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US 5,511,948 AGranted
Rotor blade damping structure for axial-flow turbine
AssigneeKabushiki Kaisha Toshiba
InventorsAtsuhide Suzuki, Hirotsugu Kodama, Toshio Suzuki
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AssigneeKabushiki Kaisha Toshiba
InventorsAtsuhide Suzuki, Hirotsugu Kodama, Toshio Suzuki
Estimating the term…
In an axial-flow turbine, at least one of front and rear side contact surfaces of shrouds (3a or 3b) of blades (1a or 1b) with respect to the turbine rotational direction is formed at certain angle with respect to a radial line connecting the rotor center and the contact surface. The shroud (3a) of the blade (1a) of a first kind is formed in a trapezoidal shape converging radially outward in cross section taken in a plane perpendicular to the turbine axial direction, and the shroud (3b) of the blade (1b) of a second kind is formed in an inverted trapezoidal shape converging radially inward in the cross section. Further, half of an angle (2.alpha.) between the front and rear side contact surfaces of the shrouds (3a or 3b) is made smaller than a static frictional angle of the contact surface. Since the shroud contact surfaces of two adjacent blades can be kept in pressure contact with each other under all operating conditions, a large dynamic stress reduction and superior damping properties can be obtained without producing excessive initial stresses at the blade airfoil and blade dovetail attachment portion.
A rotor blade damping structure for an axial-flow turbine having blades arranged around a rotor in a turbine circumferential direction, said blades each having a shroud formed integrally therewith at a radially outer end thereof, each of said shrouds having opposite front and rear contact surfaces with respect to a turbine rotational direction, said shrouds being arranged in such a way that shrouds of two adjacent blades are brought into contact with each other at said contact surfaces during rotation, wherein:
A rotor blade damping structure for an axial flow turbine having blades arranged around a rotor in the turbine circumferential direction, wherein:
Dependencies are inferred from the claim text.