Combustion Liner Support for Combustion Apparatus

1. Field of the Invention

The present invention relates to a combustion liner support for use in a combustion apparatus as for a gas turbine engine.

2. Description of the Prior Art

In a typical gas turbine combustion apparatus, a combustion liner, that defines therein a combustion chamber, is installed in a combustion outer casing in a manner to cooperate therewith to define an annular air conduit through which air is supplied under pressure into the combustion chamber for combustion of fuel. Various combustion liner support structures have been proposed but there is none that is satisfactory both in cost and durability. With the prior art support structures, the combustion liner is mounted rigidly on the combustor outer casing.

In accordance with the present invention, there is proposed an improved combustion liner support for a combustion apparatus. The combustion liner support comprises means for providing an outward projection to an annular axial end of a combustion liner, an annular supporting bracket encircling a fuel injection nozzle attached to a combustion liner outer casing and having an end secured to the combustion liner outer casing and the other end receiving therein the combustion liner end, means for providing an inward projection to the other end of the annular supporting bracket, a pusher ring cooperating with the supporting bracket inward projection to interpose therebetween a combustion liner outward projection, and biasing means for resiliently urging the pusher ring against the supporting bracket inward projection so that the combustion liner is resiliently supported on the combustion liner outer casing, in which the supporting bracket is of one piece.

The above structure makes it possible to form the supporting bracket from ceramic while the combustion liner from ordinary metal and provides an excellent combustion liner support that is satisfactory both in cost and durability.

It is accordingly an object of the present invention to provide a combustion liner support for a combustion apparatus that is satisfactory both in cost and durability.

It is another object of the present invention to provide a combustion liner support of the above-described character that is adapted to resiliently support the combustion liner relative to the combustion liner outer casing.

It is a further object of the present invention to provide a combustion liner support of the above-described character that makes it possible to form the supporting bracket from ceramic while the combustion liner from ordinary metal.

It is a still further object of the present invention to provide a combustion liner support of the above described character that is particularly suited for adoption in an automotive gas turbine engine.

The features and advantages of the combustion liner support according to the present invention will become more clearly appreciated from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate like or corresponding parts in the several views and wherein:

FIG. 1 is an axially sectional view of a support adapted to resiliently support a combustion liner;

FIG. 2 is a view similar to FIG. 1, though some parts and portions are broken away, but shows a combustion liner support according to an embodiment of the present invention;

FIG. 3 is a cross-sectional view taken along the line III--III of FIG. 2;

FIG. 4 is a view similar to FIG. 1, though some parts and portions are broken away, but shows a combustion liner support according to another embodiment of the present invention;

FIG. 5 is a perspective view, partly cutaway, of a combustion liner supporting brackets and its associated parts utilized in the support of FIG. 4; and

FIG. 6 is a view similar to FIG. 1, though some parts and portions are broken away, but shows a combustion liner support according to a further embodiment of the present invention.

For better understanding of this invention, reference is first made to FIG. 1 which shows a combustion apparatus adapted for adoption in a gas turbine engine and having a combustion liner support operative to effect a resilient supporting action. The structure shown in FIG. 1 is similar to those disclosed in Japanese Patent Application No. 56-12904 and Japanese Utility Model Application No. 56-1472202, both of which have been assigned to the same assignee as the subject application, but not applicable to the present invention as a prior art under the Patent Law.

In FIG. 1, the combustion liner is generally indicated by 10 and shown as comprising an annular outward flange 12a provided to the upstream end of a generally cylindrical combustion liner 12, a plurality of brackets 14 bolted to or otherwise secured at an end to an upstream end of a generally cylindrical combustion outer casing 16 and cooperative to form at the other end an annular inward finger 14a engaging the combustion liner outward flange 12a, a pusher ring 18 cooperating with the bracket finger 14a to clamp therebetween the combustion liner outward flange 12a, and a spring 20 urging the pusher ring 18 against the bracket finger 14a.

