GB2375798A - A gas turbine engine fan blade containment assembly - Google Patents

A gas turbine engine fan blade containment assembly Download PDF

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Publication number
GB2375798A
GB2375798A GB0111948A GB0111948A GB2375798A GB 2375798 A GB2375798 A GB 2375798A GB 0111948 A GB0111948 A GB 0111948A GB 0111948 A GB0111948 A GB 0111948A GB 2375798 A GB2375798 A GB 2375798A
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GB
United Kingdom
Prior art keywords
casing
containment
gas turbine
turbine engine
fan blade
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Withdrawn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
GB0111948A
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GB0111948D0 (en
Inventor
Kenneth Franklin Udall
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 GB0111948A priority Critical patent/GB2375798A/en
Publication of GB0111948D0 publication Critical patent/GB0111948D0/en
Publication of GB2375798A publication Critical patent/GB2375798A/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Withdrawn legal-status Critical Current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
    • F01D21/00—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for
    • F01D21/04—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for responsive to undesired position of rotor relative to stator or to breaking-off of a part of the rotor, e.g. indicating such position
    • F01D21/045—Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for responsive to undesired position of rotor relative to stator or to breaking-off of a part of the rotor, e.g. indicating such position special arrangements in stators or in rotors dealing with breaking-off of part of rotor
    • 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
    • F05D2220/00—Application
    • F05D2220/30—Application in turbines
    • F05D2220/32—Application in turbines in gas turbines
    • F05D2220/327—Application in turbines in gas turbines to drive shrouded, high solidity propeller
    • 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

A fan blade containment assembly 138 for a turbofan gas turbine engine comprises a generally cylindrical or frustoconical containment casing 140 having a rib 142 at its upstream end which extends circumferentially around the containment casing 140, and an intake casing 146 with a bulkhead 160 at its downstream end which extends circumferentially around the intake casing 146. The bulkhead 160 is directly fastened to the rib 142 of the containment casing 140, and curved ribs 156, 158 which extend circumferentially around the containment casing 140 are connected at their radially outer ends 166, 168 to the outer end 164 of the bulkhead 160. The ribs 156, 158 have spring fingers 172, 176 which allow for ease of assembly and removal. In an alternative embodiment, three curved ribs (156-158, Fig.5) are bonded or welded at their radially inner ends to the containment casing. A V-shaped projection 188 on door 186 engages in a V-shaped groove 184.

Description

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A GAS TURBINE ENGINE BLADE CONTAINMENT ASSEMBLY The present invention relates to gas turbine casings, particularly gas turbine engine fan casings, more particularly to an improved blade containment assembly for use within or forming part of the gas turbine engine casing.
Turbofan gas turbine engines for powering aircraft conventionally comprise a core engine, which drives a fan.
The fan comprises a number of radially extending fan blades mounted on a fan rotor which is enclosed by a generally cylindrical, or frustoconical, fan casing. The core engine comprises one or more turbines, each one of which comprises a number of radially extending turbine blades enclosed by a cylindrical, or frustoconical, casing.
There is a remote possibility with such engines that part, or all, of a fan blade could become detached from the remainder of the fan blade or fan rotor. This may occur as the result of, for example, the turbofan gas turbine engine ingesting a bird or other foreign object.
The use of containment rings for turbofan gas turbine engine casings is well known. The aim of the containment rings is to absorb the kinetic energy of the fan blade and prevent debris escaping form the gas turbine engine. It is known to provide generally cylindrical, or frustoconical, relatively thick metallic containment casings. It is also known to provide generally cylindrical, or frustoconical, locally thickened, isogrid or circumferentially ribbed metallic containment casings. Furthermore it is known to provide strong fibrous material wound around relatively thin metallic casings or around the above mentioned containment casings. In the event that a fan blade becomes detached it passes through the casing and is contained by the fibrous material.
