Abstract: A variable stator vane airfoil is mounted on a button centered about a rotational axis and includes circular leading and trailing edges circumscribed about the rotational axis at a button radius. Contoured pressure and suction sides extend from the circular leading edge to the circular trailing edge and are recessed inwardly from a perimeter circumscribed about the rotational axis at the button radius. One of upstream and downstream pressure side portions of the contoured pressure side is straight and another of the upstream and downstream pressure side portions is convexly curved. One of the upstream and downstream suction side portions is straight and another of the upstream and downstream suction side portions is convexly curved. One of the upstream pressure side portion and upstream suction side portion is straight and another of the upstream pressure side portion and upstream suction side portion is convexly curved.

Abstract: A process by which a nickel-based superalloy substrate prone to deleterious reactions with an aluminum-rich coating can be stabilized by carburization. The process generally entails processing the surface of the substrate to be substantially free of oxides, heating the substrate in a non-oxidizing atmosphere to a carburization temperature, and then contacting the surface of the substrate with a carburization gas mixture comprising a diluted low activity hydrocarbon gas while maintaining the substrate at the carburization temperature. While at the carburization temperature and contacted by the carburization gas, carbon atoms in the carburization gas dissociate therefrom, transfer onto the surface of the substrate, diffuse into the substrate, and react with refractory metals within the substrate to form refractory metal carbides within a carburized region beneath the surface of the substrate. The substrate is then cooled in a non-oxidizing atmosphere to terminate carbide formation.

Abstract: A direct metal laser sintered material including a substrate formed from a laser sintering process, the substrate having at least one surface, and a cladding material brazed onto at least a portion of the surface.

Abstract: An aircraft engine exhaust nozzle basesheet includes longitudinally extending plurality of basesheet segments having panel bodies between segment leading and trailing edges and slidable sealing joints with slidingly un-restrained center surfaces between adjacent segment leading and trailing edges. Segmented first and second basesheet side edges include first and second segment side edges of the basesheet segments respectively. Slidably sealingly engaged overlapping flanges at the segment leading and trailing edges include tacked together transversely spaced apart first and second distal ends of the overlapping flanges. A basesheet assembly includes a frame includes first and second side rails supporting the first and second basesheet side edges. An aircraft gas turbine engine exhaust nozzle includes divergent seals with the basesheet assemblies in sealing engagement against divergent flaps along the first and second side rails.

Abstract: Erosion- and impact-resistant ceramic coatings suitable for protecting surfaces subjected to collisions with particles, including nominally round particles that typically inflict impact damage and more aggressive irregular-shaped particles that typically inflict erosion damage. The ceramic coating is formed to have one of three compositions: at least one layer of titanium aluminum nitride (TiAlN) having a thickness of about 25 to about 100 micrometers; multiple layers of chromium nitride (CrN) and TiAlN, each layer having a thickness of about 0.2 to about 1.0 micrometers to yield a total coating thickness of at least about 3 micrometers; and at least one layer of titanium silicon carbonitride (TiSiCN) having a thickness of about 15 to about 100 micrometers. The ceramic coating preferably has a total coating thickness of up to about 100 micrometers, and is deposited by a physical vapor deposition process to have a columnar and/or dense microstructure.

Abstract: A gas turbine engine turbine cooling system includes an impeller and a diffuser directly downstream of the impeller, a bleed for bleeding clean cooling air from downstream of the diffuser, and one or more channels in fluid communication with the bleed. Each of the channels having a generally radially extending section followed by a generally axially aftwardly extending section terminating at an annular cooling air plenum connected to accelerators. The radially and axially aftwardly extending sections may be connected by a bend section of the cooling air channel and the axially aftwardly extending section may be angled radially inwardly going from the bend section to the cooling air plenum. Each of the cooling channels includes an inner wall formed by a forward end wall extending radially outwardly from an inner combustor casing, an annular cover covering a radially inner portion of the forward end wall, and the inner combustor casing.

Abstract: Apparatus and method of operating a centrifugal compressor and active control system includes a centrifugal compressor with compressor blades mounted on an impeller, an annular cavity bounded in part by a shroud adjacent to the blades, and an active control system for controlling a clearance between the shroud and the blades by controlling a cavity pressure in the cavity. An electronic controller for controlling a control pressure valve for pressurizing using a source of compressor discharge pressure air and depressurizing the cavity respectively may open and close the valves using pulse width modulation. Pressure and clearance sensors positioned for measuring the cavity pressure the blade tip clearance respectively in signal supply communication with the electronic controller may be used. The shroud may be supported by radially spaced apart annular radially outer and inner supports connected to a casing by a bolted joint bounding the cavity.

