Tip clearance control for turbine blades

Patent metadata

Field	Value
Publication number	US-10119413-B2
Application number	US-201514967875-A
Country	US
Kind code	B2
Filing date	Dec 14, 2015
Priority date	Dec 16, 2014
Publication date	Nov 6, 2018
Grant date	Nov 6, 2018

Abstract

An engine includes circumferentially spaced turbine blades radially inward a casing and circumscribed by a carrier section having segments, each having a carrier wall radially inward the casing and radially outward the turbine blades. The wall has one or more portions facing the casing. At least one of the portions has one or more impingement apertures for air passage of a predetermined temperature from a feed source into impingement onto the casing. The segments are radially inward the casing and radially outward the turbine blades, with the portions of their respective walls facing the casing. A method of controlling the gas turbine engine turbine casing temperature includes: passing air of a predetermined temperature from a feed source through the apertures in the one or more portions and into impingement on the casing; and optionally exhausting the air impinged onto the casing from a space between the segment and the casing.

First claim

The invention claimed is:

1. A method of controlling a temperature of a turbine casing of a gas turbine engine, the engine including an array of circumferentially spaced turbine blades disposed radially inwardly of the casing and circumscribed by a carrier section comprising a plurality of carrier segments, each carrier segment being disposed radially inwardly of the casing and radially outwardly of the turbine blades and each carrier segment including a pair of carrier walls including a radially outer carrier wall and a radially inner carrier wall, and the radially outer carrier wall comprising one or more portions facing the casing, wherein at least one of the one or more portions of the radially outer carrier wall is provided with one or more impingement apertures therein, including a main set of impingement apertures, for passage therethrough of air of a predetermined temperature from a feed source and into impingement onto the turbine casing, and each carrier wall extending between front and rear carrier ends, wherein the pair of carrier walls define therebetween one or more chambers for receiving therein heating or cooling air from the feed source via said front end, and each carrier segment further comprises one or more extension sections extending axially, relative to the engine's longitudinal axis, from a main carrier wall section via which the radially outer carrier wall is united with a remainder of the carrier segment, and wherein the or each extension section includes an extension wall that is provided with an extension set of impingement aperture(s) therein,
wherein the method comprises, in the or each carrier segment:
in a first mode, passing air of the predetermined temperature (i) from the feed source through the extension set of impingement aperture(s) to an extension impingement space, which is between the extension wall and the casing, and into impingement on the casing, and (ii) from the feed source through the main set of impingement aperture(s) to a main impingement space, which is between the radially outer carrier wall and the casing, and into impingement on the casing, so that the temperature of the casing is controlled in dependence on the predetermined temperature of the impinging airflow thereon, wherein, in the first mode, the air passing through the extension set of impingement aperture(s) travels to the main impingement space; and
in a second mode, once the air has impinged onto the casing, exhausting the air radially outboard of the extension section from the main impingement space and from the extension impingement space, wherein, in the second mode, the air passing through the main set of impingement aperture(s) travels to the extension impingement space and then exhausts radially outboard of the extension section.

2. A method according to claim 1 , wherein, in the second mode, the step of exhausting the air from the spaces between the carrier segment and the casing comprises exhausting it at least partially to an outboard side of the engine.

3. A method according to claim 1 , wherein air of the predetermined temperature that is passed through the one or more impingement apertures into impingement on the casing is such that the casing is heated thereby.

4. A method according to claim 1 , wherein, in the or each carrier segment, the carrier wall, whose one or more casing-facing portions have the one or impingement apertures formed therein, is an integrally formed wall of the carrier segment.

5. A method according to claim 1 , wherein, in the or each carrier segment, the one or more chambers defined between the pair of carrier walls includes a dedicated holding chamber for supplying heating air from a respective feed source thereof to at least the main set of impingement aperture(s) in the radially outer carrier wall and onward into impingement onto the turbine casing.

6. A method according to claim 1 , wherein, in the or each carrier segment, the carrier segment is supported or mounted in the engine by a support or mounting rail or hook, which includes one or more cut-out sections or apertures therein, wherein the method further includes passing air between the main impingement space and the extension impingement space through the cut-out sections or apertures.

7. A method according to claim 1 , wherein, in the or each carrier segment, the overall flow of air of the predetermined temperature from the feed source into impingement onto the casing via the one or more impingement apertures in the carrier wall is controlled or regulated by a control device including at least one valve.

8. A method according to claim 7 , wherein the at least one valve is located in a potential airflow path between the carrier segment and the casing axially forward of the carrier section of the engine in which the carrier segment is mounted.

9. A method according to claim 1 , wherein, in the second mode, any air passing through the main set of impingement aperture(s) is exhausted only by first traveling to the extension impingement space and then being exhausted radially outboard of the extension section.

10. A method according to claim 1 , wherein gas turbine engine further includes a liner segment that is carried on the or each carrier segment, and the radially inner carrier wall and the liner segment define therebetween one or more cooling chambers.

11. A method of operating a gas turbine engine, the engine including an array of circumferentially spaced turbine blades disposed radially inwardly of a turbine casing of the gas turbine engine and circumscribed by a carrier section comprising a plurality of carrier segments, each carrier segment being disposed radially inwardly of the casing and radially outwardly of the turbine blades and each carrier segment including a pair of carrier walls including a radially outer carrier wall and a radially inner carrier wall, and the radially outer carrier wall comprising one or more portions facing the casing, wherein at least one of the one or more portions of the radially outer carrier wall is provided with one or more impingement apertures therein, including a main set of impingement apertures, for passage therethrough of air of a predetermined temperature from a feed source and into impingement onto the turbine casing, and each carrier wall extending between front and rear carrier ends, wherein the pair of carrier walls define therebetween one or more chambers for receiving therein heating or cooling air from the feed source via said front end, and each carrier segment comprises one or more extension sections extending axially, relative to the engine's longitudinal axis, from a main carrier wall section via which the radially outer carrier wall is united with the remainder of the carrier segment, and wherein the or each extension section includes an extension wall that is provided with an extension set of impingement aperture(s) therein,
wherein the method comprises:
running the engine under at least one transient operating condition of increased power, and
during said at least one transient operating condition, feeding air of a predetermined temperature (i) from the feed source through the main set of impingement aperture(s), and (ii) from the feed source through the extension set of impingement aperture(s), and into impingement on the turbine casing, so as to control the temperature of the casing in dependence on the predetermined temperature of the impinging airflow thereon; and
opening an exhaust located in a wall of the turbine casing which provides a flow path to the outside of the turbine casing and exhausting the air from a main impingement space, which is between the radially outer carrier wall and the casing, and to outside of the turbine casing once

Assignees

• Rolls Royce Plc

Inventors

• Jones Simon Lloyd

Classifications

• F01D25/28

  Supporting or mounting arrangements, e.g. for turbine casing · CPC title

• F01D25/24

  Casings (modified for heating or cooling F01D25/14); Casing parts, e.g. diaphragms, casing fastenings (casings for rotary machines or engines in general F16M {; special arrangements in stators dealing with breaking-off of part of rotor F01D21/045}) · CPC title

• F05D2240/14

  Casings or housings protecting or supporting assemblies within · CPC title

• F01D5/12

  Blades ({specially adapted for radial flow machines or engines F01D5/04}; blade roots F01D5/30; rotors with blades adjustable in operation F01D7/00; stator blades F01D9/02) · CPC title

• F05D2260/201

  by impingement of a fluid · CPC title