GB2129541A - Gas turbine engine fuel manifold/burner assembly - Google Patents

Abstract

A gas turbine engine fuel manifold/ burner assembly (16) comprises an array of fuel burners (18) which are interconnected by manifold members (19). Each manifold member (19) comprises a sealingly telescoped duct (26) which is retained on adjacent burners (19) by fasteners (33,35). Each of the fasteners (33,35) is provided with a shroud portion (38,40) which extends over the telescoped duct (26). Adjacent shroud portions (38,40) are sealingly telescoped to define shrouds around the telescoped ducts (26). <IMAGE>

Description

SPECIFICATION Gas turbine engine fuel manifold/burner assembly This invention relates to a gas turbine engine fuel manifold/burner assembly.

The combustion equipment of a gas turbine engine conventionally comprises an annular array of burners which project into one or more combustion chambers, each of the burners directing fuel into the combustion chamber or chambers. The burners extend radially outwardly from the casing of the engine and are interconnected by a manifold which supplies the burners with fuel.

There are necessarily joints between the burners and the manifold and these can give rise to fuel leakage problems which in turn provide a fire hazard. There is also a fire hazard in the event of the manifold itself failing and causing a fuel leakage.

One method of reducing the fire hazard is to ensure that the burner/manifold assembly is so positioned that the air flow over it is sufficiently high to prevent ignition of any leaked fuel. This method can, however, be detrimental to the efficiency of the engine. Another method consists of shrouding the manifold with suitable conduits so that in the event of a leak, the leaked fuel passes into the space between the manifold and the conduit. The drawback to this solution is that engine vibration can cause fretting between the manifold and the conduit which in turn can lead to the early failure of the manifold or the conduit. Moreover there can be difficulties in effectively locating the conduits on the manifold and preserving manifold integrity because of the relative circumferential movement which occurs between the burners.

It is an object of the present invention to provide a gas turbine engine fuel manifold in which such drawbacks are substantially avoided.

According to the present invention a gas turbine engine fuel manifold/burner assembly comprises an annular array of fuel burners and a plurality of manifold members which interconnect adjacent fuel burners, each of said manifold members ocmprising a sealinglytelescoped duct memberwhich engages and interconnects adjacent burners, each of said burners having a first passage therein which provides communication between the telescoped duct members which engage it and a second passage which provides communication between said first passage and the fuel outlet of said burner, the ends of each of said telescoped duct members which engage said burners being retained in position thereon by fastener members having shroud portions configured such that adjacent shroud portions cooperate to define sealingly telescoped shrouds around each of said telescoped fuel ducts whereby at least one annular space is defined between each of said telescoped fuel ducts and its surrounding telescoped shroud, said assembly being provided with drain means to drain away any fuel which may in operation have leaked into said annular spaces.

The invention will now be described, byway of example, with reference to the accompanying drawings in which: Figure l is a side view of a gas turbine engine provided with a fuel manifold/burner assembly in accordance with the present invention, Figure 2 is a view on arrow A of Figure 1 of a partially sectioned portion of the fuel manifold/ burner assembly.

With reference to Figure 1, a gas turbine propulsion engine generally indicated at 10 is of conventional construction and comprises, in axial flow series, an air intake 11, a compressor section 12, combustion equipment 13, aturbinesection 14and a propulsion nozzle 15. The gas turbine engine 10 functions in the conventional manner, that is, air drawn in through the air inlet 11 is compressed in the compressor section 12 before being mixed with fuel and the mixture combusted in the combustion equipment 13. The resultant combustion products expand through the turbine 14, (which is drivingly connected to the compressor section 12) before being exhausted to atmosphere through the propulsion nozzle 15.

Fuel is supplied to the air which has been compressed in the compressor section 12 by means of an annularfuel manifold/burner assembly 16 which is in turn supplied with fuel through a supply pipe 17.

The fuel manifold/burner assembly 16 comprises an annular array of fuel burners 18 which are interconnected by a plurality of manifold members 19.

Each fuel burner 18, which can be seen more clearly in Figure 2, comprises a feed arm 20 which projects through the casing of the engine 10 to terminate in a fuel outlet nozzle 21 positioned immediately upstream of the combustion chamber of the combustion equipment 13.

A fuel supply passage 22 extends through the feed arm 20 to interconnect the nozzle 21 with a further fuel supply passage 23 which extends through the portion 24 ofthe burner 20 which is located externally of the casing of the gas turbine engine 10. The external burner portion 24 is provided with crosswise extending pieces 25 which contain the fuel supply passage 23. The cross-wise extending pieces 25 of adjacent burners 18 are interconnected by a manifold member 19 so that in combination the manifold members 19 and the portions of burners 18 which contain the fuel supply passages define an annular manifold around the gas turbine engine 10.

Each manifold member 19 comprises a sealingly telescoped duct 26 which interconnects the fuel supply passages 23 of adjacent burners 20. Each telescoped duct 26 consists of a first pipe 27, one end of which is provided with two partially rounded cross-wise section axially spaced apart flanges 28 and 29 and a second, shorter pipe 30, also provided with two partially rounded cross-section axially spaced apart flanges 31 and 32, one at each end thereof. The internal diameter of the second pipe 30 is substantially the same as the outer diamter of the unflanged end of the first pipe 27 so as to permit the first pipe 27 to slide within the second pipe 30.

