EP0076256B1 - Anneau de commande d'expansion flottant - Google Patents

Anneau de commande d'expansion flottant Download PDF

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Publication number
EP0076256B1
EP0076256B1 EP19810901830 EP81901830A EP0076256B1 EP 0076256 B1 EP0076256 B1 EP 0076256B1 EP 19810901830 EP19810901830 EP 19810901830 EP 81901830 A EP81901830 A EP 81901830A EP 0076256 B1 EP0076256 B1 EP 0076256B1
Authority
EP
European Patent Office
Prior art keywords
turbine
expansion control
control ring
turbine wheel
axis
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.)
Expired
Application number
EP19810901830
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German (de)
English (en)
Other versions
EP0076256A4 (fr
EP0076256A1 (fr
Inventor
Warren W. Davis
Michael W. Kipling
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.)
Caterpillar Inc
Original Assignee
Caterpillar Inc
Caterpillar Tractor Co
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 Caterpillar Inc, Caterpillar Tractor Co filed Critical Caterpillar Inc
Publication of EP0076256A1 publication Critical patent/EP0076256A1/fr
Publication of EP0076256A4 publication Critical patent/EP0076256A4/fr
Application granted granted Critical
Publication of EP0076256B1 publication Critical patent/EP0076256B1/fr
Expired legal-status Critical Current

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Classifications

    • 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
    • F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator

