GB2573623A

GB2573623A - Fuel injector arrangement

Info

Publication number: GB2573623A
Application number: GB1903235.8A
Authority: GB
Inventors: Tentorio Luca
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 2018-04-10
Filing date: 2019-03-11
Publication date: 2019-11-13
Anticipated expiration: 2039-03-11
Also published as: US20190316776A1; GB201805955D0; GB201903235D0; GB2573623B

Abstract

A fuel injector (23, Figure 2) for a gas turbine engine (10, Figure 1), comprising a fuel spray nozzle (26, Figure 2) with an engaging feature 40, and a burner sleeve 30 having a swirler 37 and a connecting feature (34, Figure 2). The engaging and connecting features are releasably attached, inhibiting relative movement between the nozzle (26, Figure 2) and swirler 37. The pair of engaging and connecting features may be a protrusion 40 and track, and a second pair may be located on the burner sleeve, diametrically opposite the first pair, defining a rotation axis A for the nozzle. The burner sleeve 30 may have a hole 31 for receiving the nozzle. The track may have a receiving portion 42 and a locking portion 44, together defining a movement path, wherein the locking portion defines a locking region 44. The receiving portion width may narrow to guide the protrusion. The burner sleeve may be connected to the combustor liner (33, Figure 2) via the combustor head (36, Figure 2), and the connection may permit relative axial and radial movement but inhibit rotational motion. The arrangement may comprise a nozzle stem, and a nozzle head.

Description

This disclosure relates to a fuel injector arrangement for a gas turbine engine comprising a fuel spray nozzle and a burner sleeve comprising a swirler.

A typical gas turbine engine comprises a combustor arrangement in which combustion takes place. A fuel injector arrangement provides fuel and air into a combustion chamber in which the fuel and air is mixed and ignited. The resultant heated highvelocity air is exhaust through a nozzle, providing propulsion to the engine.

A conventional arrangement for providing fuel into a combustor liner includes the use of a fuel injector apparatus comprising a fuel spray nozzle (FSN) stem and a fuel spray nozzle (FSN) head. An outer swirler is provided on the fuel spray nozzle head for swirling the air from the compressor, mixing the fuel and air. During assembly of the combustor arrangement, the fuel spray nozzle and swirler are fitted to the combustor liner.

According to a first aspect, there is provided a fuel injector arrangement for a gas turbine engine, the fuel injector arrangement comprising: a fuel spray nozzle comprising an engaging feature; and a burner sleeve comprising a swirler; wherein the burner sleeve comprises a connecting feature; wherein the engaging and connecting features are engageable so as to removably couple the fuel spray nozzle to the burner sleeve and inhibit relative movement between the fuel spray nozzle and the swirler.

Inhibiting relative movement between the fuel spray nozzle and the swirler using complementary features of the nozzle and burner sleeve may provide improved performance of the fuel spray nozzle and thereby greater efficiency. Removably coupling the fuel spray nozzle to the burner sleeve may inhibit relative movement between the fuel spray nozzle and the burner sleeve. The swirler may be fixed in position relative to the burner sleeve such that removably coupling the fuel spray nozzle to the burner sleeve may inhibit relative movement between the fuel spray nozzle and the swirler. The swirler may be formed integrally as part of the burner sleeve.

The engaging feature may be contiguous with the fuel spray nozzle. The engaging feature may be integral to the fuel spray nozzle. The engaging feature may be a surface feature formed on the surface of the fuel spray nozzle. The connecting feature may be contiguous with the burner sleeve. The connecting feature may be integral to the burner sleeve. The connecting feature may be a surface feature formed on the surface of the burner sleeve. Inhibiting relative movement may comprise preventing relative movement in one or more degrees of freedom. The one or more degrees of freedom may comprise an axial direction, a rotational, or a radial direction.

