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GB2201731A - Fan casing and fan blade loading/unloading - Google Patents
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GB2201731A - Fan casing and fan blade loading/unloading - Google Patents

Fan casing and fan blade loading/unloading Download PDF

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Publication number
GB2201731A
GB2201731A GB08801047A GB8801047A GB2201731A GB 2201731 A GB2201731 A GB 2201731A GB 08801047 A GB08801047 A GB 08801047A GB 8801047 A GB8801047 A GB 8801047A GB 2201731 A GB2201731 A GB 2201731A
Authority
GB
United Kingdom
Prior art keywords
fan
slot
casing
blades
bearing
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.)
Granted
Application number
GB08801047A
Other versions
GB8801047D0 (en
GB2201731B (en
Inventor
Derick Alfred Perry
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
Publication of GB8801047D0 publication Critical patent/GB8801047D0/en
Publication of GB2201731A publication Critical patent/GB2201731A/en
Application granted granted Critical
Publication of GB2201731B publication Critical patent/GB2201731B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01DNON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D11/00Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/08Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01DNON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D5/00Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/30Fixing blades to rotors; Blade roots ; Blade spacers
    • F01D5/3023Fixing blades to rotors; Blade roots ; Blade spacers of radial insertion type, e.g. in individual recesses
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01DNON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D7/00Rotors with blades adjustable in operation; Control thereof
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05DINDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2260/00Function
    • F05D2260/70Adjusting of angle of incidence or attack of rotating blades
    • F05D2260/74Adjusting of angle of incidence or attack of rotating blades by turning around an axis perpendicular the rotor centre line
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05DINDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2260/00Function
    • F05D2260/70Adjusting of angle of incidence or attack of rotating blades
    • F05D2260/76Adjusting of angle of incidence or attack of rotating blades the adjusting mechanism using auxiliary power sources
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05DINDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2260/00Function
    • F05D2260/70Adjusting of angle of incidence or attack of rotating blades
    • F05D2260/79Bearing, support or actuation arrangements therefor
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00Aeronautics or air transport
    • Y02T50/60Efficient propulsion technologies, e.g. for aircraft