Sealing of the sliding joint between the first and second pipes 27 and 30 is provided by a flexible, corrugated tube 48 which encloses part of the first pipe 27 and the ends of which are respectively attached to the first and second pipes 27 and 30. The first pipe 27 is retained in position on the cross-wise extending piece 25 of one of the burners 25 by means of a fastener 33. The fastener 33 is internally threaded to locate on a corresponding externally threaded portion of the cross-wire extending piece 25.

A radially inwardly directed flange 34 on the fastener 33 engages one of the flanges 29 on the pipe 27 so that the other flange 28 thereon is urged into engagement with the cross-wise extending piece 25. The portion of the fastener 33 which separates the internally threaded portion from the inwardly directed flange 34 is radially spaced apart from the pipe 27 so that an annular space 43 is defined between them.

The shorter second pipe 30 is similarly retained in position on the adjacent burner 18 by means of a fastener 35. Thus the fastener 35 is internally threaded to locate on a corresponding externally threaded portion of the cross-wise extending piece 25. A radially inwardly directed flange 36 is provided on the fastener 35 to engage one of the flanges 31 on the pipe 30 so that the other flange 32 thereon is urged into engagement with the cross-wise extending piece 25. As in the case of the previous fastener 33, the portion of the fastener 35 which separates the internally threaded portion from the inwardly directed flange 36 is radially spaced apart from the pipe 30 so that an annular space 44 is defined between them.This arrangement ensures that tightening of the fastener 35 produces compression within the shorter pipe 30 which in turn leads to a radially inwardly directed load being exerted upon the first pipe 27, thereby improving the fit between the pipes 27 and 30.

The fastener 33 is provided with two shroud portions 37 and 38. The first shroud portion 37 extends over a part of the cross-wise extending burner piece 25 and a sealing member 39 is interposed between them. The second shroud portion 38 extends over a portion of the first pipe 27.

The fastener 35 on the adjacent burner 18 is also provided with two shroud portions 39 and 40. The first shroud portion 39 extends over a part of the cross-wise extending burner piece 25 and a sealing member 41 is interposed between them. The second shroud portion 40 extends over a portion of the first pipe 27, and is of a smaller diameter than the second shroud portion 38 of the other fastener 33. The second shroud portion 40 of the fastener 35 locates within the second shroud portion 38 of the fastener 33 so that a telescoped shroud is defined around the first pipe 27. A sealing member 41 provides a seal between the second shroud portions 38 and 40.

It will be seen therefore that the second shroud portions 38 and 40, and the pipe 27 cooperate to define an annular space 42. Thus the telescoped duct 26 is surrounded by three annular spaces 42,43 and 44 into which fuel would pass in the event of a leak developing in the telescoped duct 26 or at its points of engagement with the burners 18.

In order to permit the detection of any leaked fuel within the annular spaces 42,43 and 44, passages 45 and 46 are respectively provided in the flanges 34 and 36 so as to permit the flow of fuel between the spaces 42,43 and 44. Further passages 47 which are in communication with the annular spaces 43 and 44 are provided in the cross-wise extending pieces 25 so that the annular spaces 42,43 and 44 of each of the manifold members 19 are all in communication with each other. A suitable witness drain (not shown) is provided to receive any fuel which has leaked into the annular spaces 42,43 and 44.

The invention therefore provides a high integrity fuel manifold/burner assembly which is capable of containing any fuel leakages from the joints therein.

Moreover since it is provided with fuel ducts and shroud portions which are sealingly telescoped, it permits a limited degree of relative circumferential movement between the burners 18 without the danger of undesirable stresses being generated within the assembly. A further advantage of the assembly of the present invention is the ease with which any individual manifold members 19 may be removed from the assembly in the event of its failure. Thus all that is required is that the fasteners 33 and 35 are unscrewed and the member 19 compressed whereupon it can easily be lifted clear of the assembly.

Claims (4)

1. A gas turbine engine fuel manifold/burner assembly comprising an annular array of fuel burners and a plurality of manifold members which interconnect adjacent fuel burners, each of said manifold members comprising a sealinglytelescoped duct member which engages and interconnects adjacent burners, each of said burners having a first passage therein which provides communication between the telescoped duct members which engage it and a second passage which provides communication between said first passage and the fuel outlet of said burner, the ends of each of said telescoped duct members which engage said burners being retained in position thereon by fastenere members having shroud portions configured such that adjacent shroud portions cooperate to define sealingly telescoped shrouds around each of said telescoped fuel ducts whereby at least one annular space is defined between each of said telescoped fuel ducts and its surrounding telescoped shroud, said assembly being provided with drain means to drain away any fuel which may in operation, have leaked into said anular spaces.

2. A gas turbine engine fuel manifold/burner assembly as claimed in Claim 1 wherein said sealingly telescoped duct member comprises first and second pipes, said second pipe being shorter than said first pipe and having a flange on each end thereof, said first pipe being telescoped within said second pipe, means being provided to exert on axial compressive load upon said second pipe via said flanges to cause in turn said second pipe to exert a radially inwardly directed load upon said first pipe, thereby improving the fit between said first and second pipes.

3. Agasturbineenginefuel manifold/burner assembly as claimed in Claim 2 wherein the seal between said first and second pipes comprises a flexible corrugated tube which encloses a portion of said first pipe and the ends of which are respectively attached to said first and second pipes.

4. A gas turbine engine fuel manifold/burner assembly substantially as hereinbefore described with reference to and as shown in the accompanying drawings.