GB2049913A

GB2049913A - Supporting gas turbine combustion chambers

Info

Publication number: GB2049913A
Application number: GB7917787A
Authority: GB
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 1979-05-22
Filing date: 1979-05-22
Publication date: 1980-12-31

Abstract

The support comprises radially extending dowels 25 secured to the engine casing 20a, b and slidably engaging cooperating holes within a portion 22 of the combustion chamber. <IMAGE>

Description

SPECIFICATION Improvements in or relating to gas turbine engines This invention relates to gas turbine engines and in particular to means for supporting an annular combustion chamber in such an engine.

Annular combustion chambers are at present usually secured within gas turbine engines at their upstream end by means of a radially extending flange which is secured to or forms a part of the combustion chamber and which is bolted to a portion of the engine casing. This however suffers a disadvantage in that the combustion chamber, its associated flange and the casting portion to which it is attached, are each subjected to widely differing temperatures during the operating cycle of the engine. Thus the respective parts expand and contract at varying rates and this often leads to overstressing and distortion or occasionally even actual breakage of one of the components.

An object of the present invention is to provide means for supporting a gas turbine engine combustion chamber which substantially eliminates the aforementioned problems.

According to the present invention means for supporting a combustion chamber within a gas turbine engine comprises location means secured to and extending radially inwardly from a portion of the engine casing and further means provided upon a portion of the combustion chamber which cooperate with said location means such that the combustion chamber is maintained concentric with the engine casing portion but may move radially with respect of it.

Preferably the location means secured to and extending from a portion of the engine casing comprise four sets of equally spaced radially inwardly extending members which are adapted to be slidably mounted within the further means which are provided upon a portion of the combustion chamber.

Furthermore each set of radially extending members comprises three square section dowels each of which fits into a corresponding hole provided within the further means secured to the combustion chamber. The square section dowels have threaded internal portions by means of which they are secured to the engine casing by means of bolts.

Preferably the further means comprises a radially extending flange situated at the upstream end of the combustion chamber.

For better understanding of the invention an embodiment thereof will be more particularly described by way of example only and with reference to the accompanying drawings in which: Figure 1 shows a diagrammatic side view partly in cross-section of a gas turbine engine showing a diagrammatic embodiment of the present invention.

Figure 2 shows an enlarged cross-sectional view in greater detail of the embodiment shown diagrammatically at Figure 1.

Figure 3 shows a pictorial view of a portion of the view of the embodiment shown at Figure 2.

Referring to the drawings a gas turbine engine shown generally at 10 comprises in flow series a front fan 12 intermediate and high pressure compressors 13 and 14, combustion equipment 15, high pressure turbine 16, intermediate turbine 17, low pressure turbine 18, the engine terminating in an exhaust nozzle 19. The combustion equipment 1 5 comprises an annular combustion chamber which is supported from the engine casing 20 by means of a support shown generally at 21 which is shown in a detailed crosssectional view at Figure 2.

The engine casing 20 includes two concentrically disposed walls 20a and 20b from which is located the upstream portion of the combustion chamber by means of a radially extending flange 22 which terminates in four equally spaced portions 23. One of the portions is shown pictorially at Figure 2 and includes three square section holes 24 in which square section dowels 25 are adapted to be a sliding fit. The dowels 25 are provided with a screw threaded hole by means of which they are secured to the engine casing by means of radially extending bolts 26 which are located within holes in the casing. A further larger aperture is provided within the portion 23 through which the towers of the fuel burners 28 are adapted to pass.

As previously stated the combustion chamber is supported by means of sets of dowels 25 extending from the engine casing and are a sliding fit within the four separate support portions 23 which are usually spaced about the periphery of the flange 22. In this way the combustion chamber is supported concentrically with respect to the engine casing, however either the engine casing or the combustion chamber may expand or contract radially with respect to each other whilst remaining concentric. This arrangement therefore minimises the chance of distortion or strain occurring within the respective components.

1. Means for supporting chamber within a gas turbine engine comprising locating means secured to and extending radially inwardly of a portion of the engine casing, and further means provided upon a portion of the combustion chamber which cooperates with said location means such that the combustion chamber is maintained substantially concentric with the engine casing portion but may move radially with respect of it.

2. A support as claimed in claim 1 in which the location means secured to and extending from a portion of the engine casing comprises four sets of equally spaced radially inwardly extending members which are adapted to be slidably mounted within further means which are provided upon a portion of the combustion chamber.

