Currently, active blade tip clearance control ACC on aero engine turbine is performed using engine shroud thermal expansion. The enormous thermal capacity of the shroud and weak convective cooling…

This federal contract award, with ID NNX15AR27A, was issued by the Shared Services Center, a civilian federal agency, to RTX Corporation's Raytheon Technologies Research Center. The $796,840 Cooperative Agreement is for the "Electro-Thermally Active Seal for Fast Response Tip Clearance Control (Phase II, P.100.0738)" program. The objective is to mature a novel electrothermal active seal concept that can rapidly control turbine blade tip clearance, improving engine performance, fuel efficiency, and emissions. This Phase II effort will experimentally validate the fast-response tip clearance modulation capability in an elevated temperature and pressure environment. The contract does not have a set-aside designation, reflecting RTX's status as a large defense contractor. The Raytheon Technologies Research Center has significant experience supporting federal agencies like the Department of Defense, Department of Energy, and NASA on advanced aerospace and defense R&D efforts through both prime contracts and subcontract work.

Currently, active blade tip clearance control ACC on aero engine turbine is performed using engine shroud thermal expansion. The enormous thermal capacity of the shroud and weak convective cooling by fan air, however, slows the response of clearance control, rendering IT inadequate for transient maneuvers. Consequently, the nominal turbine blade tip clearance is set larger than optimum to prevent rubbing of blade tips during transient events, which worsens fuel economy during cruise. Actively maintaining tight turbine blade tip clearance reduces gas path leakage, benefits engine performance through reduced fuel burn, lowers emissions, and extends service life. A reduction of 0.01 in in turbine blade tip clearance achieves about a 1 percent improvement in specific fuel consumption SFC and approximately a 10 degrees celcius reduction in exhaust gas temperature.the objective of this learn i phase II program is to mature the novel concept of electro thermal active seal concept developed in phase i for ACC which can significantly improve response times while preserving the simplicity and robustness of the current thermal expansion approach in harsh engine environment. The technical approach involves a topologically designed sparse structural actuator array with extremely low thermal mass and electrically controllable active elements. IT has been proven analytically an order of magnitude faster in response time than the conventional ACC system. The 12 month phase II program is to experimentally validate the fast response tip clearance modulation with a large scale actively controlled truss array in an elevated temperature and pressure environment. The program team also experimentally investigates the novel alloy materials which are essential to the effectiveness of the active truss modulation. We expect to reach technology readiness level two at the exit of the program and be ready to fuse the technology into armd applications. This abstract does not contain any technical data subject to the ear or the itar.