The intake casing of the turbofan gas turbine engine is only attached to the fan containment casing. Therefore the intake casing has to be protected from failure of the
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fasteners, bolts, fastening the fan containment casing and the intake casing together due to distortion of the fan containment casing in the event that a fan blade becomes detached. The distortion of the fan containment casing is reduced, but not eliminated, by any stiffening ribs. The intake casing comprises a stiff bulkhead at its downstream end. The intake casing is protected from the failure of the fasteners by the provision of a deflection isolation casing between the intake casing and the fan containment casing.
This fan containment casing and intake casing arrangement is relatively heavy, expensive and does not provide sufficient stiffness of the fan containment casing.
Accordingly the present invention seeks to provide a novel containment which reduces, preferably overcomes, the above mentioned problems.
Accordingly the present invention provides a turbofan gas turbine engine fan blade containment assembly comprising a generally cylindrical, or frustoconical, containment casing, the containment casing having at least one rib extending radially outwardly from and circumferentially around the containment casing, an intake casing arranged upstream of the containment casing, the intake casing having at least one bulkhead extending radially and circumferentially around the intake casing, the at least one bulkhead is at the downstream end of the intake casing, the intake casing is directly fastened to the fan containment casing and the at least one rib is fastened to the at least one bulkhead.
Preferably the at least one bulkhead extends substantially straight in radial cross-section.
Preferably the fan containment casing comprises a plurality of axially spaced circumferentially extending ribs. Preferably there are three axially spaced ribs.
Alternatively there may be four axially spaced ribs.
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Preferably at least one of the ribs is curved in radial cross-section.
Preferably the radially outer end of at least one rib abuts the radially outer end of at least one adjacent rib or the radially outer end of the bulkhead to support the at least one adjacent rib or the bulkhead.
In operation a first one of the ribs may be arranged at the upstream end of the containment casing, a second one of the ribs is arranged in a plane perpendicular to the axis of the containment casing substantially at the trailing edge of the fan blades, a third one of the ribs is arranged in a plane perpendicular to the axis of the containment casing substantially at the mid-chord position of the fan blades and a fourth one of the ribs is arranged in a plane perpendicular to the axis of the containment casing substantially at the leading edge of the fan blades.
Preferably in operation a first one of the ribs is arranged at the upstream end of the containment casing, a second one of the ribs is arranged in a plane perpendicular to the axis of the containment casing between a plane perpendicular to the axis of the containment casing at the trailing edge of the fan blades and a plane perpendicular to the axis of the containment casing at the mid-chord position of the fan blades and a third one of the ribs is arranged in a plane perpendicular to the axis of the containment casing between a plane perpendicular to the axis of the containment casing at the mid-chord position of the fan blades and a plane perpendicular to the axis of the containment casing at the leading edge position of the fan blades.
Preferably the at least one rib is fastened to the at least one bulkhead by bolted fastenings.
Preferably the at least one rib is at the upstream end of the containment casing and the at least one rib is fastened to the radially inner end of the bulkhead.
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Preferably the containment casing is formed from a different material to the intake casing and at least one bulkhead.
The at least one rib and the containment casing may be integral. The at least one rib may be bonded, welded, friction welded or diffusion bonded to the containment casing.
The at least one rib may abut the containment casing.
The radially inner end of the at least one rib may have axially extending spring fingers arranged to spring radially inwardly.
The containment casing may be frustoconical and comprises at least one circumferentially extending projection, the axially extending spring fingers abut the projection to locate the rib axially on the containment casing.
The containment casing may comprise a steel alloy, aluminium, an aluminium alloy, magnesium, a magnesium alloy, titanium, a titanium alloy, nickel or a nickel alloy.
The intake casing and at least one bulkhead may comprise a steel alloy, aluminium, an aluminium alloy, magnesium, a magnesium alloy, titanium, a titanium alloy, nickel or a nickel alloy.
The at least one rib may comprise a steel alloy, aluminium, an aluminium alloy, magnesium, a magnesium alloy, titanium, a titanium alloy, nickel or a nickel alloy.
