Abstract: A stator shroud segment is provided that includes an outer shroud having a leading edge groove and a trailing edge groove; and a plurality of inner shrouds each having a leading edge hook and a trailing edge hook, the leading and trailing hooks of each of the inner shrouds being respectively engaged with the leading and trailing edge grooves of the outer shroud so as to axially and radially lock the inner shrouds to the outer shrouds. At least one of the trailing edge hook of the inner shroud and the trailing edge groove of the outer shroud includes a sloped surface disposed at an angle to an axial direction of the rotor and to a radial direction of the rotor and facing the other of the inner and outer shrouds whereby a radial inward force on the inner shroud is transformed into a force in axial and radial directions to force the inner shroud to tightly seal a radial gap between the inner and outer shrouds.

Abstract: The present application provides an angel wing seal for a turbine bucket. The angel wing seal may include a first wing with a sinusoidally-shaped outer edge and a number of wing teeth positioned thereon.

Abstract: A turbine bucket for a turbomachine includes a main body portion having a base portion and an airfoil portion, the base portion includes a bucket cavity forward region and a shank cavity. The turbine bucket also includes a cooling channel that extends through the main body portion. At least one flow passage extends between one of the cooling channel and the shank cavity, toward the bucket cavity forward region. The at least one flow passage delivers a flow of cooling gas toward the bucket cavity forward region. The flow of cooling gas limits ingestion of hot gases into the bucket cavity forward region.

Abstract: A damper pin for a turbine bucket includes an elongated main body portion of substantially uniform cross-sectional shape having opposite ends, one only of said opposite ends coated with a corrosion and oxidation-resistant coating.

Abstract: A turbine component includes a flow path surface and a trench disposed in the flow path surface. At least one cooling through hole is located in the trench and is capable of injecting a cooling flow onto the flow path surface of the turbine component. The cooling flow forms a cooling film on the flow path surface. A method of cooling a turbine component includes injecting a cooling flow onto a flow path surface of the turbine component through at least one cooling through hole disposed in a trench in the turbine component. A cooling film is formed by the cooling flow between the flow path surface and a hot gas flow.

Abstract: Methods and apparatus for cooling rotor blades of a gas turbine are provided. The turbine blade has an airfoil connected to the platform and a dovetail extending from the platform. A main cooling circuit extends through the dovetail and into the airfoil. The main cooling circuit includes an exit for main cooling flow from the airfoil to exit out through the dovetail. In one aspect, the method includes the steps of extracting a portion of the coolant flowing through the main cooling circuit into a platform cooling circuit. After cooling a portion of the platform, the platform cooling flow splits with one portion of the flow rejoining the main cooling circuit and is used to cool the airfoil. The rest of the platform cooling flow continues to cool the platform and then returns to the main cooling circuit to flow through the exit.

Abstract: A turbine airfoil includes a leading edge having a concave cooling flow passage. An apex of the concave cooling flow passage divides the flow passage into adjacent regions. The turbine airfoil includes a first plurality of turbulators disposed in one of the adjacent regions, and a second plurality of turbulators disposed in the other of the adjacent regions. The first and second pluralities of turbulators are positioned relative to one another to divert cooling flow in opposing swirl streams that recombine along the apex and to effect a desired heat transfer and pressure loss.

Abstract: A stator shroud segment is provided that includes an outer shroud having a leading edge groove and a trailing edge groove; and a plurality of inner shrouds each having a leading edge hook and a trailing edge hook, the leading and trailing hooks of each of the inner shrouds being respectively engaged with the leading and trailing edge grooves of the outer shroud so as to axially and radially lock the inner shrouds to the outer shrouds. At least one of the trailing edge hook of the inner shroud and the trailing edge groove of the outer shroud includes a sloped surface disposed at an angle to an axial direction of the rotor and to a radial direction of the rotor and facing the other of the inner and outer shrouds whereby a radial inward force on the inner shroud is transformed into a force in axial and radial directions to force the inner shroud to tightly seal a radial gap between the inner and outer shrouds.

Abstract: A damper pin for a turbine bucket includes an elongated main body portion of substantially uniform cross-sectional shape having opposite ends, one only of said opposite ends coated with a corrosion and oxidation-resistant coating.

Abstract: In a turbine bucket having an airfoil portion and a root portion with a substantially planar platform at an interface between the airfoil portion and the root portion, a platform cooling arrangement including a cavity extending along the forward portion of the platform, and at least one inlet bore extending from a source of cooling medium to the cavity, and at least one outlet opening for expelling cooling medium from the cavity.

Abstract: Damper pins are disposed in circumferentially registering grooves of turbine bucket platform slash faces. The pins have a plurality of channels formed about peripheral portions thereof for flowing leakage cooling air from below the platform past the pin and groove into the interplatform gap. The channels may be staggered in an axial direction. By flowing cooling air through the channels, the slash faces are convectively cooled, opposite slash faces to the channels are impingement cooled and the exiting cooling air purges the gap between the slash faces adjacent the hot gas path. Alternatively, the channels may be formed in the grooved surfaces and a cylindrical damping pin may be inserted with similar cooling effects.

