An airfoil for a gas turbine engine according to an example of the present disclosure includes a platform section and an airfoil section extending in a spanwise direction from the platform section to a tip portion establishing a tip. The airfoil section has an external wall defining pressure and suction sides extending in a chordwise direction between a leading edge and a trailing edge, and the pressure and suction sides are spaced apart in a thickness direction between the leading edge and the trailing edge. The tip portion includes a tip pocket and a tip shelf extending inwardly from the tip. The tip pocket and tip shelf are on opposite sides of a shelf wall.

An airfoil for a gas turbine engine includes a fiber-reinforced laminate composite airfoil fairing that defines a platform that has first and second radial sides, an airfoil section that extends off of the first radial side, and a branched flange that extends off of the second radial side. The branched flange includes a trunk that radially extends off of the second radial side and at least one branch that extends off of the trunk.

An airfoil for a gas turbine engine includes a fiber-reinforced laminate composite airfoil fairing that defines a platform that has first and second radial sides, an airfoil section that extends off of the first radial side, and a branched flange that extends off of the second radial side. The branched flange includes a trunk that radially extends off of the second radial side and at least one branch that extends off of the trunk.

A moving blade 21d is disposed in a last stage closest to a diffuser 10 among a plurality of stages of a turbine 9 including a turbine rotor 12 and a stationary body 14. The diffuser 10 is connected to an outlet side of the stationary body 14. A distal end of the moving blade 21d is opposed to a seal fin 38 provided in the stationary body 14. The moving blade 21d includes a blade section 26, a cover 27 and a guide 32 provided on a moving blade distal end face 31, which is a surface of the cover 27. The moving blade distal end face 31 extends in a rotation axis direction of the turbine rotor 12, and the guide 32 includes a guide surface 41 located on a side close to the diffuser 10 with respect to the seal fin 38 and formed to incline upward in a direction from the seal fin 38 toward the diffuser 10.

A moving blade 21d is disposed in a last stage closest to a diffuser 10 among a plurality of stages of a turbine 9 including a turbine rotor 12 and a stationary body 14. The diffuser 10 is connected to an outlet side of the stationary body 14. A distal end of the moving blade 21d is opposed to a seal fin 38 provided in the stationary body 14. The moving blade 21d includes a blade section 26, a cover 27 and a guide 32 provided on a moving blade distal end face 31, which is a surface of the cover 27. The moving blade distal end face 31 extends in a rotation axis direction of the turbine rotor 12, and the guide 32 includes a guide surface 41 located on a side close to the diffuser 10 with respect to the seal fin 38 and formed to incline upward in a direction from the seal fin 38 toward the diffuser 10.

A turbine rotor blade that includes a tip shroud attached to the outboard tip of the airfoil. The tip shroud may include an axially and circumferentially extending planar component in which an inboard surface opposes an outboard surface, and a shroud edge that connects the inboard surface to the outboard surface and defines an outboard profile of the tip shroud. The tip shroud may include a seal rail protruding from the outboard surface of the tip shroud and a cutter tooth disposed on the seal rail. The cutter tooth may be formed as a circumferential section of the seal rail that is axially thickened. The seal rail may further include a leakage gap formed therethrough that is configured to increase a leakage level during operation.

A turbine rotor blade that includes a tip shroud attached to the outboard tip of the airfoil. The tip shroud may include an axially and circumferentially extending planar component in which an inboard surface opposes an outboard surface, and a shroud edge that connects the inboard surface to the outboard surface and defines an outboard profile of the tip shroud. The tip shroud may include a seal rail protruding from the outboard surface of the tip shroud and a cutter tooth disposed on the seal rail. The cutter tooth may be formed as a circumferential section of the seal rail that is axially thickened. The seal rail may further include a leakage gap formed therethrough that is configured to increase a leakage level during operation.

An abradable powder composition is includes a metal component, a lubricant component, and a polymer component. A portion of the metal component is wrapped in the lubricant component to achieve high lubricity and abradability. The abradable powder composition can be used to form an abradable seal coating provided for use in a turbo machinery having a housing and a wheel having multiple blades. The housing houses the wheel which rotates therein. The seal coating is formed on the inner walls of housing adjacent where the wheel blades pass during their rotation. When the wheel is rotated such that, the blades contact the seal coating, it is abraded to form a close fit gap. The abradable seal coating preferably does not produce significant wear of the blade tips or transfer abradable material significantly to the blade tips upon being abraded.

A rotor blade system includes a rotor, a casing radially spaced apart from the rotor, and a plurality of blades coupled to the rotor and positioned between the rotor and the casing. The one or more of the plurality of blades have a radial length different from a remaining one or more of the plurality of blades so as to vary a tip gap between a tip of the one or more of the plurality of blades and the casing to break up a frequency content of a leakage vortex at the tip to modify natural frequencies of the plurality of blades and mode shapes to reduce or substantially eliminate flutter.

A rotor blade system includes a rotor, a casing radially spaced apart from the rotor, and a plurality of blades coupled to the rotor and positioned between the rotor and the casing. The one or more of the plurality of blades have a radial length different from a remaining one or more of the plurality of blades so as to vary a tip gap between a tip of the one or more of the plurality of blades and the casing to break up a frequency content of a leakage vortex at the tip to modify natural frequencies of the plurality of blades and mode shapes to reduce or substantially eliminate flutter.