A valve assembly for an active clearance control (ACC) system in a gas turbine engine. The assembly comprises a first valve disc positioned within a first outlet duct, a second valve disc positioned within the second outlet duct, and a shaft coupled to the first and second valve discs such that rotation of the shaft rotates both the first and second valve discs within the first and second outlet ducts, respectively. A flow control member in the second outlet duct surrounds the second valve disc, and is configured to restrict fluid flow passing through the second outlet duct to a greater extent than the fluid flow passing through the first outlet duct for a given degree of rotation of the first and second valve discs. A corresponding ACC system, gas turbine and method is also provided.

Lubricant pump systems and associated methods for aircraft engines are provided. The method includes receiving an input torque, dividing the input torque between a first load path receiving a first portion of the input torque, and a second load path receiving a second portion of the input torque. A first lubricant pump of the aircraft engine is driven via the first load path using the first portion of the input torque. A second lubricant pump of the aircraft engine is driven via the second load path using the second portion of the input torque. When a malfunction of the second lubricant pump occurs, the method includes ceasing to drive the first lubricant pump and the second lubricant pump using the input torque.

A turbine shaft used for a turbocharger including a turbine and a compressor includes a turbine impeller, and a rotor shaft joined on one end side to the turbine impeller. The rotor shaft includes a fitting region configured to fit with a compressor impeller of the compressor by inserting the other end side of the rotor shaft into a through hole formed in the compressor impeller, a fastening region formed between the fitting region and the other end side of the rotor shaft, and configured to allow fastening by a fastening part, and a tapered part having a maximum outer diameter at a position closest to the turbine impeller in the fitting region and formed such that an outer diameter of the rotor shaft decreases from the position closest to the turbine impeller toward a tip side of the compressor impeller.

A compressor section of a gas turbine engine includes an upstream portion and a downstream portion. The upstream portion includes at least one stage of stator vanes and at least one stage of blades configured to rotate about an axial centerline of the compressor section. The at least one stage of stator vanes and the at least one stage of blades are in an alternating arrangement along an axial direction of the gas turbine engine. The downstream portion is disposed immediately adjacent to and downstream along the axial direction from the upstream portion. The downstream portion includes a first set of rotating blade rows and a second set of rotating blade rows. The first and second sets of rotating blade rows are in an alternating arrangement along the axial direction of the gas turbine engine. The first and second sets of rotating blade rows are in a counter-rotating arrangement.

An auxiliary power unit (APU) includes, in serial flow communication: an engine compressor, a combustor and a turbine, the turbine rotatable about an engine axis. A first shaft operatively connects the turbine to the engine compressor and extends non-parallel to the engine axis. A second shaft operatively connects the turbine to a load and extends non-parallel to the engine axis. A method of operating an APU is also described.

A gas turbine engine (10) comprising: a high pressure turbine (17); a low pressure turbine (19); a high pressure compressor (15) coupled to the high pressure turbine (17) by a high pressure shaft (27); a propulsor (23) and a low pressure compressor (14) coupled to the low pressure turbine (19) via a low pressure shaft (26) and a reduction gearbox (30); wherein the low pressure compressor (14) consists of four compressor stages (14) and defines a cruise pressure ratio of between 2.4:1 and 3.3:1; the high pressure compressor (15) defines a cruise pressure ratio of less than 17:1; and the high pressure compressor (15) and low pressure compressor (14) together define a cruise core overall pressure ratio of greater than 36:1.

A turbomachine engine includes a core engine having one or more compressor sections, one or more turbine sections that includes a power turbine, and a combustion chamber in flow communication with the compressor sections and turbine sections. The turbomachine engine also includes a shaft coupled to the power turbine and characterized by a midshaft rating (MSR) between two hundred (ft/sec).sup.1/2 and three hundred (ft/sec).sup.1/2. In one aspect, the shaft has a redline speed between fifty and two hundred fifty feet per second (ft/sec). In another aspect, the shaft has a length L, an outer diameter D, and a ratio of L/D between twelve and thirty-seven.

A method for shimming a thrust bearing for an accessory power take off shaft to obtain optimal meshing of bevel gears within the internal gearbox (IGB) without disassembly of the IGB is enabled by relocating the thrust bearing from the engine sump. The accessory gearbox (AGB) is driven from a power off-take from the turbine spool via the IGB. The radial position of the power take-off bevel gear is established by a radial position of the thrust bearing attached to the exterior of the casing via a housing. Candidate shims are selected from a set each having different thicknesses, the shims are formed of two halves and placed between the housing and the engine casing to adjust the radial position of the thrust bearing and consequently the power take-off bevel gear, without requiring the disassembly of the IGB.

A method for generating material test samples for conducting material tests of a legacy steam turbine rotor having an inter-blade region rotor surface, and an inlet region rotor surface adjoining the inter-blade region rotor surface. The method includes forming an annular ring of rotor material in the sample area and forming a material test sample from a portion of the annular ring. Also described is a legacy steam turbine rotor including an inter-blade region rotor surface, and an inlet region rotor surface adjoining the inter-blade region rotor surface. The steam turbine rotor having a groove formed therein, and wherein the groove is machined to enable removal of material from the steam turbine rotor to form samples configured to enable at least one of conducting material property tests and operating the improved legacy steam turbine rotor at an expanded thermal stress compared to the legacy steam turbine rotor.

A gas turbine engine is provided. The gas turbine engine includes a turbomachine having a low speed spool and a high speed spool; a rotor assembly coupled to the low speed spool; an electric machine rotatable with the low speed spool for extracting power from the low speed spool, for adding power to the low speed spool, or both; and an inter-spool clutch positioned between the low speed spool and the high speed spool for selectively coupling the low speed spool to the high speed spool.