The burner sleeve may have an internal bore for receiving the fuel spray nozzle. The internal bore may be substantially cylindrical or may be elliptical. The swirler may be arranged coaxially with the internal bore so as to surround the internal bore. The swirler may be arranged concentrically around the internal bore. The fuel spray nozzle may comprise a head portion. The head portion of the fuel spray nozzle may comprise a cylindrical outer surface, a part spherical outer surface or an elliptical outer surface. The internal bore of the burner sleeve may be configured to receive the head portion of the fuel spray nozzle.

The swirler may be an outer swirler. The swirler may be an axial swirler or a radial swirler. The swirler may comprise swirl vanes arranged to swirl air.

The burner sleeve may comprise a second connecting feature. The fuel spray nozzle may comprise a second engaging feature. The second engaging feature and the second connecting feature may be engageable so as to removably couple the fuel spray nozzle to the burner sleeve. The second engaging feature and the second connecting feature may be engageable so as to inhibit relative movement between the fuel spray nozzle and the swirler. The second engaging feature and the second connecting feature may be engageable so as to inhibit relative movement between the fuel spray nozzle and the burner sleeve. The second connecting feature may be substantially similar to the connecting feature. The second engaging feature may be substantially similar to the engaging feature.

The second engaging feature may be arranged on the fuel spray nozzle substantially diametrically opposite the engaging feature. The second engaging feature may be arranged on the fuel spray nozzle at substantially 180 degrees to the engaging feature. The second connecting feature may be arranged on the burner sleeve substantially diametrically opposite the first connecting feature. The second connecting feature may be arranged on the burner sleeve at substantially 180 degrees to the first connecting feature.

The engaging feature and the second engaging feature may define an axis about which the fuel spray nozzle can be rotated. The fuel spray nozzle may be rotatable about the axis during installation of the fuel spray nozzle to the burner sleeve.

One of the connecting feature and the engaging feature may comprise a track. The track may also be referred to as a slot, groove or recess. The track may be machined into the fuel spray nozzle or the burner sleeve. The other of the connecting feature and the engaging feature may comprise a protrusion. The other of the connecting feature and the engaging feature may comprise a rail or a runner. The connecting feature may comprise a track, and the engaging feature may comprise a protrusion, rail or runner. The engaging feature may comprise a track, slot, groove or recess, and the connecting feature may comprise a protrusion, rail or runner. The protrusion, rail or runner may be configured to be received by the track. The protrusion, rail or runner may be retained by the track.

In at least a portion of the track, the fuel spray nozzle may be rotatable about the axis defined by the engaging feature and the second engaging feature.

The track may define a path along which the protrusion can be moved. The protrusion be slidable within the track. Moving the protrusion along the track may cause the fuel spray nozzle and the swirler to slide relative to one another. Moving the protrusion along the track may cause the fuel spray nozzle and the burner sleeve to slide relative to one another.

The track may comprise a receiving portion and a locking portion.

The locking portion of the track may define a locking region in which the protrusion is locked in position to inhibit relative movement between the fuel spray nozzle and the swirler in at least one degree of freedom. The locking portion of the track may define a locking region in which the protrusion is locked in position to inhibit relative movement between the fuel spray nozzle and the burner sleeve in at least one degree of freedom. Inhibiting relative movement may comprise preventing relative movement in one or more degrees of freedom. The one or more degrees of freedom may comprise an axial direction, a rotational direction, or a radial direction. The fuel spray nozzle may be rotatable about the axis defined by the engaging feature and the second engaging feature when the protrusion is in the receiving portion, and may be substantially prevented from rotation when in the locking portion.

The receiving portion may have a narrowing width for guiding the protrusion to the locking portion. The narrowing width may define a funnel-like guide for guiding the protrusion to the locking portion.

The receiving portion may define a movement path for the protrusion in a first direction. The locking portion may define a movement path for the protrusion in a second direction. The second direction may be different to the first direction. The track may define a curved path.

The connecting feature may comprise the track and the engaging feature may comprise the protrusion. The track may be machined into the burner sleeve.

The fuel injector arrangement may further comprise a combustor liner. The burner sleeve may be disposed on the combustor liner.

