Patent Application
20230022776
The present invention relates to a method of assembling and disassembling a gas turbine engine and particularly but not exclusively a turbine or compressor module of a gas turbine engine. The present invention further relates to an assembly of a turbine module and a fixture.
The turbine section of a gas turbine engine comprises alternating stator and rotor stages and may be assembled to and disassembled from a rotor shaft either sequentially or by modular build assembly methods. The sequential assembly method is where a first stator stage is assembled to the rotor shaft followed by a first rotor stage, then a second stator stage and so on. The modular assembly method is where the first stator stage, the first rotor stage, the second stator stage and second rotor stage etcetera are pre-assembled as a turbine module using a frame to maintain the relative positioning of the rotor stages and stator stages. The turbine module is then assembled to the rotor shaft and other supporting structure of the gas turbine. The modular assembly method enables simpler servicing in the event of a turbine or compressor section replacement and a reduced downtime for the customer.
However, for a gas turbine engine having a centre-bolt arrangement, as will be described with reference to the present invention, for securing the turbine section to the rotor shaft the turbine section must be assembled sequentially. In other words, each rotor stage and each stator stage must be assembled and disassembled separately and sequentially.
Thus, an object of the presently disclosed method of assembly and disassembly of a gas turbine engine compressor or turbine module and the herein disclosed apparatus for carrying out the method is to provide a simpler and quicker method of assembling and disassembling a compressor or turbine module for new build and/or for servicing purposes. Another object of the presently disclosed method of assembling and disassembling and apparatus is to provide improved handling of the compressor or turbine module.
The above objects are achieved by a method of disassembling a rotor module from a gas turbine engine, the gas turbine engine comprises a rotor output shaft and the rotor module. The rotor module comprises a centre-bolt, a sleeve, at least one rotor stage, at least one stator stage, a casing and an axis. The method comprises the steps attaching a fixture to the at least one rotor stage, attaching the fixture to the casing, detaching the centre-bolt from the at least one rotor stage, detaching the sleeve from the output shaft, attaching the fixture to the sleeve and removing the rotor module and fixture from the rotor output shaft.
In another aspect of the present disclosure, the above objects are achieved by a method of assembling a rotor module to a gas turbine engine. The gas turbine engine comprises a rotor output shaft and the rotor module. The rotor module comprises a centre-bolt, a sleeve, at least one rotor stage, at least one stator stage, a casing and an axis. The method comprises the steps placing the rotor module on to the rotor output shaft, detaching a fixture from the sleeve, attaching the sleeve to the output shaft, attaching the centre-bolt to the at least one rotor stage, detaching the fixture from the casing and detaching the fixture from the at least one rotor stage.
The methods may comprise the step translating the sleeve in an axial direction relative to the at least one rotor stage.
In the method of assembling, the sleeve may comprise a radially extending land that, as a consequence of the step of attaching the fixture to the sleeve a compressive force is provided across the at least one rotor stage between the radially extending land and the fixture.
In the method of assembling, the sleeve may comprise a radially extending land that, as a consequence of the step of detaching the fixture from the sleeve releases a compressive force across the at least one rotor stage between the radially extending land and the fixture respectively.
In the method of disassembling, the method may comprise the step detaching the centre-bolt from the gas turbine engine at a rearward end of the centre-bolt and the step of removing the rotor module and fixture from the rotor output shaft also comprises removing the centre-bolt.
In another aspect of the present disclosure, the above objects are achieved by a rotor module for a gas turbine engine and a fixture. The rotor module comprises a centre-bolt, a sleeve, at least one stator stage, at least one rotor stage, a casing, an axis and a fixture. The sleeve surrounds at least a part of the centre-bolt, the at least one stator stage and the at least one rotor stage surround the sleeve, the casing surrounds the at least one stator stage and the at least one rotor stage. Wherein the fixture is attached to and secures together the casing, the at least one rotor and a forward end of the sleeve, wherein the sleeve comprises a radially extending land that engages an opposing side of the at least one rotor stage thereby the fixture and sleeve providing a compressive force across the at least one rotor stage.
