Sealing attachment for a gas turbine engine

A gas turbine including: a wall component having a gas-facing surface bounding the main gas path; a male-female sealing attachment having a male or female part in which: the male-part includes a component having a main-body, which has first and second arms extending in a common direction and either side of a mid-line plane, wherein the arms are convexly curved in relation to the mid-line plane so as to provide a contact-portion along the length of the arm, the contact-portion being furthest from the mid-line plane; and, the female-part includes a component having a main-body, which includes first and second arms extending therefrom in a common direction and either side of a mid-line plane, wherein the first and second arms are concavely curved in relation to the mid-line plane so as to provide a contact-portion along the length of the arm, the contact portion being closest to the mid-line plane.

TECHNICAL FIELD OF INVENTION

This invention relates to a sealing attachment for a gas turbine engine. In particular, the invention relates to a sealing attachment for radially attachment of a gas turbine wall to an engine casing. The preferable application of the invention is in a turbine stage of a gas turbine engine, however other areas of application are feasible and envisaged.

BACKGROUND OF INVENTION

FIG. 1shows a ducted fan gas turbine engine10comprising in axial flow series: an air intake12, a propulsive fan14having a plurality of fan blades16, an intermediate pressure compressor18, a high-pressure compressor20, a combustor22, a high-pressure turbine24, an intermediate pressure turbine26, a low-pressure turbine28and a core exhaust nozzle30. A nacelle32generally surrounds the engine10and defines the intake12, a bypass duct34and a bypass exhaust nozzle36. The engine has a principal axis of rotation31.

Air entering the intake12is accelerated by the fan14to produce a bypass flow and a core flow. The bypass flow travels down the bypass duct34and exits the bypass exhaust nozzle36to provide the majority of the propulsive thrust produced by the engine10. The core flow enters in axial flow series the intermediate pressure compressor18, high pressure compressor20and the combustor22, where fuel is added to the compressed air and the mixture burnt. The hot combustion products expand through and drive the high, intermediate and low-pressure turbines24,26,28before being exhausted through the nozzle30to provide additional propulsive thrust. The high, intermediate and low-pressure turbines24,26,28respectively drive the high and intermediate pressure compressors20,18and the fan14by concentric interconnecting shafts38,40,42.

The turbines and compressors are constructed from axial arranged pairs of nozzle guide vanes and blades which are relatively rotatable. The vanes and blades each comprise aerofoil portions and platforms located at opposing ends of the aerofoils which define the main gas path. Thus, a nozzle guide vane may have radially inner and outer platforms with the aerofoil extending therebetween, and the blades may have inner platforms which are rotatably separated from the nozzle guide vane platforms. The tips of the blades may be so-called shrouded blades having integral shrouds which circumferentially combine to provide an annular wall which rotates with the blades. Such are arrangements and others are well known in the art.

A result of having relative rotation between the blades and vanes means that the main gas path wall is necessarily axially segmented. Axial segmentation of the gas path wall also aids construction and assembly of the engines amongst other advantages.

FIG. 2shows a partial streamwise section of an intermediate pressure turbine210as highlighted inFIG. 1. The turbine includes a blade212and downstream vane214which forms part of the following vane-blade stage. The turbine blade212and vane214have aerofoil portions located within the main gas path216. The blade212is a shrouded blade meaning that the tip of the blade terminates with a shroud platform218which circumferentially engages with adjacent shroud platforms to provide a full annulus. A seal segment220is positioned radially outboard of the shroud platform218.

The downstream vane214includes an outer platform222which is integrally formed with the aerofoil portion. Both the seal segment220and outer vane platform222are held in a substantially stationary relation to the engine casing224. The seal segment220and outer platform222are separate components which are axially separate but attached to one another to provide a substantially continuous gas path wall.

The seal segment220and outer platform222are attached to one another and to the engine casing224. The attachments used can be any suitable type but are typically male and female connectors in the form of hook and grooves or so-called birdsmouth couplings226. The birdsmouth couplings226include corresponding hook and groove formations on each of the components which engage axially with each other to provide an attachment therebetween. The birdsmouth couplings226principally provide radial restraint to the components with axial restraint provided by other means. It will be appreciated that hooks and grooves extend circumferentially around the seal shroud platform to the extent required to provide the radial restraint.

A problem with providing birdsmouth coupling226is that they have a tendency to leak during the inevitable relative movement between the axially adjacent parts. To combat this, the birdsmouth attachments226are often accompanied by one or more seals. Such a seal is shown inFIG. 2and is in the form of a baffle seal228.

The present invention seeks to provide an improved seal arrangement.

STATEMENTS OF INVENTION

The present invention provides male and female sealing attachments according to the appended claims.