The at least one rib may be formed from a different material to the containment casing.
A radially inwardly and circumferentially extending rib may be arranged at the upstream end of the containment casing.
The present invention will be more fully described by way of example with reference to the accompanying drawings in which :-
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Figure 1 shows a turbofan gas turbine engine having a prior art fan blade containment assembly.
Figure 2 is an enlarged axial cross-sectional view through the turbofan gas turbine engine of figure 1 showing the fan blade containment assembly.
Figure 3 shows a turbofan gas turbine engine having a fan blade containment assembly according to the present invention.
Figure 4 is an enlarged axial cross-sectional view through the turbofan gas turbine engine of figure 3 showing the fan blade containment assembly according to the present invention.
Figure 5 is an enlarged axial cross-sectional view through the turbofan gas turbine engine of figure 3 showing an alternative fan blade containment assembly according to the present invention.
A prior art turbofan gas turbine engine 10, as shown in figures 1 and 2, comprises in flow series an intake 12, a fan section 14, a compressor section 16, a combustor section 18, a turbine section 20 and an exhaust 22. The turbine section 20 comprises one or more turbines arranged to drive one or more compressors in the compressor section 16 via shafts (not shown). The turbine section 20 also comprises a turbine to drive the fan section 14 via a shaft (not shown). The fan section 14 comprises a fan duct 24 defined partially by a fan casing 26. The fan duct 24 has an outlet 28 at its axially downstream end. The fan casing 26 is secured to the core engine casing 36 by a plurality of radially extending fan outlet guide vanes 30. The fan casing 26 surrounds a fan rotor 32, which carries a plurality of circumferentially spaced radially extending fan blades 34. The fan rotor 32 and fan blades 34 rotate about the axis X of the gas turbine engine 10, substantially in a plane Y perpendicular to the axis X. The fan casing 26 also comprises a fan blade containment
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assembly 38, which is arranged substantially in the plane Y of the fan blades 34.
The fan casing 26 and the fan blade containment assembly 38 is shown more clearly in figure 2. The fan blade containment assembly 38 comprises a metal cylindrical, or frustoconical, containment casing 40. The metal containment casing 40 comprises an upstream flange 42 by which the fan blade containment assembly 38 is connected to an intake casing 46 of the fan casing 26. The metal containment casing 40 also comprises a downstream flange 44 by which the fan blade containment assembly 38 is connected to a rear portion 48 of the fan casing 26.
The metal containment casing 40 provides the basic fan blade containment and provides a connection between the intake casing 46 and the rear portion 48 of the fan casing 26.
The metal containment casing 40 comprises an upstream portion 50, a transition portion 52, a main blade containment portion 54 and a downstream portion 56. The upstream portion 50 comprises the flange 42 and the downstream portion 56 comprises the flange 44.
The upstream portion 50 is upstream of the plane Y of the fan blades 34 and provides debris protection for the fan blade containment assembly 38. The main blade containment portion 54 is substantially in the plane Y of the fan blades 34 and comprises a radially inwardly and axially downstream extending flange, or hook, 58 at its upstream end. The hook 58 is arranged in a plane upstream of the leading edge of the fan blades 34. The main blade containment portion 54 also comprises one, or more, integral T section ribs 60, which extend radially outwardly from the main blade containment portion 54. The T section ribs 60 extend circumferentially around the main blade containment portion 54 to stiffen the metal containment casing 40 to improve the fan blade 34 containment properties.
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One of the ribs 60 is arranged in a plane perpendicular to the axis X between a plane U containing the leading edges of the fan blades 34 and a plane V containing the mid chord of the fan blades 34. Another of the ribs 60 is arranged in a plane perpendicular to the axis X between a plane W containing the trailing edges of the fan blades 34 and the plane V containing the mid chord of the fan blades 34.
