Strategic Thrust 3: Ultra-Efficient Commercial Vehicles in the ARMD "Strategic Implementation Plan" establishes specific efficiency levels for subsonic transport aircraft. Key to obtaining these ambitious goals will be development of more efficient, higher-fan-BPR engine architectures, which because of physical limitations on fan size will require more compact engine cores. This need motivates the Advanced Air Transport Technology (AATT) Project's Technical Challenge (TC) 4.2 to investigate materials and concepts for a "Compact High OPR Gas Generator." By developing solutions for mitigating tip leakage and other secondary flows in small-core engine designs, the technologies to be developed in the proposed effort have the potential to make substantial contributions toward realizing the aircraft engine architecture and fuel efficiency targets set forth by NASA. The proposed effort will also be aligned with the objective of TC4.2, developing OPR 50+ gas generators without affecting noise or component life, and well timed with the goal of achieving TRL4 technologies by 2019. In particular, NASA's Compact Gas Turbine Sub-Project has awarded NRA contracts under TC4.2 to Pratt & Whitney and General Electric to begin developing high-pressure compressor technologies and loss mitigation methods. ATA intends to engage both organizations in the performance of the envisioned project to investigate technology transfer opportunities.
The turbomachinery efficiency improvements that may be realized by the envisioned aerodynamic devices (blade tip geometries, rotor casing, and/or endwall treatment) will provide ubiquitous benefit to nearly all turbomachinery applications. In addition to aircraft propulsion applications, the technologies could enable reduced fuel consumption and carbon emissions for a wide spectrum of Brayton-cycle power-generation applications. Secondary applications with similar increasing demands on efficiency include auxiliary power units (APUs), industrial power generation, and turbine-electric transmissions such as those on ocean vessels. Because the tip leakage mitigation mechanisms may have applicability in both the compression and turbine stages of these products, numerous derivative applications may be possible.