Abstract: A rotor system for a gas turbine engine is provided having an outer rotor which includes an annular outer spool that comprises at least one ring portion of increased thickness with respect to the remainder of the outer spool, attached to a relatively thinner, axially extending arm portion. A plurality of outer turbine blades are attached to the ring portion of the outer spool and extend radially inwardly into a working gas flowpath of the engine. A casing surrounds the outer spool and defines an annular cavity between the casing and the outer spool, which is sealed by forward and aft brush seals at the forward and aft ends thereof. At least one inlet port is formed through the casing for admitting a flow of cooling air to the annular cavity. Means are provided for directing this cooling air flow to the ring portion of the outer spool.

Abstract: A butterfly valve for a gas turbine engine includes a valve shaft and a valve disk. The valve disk has a centerline axis that extends through the valve disk. The valve disk also includes a shaft opening, an outer periphery, an outer surface, a first side, and a second side. The first side is opposite the second side. The shaft opening extends through the valve disk adjacent the centerline axis, and is sized to receive the valve shaft therein. The disk outer surface extends over the first and second sides, and is tapered between the outer periphery and the centerline axis over at least one of the disk first and second sides.

Abstract: A method of analyzing the power distribution in a chip containing one or more voltage islands, each voltage island having a power distribution network connected to a chip-level power distribution network by one or more voltage translation interface circuits. The method comprising: analyzing the voltage-island power distribution networks independently of the chip-level power distribution network to obtain voltage translation interface circuit currents; using the voltage translation interface circuit currents as input to a model of the chip-level power distribution network to obtain voltage translation interface circuit input voltages; and calculating voltage translation interface circuit output voltages based on the voltage translation interface circuit input voltages, the voltage translation interface circuit currents, and current-voltage characteristics of the voltage translation interface circuits.

Abstract: A method of analyzing the power distribution in a chip containing one or more voltage islands, each voltage island having a power distribution network connected to a chip-level power distribution network by one or more voltage translation interface circuits. The method comprising: analyzing the voltage-island power distribution networks independently of the chip-level power distribution network to obtain voltage translation interface circuit currents; using the voltage translation interface circuit currents as input to a model of the chip-level power distribution network to obtain voltage translation interface circuit input voltages; and calculating voltage translation interface circuit output voltages based on the voltage translation interface circuit input voltages, the voltage translation interface circuit currents, and current-voltage characteristics of the voltage translation interface circuits.

Abstract: A method of analyzing I/O cell layouts for integrated circuits, such as ASICs, includes defining a proposed I/O cell layout on a selected chip image, providing a set of limit rules for electromigration, IR voltage drop and di/dt noise for the selected chip image, providing characteristics for each I/O cell type used in the proposed I/O cell layout, checking the proposed I/O cell layout by applying the limit rules to the proposed I/O cell layout and reporting all I/O cells used in the proposed I/O cell layout that do not meet the limit rules for the selected chip image.

Abstract: A gas turbine engine includes a compressor including a casing and a stator assembly. The casing extends around the stator assembly, the stator assembly including a plurality of stator vanes, and a plurality of bleed scoops. Adjacent stator vanes define a static high-pressure region, the bleed scoops formed at least partially within the high pressure region.

Abstract: A butterfly valve for a gas turbine engine includes a valve shaft and a valve disk. The valve disk has a centerline axis that extends through the valve disk. The valve disk also includes a shaft opening, an outer periphery, an outer surface, a first side, and a second side. The first side is opposite the second side. The shaft opening extends through the valve disk adjacent the centerline axis, and is sized to receive the valve shaft therein. The disk outer surface extends over the first and second sides, and is tapered between the outer periphery and the centerline axis over at least one of the disk first and second sides.

Abstract: A gas turbine engine includes a compressor including a casing and a stator assembly. The casing extends around the stator assembly, the stator assembly including a plurality of stator vanes, and a plurality of bleed scoops. Adjacent stator vanes define a static high-pressure region, the bleed scoops formed at least partially within the high pressure region.

Abstract: A method for improving the crosstalk and time-of-flight performance for signals in an integrated circuit with respect to the package-related wiring. I/O pads in the package-related wiring of a logic design meeting specified crosstalk and time-of-flight constraints are identified using a software tool. The tool produces a graphical display in which the identified I/O pads are highlighted. The tool enables a user to graphically manipulate the display to assign, i.e., establish an electrical connection, between I/O circuits corresponding to the signals and the highlighted I/O pads.

Abstract: A brush seal segment useful, when circumferentially arrayed with other such segments, to seal the gap between a rotor and a surrounding casing of a rotary machine such as a gas or steam turbine. Brush-seal bristles are positioned between a brush-seal back plate and a brush-seal front plate with the free end of each bristle extending beyond the edges of the plates. The front plate has a portion extending to the edge of the front plate with the portion spaced apart from the bristles. In one example, the portion has an array of through holes. In another example, the portion has a ledge projecting generally away from the bristles.

Abstract: An apparatus for cooling a gas turbine engine annular rear turbine frame includes a first plenum box having an inlet for receiving cooling air and an annular first manifold tube in fluid communication with a first outlet of and extending in a first circumferential direction away from the plenum box. The first manifold tube is circumscribed radially outward of and around a centerline and has axially spaced apart first arcuate sections circumscribed about and perpendicular to the centerline. Each of the first arcuate sections of the first manifold tube has a corresponding portion of a first plurality of impingement cooling holes disposed through the first manifold tube and aimed generally radially inward. In one embodiment the impingement cooling holes are aimed towards a first circumference on the frame and A cooling air bleed is preferably connected to the plenum box with a selectable on and off control valve therebetween.

