Advanced Seal Technology Role in Meeting Next Generation Turbine Engine Goals

Abstract

Cycle studies have shown the benefits of increasing engine pressure ratios and cycle temperatures to decrease engine weight and improve performance in next generation turbine engines. Advanced seals have been identified as critical in meeting engine goals for specific fuel consumption, thrust-to-weight, emis-sions, durability and operating costs. NASA and the industry are identifying and developing engine and sealing technologies that will result in dramatic improvements and address the goals for engines entering service in the 20052007 time frame. This paper provides an overview of advanced seal technology requirements and highlights the results of a preliminary design effort to implement advanced seals into a regional aircraft turbine engine. This study examines in great detail the benefits of applying advanced seals in the high pressure turbine region of the engine. Low leakage film-riding seals can cut in half the estimated 4 % cycle air currently used to purge the high pressure turbine cavities. These sav-ings can be applied in one of several ways. Holding rotor inlet temperature @IT) constant the engine spe-cific fuel consumption can be reduced 0.9%, or thrust could be increased 2.5%, or mission fuel bum could be reduced 1.3%. Alternatively, RIT could be low-ered 20 “F resulting in a 50 % increase in turbine blade life reducing overall regional aircraft mainte-nance and fuel bum direct operating costs by nearly 1%. Thermal, structural, secondary-air systems, safety (seal failure and effect), and emissions analy-ses have shown the proposed design is feasible.