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GB2447892A - Sealing assembly - Google Patents

Sealing assembly Download PDF

Info

Publication number
GB2447892A
GB2447892A GB0705679A GB0705679A GB2447892A GB 2447892 A GB2447892 A GB 2447892A GB 0705679 A GB0705679 A GB 0705679A GB 0705679 A GB0705679 A GB 0705679A GB 2447892 A GB2447892 A GB 2447892A
Authority
GB
United Kingdom
Prior art keywords
sealing means
groove
groove portion
fin portion
fin
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Withdrawn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
GB0705679A
Other versions
GB0705679D0 (en
Inventor
Nigel James David Chivers
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 GB0705679A priority Critical patent/GB2447892A/en
Publication of GB0705679D0 publication Critical patent/GB0705679D0/en
Publication of GB2447892A publication Critical patent/GB2447892A/en
Withdrawn legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/44—Free-space packings
    • 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
    • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/02—Preventing or minimising internal leakage of working-fluid, e.g. between stages by non-contact sealings, e.g. of labyrinth type
    • 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
    • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/001—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between stator blade and rotor
    • 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
    • F01D11/00—Preventing or minimising internal leakage of working-fluid, e.g. between stages
    • F01D11/02—Preventing or minimising internal leakage of working-fluid, e.g. between stages by non-contact sealings, e.g. of labyrinth type
    • F01D11/025—Seal clearance control; Floating assembly; Adaptation means to differential thermal dilatations
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/08—Sealings
    • F04D29/083—Sealings especially adapted for elastic fluid pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/08—Sealings
    • F04D29/16—Sealings between pressure and suction sides
    • F04D29/161—Sealings between pressure and suction sides especially adapted for elastic fluid pumps
    • F04D29/164—Sealings between pressure and suction sides especially adapted for elastic fluid pumps of an axial flow wheel
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/44—Free-space packings
    • F16J15/447—Labyrinth packings
    • F16J15/4472—Labyrinth packings with axial path
    • 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
    • F05D2250/00—Geometry
    • F05D2250/10—Two-dimensional
    • F05D2250/18—Two-dimensional patterned
    • F05D2250/181—Two-dimensional patterned ridged
    • 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
    • F05D2250/00—Geometry
    • F05D2250/20—Three-dimensional
    • F05D2250/25—Three-dimensional helical
    • 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
    • F05D2260/00—Function
    • F05D2260/60—Fluid transfer
    • F05D2260/602—Drainage
    • F05D2260/6022—Drainage of leakage having past a seal

Landscapes

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

Abstract

The assembly seals a radial gap 30 between two relatively rotatable coaxial members, e.g. the stator 8, 16 and the rotor 6, 14 of a gas turbine compressor. The stator has a fin portion 20 extending axially with an end flange 28 and the rotor has a radially opposed groove portion 32. The fin portion 20 impedes gas flow between the two members and the groove portion 32 is positioned to disrupt gas flow over the fin portion. In use, the rotating rotor centrifugally widens the gap 30 between it and the fin portion 20.

