Cooling structures in the tips of turbine rotor blades

Patent metadata

Field	Value
Publication number	US-9297262-B2
Application number	US-201213479683-A
Country	US
Kind code	B2
Filing date	May 24, 2012
Priority date	May 24, 2012
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

A turbine rotor blade for a gas turbine engine is described. The turbine rotor blade includes an airfoil that includes a tip at an outer radial end. The tip includes a rail that defines a tip cavity; and the rail includes a circumscribing rail microchannel. The circumscribing rail microchannel is a microchannel that extends around at least a majority of the length of the inner rail surface.

First claim

We claim:

1. A turbine rotor blade for a gas turbine engine, the turbine rotor blade comprising an airfoil that includes a tip at an outer radial end;
wherein the tip includes a rail that defines a tip cavity;
wherein the rail includes a circumscribing rail microchannel; and
wherein:
the airfoil includes a pressure sidewall and a suction sidewall that join together at a leading edge and a trailing edge of the airfoil, the pressure sidewall and the suction sidewall extending from a root to the tip and defining an airfoil chamber therein;
the tip includes a tip plate, the rail being disposed near or at a periphery of the tip plate;
the rail includes an inner rail surface, which faces inwardly toward the tip cavity, and an outer rail surface; and
the circumscribing rail microchannel comprises a microchannel that extends around at least a majority of the length of the inner rail surface;

further comprising a feed microchannel that extends across the tip plate and a portion of the rail, the feed microchannel comprising an upstream end, which is positioned on the tip plate, and a downstream end, which is positioned on the rail;
wherein the upstream end of the feed microchannel connects to a coolant passageway that passes through the tip plate to an airfoil chamber; and
wherein the downstream end fluidly connects to the circumscribing rail microchannel.

2. The turbine rotor blade according to claim 1 , wherein the circumscribing rail microchannel comprises a microchannel that extends around the inner rail surface to surround the tip cavity; and
wherein the circumscribing rail microchannel comprises a looped coolant path.

3. The turbine rotor blade according to claim 1 , wherein the pressure sidewall comprises an outer radial edge and the suction sidewall comprises an outer radial edge, the airfoil being configured such that the tip plate extends axially and circumferentially to connect the outer radial edge of the suction sidewall to the outer radial edge of the pressure sidewall;
wherein the rail includes a pressure side rail and a suction side rail, the pressure side rail connecting to the suction side rail at the leading edge and the trailing edge of the airfoil;
wherein the pressure side rail extends radially outward from the tip plate, traversing from the leading edge to the trailing edge such that the pressure side rail approximately aligns with the outer radial edge of the pressure sidewall; and
wherein the suction side rail extends radially outward from the tip plate, traversing from the leading edge to the trailing edge such that the suction side rail approximately aligns with the outer radial edge of the suction sidewall.

4. The turbine rotor blade according to claim 3 , wherein the pressure side rail and the suction side rail are substantially continuous between the leading edge to the trailing edge of the airfoil, and define the tip cavity therebetween; and
wherein the airfoil chamber comprises an internal chamber configured to circulate a coolant during operation.

5. The turbine rotor blade according to claim 4 , further comprising:
a source connector, wherein the source connector comprises a hollow passageway fluidly connecting the circumscribing rail microchannel to the airfoil chamber; and
an outlet, wherein the outlet comprises a hollow passageway fluidly connecting the circumscribing rail microchannel to a port formed on the inner rail surface.

6. The turbine rotor blade according to claim 1 , wherein the circumscribing rail microchannel comprises a non-integral cover which encloses a machined groove; and
wherein the non-integral cover comprises one of a coating, a sheet, foil, and a wire.

7. The turbine rotor blade according to claim 1 , wherein the circumscribing rail microchannel is disposed to traverse through an area on the rail that is a known hotspot.