Described below is a wall component for a gas turbine engine, the wall component comprising: a gas facing surface which bounds the main gas path; a male part of a male-female sealing attachment which radially locates a component within the gas turbine engine, the male part comprising: a main body having first and second arms extending therefrom in a common direction and either side of a mid-line plane, wherein either or both of the first and second arms are convexly curved in relation to the mid-line plane so as to provide a contact portion along the length of the arm, the contact portion being furthest from the mid-line plane.

The male-female sealing attachment may be a hook and groove attachment in which the hook and groove extend longitudinally in a circumferential direction. The male part may be an integral part of the wall component.

A male part of a male-female sealing attachment which radially locates a component within a gas turbine engine may comprise: a main body having first and second arms extending therefrom in a common direction and either side of a mid-line plane, wherein either or both of the first and second arms are convexly curved in relation to the mid-line plane so as to provide a contact portion along the length of the arm, the contact portion being furthest from the mid-line plane.

The first and second arms may be symmetrically arranged about the mid-line plane. The first and second arms may be coterminous at the distal ends thereof. The distal ends of the first and second arms may be connected via an end cap. The end cap may be convexly curved in relation to the main body.

The lateral thickness of the arms may be in the range of between 0.3 mm to 1.5 mm. The exterior span of the unengaged arms may be in the range of between 2.5 mm and 8 mm.

A female part of a male-female mechanical engagement for radially locating a component within a gas turbine engine may comprise: a main body having first and second arms extending therefrom in a common direction and either side of a mid-line plane, wherein either or both of the first and second arms are concavely curved in relation to the mid-line plane so as to provide a contact portion along the length of the arm, the contact portion being closest to the mid-line plane.

The first and second arms may be symmetrically arranged about the mid-line plane. The first and second arms may be cantilevered from the main body.

The thickness of the arms may be in the range: 0.3 mm to 1.5 mm.

A gas turbine may comprise: a wall component having a gas facing surface which bounds the main gas path; a male-female sealing attachment having either or both of a male part or female part in which: the male part includes a component having a main body, the main body having first and second arms extending therefrom in a common direction and either side of a mid-line plane, wherein either or both of the first and second arms are convexly curved in relation to the mid-line plane so as to provide a contact portion along the length of the arm, the contact portion being furthest from the mid-line plane; and, the female part includes a component having a main body, the main body having first and second arms extending therefrom in a common direction and either side of a mid-line plane, wherein either or both of the first and second arms are concavely curved in relation to the mid-line plane so as to provide a contact portion along the length of the arm, the contact portion being closest to the mid-line plane.

The male and female parts may be sealably engaged.

The wall component may be located in a turbine section of the gas turbine engine.

A male-female sealing attachment for radially locating a component within a gas turbine engine may comprise: a male part and a female part, either or both of the male and female parts having first and second arms extending from a main body on either side of an imaginary mid-line plane, wherein either or both of the first and second arms are resiliently deformable and curved to provide a contact portion which compressibly engages with an opposing corresponding surface of the other of the male or female part.

Within the scope of this application it is expressly envisaged that the various aspects, embodiments, examples and alternatives, and in particular the individual features thereof, set out in the preceding paragraphs, in the claims and/or in the following description and drawings, may be taken independently or in any combination. For example features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.

DETAILED DESCRIPTION OF INVENTION

FIG. 3shows a male part310of a male-female seal which radially locates a component within a gas turbine engine. The male part310includes a portion of a component having a body312which is either directly or indirectly attached to a wall which bounds the main gas path of the gas turbine engine. The component can be part of a turbine stage and include any one or more of: a nozzle guide vane, blade platform, seal segment, carrier or an engine casing.

The main body312has first314and second316arms extending therefrom in a common direction. The arms314,316are elongate having a longitudinal axis and proximal and distal ends relative to the main body312. The arms314,316are arranged either side of a mid-line plane318which sits between the arms314,316and extends away from the main body312. In the example shown inFIG. 3, the arms314,316are symmetrically arranged in relation to the mid-line plane318, however, although preferable, this may not be the case and the arms314,316may have different forms depending on the sealing requirements.

The arms314,316are curved so as to be convex such that a contact portion320is provided along the length of the arm320, the contact portion320being furthest from the mid-line plane318. The contact portion320is arranged to sealably contact against a corresponding portion of a female part of the male-female seal. The contact portion320shown is provided at an approximate mid-point along the length of the arms314,316, but this need not be so and a contact portion may be provided more distally or proximally as required.

The arms314,316extend a similar distance from the main body312and as such are coterminous. The distal ends of the arms314,316are connected by a lateral (with respect to the longitudinal axis of the arms) plate or end cap322. The end cap322includes an optional convex curvature which is similar to that of the arms314,316. The convex curvature provides an end contact portion324on the end face of the male part which sealably abuts a corresponding surface of the female part.