Description

SEALING MEANS
This invention relates to sealing means for sealing a gap between two relatively rotatable coaxial members.
Labyrinth seals are widely used for obstructing a gas flow path connecting different regions in a system, for example in an air system of a gas turbine engine. In use, labyrinth seals create a resistance to gas flow by forcing gas to traverse through a series of fins. The fins run close to the seal's outer lining, and pressure losses are generatecj by the acceleration and expansion of the gas as it passes between each fin tip and the lining.
In many cases centrifugal forces cause the fins to contact the outer lining of the seal.
Consequently, labyrinth seals are often designed with an abradable lining that tolerates rub. When the seal is first used the fin tips cut grooves in the lining, thereafter the fins tend not to rub except in cases of abnormal operation, for example in a gas turbine engine during hard landings. The grooves can serve to further disrupt gas flow over the fin tips improving sealing performance.
It is sometimes necessary to obstruct a gas flow path between two components, which in use separate under centrifugal forces. The traditional labyrinth seal is less efficient under such conditions as the gap between the fin tips and outer casing enlarges as the surfaces separate, which in turn reduces the pressure losses generated.
According to an aspect of the present invention there is provided sealing means for sealing a gap between two relatively rotatable coaxial members comprising a fin portion and radially opposed groove portion, which fin portion extends from one member towards the other member to impede gas flow between them, which groove portion is located on the other member to disrupt gas flow over the fin portion, where in use the radially outer portion rotates faster than the radially inner portion which centrifugally widens the gap between them.
The invention will now be described by way of example only, with reference to the accompanying drawings in which: Figure 1 is a diagrammatic view of a gas turbine engine having sealing means according to the present invention; Figure 2 is a cross-section view of sealing means according to the present invention; Figure 3 is a detailed view of the groove portion from Figure 2; Figure 4 is a detailed view of an alternative profile of the groove portion from Figure 2.
In Figure 1 there is shown a gas turbine engine 2, having a compressor 4, comprising rotor blades 6 and stator blades 8. In flow series with compressor 4 is combustion equipment 10 and turbine 12.
In Figure 2 rotor blade 6 is located on a rotor disc 14, and stator blade 8 is located on an annular casing 16 to define two relatively rotatable coaxial members: rotor assembly 6, 14 and stator assembly 8, 16. An axial gap 18 exists between the two members over which an annular fin portion 20 extends, from a corner between edge 22 and inner surface 24 of casing 16, towards rotor disc 14. The extension of fin portion 20 is greater than the width of the axial gap 18 but shorter than the distance from edge 22 to an inner surface 26 of rotor disc 14. At the distal end of fin portion 20 there is a flange 28, which extends radially outward towards rotor disc 14 but maintains a clearance to define a radial gap 30.
An annular groove portion 32 is located on inner surface 26 of rotor disc 14, radially opposite and outward of flange 28. As viewed more particularly in Figure 3, groove portion 32 is formed with five circumferential annular grooves 34 to 42 and the total width of the groove portion overlaps both sides of flange 28. The profile of each groove is identical and is defined by two walls, a base and a tip, features 44, 46, 48 and 50 respectively when taking groove 34 as an example. The walls of each of grooves 34 to 42 are inclined towards their respective groove's centre to define a substantially buttress shaped profile.
In operation stator assembly 8, 16 is stationary and rotor assembly 6, 14 rotates at very high speed such that radial gap 30 circumferentially increases from its resting size.
Due to a pressure gradient there is an airflow leakage path through axial gap 18 that reduces engine performance. Fin portion 20 impedes airflow through axial gap 18 and re-directs some air back into the path of rotor blade 6 and stator blade 8. Any remaining airflow is re-directed through radial gap 30. Flange 28 and groove portion 32 generate pressure losses in the remaining airflow as it passes between them which further disrupts its path to re-direct more air back towards the path of rotor blatie 6 and stator blade 8.
The advancement in the art provided by the present invention is the presence of fin portion 20 together with groove portion 32 which act constructively to counteract the sealing inefficiencies caused by widening radial gap 30. Impeding and disrupting the airflow in this manner reduces inefficiencies caused by the leakage path to improve engine performance.
Figure 4 is a section similar to Figure 3, but in this arrangement walls 44 and 46 of groove 34 are vertical to define a substantially square shaped profile that is identical for all grooves 34 to 42.
Although aspects of the present invention have been described with reference to the embodiments shown in the accompanying drawings, it is to be understood that the present invention would be equally as effective in other turbo machinery such as the Rolls-Royce LiftFan . The present invention also encompasses embodiments where the groove portion comprises at least one circumferential helical groove.

Claims (13)

1 Sealing means for sealing a gap between two relatively rotatable coaxial members comprising a fin portion and radially opposed groove portion, which fin portion extends from one member towards the other member to impede gas flow between them1 which groove portion is located on the other member to disrupt gas flow over the fin portion, where in use the radially outer portion rotates faster than the radially inner portion which centrifugally widens the gap between them.
2 Sealing means as claimed in claim 1 wherein the width of the groove portion overlaps the distal end of the fin portion.
3 Sealing means as claimed in claims I or 2 wherein the distal end of the fin portion maintains a clearance with the groove portion.
4 Sealing means as claimed in claims 1, 2 or 3 wherein one member is stationary and the fin portion extends from the stationary member and is radially interior of the groove portion.
Sealing means as claimed in any preceding claim wherein the fin portion has a flange at its distal end on the surface opposite the groove portion.
6 Sealing means as claimed in claim 5 wherein the width of the groove portion overlaps both sides of the flange.
7 Sealing means as claimed in claims I to 6 wherein the groove portion has at least one circumferential annular groove.
8 Sealing means as claimed in claims 1 to 6 wherein the groove portion has at least one circumferential helical groove.
9 Sealing means as claimed in claims 7 or 8 wherein the profile of the or each groove is substantially square shaped.
Sealing means as claimed in claims 7 or 8 wherein the walls of the or each groove are inclined towards their respective grooves centre to define a substantially buttressed shaped profile.
11 Sealing means as claimed in any preceding claim wherein one of the members is a rotor disc.
12 A gas turbine or the like including sealing means as claimed in any one of claims 1 to 11.
13 Sealing means substantially as hereinbefore described with reference to Figures 1, 2, 3 and 4 of the accompanying drawings.
GB0705679A 2007-03-24 2007-03-24 Sealing assembly Withdrawn GB2447892A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB0705679A GB2447892A (en) 2007-03-24 2007-03-24 Sealing assembly

