GB2238082A

GB2238082A - Disassembling and removing ultra high bypass gas turbine engine components

Info

Publication number: GB2238082A
Application number: GB9019356A
Authority: GB
Inventors: Eugene Jesus Antuna; Donald Frederick Keck
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1989-09-07
Filing date: 1990-09-05
Publication date: 1991-05-22
Also published as: JPH03141829A; GB9019356D0; DE4025775A1; CA2021087A1; IT9021336A0; FR2651537A1; IT9021336A1; IT1242998B

Abstract

For enabling transport of very large diameter gas turbine engines, the engine is separated into a stator module (14) (Fig 1) and a core module (12), which includes the turbine and compressor stages of the engine. In one form, the stator module includes an integrated fan case, fan cowl, and inlet 40. The stator module (14) supports at least a forward portion of the core module via a plurality of circumferentially spaced structural outlet guide vanes 30 and struts 48. The vanes and struts are detachable from the core module to enable its removal from the stator module. The fan blades and spinner are separable from the core module to allow separation of the modules. <IMAGE>

Description

--.7,39-, 7 - ULTRA HIGH BYPASS ENGINE INTEGRATED FAN/COW AND

TRANSPORTATIONIREMOVAL 13DV-9908 The present invention relates to a method and apparatus for assembly and mounting of a turbofan gas turbine engine, to integration of an engine fan casing with engine cowling, and a mounting arrangement which permits disassembly of the core engine from the external fan assembly.

Turbofan gas turbine engines generally include engine coupled in driving relationship to fan module. The fan module, in a a core forward mounted a high-bypass ratio engine. includes a large diameter single stage fan and a multiple stage intermediate pressure compressor or booster. The fan is surrounded by a fan casing supported by a plurality of structural outlet guide vanes which are. in turn. supported on a casing surrounding the booster. The core engine includes a high pressure compressor, a combustor and a multi-stage turbine for extracting energy from combustion gases exiting the combustor for driving the compressors and fan.

13DV-9908 Mounting of such high-bypass engines on an aircraft generally requires one or more structural supports which connect the engine to a structural member. sometimes referred to as a strut or pylon. in a wing or fuselage. depending upon the mounting location. The structural supports extend through an aerodynamic cowling. sometimes referred to as a nacelle. and couple to the engine casing. Coupling may be to the fan casing (or shroud) and to the casing surrounding the turbine. In general, some form of structural yoke is attached to the engine casing and the structural supports attach to the yoke.

As gas turbine engines have become more powerful and larger, a concern has developed with handling and is transporting of such engines. In particular, engines are now being developed with fans and fan casings having diameters in the range of twelve feet.

Transporting of such engines by air or ground is not practical with current commercial aircraft and over the-road transportation guidelines. Accordingly, it is desirable to provide a method of assembling such engines which permits transport without exceeding aircraft or ground transport size limitations.

The problems associated with handling and transporting of such large engines extends beyond shipments to the installation. removal. and handling of the engines in aircraft servicing. It is therefore further desirable to provide a method and apparatus for servicing of such engines which overcomes the problems associated with such large diameter fans.

i 13DV-9908 3 - is An embodiment of the present invention seeks to provide' a method and apparatus for assembly and mounting of a highbypass ratio gas turbine engine which overcomes the above mentioned disadvantages of such engines.

Another embodiment of the present invention seeks to provide a method and apparatus which permits separation of the fan and core engine plus booster without affecting acceptance testing of the engi.ne.

Yet another embodiment of the present invention seeks to provide a method and apparatus for incorporation of a lan shroud into an engine nacelle with structural support for the core engine derived from the nacelle.