The transition portion 52 connects the main blade containment portion 54 and the upstream portion 50 to transmit loads from the main blade containment portion 54 to the upstream flange 42 on the upstream portion 50.
The downstream portion 56 is downstream of the plane Y of the fan blades 34, and provides protection for where a root of a fan blade 34 impacts the fan blade containment assembly 38.
A cylindrical, or frustoconical, deflection isolation casing 62 is arranged between the intake casing 46 and the upstream portion 50 of the metal containment casing 40.
The deflection isolation casing 62 has a flange 64 at its upstream end and a flange 66 at its downstream end. The flange 64 is fastened to a flange 68 at the downstream end of the intake casing 46 and the flange 66 is fastened to the upstream flange 42 on the upstream portion 50 of the metal containment casing 40. The flanges are generally fastened together by bolted fastenings.
The deflection isolation casing 62 and the upstream portion 50 of the metal containment casing 40 are thinner than the remainder of the metal containment casing 40 and intake casing 46 such that they are able to flex or bend.
The intake casing 46 is only secured to the metal containment casing 40 by the deflection isolation casing 62. The flange 68 forms a radially deep and stiff bulkhead at the downstream end of the intake casing 46 to provide support to the fan casing 26 upstream of the flange, or bulkhead, 68.
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The engine accessories 74 are mounted on a casing 76, which is fastened to the flange 42 on the metal containment casing 40. The nacelle 80 has a door 82 to provide access to the engine accessories 74. However, the door 82 does not provide a load path for supporting the intake casing 46.
The metal containment casing 40, the intake casing 46 and the deflection isolation casing 62 are provide with acoustic liners 70,72 and 74 respectively on their radially inner surfaces to absorb noise generated in the fan duct 24.
In operation, in the event of a fan blade 34 striking the metal containment casing 40, the hook 58 prevents the fan blade 34 moving axially forward out of the turbofan gas turbine engine 10. The ribs 60 are stiff to absorb the energy of the impact of the fan blade 34. The deflection isolation casing 62 and the upstream portion 50 protect the fastenings, the bolts, between the flanges 64 and 68 and flanges 42 and 66 from failing and hence ensures that the intake casing 46 does not become detached from the turbofan gas turbine engine 10 because of the impact of the fan blade 34.
A gas turbine engine 100 having a fan blade containment assembly according to the present invention is shown in figures 3 and 4. The turbofan gas turbine engine 100 is substantially the same as that shown in figures 1 and 2 and comprises in flow series an intake 112, a fan section 114, a compressor section 116, a combustor section 118, a turbine section 120 and an exhaust 122. The turbine section 120 comprises one or more turbines arranged to drive one or more compressors in the compressor section 16 via shafts (not shown). The turbine section 120 also comprises a turbine to drive the fan section 114 via a shaft (not shown). The fan section 114 comprises a fan duct 124 defined partially by a fan casing 126. The fan duct 124 has an outlet 128 at its axially downstream end.
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The fan casing 126 is secured to the core engine casing 136 by a plurality of radially extending fan outlet guide vanes 130. The fan casing 126 surrounds a fan rotor 132, which carries a plurality of circumferentially spaced radially extending fan blades 134. The fan rotor 132 and fan blades 134 rotate about the axis X of the gas turbine engine 110, substantially in a plane Y perpendicular to the axis X. The fan casing 126 also comprises a fan blade containment assembly 138, which is arranged substantially in the plane Y of the fan blades 134.
The fan casing 126 and the fan blade containment assembly 138 is shown more clearly in figure 4. The fan blade containment assembly 138 comprises a metal cylindrical, or frustoconical, containment casing 140. The metal containment casing 140 comprises an upstream radially outwardly and circumferentially extending rib, or flange 142, by which the fan blade containment assembly 138 is connected to an intake casing 146 of the fan casing 126.
The metal containment casing 140 also comprises a downstream radially outwardly and circumferentially extending rib, or flange, 144 by which the fan blade containment assembly 138 is connected to a rear portion 148 of the fan casing 126.
