of the fuel directly into the flameholder wake to control the wake fuel-air ratio. Using a combined numerical/experimental approach in Phase I, the feasibility of the wake injection concept was demonstrated on a benchscale 0.75” flameholder. In Phase II, the wake fuel concept will be adapted to a more realistic 1.5” flameholder that employs a closed V-gutter arrangement. This flameholder will include two fuel circuits (main and wake) and flameholder cooling air discharging into the wake. Three rounds of design, fabrication, and testing will be conducted; the first round focusing on the basic features of the design, the second round on design optimization, and the third round on testing a near engine-quality design. At the end of Phase II, the concept will be at TRL 4 and ready for sector testing at GE in Phase III/CPP, followed by potential full engine testing.