8. The turbine rotor blade according to claim 1 , wherein the circumscribing rail microchannel comprises an enclosed hollow passageway that extends near and approximately parallel to the inner rail surface of the rail; and
wherein the circumscribing rail microchannel extends around the inner rail surface in spaced relation to the tip plate.

9. The turbine rotor blade according to claim 8 , wherein the circumscribing rail microchannel resides less than about 0.05 inches from the inner rail surface;
wherein the circumscribing rail microchannel comprises a cross-sectional flow area of less than about 0.0036 inches 2 ; and
wherein the circumscribing rail microchannel comprises an average height of between 0.02 and 0.06 inches and an average width of between 0.02 and 0.06 inches.

10. The turbine rotor blade according to claim 8 , wherein the circumscribing rail microchannel resides between about 0.04 and 0.02 inches from the inner rail surface;
wherein the circumscribing rail microchannel comprises a cross-sectional flow area of between about 0.0025 and 0.0009 inches 2 ; and
wherein the circumscribing rail microchannel comprises an average height of between 0.02 and 0.06 inches and an average width of between 0.02 and 0.06 inches.

11. The turbine rotor blade according to claim 1 , wherein the coolant passageway through the tip plate comprises an outlet that is configured to function as a film coolant outlet; and
wherein the feed microchannel is configured to direct the coolant that would have exited the turbine blade from the film coolant outlet to the circumscribing rail microchannel.

12. A turbine rotor blade for a gas turbine engine, the turbine rotor blade comprising an airfoil that includes a tip at an outer radial end; wherein the tip includes a rail that defines a tip cavity; wherein the rail includes a circumscribing rail microchannel; and wherein the airfoil includes a pressure sidewall and a suction sidewall that join together at a leading edge and a trailing edge of the airfoil, the pressure sidewall and the suction sidewall extending from a root to the tip and defining an airfoil chamber therein; the tip includes a tip plate, the rail being disposed near or at a periphery of the tip plate; the rail includes an inner rail surface, which faces inwardly toward the tip cavity, and an outer rail surface; the circumscribing rail microchannel comprises a microchannel that extends around at least a majority of the length of the inner rail surface; wherein the circumscribing rail microchannel are formed intermittently along the at least majority of the length of the inner rail surface; wherein the intermittent formation comprises at least a plurality of discrete microchannel spans; wherein the intermittently formed circumscribing rail microchannel includes an outboard intermittently formed circumscribing rail microchannel and an inboard intermittently formed circumscribing rail microchannel, the outboard and inboard intermittently formed circumscribing rail microchannels being staggered such that the gaps of each do not coincide and the microchannels of each overlap.

13. The turbine rotor blade according to claim 12 , wherein the intermittently formed circumscribing rail microchannels comprise gaps formed between each of the plurality of discrete microchannel spans; and
wherein each of the plurality of discrete microchannel spans include a dedicated coolant supply.

14. The turbine rotor blade according to claim 13 , wherein each of the discrete microchannel spans comprises one or more outlets, each of the outlets comprising a port disposed on the inner rail surface.

15. The turbine rotor blade according to claim 14 , wherein each of the discrete microchannel spans comprises at least two outlets;
wherein one of the two outl

Assignees

• Zhang Xiuzhang James
• Smith Aaron Ezekiel
• Giglio Anthony Louis
• Arness Brian Peter
• Lacy Benjamin Paul
• Gen Electric

Inventors

• Zhang Xiuzhang James
• Smith Aaron Ezekiel
• Giglio Anthony Louis
• Arness Brian Peter
• Lacy Benjamin Paul

Classifications

• F01D5/20 Primary

  Specially-shaped blade tips to seal space between tips and stator {(F01D5/225 takes precedence)} · CPC title

• F01D5/186

  Film cooling (F01D5/187 takes precedence) · CPC title

• F01D5/18 Primary

  Hollow blades, {i.e. blades with cooling or heating channels or cavities (structure of hollow blades in general F01D5/147)}; Heating, heat-insulating or cooling means on blades · CPC title