More specifically, the combustion liner 12 is arranged concentrically within the outer casing 16 to define therebetween an annular air conduit through which air is supplied under pressure into the combustion chamber defined by the combustion liner 12 for combustion of fuel. The combustion liner 12 is reduced in diameter at the upstream end to have a smaller diameter portion 12b from which the foregoing flange 12a extends radially outwardly. The flange 12a and smaller diameter portion 12b are coaxially or concentrically arranged with respect to the axis of the combustion liner 12. The brackets 14 are joined to form an annular shape with a central opening 14b including a smaller bore portion 14c and a larger bore portion 14d located nearer to the combustion liner 12 than the smaller bore portion 14c. A nozzle holder 22 secured to the outer casing 16 has a sleeve 22a received in the bracket smaller bore portion 14c to hold therein a fuel injection nozzle 24 that partially protrudes from the holder 22 into the bracket larger bore portion 14d. The fuel injection nozzle 24 includes a slidable outer sleeve 24a slidably received in the nozzle holder 22. The injection nozzle outer sleeve 24a has a rim 24b adjacent the combustion liner side end thereof. A swirler 26 of annular configuration is disposed in the bracket larger bore portion 14d and fitted on the combustion liner side end of the injection nozzle outer sleeve 24a in a manner to abut at the inner peripheral portion thereof onto the rim 24b so that it is movable together with the injection nozzle outer sleeve 24a. The swirler 26 also has at the outer periphery thereof an integral flanged wall portion that constitutes the foregoing pusher ring 18. The pusher ring 18 consists of a cylindrical body portion 18a and an annular flange portion 18b extending radially outwardly. The cylindrical body portion 18a is adapted to fit in the combustion liner smaller diameter portion 12b for thereby aligning the combustion liner 12 with the fuel injection nozzle 24. The pusher ring flange portion 18b cooperates with the bracket finger 14a to firmly clamp therebetween the combustion liner 12 under the bias of the spring 20. The spring 20 is a compression coil spring and disposed within the nozzle holder 22 in a manner to constantly urge the fuel injection nozzle outer sleeve 24a in the direction projecting from the nozzle holder 22, thereby allowing the pusher ring 18 to be pressed against the combustion liner flange 12a.

The brackets 14 further have a plurality of air inlets 14e through which air under pressure is supplied further through the swirler 26 into the combustion chamber defined by the combustion liner 12 for combustion of fuel injected from the fuel injection nozzle 24.

From the foregoing, it is to be understood that the combustion liner support 10 is adapted to effect a resilient supporting action, i.e., adapted to resiliently hold the combustion liner 12 relative to the combustion outer casing 16. This structure is quite advantageous since it is not substantially affected by the expansion or contraction of the combustion liner 12 and other associated parts and makes it possible to form the brackets 14 from ceramic while the combustion liner 12 from ordinary metal. When the brackets 14 are formed from ceramic while the combustion liner 12 from metal, there will be a large difference in thermal expansion therebetween. The above support structure 10 is not affected at all by such a difference in thermal expansion therebetween. The above support structure 10 is not affected at all by such a difference in thermal expansion that will otherwise cause a crack or cracks in the ceramic brackets 14.

The above combustion liner support, however, is costly both in manufacture and assembly since it requires a plurality of separate or independent brackets. This is particularly true when the brackets are made of ceramic.

Referring now to FIGS. 2 and 3, a combustion liner support according to an embodiment of the present invention is generally indicated by 28 and comprises a one-piece annular ceramic bracket 30 having at the combustion liner side end thereof a plurality of arcuated inward fingers 30a forming part of a common annular shape and arranged with equal intervals or equal arcuated notches 30e. In this embodiment, the supporting bracket 30 is formed with three inward fingers 30a and three notches 30e. Similarly to the supporting brackets 14 of FIG. 1, the supporting bracket 30 is bolted to or otherwise secured to the combustion outer casing 16 and has a central opening 30b including a smaller bore portion 30c and a larger bore portion 30d.

A combustion liner 32 has at the upstream end thereof a smaller diameter portion 32b and a plurality of arcuate outward flanges 32a corresponding in number to the bracket fingers 30a. The combustion liner flanges 32a form part of a common annular shape and are arranged with equal intervals or equal arcuated notches 32c. The above flanges and fingers are so constructed and arranged that the combustion liner flanges 32a are insertable through bracket notches 30e into the larger bore portion 30d of the bracket central opening 30b.