The metal containment casing 140 provides the basic fan blade containment and provides a connection between the intake casing 146 and the rear portion 148 of the fan casing 126.
The metal containment casing 140 comprises a main blade containment portion 150 and a downstream portion 152.
The main blade containment portion 150 comprises the rib 142 and the downstream portion 152 comprises the rib 144.
The main blade containment portion 150 is substantially in the plane Y of the fan blades 134 and comprises a radially inwardly, axially downstream and circumferentially extending rib, or hook, 154 at its upstream end. The hook 154 is arranged in a plane upstream
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of the leading edge of the fan blades 134. The hook 154 in this example is in the same plane as the rib 142. The main blade containment portion 150 also comprises one, or more, ribs 156 and 158, which extend radially outwardly from the main blade containment portion 150. The ribs 156 and 158 extend circumferentially around the main blade containment portion 150 to stiffen the metal containment casing 140 to improve the fan blade 134 containment properties.
The radially inner end 170 of the rib 156 is arranged in a plane perpendicular to the axis X between a plane U containing the leading edges of the fan blades 134 and a plane V containing the mid chord of the fan blades 134.
The radially inner end 174 of the rib 158 is arranged in a plane perpendicular to the axis X between a plane W containing the trailing edges of the fan blades 134 and the plane V containing the mid chord of the fan blades 134.
The downstream portion 152 is downstream of the plane Y of the fan blades 134, and provides protection for where a root of a fan blade 134 impacts the fan blade containment assembly 138.
The intake casing 146 has a flange 160 at its downstream end, which is secured to the rib 142 at the upstream end of the metal containment casing 140. The intake casing 146 is only secured to the metal containment casing 140. The flange 160 forms a radially deep and stiff bulkhead at the downstream end of the intake casing 146 to provide support to the nacelle 180 upstream of the flange, or bulkhead, 160. The flange 160 has a kink 162 to absorb local radial deflection mismatch energy. The radial position of the kink 162 is selected to provide stability and protection of the joint between the flange 160 on the intake casing 146 and the rib 142 on the metal containment casing 140. The joint comprises suitable fasteners, for example a bolted fastening comprising nuts and bolts.
The ribs 156 and 158 are also radially deep and form stiff bulkheads for the intake casing 146. In particular
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the ribs 156 and 158 are curved in an axially upstream direction such that the radially outer end 166 of the rib 156 abuts the radially outer end 164 of the rib 160, and the radially outer end 168 of the rib 158 abuts the radially outer end 166 of the rib 156. The radially outer ends 164,166 and 168 of the flange 160 and ribs 156 and 158 respectively are joined together by suitable fasteners, for example a bolted fastening comprising nuts and bolts.
The ribs 156 and 158 provide an alternative load path for the retention of the intake casing 146.
The radially inner end 170 of the rib 156 has a plurality of circumferentially spaced spring fingers 172, which extend in an axially downstream direction. Similarly the radially inner end 174 of the rib 158 has a plurality of circumferentially spaced spring fingers 176 which extend in an axially downstream direction.
The radially outer surface of the metal containment casing 140 is frustoconical and has axially spaced annular projections 178 and 180. The radially inner ends 170 and 174 of the ribs 156 and 158 respectively abut the radially outer surface of the metal containment casing 140. The radially inner end 170 of the rib 156 abuts the radially outer surface of the metal containment casing 140 upstream of the annular projection 178 and the spring fingers 172 abut the upstream radial face of the projection 178. The radially inner end 174 of the rib 158 abuts the radially outer surface of the annular projection 178 and the spring fingers 176 abut the upstream radial face of the projection 180.
The frustoconical metal containment casing 140 and the spring fingers 172 and 176 allow the ribs 156 and 158 to be quickly assembled by pushing the ribs 156 and 158 sequentially axially in an upstream direction along the metal containment casing 140. The spring fingers 172 and 176 allow the ribs 156 and 158 to be quickly removed by
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lifting the spring fingers 176 or 172 radially and pulling the ribs 158 or 156 in an axially downstream direction.
