Advanced seals for engine secondary flowpath

Abstract

Labyrinth seal design is a mature technology and no significant improvement in leakage reduction capability is foreseen. Other sealing approaches for critical locations are being sought. A 14.7-in.-diam all-metal aspirating face seal was designed to fit a General Electric Advanced Technology Demonstrator Engine (XTE45) at turbine inducer seal operating conditions and space envelop. The aspirating seal design utilizes a thin air film established from the pressure differential (AP) across the seal to prevent rubbing between stationary and rotating seal components. Over 1000 h of rig testing of the prototype seal has been conducted in a dynamic test rig facility located at Stein Seal Company. The seal performed flawlessly for the operating conditions up to 11,500 rpm (740-ft/s surface speed), 100-psi pressure differential, and 1000°F temperature. Test results indicated the aspirating seal offers an order of magnitude reduction (approximately an 80% reduction) in leakage flow when compared to an equivalent four-tooth labyrinth seal of the same diameter. Test hardware showed no deterioration over the entire test period.