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Description

1 2 20 l 731 1 FAN CASING AND FAN BLADE LOADING/UNLOADING The present
invention relates to fan casings and fan blades of turbofan gas turbine engines and is particularly -concerned with an arrangement for loading or unloading of the fan blades from the fan rotor.
The fan blades of turbofan gas turbine engines are loaded onto or unloaded from the fan rotor only when the fan casing has been moved, or removed at least partially, so to allow access to the fan blades and fan rotor.
This necessitates the removal of the complete or whole turbofan engine from an associated aircraft should it be necessary to replace a damaged fan blade.
The present invention seeks to provide a fan casing and fan blade load inglunload ing arrangement in which the fan blades can he removed from the turbofan gas turbine engine without moving or removing the fan casing of the turbofan gas turbine engine.
Accordingly the present invention provides a fan assembly for a -turbofan gas turbine engine comprising a fan rotor, a plurality of fan blades and an annular fan casing, the fan blades being removably secured to the fan rotor, the fan blades having tips at their radially outer extremity and root portions at their radially inner.extremity, the fan casing being arranged coaxially with the fan rotor and surrounding the fan blades, the fan casing having an interior surface and an exterior surface, the fan casing having a slot, the slot being formed on the interior surface of the fan casing, the fan casing having a plug, the plug being removably secured in the slot to form a continuation of the interior surface of the fan casing, the slot in the fan casing being in substantially the same plane as the fan blades, the slot in the fan casing being dimensioned so as to receive the tip of a fan blade, 1 4 k 2 the tips of the fan blades being alignable with the slot in the interior surface of the fan casing, and the tips of the fan blades being insertable into the slot in the interior surface of the fan casing to allow loading or unloading of the fan blades.
The fan blades may be variable pitch fan blades, the pitch of the fan blades is variable such that their tips are alignable with the slot in the interior surface of the fan casing, the root portions of the fan blades being detachable from the fan rotor such that the tips of the fan blades are insertable into the slot, the root portions of the fan blades being moveable in both radial, and axial directions to allow loading or unloading of said fan blades.
The slot may have an aerofoil section.
The slot may extend in a circumferential direction.
The fan casing may comprise a containment ring, the slot being formed at least partially in the containment ring.
The containment ring may comprise a continuous single hoop of a woven fibrous material, the slot being formed in the woven fibrous material.
The containment ring may comprise two continuous hoops of a woven fibrous material, the two continuous hoops being axially spaced, the slot being formed axially between the two continuous hoops.
The fan assembly, may comprise a plurality of bearing assemblies and a plurality of bearing casings, the root portion of each fan blade being rotatably mounted on the fan rotor bv one of the bearing assemblies and one of the bearing casings, the root portion, the said bearing assembly and the said bearing casing forming an integral assembly.
Each of the bearing casings may have an outer surface and a f lange, the outer surface of each of the bearing casings being screw threaded, 1 1 3 the fan rotor having a plurality of circumferentially spaced housings, each housing having an inner surface and a flange, the inner surface of each of the housings being screw threaded, each bearing casing being removably secured in a respective one of the housings, the screw thread on the outer surface of said bearing casing being engageable with the screw thread on the inner surface of said housing.
The flange on said bearing casing may be releasably secured to the flange on said housing.
The present invention will be more fully described by way of example with reference to the accompanying drawings in which:- Figure 1 is a partially cut away view of a turbofan gas turbine engine having a fan casing and fan blade loading/unloading arrangement according to the present invention.
Figure 2 is an enlarged cross-sectional view of the fan casing and fan blade of Figure 1 showing the fan blade when loaded.
Figure 3 is an enlarged c-ross-sectional view of the fan casing and fan blade of Figure 1 showing the fan blade during loading/unloading.
Figure 4 is an enlarged sectional view of the fan casing of figure 1 showing the fan casing during operation of the turbofan gas turbine engine.
A turbofan gas turbine engine 10 is shown in figure 1 and comprises an inlet 12, a fan 14, a compressor 22, a combustion chamber 24, a turbine 2t and an exhaust nozzle 28 arranged in flow series. The gas turbine engine works conventionally in that air is compressed initially by the fan, and a portion of the air flows through a fan duct 18 defined by a fan -casing liG, and the -remainder of the air flows into the compressor to be further compressed. The compressed air is supplied into the combustion chamber, where fuel is burnt in the compressed air to produce hot 1 4 gases. The hot gases flow through and drive the turbine, which is arranged to drive the fan and compressor via a shaft oi shafts.
The fan casing 16 is secured to the core engine casing 21 by a plurality of struts 20 which extend across the fan duct 18. The fan casing 16, as shown more clearly in figure 2, comprises an inner metal sheet 32 and an outer metal sheet 36 with a honeycomb structure 34 positioned therebetween. Containment rings 38 and 40 are provided in the fan casing 16 around the fan blades 14, to contain the fan blades within the fan casing should a fan blade become detached from the hub of the fan rotor during operation of the gas turbine engine.
