Additively Manufactured Low NOx Multipoint Lean Direct Injection Fuel Atomizer Concepts

摘要

In research completed in 2013, United Technologies Aerospace Systems designed and built an MLDI combustion system for low emissions in line with the NASA Environmentally Responsible Aviation (ERA) program. This system was designed to meet N+2 emissions goals of a 75% reduction in LTO NO_X from CAEP 6 standards without increasing CO or UHC The current research detailed in this paper presents three new injector designs which could be integrated into this MLDI array in place of the original high-shear airblast injectors. The new injectors are novel designs which make use of additive manufacturing, including one which is fully additive. The additive manufacturing approach enables a greater complexity of design while bypassing machining and joining operations needed for their conventional counterparts. The injectors have been studied using PIV and CFD, including NOx predictions from the CFD studies. Finally, the new injectors were tested in a high pressure combustion rig with emissions data recorded. Examining the emissions data for both the new additive injectors and the original MLDI injectors show comparable levels of NOx and CO concentrations. Achieving the target emissions with additively manufactured parts represents an advancement in MLDI technology and in the production feasibility of the multipoint concept.