The fixture may comprise an inner part, a mid-section and an outer part. The outer part is attached to the casing, the mid-section is attached to the at least one rotor stage and the inner part is attached to the sleeve.
The mid-section may be generally frustoconical or a truncated cone shape.
The fixture may be annular. Alternatively, the fixture may comprise a number of radially extending arms.
The fixture may be secured to the sleeve via a threaded ring which engages a threaded section on a forward end of the sleeve.
The at least one rotor stage may be two rotor stages. The at least one stator stage may be two stator stages. The downstream order may be a first stator stage, a first rotor stage, a second stator stage and a second rotor stage.
The at least one rotor stage may be three rotor stages. The at least one stator stage may be three stator stages. The downstream order may be a first stator stage, a first rotor stage, a second stator stage, a second rotor stage, a third stator stage and a third rotor stage.
The rotor module may be of a turbine section or a compressor section of the gas turbine engine.
The above-mentioned attributes and other features and advantages of the present disclosure and the manner of attaining them will become more apparent and the present disclosure itself will be better understood by reference to the following description of embodiments of the present disclosure taken in conjunction with the accompanying drawings, wherein:
The terms radial, circumferential and axial are with respect to the engine's rotational axis 26 or as otherwise stated. The terms upstream and downstream are with respect to the general direction of gas flow through the engine and as seen in
The compressor 14 comprises an axial series of stator vanes and rotor blades mounted in a conventional manner. The stator or compressor vanes may be fixed or have variable geometry to improve the airflow onto the downstream rotor or compressor blades. Each turbine 28, 30 comprises an axial series of stator vanes and rotor blades. The stator vanes can be mounted to a radially outer casing or a radially inner drum. The rotor blades are mounted via rotor discs arranged and operating in a conventional manner. A rotor assembly comprises an annular array of rotor blades or blades and the rotor disc.
Each combustor unit 36 is constructed from two walls, an inner wall 37 and an outer wall 39, between which is defined a generally annular space. At the head of the combustor unit 36 is a swirler 40 which comprises a swirl plate, an annular array of swirler vanes and fuel injection points as will be described in more detail later. The swirler 40 is succeeded by a pre-chamber 42 and then a main combustion chamber 38. These combustor unit 36 components are generally arranged about a combustor central axis 44.
In operation air 32 is drawn into the engine 10 through the inlet 12 and into the compressor 14 where the successive stages of vanes and blades compress the air before delivering the compressed air 34 into the combustor system 16. The compressed air 34 flows between the inner and outer walls 37, 39 and into the swirler 40. The swirler 40 creates highly turbulent air into which the fuel is injected. The air/fuel mixture is delivered into the pre-chamber 42, where mixing continues, and then into the main combustion chamber 38. In the combustion chamber 38 of the combustor system 16 the mixture of compressed air and fuel is ignited and burnt. The resultant hot working gas flow is directed into, expands and drives the high-pressure turbine 28 which in turn drives the compressor 14 via the first shaft 22. After passing through the high-pressure turbine 28, the hot working gas flow is directed into the low-pressure turbine 30 which drives the load via the second shaft 24.
The low-pressure turbine 30 can also be referred to as a power turbine and the second shaft 24 can also be referred to as a power shaft. The load is typically an electrical machine for generating electricity or a mechanical machine such as a pump or a process compressor. Other known loads may be driven via the low-pressure turbine. The fuel may be in gaseous and/or liquid form.
The turbine engine 10 shown and described with reference to
The two rotor discs 60, 62 are drivingly connected to one another via respective annular arms 70, 72 which axially extend from their respective discs 60, 62. The two annular arms 70, 72 form a seal 74 with a diaphragm 76 that radially inwardly extends from the second array of stator vanes 50. A seal arm 78 extends axially forward from the first rotor disc 60 and which seals with a static member (not shown) of the gas turbine 10.
The casing 46 is rigidly attached to forward and rearward engine casing structures (not shown) via forward and rearward flanges 80, 82 respectively and in conventional manner.