One form of the invention comprises a high-bypass ratio gas turbine engine in which the fan casing is incorporated into an aircraft mounted cowling or nacelle and the fan casing is made separable from the core engine without disturbing assembly of the intermediate stage or booster compressor. The nacelle is modified to become a structural member and is structurally attached to at least one aircraft frame member or strut. Outlet guide vanes. normally coupling the fan shroud to the booster casing, are connected between the nacelle and the booster frame to support the engine within the nacelle. The connecting supports are made separable from the booster casing to allow the core engine plus booster to be removable from the nacelle. Still further. the fan spinner and fan blades are made removable from the engine without disturbing the booster stage or removing the core engine. The entire core engine is thus intact and can 13DV-9908 be tested as a unit. The fan blades can be installed on the engine for testing purposes and removed for transporting. Such an arrangement maintains the integrity of the assembled rotating components. e.g., the compressor. turbine. booster and fan rotor. while allowing separation of elements which are either nonrotating or do not require a rotating interface. such as. for example. the nacelle. outlet guide vanes and the fan blades. Although the fan blades rotate, their connection is a fixed attachment to the fan rotor and as fan case further as a with a does not require a rotating interface.

In another form, a turbine engine comprises a generally cylindrical stator module transportable a single unit and including an integrated fan cowl, and inlet. The engine comprises a rotor module transportable single un--', tt and including a core enalne rotatable fan rotor. The rotor module is removably attachable to the stator module. A plurality of fan blades is removably attachable to the fan rotor. The stator module may include a plurality of circumferentially spaced and radially depending fan struts attached at one end along an inner surface of the stator module. Another end of the fan struts may be removably attachable to the rotor module for supporting the rotor module within at least part of the stator module. At least some of the fan struts may project substantially perpendicular toward the centerline of the rotor module while others of the fan struts may comprise structural outlet guide vanes which project obliquely toward the centerline of the rotor module. A spinner is desirably removably attached to the fan rotor forward of the fan blades.

13DV-9908 is The invention also provides a method for assembling a turbo-fan engine having a rotor module including a core engine with a rotatable fan ro'tor and further having a stator module including an integrated fan casing, fan cowl and inlet. The method comprises removably attaching the rotor module, as a single integrated unit, to the stator module and thereafter attaching a plurality of fan blades to the fan rotor. The method may further comprise affixing a plurality of circumferentially spaced fan struts to the stator module with the fan struts ektendinS generally radially from the stator module toward the rotor module and removably attaching inner ends of the fan struts to the rotor module for supporting the rotor module at least partially within the stator module.

For a better understanding of the invention, reference may be had to the detailed description taken in conjunction accompanying drawings in which:

FIG. 1 is a simplified partial cross-sectional drawing of an exemplary gas turbine engine; FIG. 2 is a simplified drawing showing mounting of the engine of FIG. 1 on an aircraft wing; FIG. 3 is a simplified drawing showing an engine arrangement in accordance with the present invention mounted to an aircraft wing; and FIG. 4 is an exploded view of the engine arrangement of FIG. 3 showing engine disassembly.

present following with the 13DV-9908 Referring first to FIG. 1. there is shown a partial cross-sectional drawing of an exemplary highbypass ratio gas turbine engine 10 having a core engine portion indicated at 12 and a fan portion indicated at 14. The core engine or core engine portion 12 may be referred to as the rotor module while the fan portion 14 may be referred to as the stator module. In general. a-:. least some extent of the rotor module lies within the stator module..' The rotor module or core engine 12 includes an intermediate pressure compressor or booster stage 16. a high pressure compressor stage 18. a combustor stage 20. a high pressure turbine stage 21, and a low pressure turbine stage 22 all aligned on an engine centerline 23. The fan portion 14 includes a plurality of fan blades 24. a fan shroud 26. a fan spinner 26 and a plurality of circumferentially spaced outlet guide vanes 30 which support the fan shroud 26. The vanes 30 are attached to engine casing 32 adjacent the booster stage 16. The engine 10 also includes an aft core cowl 33 and a primary nozzle 35. A fan shaft 37 driven by turbine stage 22 extends through the engine and is coupled in driving relationship with booster stage 16 and fan blades 24 via a fan rotor 45. The high pressure turbine stage 21 drives a compressor stage 18 through a high pressure shaft 41.

