GB2076067A - Axial-flow compressor or turbine outer casing - Google Patents

Axial-flow compressor or turbine outer casing Download PDF

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Publication number
GB2076067A
GB2076067A GB8115226A GB8115226A GB2076067A GB 2076067 A GB2076067 A GB 2076067A GB 8115226 A GB8115226 A GB 8115226A GB 8115226 A GB8115226 A GB 8115226A GB 2076067 A GB2076067 A GB 2076067A
Authority
GB
United Kingdom
Prior art keywords
outer casing
axial
inner ring
air chambers
radial
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB8115226A
Other versions
GB2076067B (en
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.)
MTU Aero Engines GmbH
Original Assignee
MTU Motoren und Turbinen Union Muenchen GmbH
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 MTU Motoren und Turbinen Union Muenchen GmbH filed Critical MTU Motoren und Turbinen Union Muenchen GmbH
Publication of GB2076067A publication Critical patent/GB2076067A/en
Application granted granted Critical
Publication of GB2076067B publication Critical patent/GB2076067B/en
Expired legal-status Critical Current

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Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01DNON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D11/00Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/08Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
    • F01D11/14Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing
    • F01D11/16Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing by self-adjusting means
    • F01D11/18Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing by self-adjusting means using stator or rotor components with predetermined thermal response, e.g. selective insulation, thermal inertia, differential expansion
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01DNON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D11/00Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/08Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00Aeronautics or air transport
    • Y02T50/60Efficient propulsion technologies, e.g. for aircraft

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

Abstract

The casing comprises at least one integral unit formed from an inner ring 5 fixedly connected to an outer ring 3 by means of radially-extending connecting webs 2 forming circumferentially-spaced air chambers 4 therebetween, wherein each web 2 has a radial gap 1 opening at the radially-inner surface of the inner ring 5, such that, in use, the gap between the casing and a rotor therein is kept constant and as small as possible. <IMAGE>