The rotor module 30 further comprises a centre-bolt or tie-shaft 84 and a sleeve 90. Each rotor disc 60, 62 has a central bore 86, 88 through which the centre bolt 84 extends in an axial direction. The sleeve 90 surrounds at least a part of the centre-bolt 84 and is located between the centre-bolt 84 and the central bores 86, 88 of the discs 60, 62. The rotor discs 60, 62, sleeve 90 and centre-bolt 84 are concentrically arranged about the engine axis 26 when in at least the assembled state in the gas turbine engine 10. Annular gaps or a clearance exist between the sleeve 90 and the bores 86, 88 of the discs 60, 62 such that the sleeve 90 and the discs 60, 62 do not touch each other.
When assembled in the gas turbine 10, the centre-bolt 84 attaches via an attachment 94 to a rotor output shaft 92 of the gas turbine 10. The attachment 94 is a spline or other threaded engagement means with corresponding features on the centre-bolt 84 and rotor output shaft 92 as is known in the art. The attachment 94 is rearward or downstream of the second rotor disc 62. As can be seen in
Thus, in the fully assembled state the rotor module 30 is attached and secured in the gas turbine 10 via the centre-bolt 84 and forward and rearward flanges of the casing 46 to associated architecture as described above.
Referring again to
Referring back to
In whichever form, the fixture 102 comprises, in radially outward sequence, a radially inner part 114, a mid-section 112 and a radially outer part 110. The radially outer part 110 of the fixture 102 is parallel and, when secured to the turbine module 30, is in contact with the forward-facing surface of the flange 80. The fixture 102 comprises a first attachment 108 that attaches to the casing 46 and specifically the flange 80 at the forward or upstream end of the casing 46. The first attachment 108 is in the form of a first clamp 108. The clamp 108 extends from the radially outer most part of the fixture 102 to contact the radially outer surface of the flange 80 and then turns radially inwardly to contact the rearward facing surface of the flange 80. The fixture 102 and clamp 108 securely hold the flange 80 and therefore casing 46 in at least the axial and the radial directions against relative movement therebetween. Alternative to the clamp 108, the flange 80 and fixture 102 (via the radially outer part 110) may be bolted together by an annular array of bolts (and nuts) in a conventional fashion.
The mid-section 112 is angled upstream or rearwardly when traversing from the radially outer part 110 to the radially inner part 114, such that the radially inner part 114 is further rearward or downstream than the radially outer part 110. Thus, the mid-section 112, or at least a part of the mid-section 112, is frustoconical or truncated cone shaped and intrinsically this shape makes the fixture 102 very stiff. The radially inner part 114 is attached to the first rotor stage 56 and specifically the first rotor disc 60. The fixture 102, at the radially inner part 114, comprises a second attachment 116 which is secured to the seal arm 78 via a second clamp 116. The radially inner part 114 contacts the forward or upstream surface of the seal arm 78 and the second clamp 116 extends axially rearward from the fixture 102 without contacting the radially outer surface of the seal arm 78, and then, extends radially inwardly to contact the rearward or downstream surface of the seal arm 78. Thus, the seal arm 78 is clamped by the second clamp's 116 opposing axial surfaces such that relative axial movement between the fixture 102 and the first rotor disc 60 is prevented.
The first and second clamps 108, 116 may be of a hook-clamp type as is well known in the art.
The fixture 102 engages the upstream or forward side 61 of the first rotor stage 56 and the land 100 engages the downstream or rearward side 63 of the second rotor stage 58. Where there is only one rotor stage or more than two rotor stages the upstream or forward side 61 is the furthest upstream or forward side of any of the rotor stages and the downstream or rearward side 63 is the furthest downstream or rearward side of any of the rotor stages. When the fixture 102 is fully attached and secured to the turbine module 30 the fixture and the land 100 engage respective forward and rearward sides of the at least one rotor stage 56, 58 and provide a compressive force across the two sides 61, 63. Even where there is just one rotor stage 56, the compressive force across the rotor stage effectively holds or clamps the rotor stage(s) in position relative to the (at least one) stator stage(s) 48 and the casing 46.