The containment rings of the fan casing are of any suitable construction as known in the art, and for example may comprise continuous wound layers of a woven fibrous material, the fibrous material may comprise glass fibres, carbon fibres, metallic fibres or aromatic polyamide f ibres. The f ibre which is most suitable is that made by - Du Pont Limited and sold under the Registered Trademark KWLAR. The containment ring could also be steel or other metallicring.
The fan casing 1f is provided with an elongate slot 30 in its inner surface which has an aerofoil section so as to receive the tip of a fan blade 14. The slot 30 is arranged to extend generally in a circumferential direction, and is a-rranged to be substantially in the same plane as the axes of the fan blades 14. The slot is dimensioned so as to receive the tip of a fan blade, and to allow a blade to be removed.
The slot 30 extends radially into, and is formed partially by, the containment ring 38, but because the slot extends circumferentially the hoop strength of the containment ring is maintained, the provision of an axially extending slot in the containment ring would greatly reduce the hoop strength and containing strength of the fan casing.
11 1 1 1 The fan blades 14 are of the variable pitch type and each has a root portion 42 which is rotatably mounted in a corresponding housing 48 of the fan rotor by a bearing assembly 44 and a bearing casing 46. The fan blades 14 are removably secured to the housing 48 of the fan rotor by suitable means as is well known in the art. Our copending British Patent application no 8618313 discloses a particularly suitable fan blade with an aerofoil and a root portion in which the bearing casing, bearing assembly and root portic)n form an integral assembly to allow easy removal of the fan blade from the housing of the fan rotor. In the fore mentioned patent application the bearing casing is secured to the housing of -the fan rotor by a screw thread arrangement 47 formed on the outer surface of the bearing casing and on the inner surface of the housing, and by nuts and bolts or other suitable fastening means, which extend through apertures in flanges 49 and 51 formed on the housing and bearing casing respectively.
A fan blade 14 is removed from the housing 48 of the fan rotor as shown in figure 3 by rotating the fan blade to fine pitch about its axis. of rotation, and also rotating the -fan about the engine axis so that the tip of the fan blade lines up with the slot 30 in the fan casing 16. The fan blade 14 is then detached from the housing 48 of the fan rotor by removing the fastening means, ie unfastening the nuts and bolts and unscrewing the bearing casing from the housing. The fan blade is moved radially outwards so that the tip of the fan blade is inserted into the slot, and the root portion is removed from the housing.
The root portion of the fan blade is moved, ie swung, in an upstream and radial direction to allow the tip of the fan blade to be removed from the slot, and so complete the removal of the fan blade.
To load a fan blade, the tip of the fan blade is aligned with the slot in the fan casing. The tip of the q_ 6 fan blade is inserted into the slot and ' the root portion of the fan blade is moved, ie swung, in a downstream and radial direction to align the root portion with the housing of the fan rotor. The fan blade is then moved radially inwards so that the tip of the fan blade leaves the slot in the fan casing and the root portion of the fan blade locates in the housing of the fan rotor. The root portion of the fan blade is then secured to the housing of the fan rotor and the fan blade is rotated about its axis to its operating position.
The slot in the fan casing may be fill-ed with a removable plug 50 which is secured to the fan casing by a screw 52 and a nut 54, the screw extends through the fan casing 16 to a recess 56 in the external surface of the fan casing 16. The plug ensures a smooth aerodynamic continuation of the interior surface of the fan casing during operation of the turbofan gas turbine engine, and is removed to allow a fan blade to be removed.
If the containment ring is formed from a woven fibrous material, the containment ring may be formed with the circumferentially extending slot, preferably by winding the woven material around a former which defines the slot, to produce a continuous single hoop of containment material with a slot formed in it. Alternatively two contipuous hoops of woven fibrous material are axially spaced to define a circumferential space, and a filler material is used to-fill the majority of the circumferential space and to define the circumferential ends of the slot.
Although the slot has been shown to extend into the containment ring, it may be possible to arrange for the slot to extend only into the honeycomb structure, and to provide the containment. ring around the honeycomb structure, and therefore the hoop strength of the containment ring is maintained.
The arrangement therefore allows a fan blade to be removed from the turbofan gas turbine engine without the V 7 need to remove the fan casing. This enables fan blades to be removed from the turbofan gas turbine engine whilst the engine is secured to the associated aircraft ie, it is not necessary to remove. the engine from the aircraft as is required by conventional arrangements.
The arrangement also allows a fan blade to be removed without any significant reduction in the hoop strength of the containment ring.
i 8

