GB2472572A - Mounting for aerofoil blade using elastomeric bush - Google Patents

Mounting for aerofoil blade using elastomeric bush Download PDF

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Publication number
GB2472572A
GB2472572A GB0913852A GB0913852A GB2472572A GB 2472572 A GB2472572 A GB 2472572A GB 0913852 A GB0913852 A GB 0913852A GB 0913852 A GB0913852 A GB 0913852A GB 2472572 A GB2472572 A GB 2472572A
Authority
GB
United Kingdom
Prior art keywords
blade
mounting
fixing
bush
vane
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB0913852A
Other versions
GB0913852D0 (en
Inventor
Kristofer John Bottome
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Rolls Royce PLC
Original Assignee
Rolls Royce PLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Rolls Royce PLC filed Critical Rolls Royce PLC
Priority to GB0913852A priority Critical patent/GB2472572A/en
Publication of GB0913852D0 publication Critical patent/GB0913852D0/en
Publication of GB2472572A publication Critical patent/GB2472572A/en
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
    • F01D25/16—Arrangement of bearings; Supporting or mounting bearings in casings
    • F01D25/162—Bearing supports
    • F01D25/164—Flexible supports; Vibration damping means associated with the bearing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/12—Blades
    • F01D5/26—Antivibration means not restricted to blade form or construction or to blade-to-blade connections or to the use of particular materials
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/30—Fixing blades to rotors; Blade roots ; Blade spacers
    • F01D5/3023—Fixing blades to rotors; Blade roots ; Blade spacers of radial insertion type, e.g. in individual recesses
    • F01D5/303—Fixing blades to rotors; Blade roots ; Blade spacers of radial insertion type, e.g. in individual recesses in a circumferential slot
    • F01D5/3038—Fixing blades to rotors; Blade roots ; Blade spacers of radial insertion type, e.g. in individual recesses in a circumferential slot the slot having inwardly directed abutment faces on both sides
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
    • F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
    • F02C7/20—Mounting or supporting of plant; Accommodating heat expansion or creep
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02K—JET-PROPULSION PLANTS
    • F02K3/00—Plants including a gas turbine driving a compressor or a ducted fan
    • F02K3/02—Plants including a gas turbine driving a compressor or a ducted fan in which part of the working fluid by-passes the turbine and combustion chamber
    • F02K3/04—Plants including a gas turbine driving a compressor or a ducted fan in which part of the working fluid by-passes the turbine and combustion chamber the plant including ducted fans, i.e. fans with high volume, low pressure outputs, for augmenting the jet thrust, e.g. of double-flow type
    • F02K3/06—Plants including a gas turbine driving a compressor or a ducted fan in which part of the working fluid by-passes the turbine and combustion chamber the plant including ducted fans, i.e. fans with high volume, low pressure outputs, for augmenting the jet thrust, e.g. of double-flow type with front fan
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2300/00—Materials; Properties thereof
    • F05D2300/40—Organic materials
    • F05D2300/43—Synthetic polymers, e.g. plastics; Rubber
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2300/00—Materials; Properties thereof
    • F05D2300/50—Intrinsic material properties or characteristics
    • F05D2300/501—Elasticity
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Abstract

An aerofoil blade (100) mounted on a blade mount (120) where a portion of the blade (100) includes a recess (118) within which is located a fixing assembly. The assembly includes an threaded inset (122) and an elastomeric bush (124), and may also include an outer bush (126), to isolate the blade from vibration in the blade mount. The mount also includes a fixing element (128) which may be a nut and bolt.