Description

SPECIFICATION An outer Casing for an Axial-flow Compressor or Turbine of a Turbomachine This invention relates to an outer casing for an axialflow compressor or a turbine 6f a turbomachine, particularly of a gas turbine engine.
It is known to provide a double-walled casing having air chambers therein. Such a casing is intended to compensate for prevailing thermal effects. The advantage afforded by effective compensation via the casing lies in the fact that radial expansion and shrinkage of thermallystressed stator casings is controlled-so as to affect advantageously the radial gap between the rotor and the stator.
Known compensating designs, comprising for example a segmented inner ring of a hook-type centering device and a control ring, suffer from considerabw functional deficiencies. In particular, the hooks tend to jam as a result of distortion suffered by the segments in operation.
This design also suffers from the disadvantage that important structural elements, such as the hook-tape centering device and segment seals are subject to wear at abutment points, so that the compensating action will suffer.
An object of the present invention is to overcome the above disadvantages and provide an outer casing which ensures optimum compensating action with a narrow and substantially constant blade tip clearance, although the design remains relatively simple and free of wear.
The invention provides an outer casing for an axial-flow compressor or a turbine of a turbomachine comprising an integral unit formed from an inner ring fixedly connected to an outer ring by means of radially-extending connecting webs forming a plurality of circumferentiallyspaced air chambers therebetween, wherein each connecting web has a radial gap extending between adjacent air chambers and opening at the radially-inner surface of the inner ring.
For the proper function of the device of the present invention the radial support elements constitute a focal point, and they are loaded, under thermal effect acting primarily on the inner wall and causing it to extend lengthwise, by compressive or tensile stresses, and under circumferential expansion of the inner wall they are loaded flexurally.
Parameters to govern the optimum configuration and the number of connecting webs and their recesses can be determined by adequate temperature estimates and stress analyses. They relate directly to actual radial and tangential casing expansions in service and to the attending flexural and compressive loads.
The optimum mass ration between inner and outer walls can be determined in a similar manner.
At the axial ends and outer rim zones of the integral ring, purely design-oriented measures are required to reduce the heat transfer at the air chambers and the control mass, where the intended seals and covers should preferably not impair the supporting elements and the inner ring in their proper function.
In use involving relatively high temperature gradients the transfer of heat at the inner rim zone can be alleviated by a suitable thermal insulation layer.
Said general system of an integral casing requires careful centering radially and fixation axially, where the connecting members leading to adjacent casing stages are variously designed to suit the use.
An embodiment of the invention will now be described with reference to the accompanying drawing, wherein: Fig. 1 is a fragmentary view in cross-section of casing unit in accordance with the present invention, Fig. 2 is an enlarged detailed view II from Fig. 1, Fig. 3 is an enlarged sectional view taken along the line Ill-Ill of Fig. 1, and Fig. 4 is a longitudinal section of part of a casing comprising two integral casing units four a multiple-stage, axial-flow compressor of a turbojet engine.
In Fig. 1, a double-walled integral casing unit comprising an outer ring 3 and an inner ring 5 interconnected by thin-walled, radially-extending connecting webs 2. Equally-spaced air chambers 4 between the webs 2 reduce heat transfer between the inner ring 5 and the outer ring 3.
This delays radial thermal expansion and contraction of the outer ring 3, and thus allows the radial expansion of the inner ring 5 to be controlled by the webs 2.
Fig. 2 and 3 provide a step-by-step description of the compensation principle and its sequence in time: When the inner ring 5 is heated, it remains briefly in its original radial position. As the webs 2 increasingly absorb heat, the inner ring 5 moves radially inwards by the amount of radial expansion 8 of the webs 2 and it will not begin to move radially outwards until the outer ring 3 is affected thermally. This radially-outward movement corresponds approximately to the amount of radial thermal expansion of the outer ring 3.
The difference in magnitude between the radial expansion of the inner ring 5 and the outer ring 3, resulting from the optimum shape of the webs 2, is a factor determining the effectiveness of compensation. The amount of tangential expansion 9 of the inner ring 5 is determined by a suitable selection of the width 7 and shape of the radial gap 1, and by an adequately selecting the pitch 6 of the inner ring.
As the inner ring 5 cools down, the above described procedure is reversed. It is here worth noting that the radius of the inner ring 5 increases briefly because of contraction of the webs 2 as the temperature drops. This is an advantage in jet engines, since when the engine is cooling or decelerating -rapidly, this effect will optimise the gap between the rotor blades and the stator casing.
The temperature drop should nevertheless be a consideration in the dimensioning of all construction elements involved.
Fig. 4 shows an alternative design for the outer casing 10 of a multiple-stage axial-flow compressor of a turbojet engine. At least one Tshaped (when viewed in longitudinal section) annularly-formed connecting member 11 is provided for centering the casing axially at 12 and radially at 13, and supporting it. A radiallyextending annular wall section 14 of the connecting element 11 rests in a frontal recess adjacent the outer ring of an integral unit, and at the other end abuts directly against a sealing member 1 5. The integral units are optionally bolted together by means of fitted bolts extending through the respective outer rings 3, sealing members 1 5 and radial wall sections 1 4 of the connecting members 11 in an axial direction along line 16.In Fig. 4, each inner ring 5 is provided with a thermal insulation 1 7 facing the compressor or turbine duct. This insulation is preferably combined with an abraidable coating for the adjoining tips of the rotor blades 1 8 of the turbine.
The insulation 7 can optionally be manufactured from a ceramic material.
As is also apparent from fig. 4, the outer casing 10 may be shaped as a gudie vane carrier at the - respectibe connecting point on the inner side of the casing between two adjacent integral units, e.g. as a circumferential slot 1 9 to accept the respective blade roots.
In Fig. 4, an annular flanged connection 20 is used to provide radial centering and sealing of the respective air chambers 4 relative to the turbine or compressor duct at the respective connecting point on the inner side of the casing between the two adjacent integral units.
Manufacturing materials and methods should be selected to best suit the intended applications and the prevailing operating conditions of the casing.
The integral components associated with the casing are preferably manufactured from, e.g., a highly heat-resistant nickel-base alloy.

