Emissions and Operability of a Multi-Point Low NO_x Staged Combustor at Intermediate Pressures

Emissions measurements were performed on a low-NO_x emission combustor concept developed by United Technologies Aerospace Systems (formerly Goodrich) for NASA’s Environmentally Responsible Aircraft (ERA) program to meet N+2 emissions goals for a 70,000 pound thrust engine application. A key enabler of this goal is to improve combustion stability at low power conditions over that of previous work. The combustion system presented potentially substitutes five radially staged small injectors for a single row of larger injectors. The test combustor has a total of 13 individual fuel injectors distributed in five rows. NO_x, CO, and UHC were measured for a variety of practical conditions, from lean blow-out to idle and simulated full power. Imaging provided insight on how the staged injectors perform and contribute to observed emissions. Conditions which yield significant NO_x reductions were identified and correlate well to existing literature. In particular, evenly distributed combustion among all 13 fuel injectors reduced regions of high temperature and resulted in significant NO_x reductions which correlate well with demonstrated performance of other multi-point combustors.