The combustor liner may comprise a combustor head. The burner sleeve may be connected to the combustor head. The burner sleeve may be manufactured integrally with the combustor head. The burner sleeve may be manufactured separately and then attached to the combustor head. The burner sleeve may act as a sleeve for the fuel spray nozzle allowing installation of the fuel spray nozzle onto the combustor head. Connecting the swirler to the burner sleeve, and therefore to the combustor head may mean that a smaller, lighter fuel spray nozzle and fuel spray nozzle stem can be provided, thereby reducing the weight of the engine. Connecting the swirler to the burner sleeve may mean that the hole into which the fuel spray nozzle fits can be smaller, which may result in a smaller stress concentration in the combustor head and thereby a longer life expectancy of the combustor head. Connecting the swirler to the burner sleeve may mean that a hole in a combustor outer casing through which the fuel spray nozzle is inserted to the combustor head can be smaller, which may result in a smaller stress concentration in the combustor outer casing and thereby a longer life expectancy of the combustor outer casing.

The combustor head and the burner sleeve may be connected so as to allow relative axial and radial movement between the combustor head and the burner sleeve. The connection may allow differential thermal expansion between the combustor head and the burner sleeve.

The combustor head and the burner sleeve may be connected so as to inhibit relative rotational movement between the burner sleeve and the combustor head. The combustor head and the burner sleeve may be connected so as to inhibit relative rotational movement between the swirler and the combustor head.

The fuel spray nozzle may comprise a fuel spray nozzle stem and a fuel spray nozzle head, the fuel spray nozzle head comprising the engaging feature.

According to a second aspect, there is provided a gas turbine engine comprising a fuel injector arrangement according to the first aspect described above.

According to a third aspect there is provided a method of assembling a fuel injector arrangement for a gas turbine engine, the method comprising: providing a burner sleeve comprising a swirler, wherein the burner sleeve comprises a connecting feature, providing a fuel spray nozzle comprising an engaging feature; wherein the method comprises bringing the engaging and connecting features into engagement so as to removably couple the fuel spray nozzle to the burner sleeve and inhibit relative movement between the fuel spray nozzle and the swirler. Inhibiting relative movement between the fuel spray nozzle and the swirler may provide guaranteed performance of the fuel spray nozzle and thereby greater efficiency.

Removably coupling the fuel spray nozzle to the burner sleeve may inhibit relative movement between the fuel spray nozzle and the burner sleeve. The swirler may be fixed in position relative to the burner sleeve such that removably coupling the fuel spray nozzle to the burner sleeve may inhibit relative movement between the fuel spray nozzle and the swirler. The swirler may be formed integrally as part of the burner sleeve.

The engaging feature may be contiguous with the fuel spray nozzle. The engaging feature may be integral to the fuel spray nozzle. The engaging feature may be a surface feature formed on the surface of the fuel spray nozzle. The connecting feature may be contiguous with the burner sleeve. The connecting feature may be integral to the burner sleeve. The connecting feature may be a surface feature formed on the surface of the burner sleeve. Inhibiting relative movement may comprise preventing relative movement in one or more degrees of freedom. The one or more degrees of freedom may comprise an axial direction, a rotational direction, or a radial direction.

The burner sleeve may have an internal bore for receiving the fuel spray nozzle. The internal bore may be cylindrical or may be elliptical. The swirler may be arranged coaxially with the internal bore so as to surround the internal bore. The swirler may be arranged concentrically around the internal bore. The fuel spray nozzle may comprise a head portion. The head portion of the fuel spray nozzle may comprise a cylindrical outer surface, a part spherical outer surface or an elliptical outer surface. The fuel spray nozzle may be received within the internal bore. The method may comprise inserting the fuel spray nozzle into the internal bore. The internal bore of the burner sleeve may receive the head portion of the fuel spray nozzle.

