(19)
(11)EP 1 528 247 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
30.12.2015 Bulletin 2015/53

(21)Application number: 04255143.2

(22)Date of filing:  26.08.2004
(51)International Patent Classification (IPC): 
F02K 1/82(2006.01)
F02K 1/12(2006.01)

(54)

Apparatus to reduce turbine engine nozzle base sheet stresses

Vorrichtung zum Vermindern der Spannungen in einer Düsengrundplatte eines Turbinentriebwerks

Dispositif de réduction des contraintes pour une plaque de base de la tuyère d'un moteur à turbine


(84)Designated Contracting States:
DE FR GB IT SE

(30)Priority: 29.10.2003 US 696319

(43)Date of publication of application:
04.05.2005 Bulletin 2005/18

(73)Proprietor: GENERAL ELECTRIC COMPANY
Schenectady, NY 12345 (US)

(72)Inventors:
  • Senile, Darrell Glenn
    Oxford Ohio 45056 (US)
  • Renggli, Bernard J.
    Cincinnati Ohio 45215 (US)
  • Burke, Christina Marie
    Hamilton Ohio 45011 (US)
  • Amneus, John Sigfrid
    Cincinnati Ohio 45215 (US)

(74)Representative: Illingworth-Law, William Illingworth et al
Global Patent Operation - Europe GE International Inc. The Ark 201 Talgarth Road Hammersmith
London W6 8BJ
London W6 8BJ (GB)


(56)References cited: : 
US-A- 5 000 386
US-A- 5 690 279
US-A- 5 683 034
US-A1- 2003 145 600
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description


    [0001] This invention relates generally to gas turbine engine exhaust nozzles and more particularly, to methods and apparatus for reducing turbine engine exhaust nozzle base sheet stresses.

    [0002] At least some known gas turbine engines include an exhaust nozzle including a variable geometry system. The variable geometry system adjusts an area of the exhaust nozzle through the use of flaps and seals. The flaps define discrete sectors of the flowpath, and the seals form the remaining flowpath between adjacent flaps. Because the exhaust nozzles are subjected to high temperatures and thermal gradients as a result of hot combustion gases exiting the engine, the variable geometry systems must maintain a coherent flowpath while shielding the structural components of the variable geometry system.

    [0003] At least some known flap systems consist of a backbone and a base sheet. The backbone secures the base sheet within the variable geometry system. To facilitate extending a useful life at high temperature operation, at least some known base sheets are fabricated from non-metallic materials, such as ceramic matrix composite (CMC) materials.

    [0004] At least some known base sheets are divergent and are attached to the backbone using mechanical fasteners, such as rivets or bolts. Over time, continued thermal expansion may create local stress concentrations within the divergent base sheets. Furthermore, continued thermal cycling may cause the divergent base sheet to deform or distort. Because such tensile strength may be a weakest load path through the base sheet, continued thermal cycling may cause premature failure of the base sheet.

    [0005] US 5,683,034 discloses a divergent flap seal for a gas turbine engine exhaust nozzle, and discloses features which generally correspond to the preamble of claim 1 herein.

    [0006] US 5,690,279 discloses a metal sheet provided with a thermal relief slot.

    [0007] In one aspect, an assembly for a gas turbine engine exhaust nozzle is provided in accordance with claim 1 herein.

    [0008] In a further aspect, a gas turbine engine including a variable engine exhaust nozzle is provided in accordance with claim 7 herein.

    [0009] The invention will now be described in greater detail, by way of example, with reference to the drawings, in which:-

    Figure 1 is a schematic illustration of a gas turbine engine;

    Figure 2 is a perspective view of a portion of a flap system that may be used with the engine shown in Figure 1; and

    Figure 3 is a perspective view of an exemplary base sheet that may be used with the gas turbine engine shown in Figure 1.



    [0010] Figure 1 is a schematic illustration of a gas turbine engine 10 including a fan assembly 12, a high pressure compressor 14, and a combustor 16. in one embodiment, engine 10 is a F414 engine available from General Electric Company, Cincinnati, Ohio. Engine 10 also includes a high pressure turbine 18 and a low pressure turbine 20. Fan assembly 12 and turbine 20 are coupled by a first shaft 24, and compressor 14 and turbine 18 are coupled by a second shaft 26.

