ASSEMBLING AID FOR ASSEMBLING/DE-ASSEMBLING A TURBINE ASSEMBLY

Abstract

An assembling aid for assembling or de-assembling a turbine assembly having at least two aerofoil assemblies connected to each other by at least two interlocking platforms, wherein the at least two aerofoil assemblies are brought from a free-state untwisted position to an assembled twisted position during assembling, including at least one slot embodied to receive at least one part of an aerofoil assembly, wherein the at least one slot has an entry aperture and an exit aperture. A width of the entry aperture of the at least one slot is wider than a width of the exit aperture of the at least one slot.

Claims

1. An assembling aid for assembling or de-assembling a turbine assembly having at least two aerofoil assemblies connected to each other by at least two interlocking platforms, wherein the at least two aerofoil assemblies are brought from a free-state untwisted position to an assembled twisted position during assembling, comprising: at least one slot embodied in such a way to receive at least one part of an aerofoil assembly, wherein the at least one slot has an entry aperture and an exit aperture, wherein a width of the entry aperture of the at least one slot is wider than a width of the exit aperture of the at least one slot.

2. The assembling aid according to claim 1, wherein the at least one slot has a depth extending from the entry aperture to the exit aperture and wherein a width of the at least one slot reduces along the depth in a continuous fashion.

3. The assembling aid according to claim 1, wherein the at least one slot has a centre line along the depth of the at least one slot and has at least one side surface extending along the depth of the at least one slot and wherein the at least one side surface is angled with a taper along the depth of the at least one slot and in respect to the centre line of the at least one slot.

4. The assembling aid according to claim 3, wherein an angle included between the at least one side surface of the at least one slot and the centre line of the at least one slot has a value between 0° and ±15°.

5. The assembling aid according to claim 1, wherein the at least one slot has a centre line along the depth of the at least one slot and has at least one side surface extending along the depth of the at least one slot and wherein the at least one side surface comprises a plurality of facets to simulate a curved along the depth of the at least one slot and in respect to the centre line of the at least one slot.

6. The assembling aid according to claim 1, wherein the at least one part of the aerofoil assembly to be received by the at least one slot has a width and wherein the width of the exit aperture is basically the width of the at least one part of the aerofoil assembly.

7. The assembling aid according to claim 1, further comprising a circular support with an outer surface and wherein the at least one slot is arranged in/at the outer surface and/or wherein the at least one slot extends basically perpendicular to a circumferential direction of the circular support and/or wherein a plurality of slots are arranged one after the other in circumferential direction of the circular support.

8. The assembling aid according to claim 1, wherein the at least one slot is of a first slot type and wherein the assembly aid comprises at least one slot of a second slot type having a constant slot width and/or wherein a width of the at least one slot of the second slot type is basically the width of the at least one part of the aerofoil assembly and/or wherein the at least one slot of the first slot type and the at least one slot of the second slot type are arranged one after the other in a direction basically perpendicular to a circumferential direction of the assembling aid.

9. The assembling aid according to claim 8, wherein the at least one slot of a second slot type has basically the same characteristics as at least one slot of a production disc of the turbine assembly that is embodied in such a way to receive at least one part of the aerofoil assembly in the fully assembled state of the turbine assembly.

10. A method for assembling a turbine assembly, having at least two aerofoil assemblies connected to each other by at least two interlocking platforms, wherein the aerofoil assemblies are brought from a free-state untwisted position to an assembled twisted position during assembling, the method comprising: applying a twisting moment to achieve the assembled twisted position to the at least two aerofoil assemblies by gradually engaging at least one tapered surface of an assembling aid resulting in the assembled twisted position of the at least two aerofoil assemblies.

11. The method according to claim 10, wherein the twisting moment results in an assembled twisted position of the aerofoil assembly in respect to its free state untwisted position with a twist angle of about 0.5° to 10°.

12. The method according to claim 10, wherein the twisting moment is applied to at least a root portion of the aerofoil assembly.

13. The method according to claim 12, wherein the root portion of the aerofoil assembly is positioned in a slot of a first slot type of the assembling aid beforehand of the application of the twisting moment, wherein a width of the at least one slot of a first slot type at its entry aperture is wider than a width (w) of the root portion of the aerofoil assembly.

14. The method according to claim 10, wherein the twisting moment is applied to the aerofoil assemblies beforehand of a positioning of the aerofoil assemblies in a production disc of the turbine assembly.