The burner sleeve may comprise a second connecting feature. The fuel spray nozzle may comprise a second engaging feature. The method may comprise bringing the second engaging feature and the second connecting feature into engagement so as to removably couple the fuel spray nozzle to the burner sleeve. The second engaging feature and the second connecting feature may be brought into engagement so as to inhibit relative movement between the fuel spray nozzle and the swirler. The second engaging feature and the second connecting feature may be engageable so as to inhibit relative movement between the fuel spray nozzle and the burner sleeve. The second connecting feature may be substantially similar to the connecting feature. The second engaging feature may be substantially similar to the engaging feature.

One of the connecting feature and the engaging feature may comprise a track. The track may also be referred to as a slot, groove or recess. The track may be machined into the fuel spray nozzle or the burner sleeve. The other of the connecting feature and the engaging feature may comprise a protrusion. The other of the connecting feature and the engaging feature may comprise a rail or a runner. The connecting feature may comprise a track, slot, groove or recess, and the engaging feature may comprise a protrusion, rail or runner. The engaging feature may comprise a track, and the connecting feature may comprise a protrusion, rail or runner. The protrusion, rail or runner may be configured to be received by the track. The protrusion, rail or runner may be retained by the track.

The track may define a path along which the protrusion can be moved. The protrusion may slide within the track. Moving the protrusion along the track may cause the fuel spray nozzle and the swirler to slide relative to one another. Moving the protrusion along the track may cause the fuel spray nozzle and the burner sleeve to slide relative to one another.

The track may comprise a receiving portion and a locking portion.

The locking portion of the track may define a locking region in which the protrusion is locked in position to inhibit relative movement between the fuel spray nozzle and the swirler in at least one degree of freedom. The locking portion of the track may define a locking region in which the protrusion is locked in position to inhibit relative movement between the fuel spray nozzle and the burner sleeve in at least one degree of freedom. Inhibiting relative movement may comprise preventing relative movement in one or more degrees of freedom. The one or more degrees of freedom may comprise an axial direction, a rotational direction or a radial direction. The fuel spray nozzle may be rotatable about the axis defined by the engaging feature and the second engaging feature when the protrusion is in the receiving portion, and may be prevented from rotation when in the locking portion.

The combustor head and the burner sleeve may be connected so as to inhibit relative rotational movement between the burner sleeve and the combustor head.

The combustor head and the burner sleeve may be connected so as to inhibit relative rotational movement between the swirler and the combustor head.

The invention may comprise any combination of the features and/or limitations referred to with respect to any of the first, second and third aspects described above, except combinations of such features as are mutually exclusive.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

Figure 1 schematically shows a gas turbine engine;

Figure 2 schematically shows a fuel injector apparatus according to the present disclosure;

Figures 3a and 3b schematically show a fuel spray nozzle of the fuel injector apparatus shown in Figure 2;

Figures 4a and 4b schematically show a combustor liner and burner sleeve of the fuel injector apparatus shown in Figure 2;

Figure 5 schematically shows the attachment of a burner sleeve to a combustor head of the fuel injector apparatus shown in Figure 2;

Figure 6 schematically shows a burner sleeve with a longer locking portion according to the present disclosure;

Figure 7 schematically shows a burner sleeve with a curved receiving portion according to the present disclosure;;

Figures 8a and 8b schematically show an alternative embodiment of the fuel injector apparatus according to the present disclosure;; and

Figures 9a-12b schematically show a method of assembling a fuel injector apparatus according to the present disclosure.

With reference to Figure 1, a gas turbine engine is generally indicated at 10, having a principal and rotational axis 11. The engine 10 comprises, in axial flow series, an air intake 12, a propulsive fan 13, an intermediate pressure compressor 14, a high pressure compressor 15, combustion equipment 16, a high-pressure turbine 17, and intermediate pressure turbine 18, a low-pressure turbine 19 and an exhaust nozzle 20. A nacelle 21 generally surrounds the engine 10 and defines both the intake 12 and the exhaust nozzle 20.