Definitions

  • Gas turbine engines in order to operate efficiently, must maintain a relatively close tolerance between the turbine blades and the surrounding engine. This is necessary in order to minimize the loss of power due to expanding gases passing between the end of the turbine blade and the surrounding shroud.
  • expansion of the turbine wheel relative the engine shroud is a problem which must be dealt with during design and in some cases, during engine operation. While this invention deals specifically with a gas turbine environment, it would be equally applicable to a steam turbine environment.
  • the efficiency of a gas turbine engine to a great extent depends on the "tightness" of the gas stream passing the gasifier turbine.
  • the hot gases impinge on the turbine wheel and the extending turbine blades, there is considerable expansion of the turbine wheel.
  • several actions can be taken. First, it is appropriate to attempt to ensure that the rate of expansion of the turbine shroud structure is essentially the same or is slightly greater than the rate of expansion of the turbine wheel. In order to achieve this, it is necessary to design the turbine shroud structure so it expands equally throughout its entire circumference.
  • US-A-4251185 discloses turbine engine apparatus of the kind (hereinafter referrred to as of the kind described) comprising a housing defining an axis; a turbine wheel mounted for rotation in the housing substantially about the axis; and a shroud assembly mounted concentrically about the axis and around the turbine wheel, and including an expansion control ring. While the structure disclosed in the aforesaid patent permits expansion of the expansion control ring concentric with the engine axis, it does not eliminate the necessity for some sort of additional clearance between the turbine blades and the shroud to compensate for transient inconsistencies in the expansion of the turbine wheel that result in temporary eccentricities of the turbine wheel during acceleration or deceleration of the engine.
  • an abradable shroud structure is also utilized.
  • Such a shroud structure permits contact of the various turbine blades with the shroud structure without undue injury to the turbine blades.
  • the abradable portion of the shroud structure is made softer than the turbine blade so that upon such contact, the shroud structure is worn away.
  • the tip of the turbine blade is designed so that a certain amount of a turbine blade tip will wear away.
  • These type turbine blades are commonly called “squealer tips” stemming from the fact that the contact of the blade with the turbine shroud causes a “squeal”.
  • a unique disadvantage of a "squealer tip” blade is that the cooling passages normally found in gasifier turbine blades are easily blocked by the abrasion of the turbine tip. Once the cooling passages are blocked in the turbine blade, the turbine blade is subject to overheating and subsequent failure.
  • the clearance between the turbine wheel and the shroud structure is permanently increased every time there is contact between the turbine wheel and the shroud structure that is sufficient to cause abrading of the metal, either on the shroud structure or the turbine tip. Not only is there a permanent increase in clearance, there is a possibility that the abraded particles may cause damage to the power turbine downstream of the gasifier turbine.
  • turbine engine apparatus of the kind described is characterized by means for permitting the expansion control ring to float freely, while the turbine wheel is rotating, in all directions perpendicularly to the axis to maintain general concentricity with the turbine wheel as the turbine wheel moves between positions eccentric and concentric to the axis.
  • the invention also includes a turbine shroud assembly having a pair of manifold rings; a spacer ring positioned between the manifold rings and defining a plurality of notches on its inner perimeter which has radius R 2 , each notch having a depth D and a width W 2 ; an expansion control ring having an outer perimeter of radius R 1 where R 1 is less than R 2 and further having a plurality of lugs extending outwardly from the outer perimeter thereof, each of the lugs having a width W 1 and a height of H, characterised in that W 1 is less than W 2 and H is less than or equal to D, the arrangement being such that the expansion control ring is permitted to float freely between the manifold rings in all directions perpendicularly to the axis of the spacer ring.
  • a turbine shroud assembly such as the shroud assembly 10 shown in Figure 1 is applicable for use in a turbine engine, in particular in a gas turbine engine, to surround the turbine wheel 11 (shown schematically in Figures 4A-E) which has extending outwardly therefrom a plurality of blades 12 upon which a stream of hot gases, as indicated by the arrow G, impinge.
  • the shroud assembly 10 is comprised of three major portions, a spacer ring 14, a pair of manifold rings 28 and 30, and an expansion control ring 20.
  • the spacer ring 14 is the outermost portion and has former therein a plurality of notches 16, each adapted to receive a corresponding lug 18 formed on an outwardly extending web 32 of expansion control ring 20.
  • Expansion control ring 20 has positioned thereon a plurality of shroud segments 22.
  • Shroud segments 22 and expansion control ring 20 provide the floating interface between the spacer ring 14 which is fixed to the surrounding engine and the rotating turbine blades 12.
  • expansion control ring 20 and the associated shroud segments 22 are floatingly affixed to the engine casing 24.
  • Spacer ring 14 is formed with a plurality of holes 26 through which a corresponding plurality of bolts 27 may be passed.
  • manifold rings 28 and 30, respectively are on either side of spacer ring 14 . The purpose of these manifold rings is more clearly set forth in US-A-4,251,185. Suffice it to say these rings in addition to providing support for the shroud assembly direct cooling air to the shroud assembly:- - .
  • bolt 27 passes through and thus affixes the manifold rings 28 and 30 and the spacer ring 14to the engine casing 24.
  • Spacer ring 14 has a slightly thicker dimension T 1 than the thickness T 2 of the web 32 of expansion control ring 20. This greater thickness permits movement of expansion control ring 20 relative the manifold rings 28 and 30 and spacer ring 14.
  • Expansion control ring 20 has an outer perimeter 34 which has a radius R 1 while spacer ring 14 has an inner perimeter 36 having a radius R 2 . It should be apparent that radius R 2 is greater than radius R 1 by a predetermined amount. Similarly, in Figure 3 it can be seen that each lug 18 has a width W 1 while each notch 16 has a width W 2 . Further, the depth of each notch is equal to a predetermined amount D, while the height of each lug is equal to H.
  • the expansion control ring 20 in a gas turbine engine may move eccentrically as described in the following paragraphs.
  • FIG. 4A the expansion control ring is shown schematically as a circle at 20, while the space ring is also shown schematically as a circle at 14.
  • a schematic turbine wheel 11 with associated turbine blades 12 is shown in an at rest position at Figure 4A.
  • Prior art devices having abradable shroud segments such as is described in US-A-4,251,185 noted above, will take the configuration shown in Figure 4B should there be a lack of concentricity between the turbine shroud 20' and the turbine wheel 11' upon start-up or during operation of the engine.
  • Figure 4B it can be seen that the turbine wheel 11' has moved downwardly so that the associated turbine blades 12' will come in contact with expansion control ring 20'.
  • FIG. 4E The present invention is shown schematically in Figure 4E wherein the turbine wheel 11 is eccentric to the housing as represented by spacer ring 14.
  • initial contact is made between the blades 12 and the shroud segment 22 best illustrated in Figure 2 with a resultant movement of the expansion control ring 20 from its concentric position represented by the phantom circle 200, to an eccentric position relative the engine axis 40, but maintaining concentricity with the turbine wheel 11.
  • the expansion control ring 20 is free to move or float relative the turbine wheel.
  • lugs 18 and notches 20 provide means for expansion control ring 20 to maintain general concentricity with turbine wheel 11, even though turbine wheel 11 is running eccentrically to the engine axis 40.
  • the expension control ring 20 is free to move in a radial direction and to a certain extent, to rotate axially. Concurrently, sufficient gap is maintained between the expansion control ring 20 and the spacer ring 14 so that any variation in the rate of expansion between the expansion control ring and the spacer ring 14 may take place without serious injury to the internal portions of the engine. It is appropriate to make the clearances between the sides of the lugs 18 and notches 16 less than the clearances between the end of the notches 16 and lugs 18 so that the radial movement of the expansion ring will be controlled by the side clerance. It is also important to understand that the clearance between the sides of the lugs and notches is not made so large so that there will be excessive movement, rather the fit should be sufficiently tight so that movement is dampened between the two portions.
  • the aforedescribed invention has particular advantages in that it overcomes the necessity for using either an abradable shroud or a "squealer tip" as described in the background of this invention.
  • abradable shrouds have been subject to oxidation and corrosion due to the high gas temperatures and have further suffered from erosion due to the high gas velocities after a short period of time.
  • the actual clearance between the turbine wheel and the expansion control ring 20 will increase due to this erosion and corrosion problem.
  • the "squealer tips" are used on all blades of the turbine wheel, there is a permanent increased clearance between all the blades and the shroud structure as shown in Figure 4D.
  • the abrasion around the end of the "squealer tip” may block off the air flow through the turbine blade, thereby having a deleterious effect on the cooling of the engine itself.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Turbine Rotor Nozzle Sealing (AREA)