15. The method according to claim 10, further comprising: transferring the aerofoil assemblies to a production disc of the turbine assembly in their twisted position simultaneously.

16. The assembling aid according to claim 4, wherein the centre line of the at least one slot has a value between 0° and ±10°.

17. The assembling aid according to claim 4, wherein the centre line of the at least one slot has a value between 0° and ±6°.

18. The assembling aid according to claim 6, wherein the width of the exit aperture is basically the width of a root portion of the aerofoil assembly.

19. The method according to claim 11, wherein the twist angle is about 1° to 3°.

20. The method according to claim 11, wherein the twist angle is about 1°.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0061] The present invention will be described with reference to drawings in which:

[0062] FIG. 1: shows a schematically and sectional view of a gas turbine engine comprising several turbine assemblies assembled with the inventive assembling aid and according to the inventive method,

[0063] FIG. 2: shows a perspective view of tree aerofoil assemblies of a turbine assembly from FIG. 1,

[0064] FIG. 3: shows a top view of two aerofoil assemblies from FIG. 2,

[0065] FIG. 4: shows in a perspective view a production disc with the three aerofoil assemblies from FIG. 2 inserted,

[0066] FIG. 5 shows in a perspective view the production disc with the three aerofoil assemblies from FIG. 4 with an aligned assembly aid,

[0067] FIG. 6: shows in a perspective view an angled slot and a constant slot of the assembly aid from FIG. 5,

[0068] FIG. 7: shows in a top view the angled slot and the from FIG. 6,

[0069] FIG. 8: shows in a perspective view the production disc and the aligned assembly aid from FIG. 5 with an alignment tool,

[0070] FIG. 9: shows in a perspective view the alignment tool from FIG. 8 positioned in the angled slot from FIG. 5 and in a slot from the production disc,

[0071] FIG. 10: shows in a perspective view the insertion of the three aerofoil assemblies from FIG. 4 into the assembling aid from FIG. 5,

[0072] FIG. 11: shows in a perspective view the transfer of the three aerofoil assemblies from the FIG. 4 assembling aid into the aligned production disc,

[0073] FIG. 12: shows in a perspective view the three aerofoil assemblies from the FIG. 4 fully assembled in the production disc,

[0074] FIG. 13: shows in a perspective view the beginning of a de-assembly of the three aerofoil assemblies from the production disc,

[0075] FIG. 14: shows schematically an alternative side surface of a slot of the assembling aid following a curve and

[0076] FIG. 15: shows schematically in an enlarged view several facets forming the curve from FIG. 14.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0077] The present invention is described with reference to the above exemplary turbine engine having a single shaft or spool connecting a single, multi-stage compressor and a single, one or more stage turbine. However, it should be appreciated that the present invention is equally applicable to two or three shaft engines and which can be used for industrial, aero or marine applications. In the present description, reference will only be made to a vane, for the sake of simplicity, but it is to be understood that the invention is applicable to both blades and vanes of a turbine engine. The terms upstream and downstream refer to the flow direction of the airflow and/or working gas flow through the engine 54 unless otherwise stated. The terms forward and rearward refer to the general flow of gas through the engine 54. If used in context to the engine 54, the terms axial, radial and circumferential are made with reference to a rotational axis 64 of the engine 54.

[0078] FIG. 1 shows an example of a gas turbine engine 54 in a sectional view. The gas turbine engine 54 comprises, in flow series, an inlet 56, a compressor section 58, a combustion section 60 and a turbine section 62, which are generally arranged in flow series and generally in the direction of a longitudinal or rotational axis 64. The gas turbine engine 54 further comprises a shaft 66 which is rotatable about the rotational axis 64 and which extends longitudinally through the gas turbine engine 54. The shaft 66 drivingly connects the turbine section 62 to the compressor section 58.

[0079] In operation of the gas turbine engine 54, air 68, which is taken in through the air inlet 56 is compressed by the compressor section 58 and delivered to the combustion section or burner section 60. The burner section 60 comprises a burner plenum 70, one or more combustion chambers 72 defined by a can 74 and at least one burner 76 fixed to each combustion chamber 72. The combustion chambers 72 and the burners 76 are located inside the burner plenum 70. The compressed air passing through the compressor section 58 enters a diffuser 78 and is discharged from the diffuser 78 into the burner plenum 70 from where a portion of the air enters the burner 76 and is mixed with a gaseous or liquid fuel. The air/fuel mixture is then burned and the combustion gas 80 or working gas from the combustion is channelled to the turbine section 62 via a transition duct 82.