As will be apparent from FIG. 1. handling of the engine 10 is a major problem for very large diameter fan blades 24. While it is possible to remove the blades 24. the practice in the art is to treat the blades 24. booster stage 16. and casing 26 as a unitary module. Some engines are constructed with a v 13DV-9908 - 7 two-piece fan shaft 37 separable aft of the booster stage 16 approximately along the line 43. These engines are identified as "split fan" engines.

Assembly and/or disassembly of split fan engines is complicated since it is difficult to attach the fan forward shaft and the fan mid shaft properly. In such fan split methods of separating an engine. the forward module or fan module includes the fan shroud 26.

structural outlet guide vanes 30, fan spinner 28. fan rotor blades 24. along with the fan rotor. booster stage 16 and the forward portion of shaft 37. Thus.

it has not been practical to separate the fan module and large external components from the core engine to facilitate handling. Furthermore, it is not desirable to separate an engine where such separation includes a rotating interface since such interface may involve bearings or critical alignments.

Turning now to FIG. 2, there is shown a simplified cross-sectional view of an engine similar to that of FIG. I mounted within an aerodynamic fan cowl 34 which is in turn coupled via a structural member 36 to an aircraft wing 38. The structural member 36 and cowling 34 are well known in the art and may be of the type shown, by way of example, in U.S. Patent No.

4.132.069. Within the fan cowl 34, the member 36 is connected to the fan shroud 26. The shroud 26 is releasably connected to the cowl 34. The cowl 34 preferably includes an inlet section 37.

FIG. 3 illustrates an arrangement in accordance with the teaching of the present invention in a stylized representation of a turbofan engine. The fan cowl. indicated at 40, is an integrated cowl incorporating the aerodynamic characteristics of the cowl 34 but including the structural features of a fan 13DV-9908 casing. In particular. the fan shroud 26 is now an integrated part of cowl 40 as shown by the increased thickness in the cross-sectional dimensions of FIG. 3.

The structural member 36 attaches to the cowl 40, or rather to the structural portion of the cowl 40 indicated by cross-sectional members 42. The outlet guide vanes 30 connect to the integrated cowl 40 and support the core engine at essentially the same location as in FIG. 2. Each of the vanes 30 is releasably connected to a booster casing 44 by bolts or other suitable means (not shown) at the location indicated at 46. The casing 44 may be referred to as the forward core cowl and is integral with the frame of the rotor module. The vanes 30 are circumferentially spaced within the cowl 40 and depend radially from an inner surface of the cowl toward the casing 44. At least som.e of the vanes 30 are affixed to the structural members 42 at their respective ends adjacent the inner surface of cowl 40. The depending ends of the vanes 30 are adapted for releasable attachment to the casing 44. The vanes 30 thus act as support members or struts for supporting at least a portion of the rotor module 12 at least partially within the stator module 14. While the vanes 30 extend substantially perpendicularly with respect to the engine centerline 23. additional support is provided by struts 48 which extend obliquely from a connection point 50 adjacent the affixed ends of vanes to a connection point 52 on the forward core cowl or casing 44. The engine 10 may include a yoke (not shown) or other mounting arrangement for releasably attaching the ends of the struts 46 to the rotor module 12.

is f 13DV-9906 - 9 FIG. 4 is an exploded view of the engine assembly of FIG. 3 which illustrates the separable elements of the engine. In particular. the fan blades 24 along with the fan spinner 28 are removable from the rotor module 12 and can be disassembled from the rotor module without removing the engine nacelle 40. The blades 24 are preferably individually detachable from a rotatable fan rotor 45 which also is part of the core engine and is coaxial with centerline 23. The method of connecting or removably attaching the vanes 30 to the fan rotor 45 may be any of the rnethod! well known to those skilled in the art including methods presently used for attaching such fan blades to fan rotors in commercially available turbofan engines.

is The fan rotor 45 is attached to the fan shaft 37 (seen in FIG. 1) for transferring power from the low pressure turbine stage 22 to the fan blades 24 and booster compressor stage 16.

