Abstract: In a steam turbine rotor wheel and bucket dovetail joint construction wherein the wheel dovetail includes three radially aligned hooks each interconnected by a neck having an upper and lower fillet, an improvement includes redesigned fillet radii which, in a first embodiment, include the upper fillet having a radius greater than the lower fillet radius. In certain embodiments, the upper fillet may have a radius twice that of the lower fillet. In other embodiments, the radii in both the upper and lower fillets have been enlarged.

Abstract: A dovetail joint between a rotor wheel and a bucket includes a male dovetail component on the rotor wheel and a female dovetail component in the bucket, wherein the male dovetail component includes four laterally projecting hooks, each hook from an uppermost hook to a lowermost hook decreasing in radial thickness and increasing in axial length. Each hook has a substantially flat top surface to effectively increase the average thickness, and a neck between the respective hooks having enlarged fillets. The new dovetail joint reduces peak stresses so as to avoid or minimize stress corrosion cracking.

Abstract: A last-stage steam turbine bucket having a profile according to the charts set forth in the specification.

Abstract: Applicants have identified and unexpected mechanism which contributes to solid particle erosion of the trailing edge of spaced apart aerodynamically shaped nozzle partitions in an axial fluid flow turbine. Particles entrained in the fluid flow pass through passages between nozzle partitions, strike rotating buckets and rebound upstream to impinge upon the suction side of the nozzle partitions in the trailing edge region. Accordingly, a nozzle partition includes a protection device disposed over at least a portion of the suction side of the nozzle partition, preferably from the trailing edge to the throat, for preventing solid particle erosion of the partition.