Claims (9)

1. An outer casing for an axial-flow compressor or a turbine of a turbomachine comprising an integral unit formed from an inner ring fixedly connected to an outer ring by means of radiallyextending connecting webs forming a plurality of circumferentially-spaced air chambers therebetween, wherein each connecting web has a radial gap extending between adjacent air chambers and opening at the radially-inner surface of the inner ring.
2. An outer casing as claimed in claim 1, comprising a plurality of axially-aligned said integral units, and a sealing member arranged between adjacent integral units for lateral and axial sealing of the air chambers and for covering the radial gaps.
3. An outer casing as claimed in claim 2, wherein a substantially T-shaped, in longitudinal section connecting member is provided for axial fixing and radial centering of the integral units, each connecting member having a radiallyextending annular wall portion which rests in a frontal recess of substantially the outer ring of one integral unit and abuts directly on the sealing element, the integral units being connected together by bolts extending through the respective outer rings, sealing elements and radial wall portions of the connecting members.
4. An outer casing as claimed in claim 3, wherein the radially inner surface of each inner ring has a thermal insulator.
5. An outer casing as claimed in claim 4, wherein the thermal insulator is combined with an abraidable coating.
6. An outer casing as claimed in claim 4 or 5, wherein the insulator is formed from a ceramic material.
7. An outer casing as claimed in any one of claims 2 to 6, wherein the inner surface of the inner rings at the join between two adjacent integral units are formed so as to be capable of receiving respective stator blade roots.
8. An outer casing as claimed in any one of claims 2 to 7, wherein the end of one inner ring at each join has an axially-extending annular flange for radially centering and sealing the respective air chambers at the join.
9. An outer casing for an axial-flow compressor on a turbine of a turbomachine, the outer casing being substantially as herein described with reference to any one of the embodiments shown in the accompanying drawing.
GB8115226A 1980-05-16 1981-05-18 Axial-flow compressor or turbine outer casing Expired GB2076067B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE3018621A DE3018621C2 (en) 1980-05-16 1980-05-16 Outer casing for axial compressors or turbines of flow machines, in particular gas turbine engines

Publications (2)

Publication Number Publication Date
GB2076067A true GB2076067A (en) 1981-11-25
GB2076067B GB2076067B (en) 1983-09-21

Family

ID=6102475

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8115226A Expired GB2076067B (en) 1980-05-16 1981-05-18 Axial-flow compressor or turbine outer casing

Country Status (5)

Country Link
JP (1) JPS5710714A (en)
DE (1) DE3018621C2 (en)
FR (1) FR2482662B1 (en)
GB (1) GB2076067B (en)
IT (1) IT1137477B (en)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4522559A (en) * 1982-02-19 1985-06-11 General Electric Company Compressor casing
US5092737A (en) * 1989-02-10 1992-03-03 Rolls-Royce Plc Blade tip clearance control arrangement for a gas turbine
GB2261708A (en) * 1991-11-20 1993-05-26 Snecma Turbo-shaft engine casing and blade mounting
WO2001044624A1 (en) * 1999-12-14 2001-06-21 Pratt & Whitney Canada Corp. Split ring for tip clearance control
GB2358674A (en) * 2000-01-05 2001-08-01 Ventilatoren Sirocco Howden Bv Fan casing segment for a ventilating fan
WO2008017681A1 (en) * 2006-08-07 2008-02-14 Abb Turbo Systems Ag Axial turbine with slotted cover ring
GB2542932A (en) * 2015-09-29 2017-04-05 Rolls Royce Plc A casing for a gas turbine engine and a method of manufacturing such a casing
US9963993B2 (en) 2012-10-30 2018-05-08 MTU Aero Engines AG Turbine ring and turbomachine