Referring now to
Thus, when the turbine module 30 is removed from the turbine engine 10, the fixture 102 securely fastens together the two rotor stages 56, 58, the two stator stages 48, 50 the casing 46 and the sleeve 90. The turbine module 30 can now be safely removed from the turbine engine 10 and maintenance can be performed on the turbine engine 10 and/or the turbine module 30 more easily. Thus, in this way the turbine module 30 may be removed and re-assembled to the turbine engine 10 more easily and in one assembly and does not require complete disassembly/assembly of the separate components, such as the turbine rotors and blades from the engine. In this way, a much quicker disassembly and assembly is possible, and which also saves significant costs and manpower as well as reduced engine downtime. The turbine module 30 may further comprise the centre-bolt 84. However, the centre-bolt 84 may be removed on its own and before the turbine module 30 is removed from the engine 10 or removed from turbine module 30 after the turbine module 30 has been removed from the turbine engine 10.
From the above description, the present method of disassembling the rotor module 30 from the gas turbine engine 10 comprising the steps: attaching the fixture 102 to one of the rotor stages 56, 58; attaching the fixture 102 to the casing 46; detaching the centre-bolt 84 from the rotor stages 56, 58; detaching the sleeve 90 from the output shaft 92 of the gas turbine engine 10; attaching the fixture 102 to the sleeve 90; and, removing the rotor module 30 and fixture 102 from the rotor output shaft 92.
In concert with the above method of disassembling the rotor module 30 there is a method of assembling or reassembling the rotor module 30 comprising the steps: placing the rotor module 30 onto the rotor output shaft 92; detaching the fixture 102 from the sleeve 90; attaching the sleeve 90 to the output shaft 92; attaching the centre-bolt 84 to the rotor stages 56, 58; detaching the fixture 102 to the casing 46; and, detaching the fixture 102 from the rotor stages 56, 58.
When the sleeve 90 is not attached to the output shaft 92, the sleeve 90 can be translated axially relative to the rotor discs 60, 62. Thus, the method of disassembling comprises the step of translating the sleeve 90 in an axial direction relative to the one rotor disc 60, 62 after detaching the sleeve 90 from the output shaft 92 and before attaching the fixture 102 to the sleeve 90. Similarly, method of assembling comprises the step of translating the sleeve 90 in an axial direction relative to the one rotor disc 60, 62 after detaching the fixture 102 from the sleeve 90 and before attaching the sleeve 90 to the output shaft 92 and before attaching. During this step, the land 100 translates between the downstream side 63 of the rotor stage 58 and the upstream surface of the output rotor shaft 92. In particular, when assembling the land 100 translates from being in contact with the downstream side 63 of the rotor stage 58 and being in contact with the upstream surface of the output rotor shaft 92. Similarly, when disassembling the land 100 translates from being in contact with the upstream surface of the output rotor shaft 92 and being in contact with the downstream side 63 of the rotor stage 58.
As a consequence of attaching the fixture 102 to the sleeve 90 a compressive force is provided across the rotor stage or rotor stages 56, 58 by virtue of the radially extending land 100 engaging the rotor disc 62 and the fixture 102 engaging the arm 78 and/or projection 118. Similarly, when assembling the turbine module 30 to the gas turbine 10, detaching the fixture 102 from the sleeve 90 releases the compressive force across the rotor stage or rotor stages 56, 58 and between the radially extending land 100 and the fixture 102 respectively.
The presently described methods of disassembling and assembling the rotor module 30 and the rotor module incorporating the fixture 102 are described with reference to a turbine system 18; however, they are intended to be applicable to the compressor section 14. Although, applicable to the compressor section 14 the fixture 102 would be attached to the compressor module from the downstream or rearward side rather than the upstream or forward side as the case is for the turbine module. Therefore, where applicable the terms upstream, downstream, forward and rearward are reversed.
All the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.
Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1917397 | Nov 2019 | GB | national |
This application is the US National Stage of International Application No. PCT/EP2020/083671 filed 27 Nov. 2020, and claims the benefit thereof. The International Application claims the benefit of United Kingdom Application No. GB 1917397.0 filed 29 Nov. 2019. All of the applications are incorporated by reference herein in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/083671 | 11/27/2020 | WO |