Abstract: A turbine nozzle is disclosed having a nozzle blade with an inner band, wherein the inner band has a region to receive a nozzle cover plate and at least one raised angel wing seal land section proximate a side of the recess; the nozzle cover plate is seated on the region of the inner band and the plate has a raised angel wing seal land section aligned with the at least one raised angel wing seal land section on the inner band, wherein the perimeter of the nozzle cover is welded to the inner band; a slot in the angel wing seal land is adjacent the perimeter of the cover plate, and the slot is filled with an insert after the cover plate is welded to the nozzle inner band.

Abstract: A pair of hollow elongated leg sections are disposed in one or more of the nozzle vane cavities of a nozzle stage of a gas turbine. Each leg section has an outer wall portion with apertures for impingement-cooling of nozzle wall portions in registration with the outer wall portions. The leg sections may be installed into the cavity separately and support rods support and maintain the leg sections in spaced relation, whereby the designed impingement gap between the outer wall portions of the leg sections and the nozzle wall portions is achieved. The support rods are secured to the inner wall portions of the leg sections by welding or brazing.

Abstract: In a gas turbine having a chordal hinge seal between an inner rail of each nozzle segment and an annular axially facing sealing surface of a nozzle support ring, a supplemental seal is disposed between the support ring and inner rail of each nozzle segment radially inwardly of the chordal hinge seal. To minimize or prevent leakage flow across the chordal hinge seal, the seal is formed of flexible sheet metal which extends between the inner rail and a seat projecting from the annular sealing surface of the support ring radially inwardly of the chordal hinge seal. A first margin of the flexible seal engages in an arcuate groove carried by the inner rail. The opposite margin extends arcuately in sealing engagement along the seat carried by the nozzle support ring.

Abstract: A coolant flow control structure is provided to channel cooling media flow to the fillet region defined at the transition between the wall of a nozzle vane and a wall of a nozzle segment, for cooling the fillet region. In an exemplary embodiment, the flow control structure defines a gap with the fillet region to achieve the required heat transfer coefficients in this region to meet part life requirements.

Abstract: In a gas turbine having a chordal hinge seal between an inner rail of each nozzle segment and an annular axially facing sealing surface of a nozzle support ring, a supplemental seal is disposed between the support ring and inner rail of each nozzle segment radially inwardly of the chordal hinge seal. To minimize or prevent leakage flow across the chordal hinge seal, the seal is formed of flexible sheet metal which extends between the inner rail and a seat projecting from the annular sealing surface of the support ring radially inwardly of the chordal hinge seal. A first margin of the flexible seal engages in an arcuate groove carried by the inner rail. The opposite margin extends arcuately in sealing engagement along the seat carried by the nozzle support ring.

Abstract: In a closed-circuit steam-cooling system for the first-stage nozzle of a gas turbine, each vane has a plurality of cavities with inserts. In the second cavity, a main insert receives cooling steam from an inner plenum for impingement-cooling of the side walls of the vane, the spent cooling steam exhausting between the main insert and the cavity walls into a steam outlet. To steam-cool a localized surface area of the vane adjacent the outer band, a secondary insert receives steam under inlet conditions from a first chamber of the outer band for impingement-cooling the localized surface area. The spent impingement-cooling steam from the secondary insert combines with the spent cooling steam from the main insert for flow to the outlet. Consequently, low-cycle fatigue is improved in the localized area by the impingement-cooling afforded by the secondary insert because of the cooler steam supplied, as well as the increased pressure drop driving the steam through the impingement openings of the secondary insert.

Abstract: A coolant flow control structure is provided to channel cooling media flow to the fillet region defined at the transition between the wall of a nozzle vane and a wall of a nozzle segment, for cooling the fillet region. In an exemplary embodiment, the flow control structure defines a gap with the fillet region to achieve the required heat transfer coefficients in this region to meet part life requirements.

Abstract: Turbine stator vane segments have radially inner and outer walls with vanes extending therebetween. The inner and outer walls are compartmentalized and have impingement plates. Steam flowing into the outer wall plenum passes through the impingement plate for impingement cooling of the outer wall upper surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. At least one film cooling hole is defined through a wall of at least one of the cavities for flow communication between an interior of the cavity and an exterior of the vane.

Abstract: An open cooling circuit for a gas turbine bucket wherein the bucket has an airfoil portion, and a tip shroud, the cooling circuit including a plurality of radial cooling holes extending through the airfoil portion and communicating with an enlarged internal area within the tip shroud before exiting the tip shroud such that a cooling medium used to cool the airfoil portion is subsequently used to cool the tip shroud.