The ribs 142 and 144 and the hook 154 are integral with the metal containment casing 140. Thus the bulkhead 160 of the intake casing 146 is integrated with the stiffening ribs 142, 156 and 158 of the metal containment casing 140.
The engine accessories (not shown) are mounted on the metal containment casing 140 and the nacelle 182 has doors 186 to allow access to engine accessories on the metal containment casing 140. The bulkhead 160 and ribs 156 and 158 are also secured at their radially outer ends to the nacelle 182. The nacelle 182, bulkhead 160 and intake casing 146 form a deep ring I beam, with the bulkhead forming the web of the I beam. The radially outer ends 164, 166 and 168 of the bulkhead 160 and ribs 156 and 158 respectively define a V-shaped groove 184. The upstream end of the door 186 has a V-shaped projection 188, which is arranged to locate in the V-shaped groove 184. A similar V-shaped groove and V-shaped projection are arranged at the downstream end of the door 186. The V-shaped groove 184 and V-shaped projection 188 provide another load path such that the nacelle 182 supports the intake casing 146.
The metal containment casing 140 and the intake casing 146 are provided with acoustic liners 190 and 192 respectively on their inner surfaces to absorb noise generated in the fan duct 24. The acoustic liners 190 and 192 generally comprises a honeycomb structure with a perforated radially inner skin.
In operation, in the event of a fan blade 134 striking the metal containment casing 140, the hook 154 prevents the fan blade 134 moving axially forward out of the turbofan gas turbine engine 110. The deep section radial ribs 156 and 158 are stiff to absorb the energy of the impact of the fan blade 134. The ribs 156 and 158 dissipate the hoop bending stresses generated by an impact of a detached fan
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blade 134 on the metal containment casing 140. The flange, bulkhead, 160 at the upstream end of the intake casing 146 is stabilised against rolling by the ribs 156 and 158. The ribs 156 and 158 provide alternative load paths for carrying the intake casing 146 in the event of a failure of the bulkhead 160 and hence ensures that the intake casing 146 does not become detached from the turbofan gas turbine engine 110 because of the impact of the fan blade 134. The kink 162 protects the fastenings, the bolts, between the flange 142 and the bulkhead 160 from failing.
An alternative fan blade containment assembly according to the present invention is shown in figures 3 and 5. This is similar to that shown in figure 4 and like parts are denoted by like numerals. This embodiment differs in that there are three ribs 156,157 and 158 which have radially outer ends 166,167 and 168 fastened to the radially outer end 164 of the bulkhead 160. The radially inner end 170 of the rib 156 is arranged in a plane adjacent the leading edge of the fan blade 134. The radially inner end 171 of the rib 157 is arranged in a plane adjacent the mid chord position of the fan blade 134 and the radially inner end 174 of the rib 158 is arranged in a plane adjacent the trailing edge of the fan blade 134.
The ribs 156,157 and 158 are bonded, diffusion bonded or welded to the metal containment casing 140. The rib 142 and 144 and the hook 154 are integral with the metal containment casing 140.
Thus the bulkhead 160 of the intake casing 146 is integrated with the stiffening ribs 142,156 and 158 of the metal containment casing 140.
Although the present invention has been described with reference to curved ribs on the metal containment casing conical ribs or other suitable shaped ribs may be used.
The ribs may be joined to annular flanges on the metal containment casing by suitable fasteners, for example a bolted joint comprising nuts and bolts. A further
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alternative is to weld, friction weld, bond or diffusion bond the ribs to the metal containment casing. Thus the ribs may be integral or fastened to the metal containment casing.
The engine accessories may be arranged on the engine core casing and the doors may not be required on the nacelle for access to engine accessories on the fan casing. The nacelle may then be an integrated structure to provide a load path for supporting the intake casing.