[0080] This exemplary gas turbine engine 54 has a cannular combustor section arrangement 60, which is constituted by an annular array of combustor cans 74 each having the burner 76 and the combustion chamber 72, the transition duct 82 has a generally circular inlet that interfaces with the combustor chamber 72 and an outlet in the form of an annular segment. An annular array of transition duct outlets form an annulus for channelling the combustion gases 80 to the turbine section 62.

[0081] The turbine section 62 comprises a number of blade carrying discs 52 or turbine wheels 84 attached to the shaft 66. In the present example, the turbine section 62 comprises four discs 52 each carry an annular array of turbine assemblies 12, which each comprises an aerofoil assembly 14, 16 embodied as a turbine blade. However, the number of blade carrying discs 52 could be different, i.e. only one disc 52 or more than four discs 52. In addition, turbine cascades 86 are disposed between the turbine blades. Each turbine cascade 86 carries an annular array of turbine assemblies 12, which each comprises an aerofoil assembly 14, 16 in the form of guiding vanes, which are fixed to a stator 88 of the gas turbine engine 54. Between the exit of the combustion chamber 72 and the leading turbine blades inlet guiding vanes or nozzle guide vanes 90 are provided and turn the flow of working gas 80 onto the turbine blades.

[0082] The combustion gas 80 from the combustion chamber 72 enters the turbine section 62 and drives the turbine blades which in turn rotate the shaft 66. The guiding vanes 90 serve to optimise the angle of the combustion or working gas 80 on to the turbine blades. The turbine section 62 drives the compressor section 58.

[0083] The compressor section 58 comprises an axial series of guide vane stages 92 and rotor blade stages 94 with turbine assemblies 12 comprising aerofoils assemblies 14, 16 or turbine blades or vanes, respectively. The rotor blade stages 94 comprise a rotor disc supporting an annular array of blades. The compressor section 58 also comprises a stationary casing 96 that surrounds the rotor stages 94 and supports the vane stages 92. The guide vane stages 92 include an annular array of radially extending vanes that are mounted to the casing 96. The vanes are provided to present gas flow at an optimal angle for the blades at a given engine operational point. Some of the guide vane stages 92 have variable vanes, where the angle of the vanes, about their own longitudinal axis, can be adjusted for angle according to air flow characteristics that can occur at different engine operations conditions

[0084] The casing 96 defines a radially outer surface 98 of the passage 100 of the compressor section 58. A radially inner surface 102 of the passage 102 is at least partly defined by a rotor drum 104 of the rotor which is partly defined by the annular array of blades.

[0085] FIG. 2 shows in a perspective view a part of a turbine assembly 12 of the gas turbine engine 54 with three exemplarily shown aerofoil assemblies 14, 16 arranged in circumferential direction 44 one after the other (only two aerofoil assemblies are marked with reference numerals). Each aerofoil assembly 14, 16 comprises an aerofoil 106 with an inner platform 108 and an outer interlocking platform 18, 20 or a shroud, respectively, at its opposed ends. Moreover, in radial direction 110 at an inner end of the inner platform 108 each aerofoil assembly 14, 16 comprises a part 24 or a root portion 38, respectively, with a Christmas tree contour 112.

[0086] In FIG. 3 the aerofoil assemblies 14, 16 are shown in a top view in an assembled twisted position where the aerofoil assemblies 14, 16 are connected to each other by the interlocking platforms 18, 20 which engage tightly in a close form fit (see straight arrow). To achieve this position the aerofoil assemblies 14, 16 had to be twisted during their assembling as it is depicted by the half circular arrows.

[0087] The inserted aerofoil assemblies 14, 16 into slots 50, 50′ of the production disc 52 is depicted in FIG. 4 that shows in a perspective view the production disc with the three aerofoil assemblies from FIG. 2 (Please note that for better presentability other slots than the occupied slots are marked with the reference numerals.). The production disc 52 has several in circumferential direction 44 arranged slots 50, 50′ with a Christmas tree contour 112.