Description

IMPROVEMENTS IN MOUNTING AEROFOIL BLADES
The present invention relates to the mounting of aerofoil blades, in particular the mounting of vanes used in gas turbine engines.
Within stator assemblies in gas turbine engines, a number of vanes are disposed within the airflow in order to direct the airflow appropriately through the engine.
Figure 1 shows in cut-away view a part of a gas turbine engine of an aircraft. A fan 10 directs air rearwardly, which air is then separated into core flow 14, that passes into the engine for compression, and bypass flow 16 that bypasses the core and is forced out at the rear of the engine, contributing to thrust. In the bypass flow a plurality of outlet guide vanes (OGV5) 18 direct the bypass air and also provide a structural mounting for the engine within the nascelle. The OGVs are mounted at one end on an inner mounting ring and at the other end on an outer mounting ring.
Figure 2 shows in more detail a part of the OGV and its mounting structure. The OGV is shown at 18 whilst the inner ring on which it is mounted is represented at 20.
On conventional aero engines with metallic vanes the inner ring 20 is a forged ring with machined stubs 22.
Metallic vanes are then welded to the stubs to form the fan OGV assembly which is basically a ring of vanes. The stub is made as small as possible so that the forging size s minimised to save cost.
However, in the interests of saving weight and also reducing costs, aero engineers are increasingly looking to composite materials (otherwise known as vcomposites) for the manufacture of primary components of aero engines.
Composite materials are those which are made from two or more constituent materials, typically comprising reinforcing fibres in a resin matrix. Mounting a composite OGV into a metallic component such as an inner ring or outer ring, introduces problems including those due to thermal growth of components during use, and also the necessary isolation of the vane from vibration and stress.
Previously considered composite vane mountings use a silicone rubber-type compound in which the vane is "potted" within the metallic stub. This can be effective but requires bulky attachment features and additional fairing components in order to smooth the aerodynamic profile.
This adds cost and complexity to the design and can also create further problems with the increased depth required for mounting due to the need to provide flanges for bolting on the vane. Weight is also added which is additionally undesirable in any aero engine.
Embodiments of the present invention aim to address at least some of the aforementioned problems with the prior art.
The present invention is defined in the attached independent claim to which reference should now be made.
Further, preferred features may be found in the sub-claims appended thereto.
According to the present invention there is provided a mounting system for mounting an aerofoil blades on a blade mount, the mounting system comprising a portion of the blade having a recess within which is located a fixing assembly, and a fixing element arrangement to engage the fixing assembly for fixing the blade to the blade mount, wherein the fixing assembly comprises an elastomeric bush for isolating the blade from vibration in the blade mount.
The fixing assembly preferably further includes an outer bush, the elastomeric bush being arranged in use to be located within the outer bush.
Preferably the fixing assembly further comprises an insert for receiving the fixing element, the insert being arranged in use to be located within, and coaxial with, the elastomeric bush.
The insert may be arranged to engage the fixing element threadedly.
The fixing element may comprise a bolt.
In a preferred arrangement the system further comprises a layer of sealant material arranging use to seal gaps between the blade and the blade mount, and at the ends of the fixing element.
The invention also includes an aerofoil blade for mounting on a blade mount, wherein a portion of the blade has a recess within which is located a fixing assembly, and a fixing element arrangement to engage the fixing assembly for fixing the blade to the blade mount, wherein the fixing assembly comprises an elastomeric bush for isolating the blade from vibration in the blade mount. The fixing assembly and/or fixing element may be in accordance with
any statement herein.
Preferred embodiments of the present invention will now be described by way of example only, with reference to the accompanying diagrammatic drawings in which: Figure 1 is a cut-away view of a part of a gas turbine engine; Figure 2 is an enlarged view of part of Figure 1 showing an inner end mounting of an outlet guide vane (OGV); Figure 3 is a cross section view of an outer end of a vane mounting in accordance with an embodiment of the present invention; Figure 4 is a cross-sectional view of an inner end of a vane mounting in accordance with an embodiment of the present invention; and Figure 5 is an end view of an outer end of a vane.
