Abstract: Embodiments of the invention relate generally to turbine blades and rotors and, more particularly, to turbine blades having, among other features, complimentarily shaped integral covers and bases capable of increasing stiffness and damping characteristics while decreasing vibratory stress. In one embodiment, the invention provides a turbine blade comprising: an elongate vane having a twisted configuration about a longitudinal axis thereof, the elongate vane having a leading face and a trailing face; a base at a proximal end of the elongate vane, the base having: a substantially planar member substantially normal to the longitudinal axis of the elongate vane; and a dovetail member on a surface of the planar member opposite the elongate vane; and a cover member at a distal end of the elongate vane, the cover member having a leading face and a trailing face.

Abstract: A dovetail for a steam turbine rotating blade and rotor wheel is provided. The dovetail design comprises a rotating blade curved axial entry dovetail having a four hook profile and a rotor wheel dovetail slot sized to receive the blade dovetail. The blade dovetail and wheel dovetail slot each comprise a plurality of slanted crush surfaces, a plurality of non-contact surfaces, and a plurality of necks that each provide a transition between a slanted crush surface to a non-contact surface. Each neck comprises a slant angle defined by the transition of the slanted crush surface to the non-contact surface. The slant angle ranges from about 60 degrees to about 82 degrees.

Abstract: A turbine blade including a root section at an end of the turbine blade, a first airfoil section adjacent to the root section, and a tip section adjacent to the airfoil section and including a material block that is incongruous with the airfoil section. A midspan section may also include a material block. Each material block can be selectively machined to customize the length of the turbine blade and the position of a tip shroud connection or midspan connection. The turbine blade can be sized for retrofitting last stage blades of older turbines. A radial position of the root mounts for the turbine blade may also be adjusted to provide further customization.

Abstract: A turbine blade including a root section at an end of the turbine blade, a first airfoil section adjacent to the root section, and a tip section adjacent to the airfoil section and including a material block that is incongruous with the airfoil section. A midspan section may also include a material block. Each material block can be selectively machined to customize the length of the turbine blade and the position of a tip shroud connection or midspan connection. The turbine blade can be sized for retrofitting last stage blades of older turbines. A radial position of the root mounts for the turbine blade may also be adjusted to provide further customization.

Abstract: A steam turbine rotating blade for a low pressure section of a steam turbine engine is disclosed. The steam turbine rotating blade includes an airfoil portion. A root section is attached to one end of the airfoil portion. A dovetail section projects from the root section, wherein the dovetail section includes a skewed axial entry dovetail. A tip section is attached to the airfoil portion at an end opposite from the root section. A cover is integrally formed as part of the tip section. The cover comprises a first flat section, a second flat section, and a depression section located laterally between the first flat section and second flat section. The depression section is located below the first flat section at a first end where the first flat section and depression section are contiguous. The depression section rises above to the second flat section at a second end where the second flat section and depression section are contiguous. The second flat section is raised above the first flat section.

Abstract: A steam turbine rotating blade for a low pressure section of a steam turbine engine is disclosed. The steam turbine rotating blade includes an airfoil portion. A root section is attached to one end of the airfoil portion. A dovetail section projects from the root section, wherein the dovetail section includes a straight axial entry dovetail. A tip section is attached to the airfoil portion at an end opposite from the root section. A cover is integrally formed as part of the tip section. The cover has a first portion that overhangs a pressure side of the airfoil portion and a second portion that overhangs a suction side of the airfoil portion. The cover is positioned at an angle relative to the tip section, wherein the angle ranges from about 15 degrees to about 35 degrees.

Abstract: Embodiments of the invention relate generally to turbine blades and rotors and, more particularly, to turbine blades having, among other features, complimentarily shaped integral covers and bases capable of increasing stiffness and damping characteristics while decreasing vibratory stress. In one embodiment, the invention provides a turbine blade comprising: an elongate vane having a twisted configuration about a longitudinal axis thereof, the elongate vane having a leading face and a trailing face; a base at a proximal end of the elongate vane, the base having: a substantially planar member substantially normal to the longitudinal axis of the elongate vane; and a dovetail member on a surface of the planar member opposite the elongate vane; and a cover member at a distal end of the elongate vane, the cover member having a leading face and a trailing face.