Claims (1)

  1. Claims: -
    A fan assembly for a turbofan gas turbine engine comprising a fan rotor, a plurality of fan blades and an annular tan casing, the fan blades being removably secured to the fan rotor, the fan blades having tips at their radially outer extremity and root portions at their radially inner extremity, the fan casing being arranged coaxially with the fan rotor and surrounding the fan blades, the fan casing having an interior surface and an exterior surface, the fan casing having a slot, the slot being formed on the interior surface of the fan casing, the fan casing having a plug, the plug being removably secured in the slot to form a continuation of the interior surface of the fan casing, the slot in the fan casing being in substantially the same plane as the fan blades, the slot in the fan casing being dimensioned so as to receive the tip of a fan blade, the tips of the fan blades being alignable with the slot in the interior surface of the fan casing, and the tips of the fan blades being insertable into the slot in the interior surface of the fan casing to allow loading or unloading of the fan blades. 2. A fan assembly as claimed in claim 2 in which the fan blades are variable pitch fan blades, the pitch of the fan blades is variable such that their tips are alignable with the slot in the interior surface of the fan casing, the root portions of the fan blades being detachable from the fan rotor such that the tips of the fan blades are insertable into the slot, the root - portions of the fan blades being moveable in both radial, and axial directions to allow loading or unloading of said fan blades. 3. A fan assembly as claimed in claim 1 or claim 2 in which the slot has an aerofoil section.
    2 r k.
    1 9 4. A fan assembly as claimed in any of claims 1 to 3 in which the slot extends in a circumferential direction.
    S. A fan assembly as claimed in claim 4 in which the fan casing comprises a containment ring, the slot being formed at least partially in the containment ring.
    6. A fan assembly as claimed in claim 5 in which the containment ring comprises a continuous 'single hoop of a woven fibrous material, the slot being formed in the woven fibrous material.
    7. A fan assembly as claimed in claim 5 in which the containment -ring comprises two continuous hoops of a woven fibrous material, the two continuous hoops being axially spaced, the slot being formed axially between the two continuous hoops.
    8. A fan assembly as claimed in any of claims 2 to 7 comprising a plurality of bearing assemblies and a plurality of bearing casings, the root portion of each fan blade being rotatably mounted on the fan rotor by one of the bearing assemblies and one of the bearing casings, the root portion, the said bearing assembly and the said bearing casing forming an integral assembly.
    9. A fan assembly as claimed.in claim 8 in which each ofthe bearingcasings has an outer surface and a flange,,the outer surface of each of the bearing casings being screw threaded, the fan rotor having a plurality of circumferentially spaced housings, each housing having an inner surface and a flange, the inner surface of each of the housings being screw threaded, each bearing casing being removably secured in a respective one of -the housings, the screw thread on the outer surface of said bearing casing being engageable with the screw thread on the inner surface of said housing.
    10. A fan assembly as claimed in claim 9 in which the flange on said bearing casing is releasably secured to the flange on said housing.
    1 1 1 11. A fan casing for a turbofan gas turbine engine, the fan casing having a slot on its interior surface and a plug being removably secured in the slot to form a continuation of the interior surface of the fan casing, whereby to allow loading or unloading of a fan blade onto or from a fan rotor within the fan casing the fan blade is aligned with the slot in the fan facing and the tip of the fan blade is inserted in the slot in the fan casing during said loading or unloading procedure.
    12. A fan casing as claimed in claim 11 in which the slot has an aerofoil section.
    13. A fan casing as claimed in claim 12 in which the slot extends in a circumferential direction.
    14. A fan casing as claimed in claim 13 in which the fan casing comprises a containment ring, the slot being forned at least partially in the containment ring.
    15. A turbofan gas turbine engine substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
    1 PublishCd 1988 at The Patent OMCC, State House, 66171 High Holborn, London WC1R 4TP. F copies may be obtained froM The Patent OffIce,
GB8801047A 1987-03-03 1988-01-18 Fan casing and fan blade loading/unloading Expired - Fee Related GB2201731B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US2134887A 1987-03-03 1987-03-03

Publications (3)

Publication Number Publication Date
GB8801047D0 GB8801047D0 (en) 1988-02-17
GB2201731A true GB2201731A (en) 1988-09-07
GB2201731B GB2201731B (en) 1990-08-29

Family

ID=21803698

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8801047A Expired - Fee Related GB2201731B (en) 1987-03-03 1988-01-18 Fan casing and fan blade loading/unloading

Country Status (4)

Country Link
JP (1) JP2860099B2 (en)
DE (1) DE3805586C2 (en)
FR (1) FR2611821B1 (en)
GB (1) GB2201731B (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6375410B2 (en) * 2000-02-07 2002-04-23 General Electric Company Frangible cover for turbofan engine blade removal and access
RU2449154C2 (en) * 2010-06-25 2012-04-27 Открытое акционерное общество "Авиадвигатель" Gas turbine propfan engine
FR3135758B1 (en) * 2022-05-20 2025-04-04 Safran Aircraft Engines Fan retention casing with a truncated spherical portion

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2851214A (en) * 1955-10-12 1958-09-09 Stork Koninklijke Maschf Axial flow fans or axial flow pumps
US3386155A (en) * 1963-07-01 1968-06-04 Dominion Eng Works Ltd Method of fitting seal rings to blades
GB1430596A (en) * 1972-07-06 1976-03-31 Rolls Royce Multi-bladed fans
US3934410A (en) * 1972-09-15 1976-01-27 The United States Of America As Represented By The Secretary Of The Navy Quiet shrouded circulation control propeller
FR2539702B3 (en) * 1983-01-20 1985-10-25 Septem Sa DEVICE FOR OPTIMIZING THE PROPULSION PERFORMANCE OF A MU VEHICLE BY A PROPELLER
DE3366618D1 (en) * 1983-10-14 1986-11-06 Howden James & Co Ltd Variable pitch axial flow fan
GB2159886B (en) * 1984-06-07 1988-01-27 Rolls Royce Fan duct casing
US4907944A (en) * 1984-10-01 1990-03-13 General Electric Company Turbomachinery blade mounting arrangement

Also Published As

Publication number Publication date
DE3805586C2 (en) 1998-01-15
DE3805586A1 (en) 1988-09-15
GB8801047D0 (en) 1988-02-17
JP2860099B2 (en) 1999-02-24
JPS63215840A (en) 1988-09-08
GB2201731B (en) 1990-08-29
FR2611821B1 (en) 1990-07-20
FR2611821A1 (en) 1988-09-09

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 20000118