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0705679A GB2447892A (en) 2007-03-24 2007-03-24 Sealing assembly

Publications (2)

Publication Number Publication Date
GB0705679D0 GB0705679D0 (en) 2007-05-02
GB2447892A true GB2447892A (en) 2008-10-01

Family

ID=38024773

Family Applications (1)

Application Number Title Priority Date Filing Date
GB0705679A Withdrawn GB2447892A (en) 2007-03-24 2007-03-24 Sealing assembly

Country Status (1)

Country Link
GB (1) GB2447892A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR3001492A1 (en) * 2013-01-25 2014-08-01 Snecma Stator i.e. high pressure distributor, for e.g. single stage high pressure turbine, of turbojet engine of aircraft, has three-dimensional patterns locally creating pressure losses at inner wall of annular radially inner platform
EP2770165A1 (en) * 2013-02-20 2014-08-27 Siemens Aktiengesellschaft Riffled seal, turbomachine with riffled seal and method of manufacturing thereof
WO2014127954A1 (en) * 2013-02-20 2014-08-28 Siemens Aktiengesellschaft Riffled seal for a turbomachine, turbomachine and method of manufacturing a riffled seal for a turbomachine
EP3153669A1 (en) * 2015-10-01 2017-04-12 United Technologies Corporation Flow expansion seal
US9695704B2 (en) 2012-04-27 2017-07-04 Nuovo Pignone Srl High damping labyrinth seal with helicoidal and helicoidal-cylindrical mixed pattern

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1088360A (en) * 1964-11-06 1967-10-25 Gen Electric Improvements in gas turbine ducted fan engine sealing means
US4801244A (en) * 1986-06-27 1989-01-31 Flygt Ab Device
GB2251040A (en) * 1990-12-22 1992-06-24 Rolls Royce Plc Seal arrangement
US5252026A (en) * 1993-01-12 1993-10-12 General Electric Company Gas turbine engine nozzle
US6091568A (en) * 1998-02-17 2000-07-18 International Business Machines Corporation Labyrinth seal for minimizing flow gradients leading to aerosoling of contaminants external to spindles
US20040258517A1 (en) * 2001-12-13 2004-12-23 Shailendra Naik Hot gas path assembly
US7121791B2 (en) * 2003-04-25 2006-10-17 Rolls-Royce Deutschland Ltd & Co Kg Main gas duct internal seal of a high-pressure turbine

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1088360A (en) * 1964-11-06 1967-10-25 Gen Electric Improvements in gas turbine ducted fan engine sealing means
US4801244A (en) * 1986-06-27 1989-01-31 Flygt Ab Device
GB2251040A (en) * 1990-12-22 1992-06-24 Rolls Royce Plc Seal arrangement
US5252026A (en) * 1993-01-12 1993-10-12 General Electric Company Gas turbine engine nozzle
US6091568A (en) * 1998-02-17 2000-07-18 International Business Machines Corporation Labyrinth seal for minimizing flow gradients leading to aerosoling of contaminants external to spindles
US20040258517A1 (en) * 2001-12-13 2004-12-23 Shailendra Naik Hot gas path assembly
US7121791B2 (en) * 2003-04-25 2006-10-17 Rolls-Royce Deutschland Ltd & Co Kg Main gas duct internal seal of a high-pressure turbine

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9695704B2 (en) 2012-04-27 2017-07-04 Nuovo Pignone Srl High damping labyrinth seal with helicoidal and helicoidal-cylindrical mixed pattern
FR3001492A1 (en) * 2013-01-25 2014-08-01 Snecma Stator i.e. high pressure distributor, for e.g. single stage high pressure turbine, of turbojet engine of aircraft, has three-dimensional patterns locally creating pressure losses at inner wall of annular radially inner platform
EP2770165A1 (en) * 2013-02-20 2014-08-27 Siemens Aktiengesellschaft Riffled seal, turbomachine with riffled seal and method of manufacturing thereof
WO2014127954A1 (en) * 2013-02-20 2014-08-28 Siemens Aktiengesellschaft Riffled seal for a turbomachine, turbomachine and method of manufacturing a riffled seal for a turbomachine
US9920644B2 (en) 2013-02-20 2018-03-20 Siemens Aktiengesellschaft Riffled seal for a turbomachine, turbomachine and method of manufacturing a riffled seal for a turbomachine
EP3153669A1 (en) * 2015-10-01 2017-04-12 United Technologies Corporation Flow expansion seal
US11493134B2 (en) 2015-10-01 2022-11-08 Raytheon Technologies Corporation Expansion seal

Also Published As

Publication number Publication date
GB0705679D0 (en) 2007-05-02

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Legal Events

Date Code Title Description
WAP Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1)