Turning to Figure 3 this shows generally at 100 an OGV of composite material having a main body 102 and outer end 104. The outer end 104 is secured by a fixing element, in the form of a bolt 106, to a mount ring 108, which itself is mountable in a conventional manner in a duct casing (not shown) of an aero engine. A metallic threaded insert 110 threadedly engages the bolt 106. The threaded insert 110 is located within a tubular elastomeric rubber bush 112 which itself is located in this embodiment within an outer bush 114 of metallic or composite material. The fixing assembly of threaded insert 110, elastomeric element 112 and outer bush 114 is located within a recess or cavity 104a which is machined or otherwise formed in the end of the vane 100. The threaded insert 110 is attached to the elastomeric rubber compound 112 which sits within the other bush 114 to form a bearing-type bushing. This can be a press fit or else can be bonded into the composite vane.
The structure shown in Figure 3 allows isolation of the vane from vibration and stress.
Turning to Figure 4, this shows the inner end 116 of the vane 100 in cross section. The composite OGV 100 is mounted in a rebate or recess 118 in a ring 120 having a vane mount in the form of a stub 120a.
The OGV 100 has a threaded inner element 122 of metallic or composite material which extends through the OGV in a through-thickness direction. The threaded inner element 122 is located within a tubular elastomeric bush 124 which itself is located within a further outer bush 126 of metallic, composite or plastic material. The fixing assembly of threaded element or insert 122, elastomeric bush 124 and outer bush 126 is located within a machined cavity 116a of the end 116 of the vane 100. A fixing element in the form of a countersunk bolt 128 extends through the stub 120a and threadedly engages the inner element 122. A countersunk nut 130 also threadedly engages the free end of the bolt 128. A elastomeric sealant 132, such as polysulphide is used to fill any gaps between the vane and the stub, and smooth over the nut 130 and head of the bolt 128. A plain inner element instead of a threaded inner element 122 can be used, but in each case this sits within a rubber/elastomeric material 124 which itself is held in a metallic or composite bush 126. Again the (outer) metallic or composite bush 126 is a press or bonded fit into the composite vane.
The countersunk bolts can be Mortorq (RTM), ACR (RTM) Phillips (RTM) or internal hexagon head type screws. Once fully assembled all of the gaps are filled with the polysuiphide or similar rubbery material to seal the gaps and to provide a smooth air-washed surface. This includes the heads of the bolts and the nuts.
In these embodiments the vane is a composite material with a matrix of PEEK, PPS, epoxy BMI or other suitable matrix. Reinforcement is provided by glass or carbon-fibre which can be unidirectional, woven, braided or else random.
Other suitable materials can be employed as the core of the vane, which can be compression moulded or, for lower cost, injection moulded.
Figure 5 shows an outer end of the vane 100 in end view. Two mountings A and B are provided at the outer end of the vane 100. Each comprises a mount ring 108, bolt 106, threaded insert 110 and elastomeric element 112 and outer bush 114.
The mounting arrangements described above in relation to the preferred embodiments provide a number of advantages. Firstly above the inner and outer mounts the system has a built in damping from vibration. Also loading on the composite vanes is reduced as they can move slightly without causing large stress to built up.
Furthermore, the system allows vanes to be readily removed and replaced. The system is also relatively compact and easily fits within current space limitations without projecting inwards. No inner fairing is required and thereby no extra component or weight fixings are necessary and the amount of complex machining, and the number of parts, is less than that when compared with previously considered approaches which involve potting vanes.
In addition, two dissimilar vane and ring materials can be used without incurring problems with thermal growth, since any such growth can be accommodated in the elastomeric elements within the mountings.
Finally, the bushes can be easily replaced and the vane can be refurbished without necessarily disposing of components. The composite vane is inexpensive to manufacture, with only mounting joints requiring machining rather than any machining of the vane surface as a whole.
Whereas the above-described embodiments are concerned with OGV5 of a gas turbine engine, the system described herein could equally be applied to other types of vane, or to fan blades or other components within an engine which require damping, such as for example core fairings.

