# US 11,905,848 B2 · Turbine blade, manufacturing method for turbine blade, and gas turbine

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- Number: US 11,905,848 B2
- Document ID: US11905848B2
- Status: Granted
- Kind: B2
- Application number: 17/598,013
- Filed: 2020-06-01
- Published: 2022-06-02
- Granted: 2024-02-20
- Earliest claimed: 2019-06-05
- Assignees: Mitsubishi Heavy Industries, Ltd.
- Applicants: Mitsubishi Power Ltd.
- Inventors: Masayoshi Hatta; Keita Takamura; Susumu Wakazono; Takashi Fujii; Hiroyuki Otomo; Yosuke Mukai; Kazuhisa Tamura; Takaaki Oda; Hiroshi Kawasaki; Hiroyuki Kishihara
- Web page: https://patentgrep.com/patent/US11905848B2

## CPC

- F01D 5/187: {Convection cooling}
- F01D 15/10: Adaptations for driving, or combinations with, electric generators
- B23H 9/10: Working turbine blades or nozzles
- B23H 9/14: Making holes
- F01D 5/18: 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
- F01D 25/00: Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
- B23H 3/00: Electrochemical machining, i.e. removing metal by passing current between an electrode and a workpiece in the presence of an electrolyte
- F05D 2220/76: an electrical generator
- F05D 2230/11: by electrochemical methods
- F05D 2240/81: Cooled platforms
- F05D 2250/292: tapered
- F05D 2260/20: Heat transfer, e.g. cooling
- F05D 2260/2214: by increasing the heat transfer surface
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- B23H: WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL (processes for the electrolytic or electrophoretic production of coatings, electroforming, or apparatus therefor C25D; processes for the electrolytic removal of material from objects C25F; manufacturing printed circuits using precipitation techniques to apply the conductive material to form the desired conductive pattern H05K3/18)
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS

## Abstract

To provide a turbine blade, a manufacturing method for a turbine blade, and a gas turbine. In the turbine blade including a cooling passage provided along a blade height direction, the cooling passage includes: a first cooling hole including one end opening toward a front end, and having an inner diameter that is constant along the blade height direction; and a second cooling hole including one end communicating with the other end of the first cooling hole without a level difference, and having an inner diameter that is increased toward a base end. A length from the one end of the first cooling hole to a position where the first cooling hole and the second cooling hole are communicated with is 40% to 60% of a length from the one end of the first cooling hole to a gas path surface on the base end.

## Claims

### Claim 1

A turbine blade comprising a plurality of cooling passages provided along a blade height direction that are disposed at intervals in a front and rear direction of the blade, wherein
the cooling passage includes:
a first cooling pass that includes
a first cooling hole that has a first end opening toward a front end of the turbine blade, and that has an inner diameter that is constant along the blade height direction, and
a second cooling hole that has a first end communicating with a second end of the first cooling hole, and that has an inner diameter that is increased by a first expansion ratio toward a base end of the turbine blade; and
a second cooling passage that includes a cooling hole having an inner diameter that is increased by a second expansion ratio from the front end toward the base end, the second expansion ratio being smaller than the first expansion ratio,
wherein a length from the one end of the first cooling hole to a position where the first cooling hole and the second cooling hole are communicated with is 40% to 60% of a length from the first end of the first cooling hole to a gas path surface on the base end.

### Claim 2 (depends on 1)

The turbine blade according to claim 1, wherein
the turbine blade has a shape in which a width of a blade cross section is narrowed from a middle part in the front and rear direction toward a leading edge and a trailing edge, and
the second cooling passage is positioned in a closest side to the leading edge or the trailing edge.

### Claim 3 (depends on 1)

The turbine blade according to claim 1, wherein the first expansion ratio is an expansion ratio of an inner diameter dimension, and ranges from 100% to 250%.

### Claim 4 (depends on 1)

The turbine blade according to claim 1, wherein the first expansion ratio is a passage area expansion ratio based on an inner diameter dimension, and ranges from 100% to 306%.

### Claim 5 (depends on 1)

The turbine blade according to claim 1, wherein an interval between the first cooling passages adjacent to each other at a middle part in the front and rear direction of the blade is larger than an interval between the other cooling passages adjacent to each other.

### Claim 6 (depends on 1)

The turbine blade according to claim 1, further comprising a non-cooling part that does not include the cooling passage at a middle part in the front and rear direction.

### Claim 7 (depends on 1)

The turbine blade according to claim 1, wherein the second cooling hole has a tapered shape in which the inner diameter is continuously increased toward the base end.

### Claim 8 (depends on 1)

The turbine blade according to claim 1, wherein the cooling passage includes
a base end-side cooling hole that includes one end opening toward the base end; and
a cavity part that has an inner diameter larger than an inner diameter of the base end-side cooling hole, wherein the cavity part communicates with a second end of the base end-side cooling hole and with an end of the first cooling passage or an end of the second cooling passage.

### Claim 9 (depends on 8)

The turbine blade according to claim 8, further comprising:
a blade part;
a platform; and
a blade root part, wherein
the cavity part is provided in the platform.

### Claim 10 (depends on 1)

A gas turbine comprising:
a compressor configured to compress air;
a combustor configured to mix compressed air compressed by the compressor with fuel and combust a resulting mixture; and
a turbine configured to obtain rotation power using a combustion gas generated by the combustor, wherein
the turbine includes the turbine blade according to claim 1.

### Claim 11

A manufacturing method for a turbine blade including a plurality of cooling passages along a blade height direction that are disposed at intervals in a front and rear direction of a blade, the manufacturing method comprising:
forming a first cooling passage by electrolytic machining while adjusting at least one of a current value and a machining speed from a front end toward a base end of the turbine blade, the first cooling passage having
a first cooling hole that has a first end opening toward the front end, and that has an inner diameter that is constant along the blade height direction, and
a second cooling hole that has a first end communicating with a second end of the first cooling hole without a level difference, and that has an inner diameter that is increased by a first expansion ratio toward the base end; and
forming a second cooling passage by electrolytic machining while adjusting at least one of a current value and a machining speed from the front end toward the base end of the turbine blade, the second cooling passage having an inner diameter that is increased by a second expansion ratio along the blade height direction, the second expansion ratio being smaller than the first expansion ratio, wherein
a length from the first end of the first cooling hole on the front end of the turbine blade to a position where the first cooling hole and the second cooling hole are communicated with is 40% to 60% of a length from the first end of the first cooling hole to a gas path surface on the base end of the turbine blade.

### Claim 12 (depends on 11)

The manufacturing method for a turbine blade according to claim 11, further comprising forming the second cooling hole by electrolytic machining while keeping a current value constant at a predetermined value or more and changing a machining speed, the second cooling hole having the inner diameter that is increased along the blade height direction.