Gas turbine and gas turbine cooling method

• US 20060034685A1
• Filed: 07/06/2005
• Published: 02/16/2006
• Est. Priority Date: 07/07/2004
• Status: Active Grant

• Current Assignee: Mitsubishi Power Limited (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Horiuchi, Yasuhiro, Noda, Masami, Kizuka, Nobuaki, Higuchi, Shinichi, Marushima, Shinya
• Granted Patent: US 7,507,069 B2
• Time in Patent Office: Days
• US Class Current: 415/191
• CPC Class Codes: F01D 11/001 for sealing space between stator blade and rotor
• CPC Class Codes: F01D 11/025 Seal clearance control; Floating assembly; Adaptation means to differential thermal dilatations
• CPC Class Codes: F01D 5/081 Cooling fluid being directed on the side of the rotor disc or at the roots of the blades F01D5/087 takes precedence

Abstract

A gas turbine includes a nozzle vane and a sealing unit engaged with the nozzle vane inside a turbine supplied with combustion gases produced by mixing and burning air for combustion and fuel. The nozzle vane and the sealing unit are disposed in a channel of the downward flowing combustion gases on the outlet side of a gas path. A plurality of engagement portions between the sealing unit and the nozzle vane are provided successively from the upstream side toward the downstream side in a direction of flow of the combustion gases, and a downstream one of the plurality of engagement portions has a contact interface formed in a direction across a turbine rotary shaft. A reduction in the thermal efficiency of the gas turbine can be suppressed.

Claims

1. A gas turbine including a nozzle vane and sealing means engaging with said nozzle vane inside a turbine supplied with combustion gases produced by mixing and burning air for combustion and fuel, said nozzle vane and said sealing means being disposed in a channel of the downward flowing combustion gases on the outlet side of a gas path,

wherein a plurality of engagement portions between said sealing means and said nozzle vane are provided successively from the upstream side toward the downstream side in a direction of flow of the combustion gases, and

downstream one of said plurality of engagement portions has a contact interface formed in a direction across a turbine rotary shaft.

2. A gas turbine including a nozzle vane and sealing means engaging with said nozzle vane inside a turbine supplied with combustion gases produced by mixing and burning air for combustion and fuel, said nozzle vane and said sealing means being disposed in a channel of the downward flowing combustion gases on the outlet side of a gas path,

wherein a plurality of engagement portions between said sealing means and said nozzle vane are provided successively from the upstream side toward the downstream side in a direction of flow of the combustion gases,

upstream one of said plurality of engagement portions has a contact interface formed in a circumferential direction of a circle about a turbine rotary shaft, and

the downstream-side engagement portion has a contact interface formed in a direction across the turbine rotary shaft.

3. A gas turbine comprising a compressor for producing compressed air, a combustor for mixing and burning the compressed air and fuel, and a turbine rotated by combustion gases exiting said combustor, said turbine including a gas path formed therein between a casing and a turbine rotor for passage of the combustion gases, a nozzle vane and a diaphragm engaging with said diaphragm which are disposed in a channel of the downward flowing combustion gases on the outlet side of said gas path, an upstream-side wheel space and a downstream-side wheel space formed between said diaphragm and corresponding rotor blades, and holes formed in upstream- and downstream-side lateral walls of said diaphragm for communication with said upstream-side wheel space and said downstream-side wheel space to supply a coolant in said diaphragm to said upstream-side wheel space and said downstream-side wheel space,

wherein said turbine further includes a plurality of engagement portions between said diaphragm and said nozzle vane, which are provided successively from the upstream side toward the downstream side in a direction of flow of the combustion gases,

a nozzle vane hook and a diaphragm hook arranged to provide upstream one of said plurality of engagement portions with a contact interface thereof formed in a circumferential direction of a circle about a turbine rotary shaft, and

a nozzle vane hook and a diaphragm hook arranged to provide a downstream one of said plurality of engagement portions with a contact interface thereof formed in a direction across the turbine rotary shaft,

wherein the downstream-side engagement portion having a lower surface of said nozzle vane hook and an upper surface of said diaphragm hook being held in contact with each other.

4. The gas turbine according to claim 3, wherein at least one of each pair of said nozzle vane hook and said diaphragm hook is formed to have a recessed step portion defined by the contact interface and a flat plane shifted from the contract interface in an axial direction of said turbine rotary shaft, thereby providing surface contact between said nozzle vane hook and said diaphragm hook.

5. The gas turbine according to claim 3, wherein, in the downstream-side engagement portion, said nozzle vane hook and said diaphragm hook are engaged with each other by a set pin, and a hole formed in said nozzle vane hook has a diameter larger than the diameter of said set pin.

6. The gas turbine according to claim 3, wherein, in the downstream-side engagement portion, a pair of said nozzle vane hook and a contact portion thereof contacting with said diaphragm hook and a pair of said diaphragm hook and a contact portion thereof contacting with said nozzle vane hook are each formed as an integral part.

7. The gas turbine according to claim 3, wherein, in the upstream-side engagement portion, a gap is left in an axial direction between said nozzle vane hook and said diaphragm hook.

8. The gas turbine according to claim 3, wherein a slope having a wall surface inclined at any desired angle from a direction perpendicular to said turbine rotary shaft is formed in at least one of said nozzle vane hook and said diaphragm hook.

9. The gas turbine according to claim 3, wherein the engagement portion is provided one on each of the upstream side and the downstream side.

10. A method of cooling a gas turbine including a nozzle vane and sealing means engaging with said nozzle vane inside a turbine supplied with combustion gases produced by mixing and burning air for combustion and fuel, said nozzle vane and said sealing means being disposed in a channel of the downward flowing combustion gases on the outlet side of a gas path, said nozzle vane and said sealing means cooperatively defining a cavity, wherein said method comprises the steps of:

providing a plurality of engagement portions between said sealing means and said nozzle vane successively from the upstream side toward the downstream side in a direction of flow of the combustion gases;

forming downstream one of said plurality of engagement portions to provide surface contact in a direction across a turbine rotary shaft; and

supplying a coolant introduced through the inside of said nozzle vane to said cavity and causing the coolant to flow toward the side upstream of said sealing means.

11. A method of cooling a gas turbine including a nozzle vane and sealing means engaging with said nozzle vane inside a turbine supplied with combustion gases produced by mixing and burning air for combustion and fuel, said nozzle vane and said sealing means being disposed in a channel of the downward flowing combustion gases on the outlet side of a gas path, said nozzle vane and said sealing means cooperatively defining a cavity, wherein said method comprises the steps of:

providing a plurality of engagement portions between said sealing means and said nozzle vane successively from the upstream side toward the downstream side in a direction of flow of the combustion gases;

forming upstream one of said plurality of engagement portions to provide surface contact in a circumferential direction of a circle about a turbine rotary shaft,

forming downstream one of said plurality of engagement portions to provide surface contact in a direction across said turbine rotary shaft; and

supplying a coolant introduced through the inside of said nozzle vane to said cavity and causing the coolant to flow toward the side upstream of said sealing means.