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2540939A1 (en) * 1983-02-10 1984-08-17 Snecma SEALING RING FOR A TURBINE ROTOR OF A TURBOMACHINE AND TURBOMACHINE INSTALLATION PROVIDED WITH SUCH RINGS
FR2559834B1 (en) * 1984-02-22 1988-04-08 Snecma TURBINE RING
DE3509192A1 (en) * 1985-03-14 1986-09-25 MTU Motoren- und Turbinen-Union München GmbH, 8000 München FLOWING MACHINE WITH MEANS FOR CONTROLLING THE RADIAL GAP
FR2607198B1 (en) * 1986-11-26 1990-05-04 Snecma COMPRESSOR HOUSING SUITABLE FOR ACTIVE PILOTAGE OF ITS EXPANSIONS AND MANUFACTURING METHOD THEREOF
FR2711730B1 (en) * 1993-10-27 1995-12-01 Snecma Turbomachine equipped with means for controlling the clearances between rotor and stator.
DE4442157A1 (en) * 1994-11-26 1996-05-30 Abb Management Ag Method and device for influencing the radial clearance of the blades in compressors with axial flow
US5645399A (en) * 1995-03-15 1997-07-08 United Technologies Corporation Gas turbine engine case coated with thermal barrier coating to control axial airfoil clearance
US5639210A (en) * 1995-10-23 1997-06-17 United Technologies Corporation Rotor blade outer tip seal apparatus
EP2722485B1 (en) * 2012-10-22 2018-07-25 MTU Aero Engines AG Inner ring for a stator assembly with adjustable vanes
CN114876584B (en) * 2022-05-12 2023-05-05 中国航发四川燃气涡轮研究院 Staggered tooth type turbine outer ring connection structure

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR975879A (en) * 1948-12-06 1951-03-12 Const Et D Equipements Mecaniq Further training in the construction of cylinders for gas turbines
NL103792C (en) * 1954-12-16
GB1335145A (en) * 1972-01-12 1973-10-24 Rolls Royce Turbine casing for a gas turbine engine
GB1548836A (en) * 1977-03-17 1979-07-18 Rolls Royce Gasturbine engine
US4131388A (en) * 1977-05-26 1978-12-26 United Technologies Corporation Outer air seal

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4522559A (en) * 1982-02-19 1985-06-11 General Electric Company Compressor casing
US5092737A (en) * 1989-02-10 1992-03-03 Rolls-Royce Plc Blade tip clearance control arrangement for a gas turbine
GB2261708A (en) * 1991-11-20 1993-05-26 Snecma Turbo-shaft engine casing and blade mounting
GB2261708B (en) * 1991-11-20 1995-01-25 Snecma Turbo-shaft engine stator
US6368054B1 (en) 1999-12-14 2002-04-09 Pratt & Whitney Canada Corp. Split ring for tip clearance control
WO2001044624A1 (en) * 1999-12-14 2001-06-21 Pratt & Whitney Canada Corp. Split ring for tip clearance control
GB2358674A (en) * 2000-01-05 2001-08-01 Ventilatoren Sirocco Howden Bv Fan casing segment for a ventilating fan
GB2358674B (en) * 2000-01-05 2004-02-18 Ventilatoren Sirocco Howden Bv A housing part for a ventilating fan
WO2008017681A1 (en) * 2006-08-07 2008-02-14 Abb Turbo Systems Ag Axial turbine with slotted cover ring
EP1890011A1 (en) * 2006-08-07 2008-02-20 ABB Turbo Systems AG Axial flow turbine with slotted shroud
US9963993B2 (en) 2012-10-30 2018-05-08 MTU Aero Engines AG Turbine ring and turbomachine
GB2542932A (en) * 2015-09-29 2017-04-05 Rolls Royce Plc A casing for a gas turbine engine and a method of manufacturing such a casing
GB2542932B (en) * 2015-09-29 2019-07-03 Rolls Royce Plc A casing for a gas turbine engine and a method of manufacturing such a casing

Also Published As

Publication number Publication date
IT8121696A0 (en) 1981-05-14
DE3018621C2 (en) 1982-06-03
GB2076067B (en) 1983-09-21
FR2482662B1 (en) 1987-01-09
IT1137477B (en) 1986-09-10
DE3018621A1 (en) 1981-12-03
FR2482662A1 (en) 1981-11-20
JPS5710714A (en) 1982-01-20

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Legal Events

Date Code Title Description
746 Register noted 'licences of right' (sect. 46/1977)

Effective date: 19930411

PCNP Patent ceased through non-payment of renewal fee

Effective date: 19960518