Claims (6)

1. Dispositif pour un moteur à turbine, comprenant un carter (24) définissant un axe (40); une roue de turbine (11) montée à rotation dans le carter (24) sensiblement autour de l'axe; et un ensemble formant enveloppe de protection monté concentriquement autour de l'axe (40) et de la roue de turbine (11), et comprenant un anneau de contrôle de dilatation (20), caractérisé par des moyens (16, 18) pour permettre à l'anneau de contrôle de dilatation (20) de flotter librement, pendant la rotation de la roue de turbine, dans toutes les directions perpendiculaires à l'axe afin de maintenir une concentricité générale avec la roue de turbine (11) lorsque celle-ci se déplace entre des positions excentrique et concentrique par rapport à l'axe (41).
2. Dispositif selon la revendication 1, dans lequel l'ensemble formant enveloppe comprend également une paire d'anneaux tubulaires (28,30) une bague d'espacement (14) placée entre les anneaux tubulaires; l'anneau de contrôle de dilatation (20) flottant entre les anneaux tubulaires et comportant plusieurs pattes (18) s'étendant vers l'extérieur sur son périmètre extérieur; et la bague d'espacement (14) comportant sur son périmètre intérieur plusieurs encoches correspondantes (16) pour recevoir les pattes (18), chacune des encoches (16) ayant une largeur, dans le sens circonférenciel, supérieure à celle de la patte correspondante (18) sur l'anneau de contrôle de dilatation (20), et une profondeur, dans le sens radial, supérieure à la hauteur de la patte correspondante (18).
3. Dispositif selon la revendication 2, dans lequel la bague d'espacement (14) a un rayon interne R2 et l'anneau de contrôle de dilatation (20) a un diamètre externe R1' chacune des pattes (18) s'étendant vers l'extérieur au-delà du rayon R1 selon une distance égale à H, chacune des pattes (18) ayant une largeur Wi, chaque encoche (16) ayant une profondeur D et une largeur W2; et la relation entre chaque encoche (16) et chaque patte (18) étant définie par:
Figure imgb0006
4. Ensemble formant enveloppe de protection de turbine ayant une paire d'anneaux tubulaires (28, 30); une bague d'espacement (14) positionnée entre les anneaux tubulaires (28, 30); et définissant plusieurs encoches (16) sur son périmètre intérieur qui a un rayon R2, chaque encoche (16) ayant une profondeur D et une largeur W2; un anneau de contrôle de dilatation (20) ayant un périmètre extérieur de rayon R1, avec R1 inférieur à R2, et en outre plusieurs pattes (18) s'étendant vers l'extérieur depuis son périmètre extérieur, chacune des pattes (18) ayant une largeur W1 et une hauteur H, caractérisé en ce que W1 est inférieur à W2 et H est inférieur ou égal à D, la disposition étant telle que l'anneau de contrôle de dilatation (20) est autorisé à flotter librement entre les anneaux tubulaires (28, 30). dans toutes les directions perpendiculaires à l'axe de la bague d'espacement (14).
5. Ensemble selon la revendication 4, dans lequel la relation entre chaque encoche (16) et chaque patte (18) est définie par:
Figure imgb0007
EP19810901830 1981-04-10 1981-04-10 Anneau de commande d'expansion flottant Expired EP0076256B1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/US1981/000481 WO1982003657A1 (fr) 1981-04-10 1981-04-10 Anneau de commande d'expansion flottant

