Abstract: An aft entry system in a gas turbine engine is provided for cooling selected one or more of aft high and low pressure turbine stages of the engine. The aft entry system includes an air flow circuit for routing low pressure cooling air radially outward from an interstage region of a multi-stage compressor of a core engine of the gas turbine engine and axially in an aft direction to a plurality of radial passages, such as provided by stationary stator and outlet guide vanes, which provide an aft entry region to the selected high and low pressure turbine stages. The pressure of the cooling air routed by the air flow circuit of the aft entry system can be lower than the pressure of air at a discharge end of the compressor but higher than the pressure of the gas stream discharging from the selected turbine stage.

Abstract: An improved seal design is provided for use in a gas turbine engine. A corrugated facing strip, with a reduced corrugation height, is attached to the exposed end faces of a seal land to reduce windage losses at the exposed end faces. The corrugated facing strip simplifies construction of the seal land and provides a low windage loss surface at seal end faces.