The gas turbine engine 10 works in the conventional manner so that air entering the intake 12 is accelerated by the fan 13 to produce two air flows: a first air flow into the intermediate pressure compressor 14 and a second air flow which passes through a bypass duct 22 to provide propulsive thrust. The intermediate pressure compressor 14 compresses the air flow directed into it before delivering that air to the high pressure compressor 15 where further compression takes place. The compressed air exhausted from the high-pressure compressor 15 is directed into the combustion equipment 16 where it is mixed with fuel and the mixture combusted. The resultant hot combustion products then expand through, and thereby drive the high, intermediate and lowpressure turbines 17, 18, 19 before being exhausted through the nozzle 20 to provide additional propulsive thrust. The high 17, intermediate 18 and low 19 pressure turbines drive respectively the high pressure compressor 15, intermediate pressure compressor 14 and fan 13, each by suitable interconnecting shafts.

With reference to Figure 2, the combustion equipment 16 comprises a fuel injector apparatus 23 comprising a combustion chamber 24 and a fuel spray nozzle (FSN) 26 arranged to spray air and fuel into the combustion chamber 24 to be ignited. The fuel spray nozzle 26 comprises a fuel spray nozzle (FSN) head 27 with a cylindrical outer surface. The fuel spray nozzle 26 is attached to a fuel spray nozzle (FSN) stem 28, which structurally supports the fuel spray nozzle 26 and supplies the fuel spray nozzle 26 with fuel. The FSN stem 28 may comprise a feed arm or be configured for attachment to a feed arm. A combustor outer casing 48 surrounds the combustion chamber 24 and the combustor outer casing 48 has a plurality of circumferentially spaced apertures 25 through which the fuel spray nozzles 26 are inserted. Each fuel spray nozzle 26 has a flange 29 to enable the fuel spray nozzle 26 to be secured to the combustor outer casing 48, for example by fasteners, e.g. bolts.

Referring to Figures 3a and 3b, the FSN head 27 comprises two protrusions 40 arranged on diametrically opposite sides of the outer surface of the FSN head 27. The protrusions 40 define between them an axis A about which the FSN head 27 can be rotated. The axis A generally extends across the diameter of the FSN head. The protrusions 40 are sized so as to be received by the tracks 34 of the burner sleeve 30, as will be discussed later.

Referring to Figures 4a and 4b, the combustion chamber 24 is defined by a combustor liner 33. The combustor liner 33 comprises a combustor head 36 at an upstream end. The combustor head 36 has one or more apertures 35. A burner sleeve 30 is located in each aperture 35 in the combustor head 36. Each burner sleeve 30 is installed on the combustor head 36. An outer swirler 37 is formed as an integral part of the burner sleeve 30. The burner sleeve 30 comprises coaxial inner and outer rings 45 and 47 respectively and a plurality of swirl vanes 49 which extend radially between the inner and outer rings 45 and 47.

The outer surface of the outer ring 47 of the burner sleeve 30 is substantially cylindrical. The inner surface 39 of the inner ring 45 of the burner sleeve 30 is partially cylindrical and defines a bore 31 having two opposing arcuate surfaces 39a separated by two substantially planar surfaces 39b disposed at opposing lateral sides of the burner sleeve 30. A track 34 is formed in each of the opposing surfaces 39b of the internal surface 39 of the burner sleeve30. The tracks 34 are machined onto the inner surface of the outer burner sleeve 30. The tracks 34 are sized to receive the corresponding protrusions 40 formed on the outer surface of the FSN head 27.

The burner sleeve 30 comprises an outer swirler 37. The outer swirler 37 is arranged concentrically around the bore 31 of the burner sleeve 30. The outer swirler 37 is provided in order to swirl the air provided from the compressor as it enters the combustion chamber 24. The outer swirler 37 comprises swirl vanes 49 which swirl the air flow as it enters the combustion chamber 24, thereby allowing fuel breakdown and mixing.

