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: 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 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 weld process cuitable for repairing precipitation-strengthened superalloys, and particularly gamma prime-strengthened nickel-based superalloys. The process entails forming a weldment in a cavity present in a surface of an article formed of a precipitation-strengthened superalloy. The cavity has a root region and a cap region between the root region and the surface of the article. A solid body formed of a superalloy composition is placed in the root region of the cavity so as to occupy a first portion but not a second portion of the root region. A first filler material formed of a solid solution-strengthened superalloy is then weld-deposited in the second portion of the root region. Subsequently, a second filler material formed of a precipitation-strengthened superalloy is weld-deposited in the cap region of the cavity.

Abstract: Grooves are formed along portions of the side edges of a turbine bucket platform and open through the side edges of the surface of the platform exposed to the hot gas path of the turbine. A bond coat is applied to the groove followed by a thermal barrier coating which is preferably plasma sprayed onto the bond coat. The thermal barrier coating thickness protects the coating beyond the surface of the bare metal of the platform side and is then abraded or ground to lie flush with the bare metal surface. Thus, the side faces of the platform have a thermal barrier coating to reduce oxidation.

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 bucket includes a platform interfacing between an airfoil and a shank. The platform is provided with a plurality of cavities covered by impingement cooling plates along the platform underside. Purge air supplied in the gaps between adjacent buckets flows through holes in the impingement plates to impingement cool opposite wall portions of the platform. The cooling air in the cavities is transmitted through film cooling holes in the platform to form a thin film of insulating air along the surface of the platform exposed to the hot gas in the hot gas path.

Abstract: The cooling system includes a plurality of generally radially extending passages within the airfoil for convectively cooling the airfoil. A predetermined number of the passages exit through the airfoil tip. One or more of the remaining passages exit into a plenum adjacent the trailing edge and airfoil tip region of the airfoil and flow radially inwardly along one or more passageways adjacent the trailing edge region. The passageways exit in openings along the pressure side of the airfoil. In this manner, the trailing edge region is convectively cooled as well as film cooled by the film of air exiting the holes.

Abstract: A bucket has an airfoil, a root and a platform between the root and airfoil. The airfoil includes a serpentine cooling circuit, and the platform includes plural cavities, one or more cavities each having a serpentine cooling circuit. Cooling medium is drawn from one of the passages of the airfoil cooling circuit for flow in the platform cooling circuit and for return either to another passage of the airfoil circuit or to a trailing edge exit. The platform cooling circuits thus convectively cool both high and low pressure sides of the platform.

Abstract: The invention relates to a cast turbine blading unit, in particular a gas turbine guide vane, having an airfoil and a platform region. The platform region is formed by a hot gas platform at the hot gas end and by a load-carrying platform opposite to it. The load-carrying platform accepts the forces so that the hot gas platform can be of thin configuration. There are particularly low thermal stresses.

Abstract: In a gas turbine bucket having a shank portion, a radial tip portion and an airfoil having leading and trailing edges and pressure and suction surfaces, and an internal fluid cooling circuit, an improvement wherein the internal fluid cooling circuit has a serpentine configuration including plural radial outflow passages and plural radial inflow passages. The radial outflow passages, in one example, are shaped to have aspect ratios of about 3.3 to 1 and Buoyancy Numbers of <0.15 or >0.80.