[0088] For the assembling of the turbine assembly 12 or the aerofoil assemblies 14, 16 in the production disc 52 an assembling aid 10 is used. The production disc 52 with the inserted aerofoil assemblies 14, 16 and an aligned assembling aid 10 and are shown in FIG. 5 that shows a perspective view of the parts after an assembly.

[0089] The assembling aid 10 has the form of a ring comprising a circular support 40 with an outer surface 42. The outer surface 42 comprises a first type of slots 22, 22′ and a second type of slots 46, 46′ (details see below). The slots 22, 22′, 46′ 46′ are embodied to receive the part 24 or the root portion 38, respectively, of the aerofoil assemblies 14, 16. The slots 22, 22′, 46, 46′ extend basically perpendicular to the circumferential direction 44 of the circular support 40 or in axial direction 48. The axial direction 48 is also the insertion direction of the aerofoil assemblies 14, 16 during the assembling. Moreover, a plurality of slots 22, 22′, 46, 46′ or the same number as aerofoil assemblies 14, 16 per each slot type are arranged one after the other in circumferential direction 44 of the circular support 40. The slots 22, 22′, 46, 46′ comprise a Christmas tree contour 112 embodied correspondingly to the contour of the root portion 38 of the aerofoil assemblies 14, 16.

[0090] Moreover, each slot 22, 22′ of the first slot type and each slot 46, 46′ of the second slot type are arranged one after the other in axial direction 48 (arranged basically perpendicular to the circumferential direction 44).

[0091] The two slot types are shown in more detail in FIGS. 6 and 7 that show a perspective view and a top view of the slots 22, 22′, 46, 46′. The following description refers exemplarily to the slots 22 and 46.

[0092] For the insertion of the aerofoil assemblies 14, 16 the slot 22 has an entry aperture 26 and for exiting the slot 22 an exit aperture 28. The slot 46 as well has an entry aperture 114 and an exit aperture 116. Furthermore, both slots 22, 46 have a depth D extending from the respective entry aperture 26, 114 to the respective exit aperture 28, 116. The depth D is the same as a depth of the root portion 38 of the aerofoil assemblies 14, 16 (not shown in detail).

[0093] For easy access of the slot 22 a width W of the entry aperture 26 is wider than a width w of the exit aperture 28. A width w of the slot 46 and its entry/exit apertures 114, 116 are the same as the width w of the exit aperture 28 of slot 22. Thus, slot 46 has a constant slot width w. Thus, side surfaces 118, 118′ of the slot 46 that extend along the depth D of the slot 46 are arranged in parallel to one another. Moreover, the slot 46 has basically the same characteristics (like contour, width w, depth D, radial length L) as the slot 50 of the production disc 52.

[0094] Both slots 22, 46 have a centre line 30 along their depth D. In this exemplary embodiment the centre lines 30 of both slots are aligned with each other, thus only one centre line 30 is shown.

[0095] The slot 22 has two side surfaces 32, 32′ extending along the depth D of the slot 22 from the entry aperture 26 to the exit aperture 28. The side surfaces 32, 32′ are oriented angled with a taper along the depth D of the slot 22 and in respect to the centre line 30. The slot 22 is an angled slot 22. Consequently, the width W, w of the at least one slot 22, 22′ reduces along the depth D in a continuous fashion. Moreover, the side surfaces 32, 32′ are also angled in respect to the side surfaces 118, 118′ of the constant slot 46.

[0096] An angle α included between the side surface 32, 32′ of the slot 22 and the centre line 30 has a value between 0° and ±15°, advantageously between 0° and ±10°, most advantageously between 0° and ±6° and in this exemplary embodiment of 3°

[0097] An assembling method will be described in the following text with reference to FIGS. 8 to 12.

[0098] FIG. 8 shows the production disc 52 with its slots 50 and the assembling aid 10 with is respective slots 22, 46 in an aligned position towards each other. To ensure concentricity and proper alignment an alignment tool 120 is used. It is embodied as a dummy root portion and is inserted with approximately equal parts in the slot 50 of the production disc 52 and the slot 46 of the assembling aid 10 (see FIG. 9). To further secure the relative position of the parts to one another the production disc 52 and the assembling aid 10 are clamped together (not shown in detail).