The tracks 34 each define a receiving portion 42 and a locking portion 44. In this embodiment, the receiving portion 42 comprises a recess which has a wide opening at the outer axial surface of the burner sleeve 30 and which narrows in the axial direction, forming a funnel shape. The receiving portion 42 ends approximately halfway along the axial length of the burner sleeve 30. The locking portion 44 comprises a recess at the narrow end of the receiving portion, which extends in a direction different to the direction of extension of the receiving portion 42. The locking portion 44 is sized to retain the protrusion 40 and inhibit axial and rotational movement of the protrusion 40, and therefore the FSN head 27 relative to the burner sleeve 30 in rotational and axial directions. Therefore, the engagement of the protrusions 40 with the tracks 34 (and in particular the locking portion 44) simultaneously removably couples the FSN head 27 to the burner sleeve 30 and inhibits relative movement between the FSN head 27 and the burner sleeve 30, thereby inhibiting relative movement between the FSN head 27 and the outer swirler 37

Referring to Figures 4a and 5, a radially extending flange 41 is provided on the outer surface of the burner sleeve 30. A retainer 38 is installed on the combustor head 36 by means of a stud 50 and a nut 51. In this example the retainer 38 is installed on the combustor head 36 by means of a plurality of studs 50 and nuts 51. The flange 41 of the burner sleeve 30 is trapped between the retainer 38 and the combustor head 36 but is arranged so as to float and allow relative motion between the burner sleeve 30 and the combustor head 36 (and therefore allow relative motion between the outer swirler 37 and the combustor head 36). In addition, an anti-rotational feature 43 is provided on the burner sleeve 30, which prevents relative rotation between the combustor head 36 and the burner sleeve 30. The retainer 38, the flange 41 and the combustor head 36 provide a sealing arrangement to prevent airflow around the burner sleeve 30. In use, the combustor head 36 will experience greater temperature fluctuations than the burner sleeve 30, it will undergo more thermal expansion and contraction than the burner sleeve 30, so this arrangement permits relative motion to allow for the differential thermal expansion of the two parts. The anti-rotational feature 43 ensures the correct orientation of the tracks 34 so that the protrusions 40 of the FSN head 27 can be located accurately in the tracks 34 during installation, and easily removed for inspection and maintenance. Figure 5 also shows that the combustion chamber 24 is an annular combustion chamber which comprises an annular combustor head 36 and a plurality of burner sleeves 30 each one of which is associated with a FSN head 27 of a fuel spray nozzle 26.

In this example the flange 41 of each burner sleeve 30 is trapped between a respective one of a plurality of retainers 38 and the combustor head 36 and each sleeve 30 is arranged so as to float and allow relative motion between the associated burner sleeve 30 and the combustor head 36. In this example each retainer 38 is installed on the combustor head 36 by means of a plurality of studs 50 and nuts 51.

The apertures 25 in the combustor outer casing 48 through which the fuel spray nozzles 26 are inserted are smaller in in diameter which results in a reduction in stress concentrations in the combustor outer casing 48.

In other embodiments, the locking portion 44 may extend a longer distance in a direction different to the direction of extension of the receiving portion 42 (as shown in Figure 6), where the receiving portion extends generally axially forward and radially downward while the locking portion extends purely axially forward. In other examples, the receiving portion 42 may define a curved path (as shown in Figure 7). A curved receiving portion 42 may ensure that when the protrusions 40 are inserted into the tracks 34, they are driven towards the locking portion 44.

As the outer swirler 37 is provided on the burner sleeve 30, the FSN stem 28 does not need to carry the additional weight of the outer swirler 37 and may therefore be smaller and lighter.

It will be appreciated that alternatively, the tracks 34 may be machined onto the outer surface of the FSN head 27, and the protrusions 40 may be formed on the inner surface of the burner sleeve 30 (as shown in Figure 8).