Abstract: To cool the shroud assembly in the high pressure turbine section of a gas turbine engine, high pressure cooling air is directed in metered flow to baffle plenums and thence through baffle perforations to impingement cool the rails and back surfaces of the shroud. Impingement cooling air then flows through elongated, convection cooling passages in the shroud sections and exits to flow along the shroud front surface with the main gas stream to provide film cooling. The aft rail of the shroud sections is provided with one or more cooling holes to impingement cool the annular retaining ring or C-clip retaining the shroud sections on the shroud hangers. This cooling air then travels aftward on the inboard side of the C-clip to provide convection cooling of the C-clip. In an alternative embodiment, cooling air is directed at the aft corners of the shroud base to avoid overheating.

Abstract: A blocker and swirl inducer hole configuration for use in connection with a high pressure turbine is described. In one embodiment, the blocker holes are oriented to a 45-degree tangential angle with respect to the direction of rotation of the seal, which results in pre-swirling the air before being injected into the swirl cavity. In addition, the number of blocker holes is reduced by as much as 50% of the number of blocker holes used in the known CFM56 turbine. Further, rather than injecting the air into the first swirl cavity as is known, the air is injected into a second swirl cavity. The combined effect of orienting the holes to the 45-degree tangential angle with respect to the direction of rotation of the seal, locating the holes to open into the second swirl cavity, and reducing the flow area by about 50%, results in an increase in blocker hole pressure ratio. Increasing the blocker hole pressure ratio results in a higher hole exit velocity which maximizes the cavity inlet swirl.

Abstract: A shroud panel for a turbine shroud includes forward and aft hooks which are used to support the panel radially above a plurality of turbine rotor blades. The panel forward hook has radially outer and inner lands, with the outer land being defined by a plurality of pads circumferentially spaced apart from each other by a respective recess. The panel forward hook is sized to engage the complementary forward slot of the turbine shroud substantially concentrically therein. The pads and recess restrict flow leakage around the panel forward hook for maintaining backflow margin and improving clearance control.

Abstract: A turbine shroud hanger is supported from an annular outer casing and includes an annular radial flange and integral forward and aft legs at a radially inner end thereof. The legs extend axially oppositely to each other and include respective distal ends configured for supporting a plurality of arcuate shroud panels radially above a plurality of turbine rotor blades to define a tip clearance therebetween. The legs include circumferentially spaced apart forward and aft slots extending axially from the distal ends thereof toward the radial flange, and completely radially therethrough to bifurcate the legs into circumferential segments for reducing transient thermal expansion of the hanger to reduce in turn expansion of the tip clearance.

Abstract: A turbine shroud includes an annular outer casing having first and second radial flanges between which are suspended an adjoining annular shroud support and an annular shroud hanger. A plurality of shroud panels are joined to the shroud hanger and are positionable radially above turbine rotor blades to define a tip clearance therebetween. The four flanges are disposed in abutting contact with each other, and respective pluralities of circumferentially spaced apart first, second, and third recesses are disposed respectively between the casing first flange and the shroud flange, between the shroud flange and the hanger flange, and between the hanger flange and the casing second flange for providing radial flowpaths therebetween.

Abstract: A turbine shroud includes an annular shroud support joined to an annular outer casing and spaced radially inwardly therefrom to define an annular flow duct for receiving compressor bleed air. A plurality of shroud panels are joined to the shroud support and have a radially inner surface positionable radially above turbine rotor blades to define a tip clearance therebetween. An isolation shield is joined to the shroud support radially above the panels and includes a plurality of open-ended cells facing radially outwardly in the duct toward the outer casing for inducing drag in the bleed air flowable axially through the duct to thermally isolate the shroud support from the bleed air for controlling the tip clearance.

Abstract: A turbine shroud hanger includes forward and aft radially outer hooks for mounting the hanger to an annular shroud support, and forward and aft radially inner hooks for supporting a shroud panel radially above a plurality of turbine rotor blades for controlling tip clearance therebetween. The hanger forward outer hook has a radially outer land defined by a pair of pads at distal ends of the hook, with a ridge extending circumferentially therebetween. The outer land is interrupted by a central recess extending between the pads and aft from the ridge to a distal edge of the hook. The forward outer hook has a predetermined radial height which is predeterminedly larger than the radial height of the corresponding forward slot in the shroud support for effecting an interference fit at least in part at the pair of pads to provide a seal against leakage of bleed air.

Abstract: A method and apparatus for film cooling of an aerodynamically shaped airfoil uses a plurality of curved slots extending through the airfoil in an area upstream of the high curvature region of the airfoil, i.e., in an area of low Mach number of the gas stream passing over the airfoil surface. The curved slots are configured to inject cooling air at an angle of about 16.5 degrees. The cooling air is injected at a blowing ratio in excess of 1.0 and yet is effective to form a film on the vane surface.

Abstract: A thermal control apparatus is provided for gas turbine engine cases and particularly for thermal control of clearances between turbine rotors and surrounding shrouds. Thermal control of an annular case section or ring is provided by counterflowing two heat transfer fluid flowpaths in heat transfer communication with the section of engine casing. The flowpaths may be in parallel or series such that there is substantially no circumferential gradient in the mass flowrate weighted average temperature of the heat transfer fluid supplied by the two counterflowing fluid flowpaths. One embodiment provides forward and aft rings cooled by three spray tubes in each of two 180.degree. sectors whereby the forward and aft spray tubes flow thermal control air flowing in one circumferential direction and the middle spray tubes flows thermal control air in an opposite circumferential direction.