The rotor module 12 is disconnectable or releasable f ron., the vanes 30 and struts 48 at the connection points 46 and 52, respectively, leaving the vanes 30 and struts 48 in their affixed depending position as shown in FIG. 4. Note also that the aft core cowl 33 may also be removed from the rotor module 12 to facilitate handling and transporting of the rotor module. Other accessory components indicated generally at 56 such as, for example, an electric generator and a hydraulic pump. may also be removed from the rotor module 12 for ease of handling. The items which can be removed from the core engine or rotor module 12 also represent items which can be replaced without affecting the integrity of the rotor module and requiring test stand operation prior to returning the engine to flight status. For engine 13DV-9908 replacement alone. i.e.. to replace only the rotor module 12. it is only necessary to remove the access panels (not shown) in the nacelle 40 to provide access to the connection points of the fan blades 24, outlet guide vanes 30 and struts 48 at the rotor module. With the fan blades 24 and spinner 28 removed. the rotor module 12 may be disconnected from the stator module 14 and moved in an aft direction to separate the two components. One advantage of this arrangement is that the rotor module 12 may be removed from an aircraft without r emoving the nacelle 40. A. more significant advantage is that the rotating components, all of which are integral with the rotor module, are separable from the engine 10 as an integral unit, i.e., the rotor module 12. so that the operational integrity of the engine is not compromised by transporting the rotor module separately from the stator module.

In use, the engine 10 can be fully assembled, performance tested and the fan blades 24 removed for transport. At an aircraft, the engine nacelle 40 is installed. followed by connection of the rotor module or core engine 12 to the nacelle by means of the forward struts 48 and outlet guide vanes 30 and an aft support 56 (the aft support 56 may be substantially identical to aft supports now in commercial use for supporting engines such as 10 to an aircraft). The fan blades 24 and spinner 28 are thereafter connected to the engine 12 to complete assembly. Alternately, the engine 10, or replacement components thereof, may be assembled after transporting but prior to installation on an aircraft. Similarly, while removal of the rotor module 12 provides an advantageous method of replacing or repairing a core engine, there may be 13DV-9908 - 11 occasions in which it is desirable to remove the entire engine. i.e., the rotor and stator modules, as an integral unit and perform disassembly after such removal. Both methods are contemplated by the present invention.

While the principles of the invention have now been made clear in illustrative embodiments, it will become apparent to those skilled in the art that many modifications of the structures, arrangements. and components presented in the above illustrations may be made in the practice of the invention in ordir to develop alternate embodiments suitable to specifi operating requirements without departing from th spirit and scope of the invention.

c e 1 13DV-9908

Claims

A high-bypass ratio gas turbine engine having a core engine portion and a fan. the core engine portion including a casing for structurally supporting -ion. the engine being adapted for the core engine port mounting in an aerodynamic nacelle supported on an aircraft. the improvement comprising: a fan shroud integrated into the nacelle, the -ructural members for supporting at nacelle including st least a portion of the core engine: a plurality of support members connected to the nacelle to the engine casing, said support members being releasably connected to the casing; and means for releasably connecting the fan to the core engine.

2. The gas turbine engine of claim 1 wherein said support members comprise outlet guide vanes.

3. The gas turbine engine of claim 1 and including a fan spinner releasably coupled to said fan blades.

M 13DV-9908 - 13 4. The gas turbine engine of claim 1 wherein said fan shroud comprises a structural member of said nacelle.