In order to assemble the fuel injector arrangement 23, the FSN head 27 of the fuel spray nozzle 26 is inserted into the internal space of the burner sleeve 30, by rotating the FSN head 27 in the axis A in a first direction (Figures 9a and 9b) (anticlockwise as shown in the arrangement of the Figures) and aligning the protrusions 40 within the receiving portions 42 of the tracks 34 (Figures 10a and 10b). The protrusions 40 are slid within the receiving portions 42 of the tracks 34 and into the locking portions 44 (Figures 11a and 11b). As the protrusions 40 are slid within the receiving portions 42, the FSN head 27 is rotated about the axis A in a second direction opposite to the first direction (clockwise as shown in the arrangement of the Figures), such that when the protrusions 40 are located in the locking portions 44 (Figures 12a and 12b), the FSN head 27 is coaxial with the burner sleeve 30 and the outer swirler 37, and the outer swirler 30 is fixed in position concentrically around the FSN head 27. Once the FSN head 27 is aligned coaxially with the burner sleeve 30 and outer swirler 37, a flange (not shown) located at the other end of the feed arm is bolted to the combustor casing (not shown) from the outside. As the outer swirler 37 and the FSN head 27 are fixed in position relative to each other, this arrangement may provide improved performance of the fuel injector arrangement 23 and increased efficiency of the engine 10.

The fuel injector arrangement can be easily disassembled, for maintenance and inspection purposes, by performing the assembly steps in reverse.

It will be appreciated that although the embodiment described here comprises two tracks 34, and two protrusions 40, embodiments can be envisaged having a single track 34 and protrusion 40, or more than two tracks 34 and protrusions 40.

The fuel spray nozzle may be a rich bum FSN or a lean burn FSN. A rich burn FSN comprises two coaxial air swirlers. A rich burn FSN comprises a main fuel passage arranged between the two coaxial air swirlers. In operation the two coaxial air swirlers are arranged to atomise the fuel supplied from the main fuel passage. A lean burn FSN comprises three coaxial air swirlers or four coaxial air swirlers. A lean burn FSN comprises a pilot fuel passage and a main fuel passage. The pilot fuel passage is arranged between two of the coaxial air swirlers and the main fuel passage is arranged between two of the coaxial air swirlers. In operation two of the coaxial air swirlers are arranged to atomise the fuel supplied from the pilot fuel passage and two of the coaxial air swirlers are arranged to atomise the fuel supplied from the main fuel passage.

Advantages of the present invention are that one of the air swirlers is provided on the burner sleeve connected to the combustor head reducing the size of the fuel spray nozzle head and hence the size of the aperture in the combustor outer casing. The fuel spray nozzle has a simpler construction, has less weight and is manufactured at reduced cost. The combustor outer casing has a reduction in stress concentrations.

The fuel spray nozzle head and the burner sleeve/outer swirler are maintained in a fixed position, or in fixed alignment, relative to each other to provide good mixing of the fuel and air and a reduction in emissions and also to reduce wear between the fuel spray nozzle head and the burner sleeve.

It will be understood that the invention is not limited to the embodiments abovedescribed and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the 10 disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.

Claims

1. A fuel injector arrangement (23) for a gas turbine engine, the fuel injector arrangement comprising:

a fuel spray nozzle (26) comprising an engaging feature (40); and a burner sleeve (30) comprising a swirler (37); wherein the burner sleeve (30) comprises a connecting feature (34);

wherein the engaging and connecting features (40, 34) are engageable so as to removably couple the fuel spray nozzle (26) to the burner sleeve (30) and inhibit relative movement between the fuel spray nozzle (26) and the swirler (37).

2. A fuel injector arrangement (23) according to claim 1, wherein the burner sleeve (30) comprises a second connecting feature (34), and the fuel spray nozzle (26) comprises a second engaging feature (40) configured to engage with the second connecting feature (34) so as to removably couple the fuel spray nozzle (26) and the burner sleeve (30) and inhibit relative movement between the fuel spray nozzle (26) and the swirler (37).

3. A fuel injector arrangement (23) according to claim 1 or 2 wherein the burner sleeve (30) comprises an internal bore 31 for receiving the fuel spray nozzle (26).