Abstract: A turbine blade including a root section at an end of the turbine blade, a first airfoil section adjacent to the root section, and a tip section adjacent to the airfoil section and including a material block that is incongruous with the airfoil section. A midspan section may also include a material block. Each material block can be selectively machined to customize the length of the turbine blade and the position of a tip shroud connection or midspan connection. The turbine blade can be sized for retrofitting last stage blades of older turbines. A radial position of the root mounts for the turbine blade may also be adjusted to provide further customization.

Abstract: A steam turbine rotating blade for a low pressure section of a steam turbine engine is disclosed. The steam turbine rotating blade includes an airfoil portion. A root section is attached to one end of the airfoil portion. A dovetail section projects from the root section, wherein the dovetail section includes a skewed axial entry dovetail. A tip section is attached to the airfoil portion at an end opposite from the root section. A cover is integrally formed as part of the tip section. The cover comprises a first flat section, a second flat section, and a depression section located laterally between the first flat section and second flat section. The depression section is located below the first flat section at a first end where the first flat section and depression section are contiguous. The depression section rises above to the second flat section at a second end where the second flat section and depression section are contiguous. The second flat section is raised above the first flat section.

Abstract: A steam turbine rotating blade for a low pressure section of a steam turbine engine is disclosed. The steam turbine rotating blade includes an airfoil portion. A root section is attached to one end of the airfoil portion. A dovetail section projects from the root section, wherein the dovetail section includes a straight axial entry dovetail. A tip section is attached to the airfoil portion at an end opposite from the root section. A cover is integrally formed as part of the tip section. The cover has a first portion that overhangs a pressure side of the airfoil portion and a second portion that overhangs a suction side of the airfoil portion. The cover is positioned at an angle relative to the tip section, wherein the angle ranges from about 15 degrees to about 35 degrees.

Abstract: A dovetail for a steam turbine rotating blade and rotor wheel is provided. The dovetail design comprises a rotating blade curved axial entry dovetail having a four hook profile and a rotor wheel dovetail slot sized to receive the blade dovetail. The blade dovetail and wheel dovetail slot each comprise a plurality of slanted crush surfaces, a plurality of non-contact surfaces, and a plurality of necks that each provide a transition between a slanted crush surface to a non-contact surface. Each neck comprises a slant angle defined by the transition of the slanted crush surface to the non-contact surface. The slant angle ranges from about 60 degrees to about 82 degrees.

Abstract: A method for forming a bucket for a steam turbine includes forming a leading edge on at least one airfoil. The leading edge is comprised of an erosion resistant material and is bonded to the airfoil.

Abstract: A new high-strength titanium-based alloy bucket specifically suited for use as the last stage buckets in steam turbine engines having vane lengths of about 40 inches or greater and the method for forming such bucket. Exemplary buckets according to the invention are formed from a titanium-based alloy containing up to about 6.25% aluminum; (b) about to 3.5% vanadium; (c) about 2.25% tin, (d) about 2.25% zirconium, (e) about 1.75% molybdenum, (f) about 2.25% chromium, (g) about 0.7% silicon; and (h) about 2.3% iron, with the balance being titanium. After forming, the bucket can be heat treated to provide stress relief and then machined in a conventional manner.

Abstract: In a turbine having closed-circuit steam-cooling passages about the rim of the rotor during steady-state operation, compressor discharge air is supplied to the rotor bore for passage radially outwardly into the wheel space cavities between the wheels and spacers. Communicating slots and channels in the spacers and wheels at circumferentially spaced positions enable egress of the compressor discharge air into the hot gas flow path. At turbine startup, cooling air flows through the closed-circuit steam passages to cool the outer rim of the rotor while compressor discharge air pre-warms the wheels and spacers. At steady-state, cooling steam is supplied in the closed-circuit steam-cooling passages and compressor discharge air is supplied through the bore and into the wheel space cavities to cool the rotor.