The contacting portions320of the first314and second316arms provide the widest lateral span of the male part and are separated by a first lateral distance L1. The end cap is separated from the main body surface by a first axial distance AL1.

The combination of the arms314,316, end cap322and main body312surface define an enclosed compressible cavity326. The arms314,316have a lateral thickness which provides them with a flexural rigidity so as to be resiliently deformable. Thus, when received within a female part of the seal, the arms314,316, and end cap322when present, can deflect so as to flatten and provide a larger contacting surface. The resulting sealing surfaces provided by the resilient deformation of the arms and contacting portions also allow for some relative radial and axial movement between the female and male parts whilst maintaining the sealing contact therebetween.

As shown inFIG. 5, the male part310of the seal is slidingly received within the corresponding female part410. In the example shown inFIG. 4, the female part410is shown as part of a generic structure. Thus, there is female part main body412having an elongate groove414in a surface thereof. The groove414includes side walls416and a base418. The side walls416are straight and separated by a uniform distance along the length thereof. The separation of the side walls416is a second distance L2which is less than the first distance L1provided by the separation between the contacting portions of the male component. Thus, when the male part310is received within the female part410, the male contacting portions engage with the entrance to the female part and laterally compress the male part310. Sliding the male part310home creates a sealing abutment between the corresponding male and female surfaces.

The male part310is inserted until the end cap322contacts the end face of the female part to create a sealing contact therebetween. In other examples, the end face may not contact on assembly but only in service under expected axial movements. Alternatively, the clearance between the end surface322and wall418may be such that there is no contact under normal operating conditions.

An alternative female part610is shown inFIG. 6. Here there is shown a female part610of a male-female sealing attachment which radially locates a component within a gas turbine engine. The female part610includes a portion of a component having a main body612which is either directly or indirectly attached to a wall which bounds the main gas path of the gas turbine engine. The main body612has first614and second616arms extending therefrom in a common direction. The arms614,616are elongate having a longitudinal axis and proximal and distal ends relative to the main body612. The arms614,616are arranged either side of a mid-line plane618which sits between the arms614,616and extends away from the main body612. In the example shown inFIG. 6, the arms614,616are symmetrically arranged in relation to the mid-line plane618, however, although preferable, this may not be the case and the arms may have different forms depending on the sealing requirements.

The arms614,616provide side walls for receiving and sealably engaging with a male part which is appropriately sized. A base is provided by the main body612. The arms614,616are curved so as to be concave such that a contact portion620is provided along the length of the each respective arm, the contact portion620being closest to the mid-line plane618and defining a minimum separation between the arms614,616. The contact portion620is arranged to sealably contact a corresponding portion of a male counterpart. The contact portion620shown is provided at an approximate mid-point along the length of the arms, but this need not be so and the contact portion620may be provided more distally or proximally as required.

The corresponding male part may be that shown inFIG. 3, or can be any suitable male component. For example, the male part may have an elongate construction with uniformly separated straight walls.

FIG. 7shows a streamwise partial section of a gas turbine engine similar to the one shown inFIG. 2. However, in the representation ofFIG. 7, the conventional birdsmouth attachments have been replaced with sealing attachments described above. Thus, there is a nozzle guide vane platform and seal segment being radially supported and located by combinations of the male and female parts ofFIGS. 3, 4 and 6and conventional counterparts. It will be appreciated that the combination of the male and female parts will be selected by according to the sealing and supporting requirements. Thus, the sealing element may include curved arms on either or both of the male or female parts. Further, the curved arms may have different geometries to each other and different from the ones described above. For example, the curvature of the female or male arms may be exclusively or a combination of concave or convex curvatures. The curvature may be defined by a single or multiple radii. One or more the arms in a male-female sealing attachment may be straight.

The components which are held in place with the hook and groove formations may provide a full annulus around the engine and main gas path. Such components may individually provide circumferential segments of the annulus. The circumferential segments may have circumferential end edges. The male and female connections of the examples described above may extend fully between the circumferential end edges.

The lateral thickness of the arms in the male and female parts may be in the range of between 0.3 mm to 1.5 mm. The maximum exterior span L1of the unengaged arms may be in the range of between 2.5 mm and 8 mm. The maximum interior span L2of the female part side walls416may be in the range of between 2 mm and 8 mm. The maximum interior span L3of the resiliently deformable arms may be in the range of between 1.5 mm to 8 mm.

The male and female parts can be made using any suitable manufacturing method as known in the art. Additive layer manufacturing techniques such as direct laser deposition are particularly suited to creating the required convex and concave features in a cost effective manner.

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