The advantages of the present invention are that the deflection isolation casing and the upstream portion of the fan containment casing are eliminated. The deep radial section ribs increase the stiffness of the fan containment casing, the deep radial section ribs provide alternative load paths to support the intake casing and the intake casing and fan containment casing have reduced weight and lower cost.

Claims (22)

  1. Claims :- 1. A turbofan gas turbine engine fan blade containment assembly comprising a generally cylindrical, or frustoconical, containment casing, the containment casing having at least one rib extending radially outwardly from and circumferentially around the containment casing, an intake casing arranged upstream of the containment casing, the intake casing having at least one bulkhead extending radially and circumferentially around the intake casing, the at least one bulkhead is at the downstream end of the intake casing, the intake casing is directly fastened to the fan containment casing and the at least one rib is fastened to the at least one bulkhead.
  2. 2. A turbofan gas turbine engine fan blade containment assembly as claimed in claim 1 wherein the at least one bulkhead extends substantially straight in radial crosssection.
  3. 3. A turbofan gas turbine engine fan blade containment assembly as claimed in claim 3 wherein the fan containment casing comprises a plurality of axially spaced circumferentially extending ribs.
  4. 4. A turbofan gas turbine engine fan blade containment assembly as claimed in claim 4 wherein there are three axially spaced ribs.
  5. 5. A turbofan gas turbine engine fan blade containment assembly as claimed in claim 3, claim 4 or claim 5 wherein at least one of the ribs is curved in radial cross-section.
  6. 6. A turbofan gas turbine engine fan blade containment assembly as claimed in claim 5 wherein the radially outer end of at least one rib abuts the radially outer end of at least one adjacent rib or the radially outer end of the bulkhead to support the at least one adjacent rib or the bulkhead.
  7. 7. A turbofan gas turbine engine fan blade containment assembly as claimed in any of claims 3 to 6 wherein in operation a first one of the ribs is arranged at the
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    upstream end of the containment casing, a second one of the ribs is arranged in a plane perpendicular to the axis of the containment casing substantially at the trailing edge of the fan blades, a third one of the ribs is arranged in a plane perpendicular to the axis of the containment casing substantially at the mid-chord position of the fan blades and a fourth one of the ribs is arranged in a plane perpendicular to the axis of the containment casing substantially at the leading edge of the fan blades.
  8. 8. A turbofan gas turbine engine fan blade containment assembly as claimed in any of claims 3 to 6 wherein in operation a first one of the ribs is arranged at the upstream end of the containment casing, a second one of the ribs is arranged in a plane perpendicular to the axis of the containment casing between a plane perpendicular to the axis of the containment casing at the trailing edge of the fan blades and a plane perpendicular to the axis of the containment casing at the mid-chord position of the fan blades and a third one of the ribs is arranged in a plane perpendicular to the axis of the containment casing between a plane perpendicular to the axis of the containment casing at the mid-chord position of the fan blades and a plane perpendicular to the axis of the containment casing at the leading edge position of the fan blades.
  9. 9. A turbofan gas turbine engine fan blade containment assembly as claimed in any of claims 1 to 8 wherein the at least one rib is fastened to the at least one bulkhead by bolted fastenings.
  10. 10. A turbofan gas turbine engine fan blade containment assembly as claimed in any of claims 1 to 9 wherein the at least one rib is at the upstream end of the containment casing and the at least one rib is fastened to the radially inner end of the bulkhead.
  11. 11. A turbofan gas turbine engine fan blade containment assembly as claimed in any of claims 1 to 10 wherein the containment casing and the at least one flange are formed
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    from a different material to the intake casing and at least one bulkhead.
  12. 12. A turbofan gas turbine engine fan blade containment assembly as claimed in any of claims 1 to 11 wherein the at least one rib and the containment casing are integral.
  13. 13. A turbofan gas turbine engine fan blade containment assembly as claimed in any of claims 1 to 11 wherein the at least one rib is bonded, welded, friction welded or diffusion bonded to the containment casing.