5. A method for assembling a high-bypass ratio gas turbine engine to an aircraft, the aircraft including an aerodynamic nacelle for receiving the engine. the nacelle including an integral cylindrical fan shroud forming a structural support portion of the nacelle and further including structural members for attaching the nacelle to the aircraft, the engine including a core portion and a detachable fan, the core portion being encased within a structural casing, the method comprising the steps of:

connecting a plurality of radially directed engine support members to an inner surface of the structural support portion of the fairing; positioning the core engine within the support members; connecting each of the support members to the engine casing to support at least one end of the engine within the fairing; and attaching the fan blades to the engine positioned so as to rotate within the integral shrouds.

6. The method of claim 5 and including the step of attaching a fan spinner to the fan.

13DV-9908 k, 7. A method for removing a high-bypass gas turbine engine from a structural nacelle in which at least a portion of the nacelle acts as a fan shroud. the engi'ne including a fan and a core portion with the core portion being supported by outlet guide vanes attached to the nacelle. the method comprising the steps of: removing a fan spinner from the engine: disconnecting each of the fan blades from the engine and removing each successively from within the nacelle: uncoupling each of the outlet guide vanes from its corresponding connection to the engine casing; detaching an aft engine support; and sliding the engine in an aft direction out of the nacelle and removing the detach engine from the aircraft.

i i 8. A turbofan engine comprising: a stator module transportable as a single unit and ncluding an integrated fan case, fan cowl, and inlet; a rotor module transportable as a single unit and ncluding a core engine with a rotatable fan rotor; means for removably attaching said rotor module to said stator module; and a plurality of fan blades removably attached to said fan rotor.

9. The turbofan engine of claim 8 wherein said stator module also includes, integrated therewith, a plurality of fan struts each having a free end, and wherein said means include means for removably attaching said rotor module to said free ends of said fan struts.

i 13DV-9908 10. The turbofan engine of claim 9 wherein at least some of said fan struts comprise structural outlet ' guide vanes which project generally perpendicularly toward the centerline of said stator module.

1 r, The turbofan engine of claim 10 wherein the remainder of said fan struts project generally obliquely toward the centerline of said stator module.

12. The turbofan engine of claim 8 also including a spinner removably attached to said fan rotor.

1'3. A turbofan engine comprisinS:

a stator module transportable as a single unit and including an integrated fan case, fan cowl. inlet, and plurality of fan struts each having a free end wherein at least some of said fan struts comprise structural outlet guide vanes which project generally perpendicularly toward the centerline of said stator module and the remainder of said fans struts project generally obliquely toward the centerline of said stator module; a rotor module transportable as a single unit and including a core engine with a rotatable fan rotor; means for removably attaching said rotor module to said free ends of said frame struts; plurality of fan blades removably attached to said fan rotor; and spinner removably attached to said fan rotor.

13DV-9906 16 - k is 14. A method for assembling a turbofan engine having a rotor module including a core engine with a rotatable fan rotor and having a stator module including an integrated fan case, fan cowl, and inlet. said method comprising the steps of: removably attaching said rotor module as a single unit to said stator module; and removably attaching a plurality of fan blades to said fan rotor.

including an n l ural itv of 15. A method for assembling a turbofan ' engine having a rotor module including a core engine with a rotatable fan rotor and having a stator module integrated fan case, fan cowl, inlet, and fan struts each having a free end, said method comprising the steps of:

removably attaching said rotor module as a single unit to said free ends oil said fan struts: and removably attaching a plurality of fan blades to said fan rotor.

16. A gas-turbine engine substantially as herein described with reference to the accompanying drawings.

17. A method of assembling an engine substantially as herein described with reference to the accompanying drawings.

18. A method of removing an engine substantially as herein described with reference to the accompanying drawings.

Published 1991 at 7be Patent Office. State House. 66/71 High Holbom. U)ndonWClR47P. Further copies may be obtained from Sales Branch. Unit 6. Nine Mile Point. Cwtnielinfach. Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques lid. St Mary Cray. Kent R a 1