Abstract: A coating process for an article having a substrate formed of a metal alloy that is prone to the formation of a secondary reaction zone (SRZ). The coating process forms a coating system that includes an aluminum-containing overlay coating and a stabilizing layer between the overlay coating and the substrate. The overlay coating contains aluminum in an amount greater by atomic percent than the metal alloy of the substrate, such that there is a tendency for aluminum to diffuse from the overlay coating into the substrate. The stabilizing layer is predominantly or entirely formed of at least one platinum group metal (PGM), namely, platinum, rhodium, iridium, and/or palladium. The stabilizing layer is sufficient to inhibit diffusion of aluminum from the overlay coating into the substrate so that the substrate remains essentially free of an SRZ that would be deleterious to the mechanical properties of the alloy.

Abstract: A counter-rotatable generator includes a generator stator concentric with concentric counter-rotatable radially inner pole and outer magnet rotors. The magnet rotor encircles the pole rotor and the pole rotor encircles the generator stator. A rotor air gap is disposed between the magnet and pole rotors, and a transformer air gap is disposed between the pole rotor and the stator. The magnet rotor includes a circular array of magnets having circumferentially alternating north/south and south/north orientations, retained within a magnet retention ring, and the magnets are circumferentially separated from each other by non-magnetic material spacers. One stator includes an annular hub, axial windings around equi-distantly spaced axial poles on the annular hub, radial cores extending radially outwardly from and equi-angularly spaced about a pole hub on the annular hub between the first and second axial windings, and radial windings around the radial cores.

Abstract: A method and system for relieving forging induced residual stresses in a rotor forging balances a pre-spin machine with the forging mounted thereon at a first rotational speed and then pre-spins the forging with it mounted on the machine at a substantially greater second rotational speed. A one per rev sensor is used for determining a weight placement angle and a vibration sensor is used for determining an amount of weight to add to a spinning assembly including the forging during the balancing. High-density non-metallic balance weights adhesively attached on an inside surface of the forging or spinning assembly may be used. The rotational inertia of the spinning assembly may be checked during a spin up period by determining a rate of rotational acceleration vs. torque applied to the spinning assembly and used to stop the pre-spinning if it is to great.

Abstract: A process for selectively stripping a coating from a component of a turbomachine, and particularly a coating having a ceramic matrix that contains metallic particles dispersed therein that render the coating more difficult to remove from the component after the component has been subjected to elevated temperatures during operation of the turbomachine. The process generally includes immersing the component in an aqueous solution containing ferric chloride, nitric acid, and phosphoric acid, for a duration sufficient to attack the metallic particles in the coating. The component is then removed from the aqueous solution and its surface rinsed of the aqueous solution. The immersing and removing steps are then sequentially repeated a sufficient number of times to sufficiently attack the metallic particles to enable the coating to be mechanically removed from the component.

Abstract: An exhaust vane disposed in a divergent section of an aircraft gas turbine engine exhaust nozzle is sideways pivotable about a vane pivot axis. The nozzle vane pivot axis may be centrally located at an unvectored nozzle throat. Transversely spaced apart upper and lower tips of the exhaust vane may be incorporated to sealingly engage a nozzle outer wall along upper and lower surfaces of the outer wall of the nozzle. The exhaust vane has flat or contoured vane sidewalls and contoured vane sidewalls may be concave. The exhaust vane may have transversely biased apart upper and lower vane sections extending transversely inwardly from the upper and lower tips of the exhaust vane respectively. The exhaust vane may be articulated having upstream and downstream sections separately sideways pivotable about the vane pivot axis and a second pivot axis downstream of and parallel to the vane pivot axis respectively.

Abstract: A coating system and coating method for damping vibration in an airfoil of a rotating component of a turbomachine. The coating system includes a metallic coating on a surface of the airfoil, and a ceramic coating overlying the metallic coating. The metallic coating contains metallic particles dispersed in a matrix having a metallic and/or intermetallic composition. The metallic particles are more ductile than the matrix, and have a composition containing silver and optionally tin. The method involves ion plasma cleaning the surface of the airfoil before depositing the metallic coating and then the ceramic coating.

