Abstract: A preloaded spring assembly is provided in a recess in each shroud in axial opposition to an aft facing sealing surface of a turbine nozzle retaining ring. Each spring assembly includes a spring, preferably a bellows type spring, with a plate mounted on one side and a sealing surface on the side of the plate remote from the spring. The sealing surface may be an abradable coating or a honeycomb seal. The seal assembly is maintained preloaded by a wrap which upon reaching turbine operating temperature disintegrates, enabling the spring to load the sealing surface against the retaining ring surface to prevent or minimize air leakage from outside the nozzle retainer ring into the hot gas path.

Abstract: A method of enhancing heat transfer and cooling efficiency in a cooling passage includes forming a plurality of turbulator rings in the passage, the rings projecting inwardly, substantially perpendicular to a cooling flow direction in the passage; and using a patterned electrode, forming at least one gap in one or more of the turbulator rings, extending substantially parallel to the flow direction.

Abstract: A steam turbine wheel has a male dovetail projecting about its peripheral margin and a gap in the margin. Buckets having bases with complementary female dovetails are disposed in the gap and register with the male dovetail of the wheel, enabling the buckets to slide about the wheel into positions stacking the bases of the buckets against one another. The final three buckets including a closure bucket are disposed about the wheel margin with two buckets straddling the closure bucket secured to the wheel margin by the dovetails. The closure bucket is secured to the straddling buckets by axially extending pins. The closure and straddling buckets, as well as the pins, are formed of materials having a higher creep rupture strength than the materials forming the remaining buckets, enhancing the capability of the closure bucket to withstand high temperature and stresses over time without creep.

Abstract: A multiple hook dovetail connection for connecting a rotor wheel and a bucket for a turbine rotor that permits the use of wider vanes at the ends of the buckets without changing the size of the wheel and the other existing components of the turbine. The dovetail connection comprises a male dovetail component and a female dovetail component. The male dovetail component includes a plurality of hooks. Each of the hooks includes a crush surface, a neck and an angle formed between the crush surface and the neck. These books are dimensioned in accordance with at least one of the included tables.

Abstract: A multiple hook dovetail connection for connecting a rotor wheel and a bucket of a turbine rotor that permits the use of wider vanes at the ends of the buckets without changing the size of the wheel and the other existing components of the turbine. The dovetail connection comprises a male dovetail component and a female dovetail component. The male dovetail component includes first and second hooks. Each of the hooks includes a crush surface, a neck and an angle formed between the crush surface and the neck. These hooks are dimensioned in accordance with at least one of the included tables.

Abstract: An annular turbine shroud separates a hot gas path from a cooling plenum containing a cooling medium. Bumps are cast in the surface on the cooling side of the shroud. A surface coating overlies the cooling side surface of the shroud, including the bumps, and contains cooling enhancement material. The surface area ratio of the cooling side of the shroud with the bumps and coating is in excess of a surface area ratio of the cooling side surface with bumps without the coating to afford increased heat transfer across the element relative to the heat transfer across the element without the coating.

Abstract: A method of enhancing heat transfer and cooling efficiency in a cooling passage includes forming a plurality of turbulator rings in the passage, the rings projecting inwardly, substantially perpendicular to a cooling flow direction in the passage; and using a patterned electrode, forming at least one gap in one or more of the turbulator rings, extending substantially parallel to the flow direction.