Publications (3)

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EP0076256A1 EP0076256A1 (fr) 1983-04-13
EP0076256A4 EP0076256A4 (fr) 1983-08-09
EP0076256B1 true EP0076256B1 (fr) 1986-07-09

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EP19810901830 Expired EP0076256B1 (fr) 1981-04-10 1981-04-10 Anneau de commande d'expansion flottant

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EP (1) EP0076256B1 (fr)
JP (1) JPS58500489A (fr)
BE (1) BE892463A (fr)
CA (1) CA1173368A (fr)
DE (1) DE3174911D1 (fr)
MY (1) MY8700851A (fr)
WO (1) WO1982003657A1 (fr)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2574473B1 (fr) * 1984-11-22 1987-03-20 Snecma Anneau de turbine pour une turbomachine a gaz
US6146091A (en) * 1998-03-03 2000-11-14 Mitsubishi Heavy Industries, Ltd. Gas turbine cooling structure
US6315519B1 (en) * 1998-09-28 2001-11-13 General Electric Company Turbine inner shroud and turbine assembly containing such inner shroud
US7094029B2 (en) * 2003-05-06 2006-08-22 General Electric Company Methods and apparatus for controlling gas turbine engine rotor tip clearances
DE10320450B4 (de) 2003-05-08 2013-07-18 Mtu Aero Engines Gmbh Dichtungsanordnung
WO2014137577A1 (fr) 2013-03-08 2014-09-12 United Technologies Corporation Support flexible annulaire

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1352276A (en) * 1918-12-06 1920-09-07 Gen Electric Elastic-fluid turbine
US2530908A (en) * 1946-09-18 1950-11-21 Allis Chalmers Mfg Co Turbine diaphragm
US3067983A (en) * 1958-07-01 1962-12-11 Gen Motors Corp Turbine mounting construction
GB881528A (en) * 1958-09-05 1961-11-01 Burnard Scott Wade Improvements in or relating to two-stroke internal-combustion engines
US3062497A (en) * 1958-11-24 1962-11-06 Ford Motor Co Gas turbine engine
FR1339482A (fr) * 1961-11-28 1963-10-04 Licentia Gmbh Joint de rotor à segments annulaires d'étanchéité radialement mobiles, notammentpour turbo-moteurs
FR2228967A1 (fr) * 1973-05-12 1974-12-06 Rolls Royce
JPS5015043U (fr) * 1973-06-04 1975-02-17
US4251185A (en) * 1978-05-01 1981-02-17 Caterpillar Tractor Co. Expansion control ring for a turbine shroud assembly
GB2050524B (en) * 1979-06-06 1982-10-20 Rolls Royce Turbine stator shroud assembly
GB2092242B (en) * 1981-01-31 1984-12-19 Rolls Royce Non-contacting gas seal

Also Published As

Publication number Publication date
JPH0423087B2 (fr) 1992-04-21
DE3174911D1 (en) 1986-08-14
EP0076256A4 (fr) 1983-08-09
MY8700851A (en) 1987-12-31
CA1173368A (fr) 1984-08-28
EP0076256A1 (fr) 1983-04-13
WO1982003657A1 (fr) 1982-10-28
JPS58500489A (ja) 1983-03-31
BE892463A (fr) 1982-07-01

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