Abstract: A system and method for sensing the periodic position of one or more objects, such as rotating blades of a turbine. The system includes a passive eddy current sensing unit having one or more magnets and first and second cores around which first and second coils are wound, respectively, which together generate first and second magnetic fields. The sensing unit is positioned so that the object periodically passes through the first and second magnetic fields in succession, and the first and second coils consequently produce first and second output signals, respectively. Each coil is individually connected to a processing circuitry that receives each of the first and second output signals. The circuitry electronically combines the first and second output signals so that common mode signals thereof electronically subtract from each other to eliminate from output of the circuitry any electromagnetic interference noise present in the first and second output signals.

Abstract: A gas turbine engine augmentor includes an annular trapped vortex cavity pilot having a cavity forward wall, a cavity radially outer wall, and a cavity aft wall, an annular cavity therebetween, and cavity fuel injector tubes operably disposed through the outer wall into the cavity. Circumferentially spaced apart radial flameholders with integral spraybars and/or radial spraybars interdigitated with the radial flameholders radially inwardly into an exhaust flowpath of the augmentor just forward and upstream of the trapped vortex cavity pilot at a radially outer portion of a combustion zone of the exhaust flowpath. An annular trapped dual vortex cavity pilot version is operable for producing trapped dual counter-rotating inner and outer vortices of fuel and air mixtures.

Abstract: A gas turbine engine assembly having one or more blade rows with blades extending radially inwardly from a rotatable drum, one or more composite fiber material rings disposed circumferentially around the rotatable drum, and the composite fiber material rings including circumferentially extending high strength fibers or filaments. The rings may be axially aligned with the blade rows. Ring widths of the rings may be less wide than blade widths at blade bases of the blades at a radially inner surface of the drum. The rings may be made of a material including a plurality of circumferentially extending reinforcing structural fibers or filaments disposed in an integral matrix. The rotatable drum, rings, and blades extending radially inwardly from the drum may be incorporated in a gas turbine engine booster having one or more rotatable booster stages or in a counter rotatable low pressure turbine.

Abstract: A system and method for sensing the periodic proximity of one or more objects, such as the rotating blades of a gas turbine. The system includes a passive eddy current sensing unit having first and second magnets and first and second coil-wound cores coupled to generate and detect first and second magnetic fields. The sensing unit is positioned relative to the object such that the first and second coil-wound cores produce outputs in response to the object periodically passing through the first and second magnetic fields, respectively. Circuitry electronically combines the outputs of the first and second coil-wound cores to produce output signals corresponding to the proximity and timing of the object as it periodically passes through the first and second magnetic fields. Electromagnetic interference noise present in the outputs of the first and second coil-wound cores is eliminated from the output signals of the circuitry.

Abstract: A method for simultaneously laser shock peening opposite laser shock peening surfaces on opposite sides of an article, such as a gas turbine engine airfoil, with varying thickness using oppositely aimed laser beams and varying surface fluence of the laser beams over the laser shock peening surfaces as a function of the thickness of the article beneath each one of a plurality of laser shock peened spots formed by the beams on the surfaces. The fluence may be equal to the thickness multiplied by a volumetric fluence factor, the volumetric fluence factor being held constant over the laser shock peening surface. The volumetric fluence factor may be in a range of about 1200 J/cm3 to 1800 J/cm3 and more particularly about 1500 J/cm3. Laser beam energy may be varied with a computer program controlling firing of the laser beam.

Abstract: A method and apparatus for controlling the thickness of a coating deposited on internal passages of a component. The coating is a diffusion coating, preferably a diffusion aluminide coating, deposited by a vapor phase process that entails placing a component within a coating chamber so that first and second conduits fluidically communicate with first and second openings in the component. The component is heated within the coating chamber, at least one reactive vapor is generated within the coating chamber, and a carrier gas is delivered through the first conduit to force the reactive vapor to enter the internal passages through the first opening in the component and exit through the second opening. Flow of the carrier gas is then reversed so that the carrier gas is then delivered through the second conduit to force the reactive vapor to enter the internal passages through the second opening and exit through the first opening.

Abstract: A protective coating for use on a silicon-containing substrate, and deposition methods therefor. The coating has a strontium-aluminosilicate (SAS) composition that is less susceptible to degradation by volatilization and in corrosive environments as a result of having at least an outer surface region that consists essentially of one or more stoichiometric crystalline phases of SAS and is substantially free of a nonstoichiometric second crystalline phase of SAS that contains a substoichiometric amount of silica. The coating can be produced by carrying out deposition and heat treatment steps that result in the entire coating or just the outer surface region of the coating consisting essentially of the stoichiometric celsian phase.