GB2121115A

GB2121115A - Aerofoil vane assembly

Info

Publication number: GB2121115A
Application number: GB08216223A
Authority: GB
Inventors: William Thomas Monaghan
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 1982-06-03
Filing date: 1982-06-03
Publication date: 1983-12-14

Abstract

The assembly consists of radially inner and outer members 23 and 24 having tensioned radially extending spokes 25 therebetween; the aerofoil vanes each being formed in two parts 26 and 27 (Fig. 5 not shown) each pair of which are located and secured about pairs of spokes 25. <IMAGE>

Description

SPECIFICATION Aerofoil vane assembly This invention relates to an aerofoil vane assembly and more particularly to such an assembly suitable for use as an outlet guide vane assembly arranged downstream of a gas turbine engine fan.

Such vane assemblies serve both to modify the flow of pressurised air exiting from the fan, and serve to support the fan duct casing relative to the core engine and also form a part of the engine structure. Due to the relatively high loading to which the assembly is subjected it must be of a relatively robust nature, and usually consists of a sheet metal fabrication which is filled with plastic foam material. Consequently the structure is relatively heavy.

An object of the present invention is to manufacture a vane assembly which substantially overcomes the aforementioned problems.

According to the present invention an aerofoil vane assembly comprises a radially innermost annular member, and a radially outermost annular member having a plurality of radially extending tensioned spokes arranged therebetween, a plurality of radially extending vanes being arranged between the radially inner and radially outer members, each vane being secured to at least one of the tensioned spokes.

Preferably the tensioned spokes are arranged in pairs, each pair serving to support one vane.

Alternatively each vane may be supported by one spoke extending through the centre of pressure of the vane.

Furthermore the tensioned spokes may each consist of separate spokes, or alternatively a plurality of spokes may be formed from a continuous length of spoke material.

Preferably the spokes may consist of high tensile metallic wires.

Alternatively the spokes may consist of a plurality of filaments of carbon or Kevlar fibres.

The spokes may be secured to the radially inner and outermost annular members by means of screw threads or alternatively by bonding.

Each aerofoil vane consists of two portions which are arranged around at least one tensioned spoke and are subsequently secured together.

Preferably the aerofoil vane portions are manufactured from carbon fibre reinforced resin.

For better understanding thereof an embodiment of the invention 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 of a portion of a ducted fan type gas turbine engine incorporating an embodiment of the present invention.

Figure 2 shows a pictorial view of a portion of the embodiment shown diagrammatically at Figure 1.

Figures 3 and 4 show alternative examples of the tensioned spokes.

Figure 5 shows a cross-sectional view through one aerofoil vane taken on line 5-5 at Figure 3.

Figure 6 shows a pictorial view in greater detail of a portion of one of the parts which make up the aerofoil vane.

Figures 7, 8, 9 and 10 each show alternative arrangements of the tensioned spokes.

Referring to the drawing a ducted fan type gas turbine engine shown generally at 10 comprises in flow series a fan 12, an intermediate compressor 13, a high pressure compressor 14, combustion equipment 15, a high pressure turbine 16, an intermediate pressure turbine 1 7 and low pressure turbine 18, the engine terminating in an exhaust nozzle 1 9. The fan 12 is located within a fan duct 20 which is provided with an outlet guide vane assembly shown generally at 21 made in accordance with an embodiment of the present invention.

Figure 2 shows a pictorial view of a portion of the vane assembly shown diagrammatically at Figure 1, and comprises a radially outermost annular member 23 and radially inner annular member 24, having a plurality of radially extending spokes 25 extending between the two members.

Each of the annular members 23 and 24 may be manufactured from either metal or alternatively a composite material consisting of fibre-reinforced resin; and either member may either form an integral part of the engine structure such as for example the outer member 23 may form a portion of the fan duct 20. Alternatively each of the member 23 and 24 may consist of separate rings which are subsequently secured to the main engine structure.