  14. 14. A turbofan gas turbine engine fan blade containment assembly as claimed in any of claims 1 to 11 wherein the at least one rib abuts the containment casing.
  15. 15. A turbofan gas turbine engine fan blade containment casing as claimed in claim 14 wherein the radially inner end of the at least one rib has axially extending spring fingers arranged to spring radially inwardly.
  16. 16. A turbofan gas turbine engine fan blade containment assembly as claimed in claim 15 wherein the containment casing is frustoconical and comprises at least one circumferentially extending projection, the axially extending spring fingers abut the projection to locate the rib axially on the containment casing.
  17. 17. A turbofan gas turbine engine fan blade containment casing as claimed in any of claims 1 to 16 wherein the containment casing comprises a steel alloy, aluminium, an aluminium alloy, magnesium, a magnesium alloy, titanium, a titanium alloy, nickel or a nickel alloy.
  18. 18. A turbofan gas turbine engine fan blade containment casing as claimed in any of claims 1 to 17 wherein the intake casing and at least one bulkhead comprises a steel alloy, aluminium, an aluminium alloy, magnesium, a magnesium alloy, titanium, a titanium alloy, nickel or a nickel alloy.
  19. 19. A turbofan gas turbine engine fan blade containment casing as claimed in any of claims 3 to 18 wherein the at least one rib comprises a steel alloy, aluminium, an
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    aluminium alloy, magnesium, a magnesium alloy, titanium, a titanium alloy, nickel or a nickel alloy.
  20. 20. A turbofan gas turbine engine fan blade containment assembly as claimed in any of claims 3 to 19 wherein the at least one rib is formed from a different material to the containment casing.
  21. 21. A turbofan gas turbine engine fan blade containment assembly as claimed in any of claims 1 to 20 wherein a radially inwardly and circumferentially extending rib is arranged at the upstream end of the containment casing.
  22. 22. A turbofan gas turbine engine fan blade containment assembly substantially as hereinbefore described with reference to and as shown in figures 3 and 4 of the accompanying drawings.
GB0111948A 2001-05-16 2001-05-16 A gas turbine engine fan blade containment assembly Withdrawn GB2375798A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB0111948A GB2375798A (en) 2001-05-16 2001-05-16 A gas turbine engine fan blade containment assembly

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0111948A GB2375798A (en) 2001-05-16 2001-05-16 A gas turbine engine fan blade containment assembly

Publications (2)

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GB0111948D0 GB0111948D0 (en) 2001-07-04
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2406615A (en) * 2003-10-03 2005-04-06 Rolls Royce Plc Combined gas turbine engine blade containment assembly and acoustic treatment
US9290274B2 (en) 2014-06-02 2016-03-22 Mra Systems, Inc. Acoustically attenuating sandwich panel constructions
EP3715588A1 (en) * 2019-03-26 2020-09-30 Hamilton Sundstrand Corporation Turbine containment arrangement

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4500252A (en) * 1981-12-21 1985-02-19 United Technologies Corporation Beam for a containment structure

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4500252A (en) * 1981-12-21 1985-02-19 United Technologies Corporation Beam for a containment structure

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2406615A (en) * 2003-10-03 2005-04-06 Rolls Royce Plc Combined gas turbine engine blade containment assembly and acoustic treatment
GB2406615B (en) * 2003-10-03 2005-11-30 Rolls Royce Plc A gas turbine engine blade containment assembly
US7338250B2 (en) 2003-10-03 2008-03-04 Rolls-Royce Plc Gas turbine engine blade containment assembly
US9290274B2 (en) 2014-06-02 2016-03-22 Mra Systems, Inc. Acoustically attenuating sandwich panel constructions
EP3715588A1 (en) * 2019-03-26 2020-09-30 Hamilton Sundstrand Corporation Turbine containment arrangement

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