4. A fuel injector arrangement (23) according to claim 3 when appended to claim 2, wherein the second engaging feature (40) is arranged on the fuel spray nozzle (26) substantially diametrically opposite the engaging feature (40), and the second connecting feature (34) is arranged on the burner sleeve (30) substantially diametrically opposite the connecting feature (34).

5. A fuel injector arrangement (23) according to claim 4, wherein the engaging feature (40) and the second engaging feature (40) define an axis (A) about which the fuel spray nozzle (26) can be rotated.

6. A fuel injector arrangement (23) according to any preceding claim, wherein one of the connecting feature (34) and the engaging feature (40) comprises a track (34), and the other of the connecting feature (34) and the engaging feature (40) comprises a protrusion (40) configured to be received and retained by the track (40).

7. A fuel injector arrangement (23) according to claim 6 when dependent on claim 5, wherein, the fuel spray nozzle (26) is rotatable about the axis (A) when the protrusion (40) is located in at least a portion of the track (34).

8. A fuel injector arrangement (23) according to any of claims 5-7, wherein the track (34) comprises a receiving portion (42) and a locking portion (44), wherein the locking portion (44) of the track (34) defines a locking region (44) in which the protrusion (40) is locked in position to inhibit relative movement between the fuel spray nozzle (26) and the swirler (37) in at least one degree of freedom.

9. A fuel injector arrangement (23) according to claim 8, wherein the receiving portion (42) has a narrowing width for guiding the protrusion (40) to the locking portion (44).

10. A fuel injector arrangement (23) according to claim 8 or 9, wherein the receiving portion (42) defines a movement path for the fuel spray nozzle (26) in a first direction, and the locking portion (44) defines a movement path for the fuel spray nozzle (26) in a second direction different to the first direction.

11. A fuel injector arrangement (23) according to any of claims 6-10, wherein the connecting feature (34) comprises the track (34) and wherein the engaging feature (40) comprises the protrusion (40).

12. A fuel injector arrangement (23) according to any preceding claim, further comprising a combustor liner (33), and wherein the burner sleeve (30) is disposed on the combustor liner (33).

13. A fuel injector arrangement (23) according to claim 12, wherein the combustor liner (33) comprises a combustor head (36), and the burner sleeve (30) is connected to the combustor head (36).

14. A fuel injector arrangement (23) according to claim 13, wherein the combustor head (36) and the burner sleeve (30) are connected so as to allow relative axial and radial movement between the combustor head (36) and the burner sleeve (30).

15. A fuel injector arrangement (23) according to claim 13 or 14, wherein relative rotational movement between the burner sleeve (30) and the combustor head (36) is inhibited.

16. A fuel injector arrangement according to claim 1, wherein the fuel spray nozzle comprises a fuel spray nozzle stem and a fuel spray nozzle head, the fuel spray nozzle head comprising the engaging feature.

17. A gas turbine engine (10) comprising a fuel injector arrangement (23) according to any preceding claim.

18. A method of assembling a fuel injector arrangement (23) for a gas turbine engine (10), the method comprising:

providing a fuel spray nozzle (26) comprising an engaging feature (40); and providing a burner sleeve (30) comprising a swirler (37); wherein the burner sleeve (30) comprises a connecting feature (34);

wherein the method comprises bringing the engaging and connecting features (40, 34) into engagement so as to removably couple the fuel spray nozzle (26) to the burner sleeve (30) and inhibit relative movement between the fuel spray nozzle (26) and the swirler (37).

19. A method of assembling a fuel injector arrangement (23) according to claim 18, wherein the burner sleeve (30) comprises an internal bore 31, and wherein the fuel spray nozzle (26) is received within the internal bore.

20. A method of assembling a fuel injector arrangement (23) according to claim 19, wherein the burner sleeve (30) comprises a second connecting feature (34) , and the fuel spray nozzle (26) comprises a second engaging feature (40), and wherein the second engaging and second connecting features (40, 34) are brought into engagement so as to removably couple the fuel spray nozzle (26) to the burner sleeve (30) and inhibit relative movement between the fuel spray nozzle (26) and the swirler (37).