In installation, the combustion liner flanges 32a are first inserted into the bracket notches 30e to abut on the pusher ring 18. The combustion liner 32 is then pushed against the pusher ring 18 so that the combustion liner flanges 32a are moved together with the pusher ring 18 into the larger bore portion 30d of the bracket centeral opening 30b, prevailing against the bias of the spring 20. The combustion liner 32 is then rotated a predetermined angle and relieved from the pushing force so that the combustion liner flanges 32a are firmly clamped between the pusher ring 18 and the bracket fingers 30a under the bias of the spring 20.

The combustion liner 32 is also formed with a plug hole 32d into which an ignition plug 34 is inserted at an end thereof. The ignition plug 34 is secured at the other end thereof to the combustion liner outer casing 16 and therefore serves as a stopper that prevents the combustion liner 32 from being rotated relative to the bracket 30 due to the vibrations and disengaged from the bracket fingers 30a.

From the foregoing, it will be understood that the combustion liner support 28 of this invention is operative to effect a coupling action like a bayonet coupling, i.e., the combustion liner 32 is easily installed in a bayonet coupling-like manner.

It will be further understood that the foregoing structure makes it possible to attain a single piece supporting bracket, considerably reducing an assembling cost as well as a manufacturing cost.

Referring to FIGS. 4 and 5, a combustion liner support according to a modified embodiment of this invention is generally indicated at 36 and shown as comprising a one-piece ceramic supporting bracket 38 having at the combustion liner side end thereof a concentric annular groove 38a of rectangular cross section. A plurality of arcuated fingers 40 each forming part of a common annular shape are fitted in the groove 38a in a manner to be movable radially of the bracket 38. The bracket 38 is also formed with a plurality of radial openings 38e that establish communication between the groove 38a and the outside of the bracket 38, i.e., that allows access to the fingers 40 from the outside of the bracket 38. Each radial opening 38e has received therein a push rod 42 operative to move the matching finger 40 radially inwardly of the bracket 38. The push rods 42 and fingers 40 are so constructed and arranged that when the push rods are arranged to have their outside ends substantially flush with the outer surface of the bracket 38, the fingers 40 protrude from the inner wall of the bracket 38 while being joined together to form an annular shape. Similarly to the brackets 14 of FIG. 1, the bracket 38 is bolted to or otherwise secured to the combustion outer casing 16 and has a central opening 38b including a smaller bore portion 38c and a larger bore portion 38d.

In installation, the fingers 40 are arranged deeply inside the groove 38a to allow the insertion of the combustion liner flange 12a into the larger bore portion 38d of the bracket central opening 38b. The fingers 40 are then pushed by the push rods 42 to protrude from the groove 38a and placed around the smaller diameter portion 12b of the combustion liner 12 as shown in FIG. 4. The combustion liner flange 12a is thus firmly clamped between the pusher ring 18 and the fingers 40 under the bias of the spring 20, not shown in FIG. 4.

A circular band 44 is placed around the bracket 38 to cover the radial openings 38e and thereby prevent the push rods 42 from protruding outside of the radial openings.

This embodiment can produce substantially the same effect as the previous embodiment.

Referring to FIG. 6, a combustion liner support according to a further modified embodiment of this invention is generally indicated by 46 and shown as comprising a one-piece supporting bracket 48 having at the combustion liner side end thereof an internally threaded cylindrical wall portion 48a. Similarly to the brackets 14 of FIG. 1, the supporting bracket 48 is bolted to or otherwise secured to the combustion outer casing 16 and has a central opening 48b including a smaller bore portion 48c and a larger bore portion 48d.

A combustion liner 50 is reduced in diameter at the upstream end to have an externally threaded smaller diameter portion 50a adapted to be screwed into the internally threaded cylindrical wall portion 48a. In this instance, it is to be noted that the threads in the bracket wall portion 48a and combustion liner smaller diameter portion 50a are not so formed as to tightly and fittingly engage with each other but to be firmly pressed at their matching thread surfaces against each other under the bias of the spring 20 for thereby allowing the combustion liner 50 to be resiliently supported on the supporting bracket 48. To this end, the combustion liner 50 has at the smaller diameter portion 50a an annular inward shoulder 50b with which the pusher ring 18 is abuttingly engaged.

The combustion liner 50 is also formed with a plug hole 50c into which the ignition plug 34 is inserted at an end thereof and prevented from being rotated relative to the supporting bracket 48.

This embodiment can produce substantially the same effect as the previous embodiments.

Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.