Claims (8)

  1. Claims: 1. A mounting system for mounting an aerofoil blade (100) on a blade mount (120), the mounting system comprising a portion of the blade (100) having a recess (118) within which is located a fixing assembly (122, 124, 126), and a fixing element (128) arrangement to engage the fixing assembly for fixing the blade to the blade mount, wherein the fixing assembly comprises an elastomeric bush (124) for isolating the blade from vibration in the blade mount.
  2. 2. A mounting system according to claim 1 wherein the fixing assembly further includes an outer bush (126), the elastomeric bush (124) being arranged in use to be located within the outer bush.
  3. 3. A mounting system according to claim 1 or claim 2 wherein the fixing assembly further comprises an insert (122) for receiving the fixing element, the insert being arranged in use to be located within, and coaxial with, the elastomeric bush.
  4. 4. A mounting system according to claim 3 wherein the insert is arranged to engage the fixing element threadedly.
  5. 5. A mounting system according to any of claims 1-4 wherein the fixing element comprises a bolt.
  6. 6. A mounting system according to any of claims 1-5 further comprising a layer of sealant material (132) arranging use to seal gaps between the blade and the blade mount, and at the ends of the fixing element.
  7. 7. An aerofoil blade for mounting on a blade mount, wherein a portion of the blade has recess (118) within which is located a fixing assembly (122, 124, 126), and a fixing element (128) arrangement to engage the fixing assembly for fixing the blade to the blade mount, wherein the fixing assembly comprises an elastomeric bush (124) for isolating the blade from vibration in the blade mount.
  8. 8. A mounting system substantially as described in this specification, with reference to and as shown in Figures 3, 4 and 5 of the accompanying drawings.
GB0913852A 2009-08-10 2009-08-10 Mounting for aerofoil blade using elastomeric bush Withdrawn GB2472572A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB0913852A GB2472572A (en) 2009-08-10 2009-08-10 Mounting for aerofoil blade using elastomeric bush

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0913852A GB2472572A (en) 2009-08-10 2009-08-10 Mounting for aerofoil blade using elastomeric bush

Publications (2)

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GB0913852D0 GB0913852D0 (en) 2009-09-16
GB2472572A true GB2472572A (en) 2011-02-16

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20230167745A1 (en) * 2021-11-26 2023-06-01 Ge Avio S.R.L Gas turbine engine including a rotating blade assembly

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US819106A (en) * 1905-08-09 1906-05-01 Wilkinson Turbine Company Turbine bucket-wheel.
GB2027496A (en) * 1978-08-09 1980-02-20 Mtu Muenchen Gmbh Turbine blade
GB2048394A (en) * 1979-04-14 1980-12-10 Mtu Muenchen Gmbh Blade mounting arrangement for a ring of blades on a turbomachine rotor
GB2050528A (en) * 1979-04-14 1981-01-07 Mtu Muenchen Gmbh Axial flow turbomachine rotor
JPS57122102A (en) * 1981-01-21 1982-07-29 Hitachi Ltd Attaching and fixing structure of rotor blade
US4541778A (en) * 1984-05-18 1985-09-17 The United States Of America As Represented By The Secretary Of The Navy Pin rooted blade biaxial air seal
EP0515006A1 (en) * 1991-05-21 1992-11-25 Siemens Aktiengesellschaft Coupling device for a shank on the periphery of a rotating body
US20050106019A1 (en) * 2003-09-19 2005-05-19 Snecma Moteurs Turbine wheel for turbomachine and the assembly method for such a wheel

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US819106A (en) * 1905-08-09 1906-05-01 Wilkinson Turbine Company Turbine bucket-wheel.
GB2027496A (en) * 1978-08-09 1980-02-20 Mtu Muenchen Gmbh Turbine blade
GB2048394A (en) * 1979-04-14 1980-12-10 Mtu Muenchen Gmbh Blade mounting arrangement for a ring of blades on a turbomachine rotor
GB2050528A (en) * 1979-04-14 1981-01-07 Mtu Muenchen Gmbh Axial flow turbomachine rotor
JPS57122102A (en) * 1981-01-21 1982-07-29 Hitachi Ltd Attaching and fixing structure of rotor blade
US4541778A (en) * 1984-05-18 1985-09-17 The United States Of America As Represented By The Secretary Of The Navy Pin rooted blade biaxial air seal
EP0515006A1 (en) * 1991-05-21 1992-11-25 Siemens Aktiengesellschaft Coupling device for a shank on the periphery of a rotating body
US20050106019A1 (en) * 2003-09-19 2005-05-19 Snecma Moteurs Turbine wheel for turbomachine and the assembly method for such a wheel

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20230167745A1 (en) * 2021-11-26 2023-06-01 Ge Avio S.R.L Gas turbine engine including a rotating blade assembly

Also Published As

Publication number Publication date
GB0913852D0 (en) 2009-09-16

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