3. A support as claimed in claim 2 in which each set of radially extending members comprise three square section dowels, each of which fits into a corresponding hole provided within the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in or relating to gas turbine engines This invention relates to gas turbine engines and in particular to means for supporting an annular combustion chamber in such an engine. Annular combustion chambers are at present usually secured within gas turbine engines at their upstream end by means of a radially extending flange which is secured to or forms a part of the combustion chamber and which is bolted to a portion of the engine casing. This however suffers a disadvantage in that the combustion chamber, its associated flange and the casting portion to which it is attached, are each subjected to widely differing temperatures during the operating cycle of the engine. Thus the respective parts expand and contract at varying rates and this often leads to overstressing and distortion or occasionally even actual breakage of one of the components. An object of the present invention is to provide means for supporting a gas turbine engine combustion chamber which substantially eliminates the aforementioned problems. According to the present invention means for supporting a combustion chamber within a gas turbine engine comprises location means secured to and extending radially inwardly from a portion of the engine casing and further means provided upon a portion of the combustion chamber which cooperate with said location means such that the combustion chamber is maintained concentric with the engine casing portion but may move radially with respect of it. Preferably the location means secured to and extending from a portion of the engine casing comprise four sets of equally spaced radially inwardly extending members which are adapted to be slidably mounted within the further means which are provided upon a portion of the combustion chamber. Furthermore each set of radially extending members comprises three square section dowels each of which fits into a corresponding hole provided within the further means secured to the combustion chamber. The square section dowels have threaded internal portions by means of which they are secured to the engine casing by means of bolts. Preferably the further means comprises a radially extending flange situated at the upstream end of the combustion chamber. For better understanding of the invention an embodiment thereof will be more particularly described by way of example only and with reference to the accompanying drawings in which: Figure 1 shows a diagrammatic side view partly in cross-section of a gas turbine engine showing a diagrammatic embodiment of the present invention. Figure 2 shows an enlarged cross-sectional view in greater detail of the embodiment shown diagrammatically at Figure 1. Figure 3 shows a pictorial view of a portion of the view of the embodiment shown at Figure 2. Referring to the drawings a gas turbine engine shown generally at 10 comprises in flow series a front fan 12 intermediate and high pressure compressors 13 and 14, combustion equipment 15, high pressure turbine 16, intermediate turbine 17, low pressure turbine 18, the engine terminating in an exhaust nozzle 19. The combustion equipment 1 5 comprises an annular combustion chamber which is supported from the engine casing 20 by means of a support shown generally at 21 which is shown in a detailed crosssectional view at Figure 2. The engine casing 20 includes two concentrically disposed walls 20a and 20b from which is located the upstream portion of the combustion chamber by means of a radially extending flange 22 which terminates in four equally spaced portions 23. One of the portions is shown pictorially at Figure 2 and includes three square section holes 24 in which square section dowels 25 are adapted to be a sliding fit. The dowels 25 are provided with a screw threaded hole by means of which they are secured to the engine casing by means of radially extending bolts 26 which are located within holes in the casing. A further larger aperture is provided within the portion 23 through which the towers of the fuel burners 28 are adapted to pass. As previously stated the combustion chamber is supported by means of sets of dowels 25 extending from the engine casing and are a sliding fit within the four separate support portions 23 which are usually spaced about the periphery of the flange 22. In this way the combustion chamber is supported concentrically with respect to the engine casing, however either the engine casing or the combustion chamber may expand or contract radially with respect to each other whilst remaining concentric. This arrangement therefore minimises the chance of distortion or strain occurring within the respective components. CLAIMS

3. A support as claimed in claim 2 in which each set of radially extending members comprise three square section dowels, each of which fits into a corresponding hole provided within the further means secured to the combustion chamber.

4. A support as claimed in claim 3 in which the square section dowels each have threaded internal portions by means of which they are secured to the engine casing by bolts,

5. A support for a gas turbine engine combustion chamber as claimed in any preceding claims and substantially as hereinbefore described by way of example only and with reference to the accompanying drawings.

5. A support as claimed in claim 3 in which the further means comprise a radially extending flange situated at the upstream end of the combustion chamber.

6. A support for a gas turbine combustion chamber as claimed in any preceding claim, and substantially as hereinbefore described by way of example only with reference to the accompanying drawings.

New claims or amendments to claims filed on July 30,1979 Superseded claims: New or amended claims: CLAIMS

1. Means for supporting a combustion chamber within a gas turbine engine comprising location means secured to, and extending radially inwardly of a portion of the engine casing, and further means provided upon a portion of the combustion chamber which cooperates with said location means such that the combustion chamber is maintained substantially concentric with the engine casing portion but may move radially with respect of it, and wherein the location means comprise at least three sets of equally spaced radially inwardly extending members each radially inwardly extending member including three square section dowels, each of which dowels fits into a corresponding hole provided within the further means secured to the combustion chamber.

2. A support as claimed in claim 1 in which the location means secured to and extending from a portion of the engine casing comprise four sets of equally spaced radially inwardly extending members.

3. A support as claimed in claim 1, in which the square section dowels, each have a threaded internal portion by means of which they are secured to the engine casing by bolts.

4. A support as claimed in claim 2 in which the further means comprises a radially extending flange situated at the upstream end of the combustion chamber.