[0099] At a subsequent step the root portions 38 are inserted in axial direction 48 into the slot 22 of the assembling aid 10 and are positioned in the free state (see FIG. 10). Along the way the root portions 38 will gradually engage at least one of the angled or tapered side surfaces 32, 32′ and will be finally positioned in the exit aperture 28 of slot 22. At this point a twisting moment to achieve the assembled twisted position is applied to the aerofoil assemblies 14, 16 resulting in the assembled twisted position of the aerofoil assemblies 14, 16. Thus, due to the positioning of the root portions 22 in the exit aperture 28 and subsequently in the slots 46 the aerofoil assemblies 14, 16 are brought simultaneously from the free-state untwisted position to the assembled twisted position during assembling.

[0100] The aerofoil assemblies 14, 16 are twisted such that the root portions 38 are at the correct assembled angle relative to a turbine engine centreline. In other words, torsion is applied to orient the root portion 38 to match the slot 50 of the production disc 52. Generally, the slot 50 in the production disc 52 would always have an angle relative to the turbine engine centreline. A twist angle is an addition, a portion of that angle (not shown in detail).

[0101] The adjustment of the correct angel is done by the engagement force acting on the root portion 38. The twisting moment results in an assembled twisted position of the aerofoil assembly 14, 16 in respect to its free state untwisted position with a twist angle of about 0.5° to 10°, advantageously about 1° to 3°, and most advantageously of about 1° (not shown in detail). The force results also in an angle of twist of the root portion 38 relative to a tip of the aerofoil assembly 14, 16. Every aerofoil assembly 14, 16 typically has the same angle of twist imparted.

[0102] At this point the aerofoil assemblies 14, 16 are constrained in the twisted condition by engagement into the constant slot 46. In the next step the aerofoil assemblies 14, 16 are transferred to the production disc 52 by applying a simultaneous force to all turbine assemblies 14, 16 in axial direction 48 or in the direction of the root portion 38 or the slots 50 of the production disc 52 or in other words by pressing the aerofoil assemblies 14, 16 into position using a helical motion or along a path to match the slot 50 of the production disc 52. It may be also possible to transfer them by continued progressively tapping the aerofoil assemblies 14, 16 until they have passed from the constant slot 46 of the assembling aid 10 into the production disc 52 to the final position. This can be seen in FIG. 11. Thus, the twisting moment is applied to the aerofoil assemblies 14, 16 beforehand of a positioning of the aerofoil assemblies 14, 16 in the production disc 52 of the turbine assembly 12. Thereafter the assembling aid 10 can be removed. This fully assembled position is shown in FIG. 12.

[0103] The assembling aid 10 can also be used for the de-assembling of the turbine assembly 12. This can be done in two ways. Either by fitting and clamping the assembling aid 10 using e.g. concentricity and timing features on the production disc 52 for alignment. Subsequently the aerofoil assemblies 14, 16 can be tapped progressively back into the assembling aid 10 (not shown). Or by progressively tapping the root portions 38 of the aerofoil assemblies 14, 16 out a small amount, like it is shown in FIG. 13. Thereafter the protruding root portions 38 can be fitted into the slots 46, 46′ of the assembling aid 10 to ensure correct alignment (not shown).

[0104] In FIGS. 14 and 15 an alternative embodiment of the slot 22 and the side surfaces 32, 32′ are shown. Components, features and functions that remain identical are in principle substantially denoted by the same reference characters. To distinguish between the embodiments, however, the letter “a” has been added to the different reference characters of the embodiment in FIGS. 14 and 15. The following description is confined substantially to the differences from the embodiment in FIGS. 1 to 13, wherein with regard to components, features and functions that remain identical reference may be made to the description of the embodiment in FIGS. 1 to 13.

[0105] In FIGS. 14 and 15 an alternative slot 22a with alternatively shaped side surfaces 32a, 32a′ is shown in a schematic depiction of the relevant features of the slot 22a. This embodiment differs in such a way from the embodiment shown in FIGS. 1 to 13 that side surfaces 32a, 32a′ comprise a plurality of facets 34, 34′ to simulate a curve 36 along a depth D of the slot 22a and in respect to a centre line 30 of the slot 22a to provide a tapered surface. FIG. 15 shows the facets 34, 34′ of the curve 36 from FIG. 14 in an enlarged view.

[0106] It should be noted that the term “comprising” does not exclude other elements or steps and “a” or “an” does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.

[0107] Although the invention is illustrated and described in detail by the preferred embodiments, the invention is not limited by the examples disclosed, and other variations can be derived therefrom by a person skilled in the art without departing from the scope of the invention.