The spokes 25 which extend between the two annular member 23 and 24 are tensioned such that the two members 23 and 24 remain concentric with respect of each other. The spokes 25 may consist of either a suitable high tensile metal, or alternatively may be manufactured from a multi-filament tow of carbon fibre or Kevlar fibre. A method of securing each type of spoke 25 with respect of the annular members 23 and 24 is iliustrated at Figure 3. For the fibre type spoke the fastening consists of a collet type fixing within which the fibre is secured with a conical wedge and subsequently bonded therein. In the case of a metal spoke this may be conveniently secured by means of nuts co-operating with screw threads.It is not however intended that this invention is restricted such types of spoke fastenings however as there are many relatively simple methods available for such applications well known to those skilled in the art.

Each spoke 25 may consist of a single straight portion extending between the two annular members 23 and 24. Alternatively more than one spoke may be formed from a continuous length of spoke material. Figure 4 of the drawings shows two spokes formed from one continuous portion of spoke material, however more spokes could be so produced if it is considered so desirable.

The spokes 25 may merely extend directly between the annular member 23 and 24, or alternatively may be arranged in a variety of ways as illustrated in Figures 7 to 10 inclusive. Choice of spoke arrangement will depend on the particular application of the completed vane assembly. The spokes serve to carry the aerofoil shape portion 26 and 27 which make up each individual vane shown generally at 28 and disposition of the spokes will depend to an extent on the particular shapes and angles required for the vanes 28.

Each aerofoil shape portion 26 and 27 may be manufactured from either sheet metal or alternatively composite material which may consist of fibre reinforced resin, and for ease of manufacture it is considered that the composite material may be injection moulded. The portions 26 and 27 are each provided with abutment portions 29 a b c etc. which are bonded together when the two respective aerofoil sections 26 and 27 are located about the spokes 25. Thereafter the two portions 26 and 27 may be provided with additional securing means comprising rivets which pass between them. The aerofoil portions 26 and 27 may be secured around one single spoke, the fibre being arranged to extend through the centre of pressure of the complete vane.

It will be appreciated that by manufacturing a complete assembly of gas turbine engine outlet guide vanes in accordance with an embodiment of the-present invention with result in a relatively strong but light-weight structure. All the main stresses and loading will be carried by the tensioned spokes, and the gas or air pressure loading will be carried by the portions 26 and 27 forming the aerofoil section vanes.

Although this invention has been particularly described with respect of an outlet guide vane assembly for a gas turbine engine it is not envisaged that the invention should be restricted to such an application. It will be readily appreciated that such a construction could be used for other vaned structures used in gas turbine engines.

Claims

1. An aerofoil vane assembly comprising a radially innermost annular member, and a radially outermost annular member having a plurality of radially extending tensioned spokes arranged therebetween, a plurality of radially extending vanes being arranged between the radially inner and radially outer members, each vane being secured to at least one of the tensioned spokes.

2. An aerofoil vane assembly as claimed in claim 1 in which the tensioned spokes are arranged in pairs, each pair serving to support one vane.

3. An aerofoil vane assembly as claimed in claim 1 in which each vane is supported by one spoke extending through the centre of pressure of the vane.

4. An aerofoil vane assembly as claimed in claim 1 in which the tensioned spokes may each consist of separate spokes, or alternatively a plurality of spokes may be formed from a continuous length of spoke material.

5. An aerofoil vane assembly as claimed in claim 1 in which the spokes consist of high tensile metallic wires.

6. An aerofoil vane assembly as claimed in claim 1 in which the spokes consist of a plurality of filaments of carbon or Kevlar fibres.

7. An aerofoil blade assembly as claimed in claim 1 in which the spokes are secured to the radially inner and outermost annular members by means of screw threads or alternatively by bonding.

8. An aerofoil vane assembly as claimed in claim 1 in which each aerofoil vane consists of two portions which are arranged around at least one tensioned spoke and are subsequently secured together.

9. An aerofoil vane assembly as claimed in claims 1 to 8 in which the aerofoil vane portions are manufactured from carbon fibre reinforced resin.

10. An aerofoil vane assembly as claimed in any preceding claim for use as a gas turbine engine outlet guide vane assembly.

11. An aerofoil vane assembly as claimed in any preceding claim substantially as hereinbefore described by way of example only and with reference to the accompanying drawings.