    [0011] In operation, air flows through fan assembly 12 and compressed air is supplied from fan assembly 12 to high pressure compressor 14. The highly compressed air is delivered to combustor 16. Airflow from combustor 16 drives rotating turbines 18 and 20 and exits gas turbine engine 10 through an exhaust system 28. Exhaust system 28 includes a variable geometry system 30.

    [0012] Figure 2 is a perspective view of an exemplary flap system 100 that may be used with engine 10 (shown in Figure 1). Figure 3 is a perspective view of an exemplary base sheet assembly 106 that may be used with gas turbine engine 10. Flap system 100 is coupled to an exhaust nozzle, such as exhaust system 28 (shown in Figure 1) to facilitate shielding variable geometry system components from high temperature combustion gases exiting the engine. More specifically, flap system 100 is coupled to the exhaust nozzle such that a flowpath side 102 of flap system 100 is exposed to combustion gases exiting engine. Accordingly, flap system flowpath side 102 defines a portion of the flowpath through the nozzle.

    [0013] Flap system 100 includes a plurality of backbones 104 and base sheet assemblies 106 extending circumferentially within the engine exhaust nozzle. More specifically, backbone 104 is exemplary and is known in the art. Base sheet assembly 106 is coupled within the engine exhaust nozzle by backbone 104, and includes has a leading edge 110 and a trailing edge 112. Base sheet assembly leading and trailing edges 110 and 112, respectively, are coupled together by a pair of side edges 114 and 116. Base sheet assembly 106 also includes an opening 118 extending through base sheet assembly 106 between opposite sides 120 and 122 of base sheet assembly 106. Opening 118 is sized to receive a fastener (not shown) therethrough for securely coupling base sheet assembly 106 to backbone 104. In the exemplary embodiment, base sheet side 120 is a flowpath side of base sheet assembly 106 and side 122 is a radially outer side of base sheet assembly 106.

    [0014] Leading edge 110 and trailing edge 112 each have a respective width W1 and W2 measured between side edges 114 and 116. In the exemplary embodiment, base sheet assembly 106 is divergent such that trailing edge width W2 is wider than leading edge width W1. A centerline axis 120 extends through base sheet assembly 106 between leading and trailing edges 110 and 112, respectively. In the exemplary embodiment, leading and trailing edges 110 and 112, respectively, are substantially perpendicular to centerline axis 120. In an alternative embodiment, leading and trailing edges 110 and 112 are non-parallel.

    [0015] In the exemplary embodiment, base sheet assembly 106 includes a plurality of relief cuts 200 which extend through base sheet assembly 106 between base sheet sides 120 and 122. In an alternative embodiment, base sheet assembly 106 only includes one relief cut 200. Each relief cut 200 extends circumferentially inward from a respective side edge 114 and 116 towards base sheet centerline axis 120. In an alternative embodiment, relief cuts 200 extend only from one of side edges 114 or 116. More specifically, in the exemplary embodiment, each relief cut 200 is oriented substantially perpendicularly to centerline axis 120. In another embodiment, each relief cut 200 is oriented obliquely with respect to centerline axis 120.

    [0016] In the exemplary embodiment, base sheet assembly relief cuts 200 include long relief cuts 230 and short relief cuts 232. Each relief cut 230 and 232 has a length LL and LS measured from a respective base sheet assembly side 114 or 116 to an end 234 and 236 of respective relief cuts 230 and 232. In the exemplary embodiment, relief cuts 230 and 232 extending inwardly from each side 114 and 116 are axially aligned with respect to each other across base sheet assembly 106, such that sides 114 and 116 are mirror images of each other. It should be noted that the size, length, width, number, orientation, and location of relief cuts 200 are variably selected, as described in more detail below, to facilitate each relief cut 200 reducing thermal stresses, deformation, and distortion of base sheet assembly 106.

    [0017] During assembly of flap system 100, initially relief cuts 200 are formed within base sheet assembly 106. More specifically, the number, size, length, width, number, orientation, and location of relief cuts 200 with respect to base sheet assembly 106 is variably selected to facilitate relief cuts reducing thermal stresses induced to base sheet assembly 106. More specifically, as base sheet assembly 106 is thermally cycled during engine operation, relief cuts 200 facilitate reducing thermal stresses induced to base sheet assembly 106 such that deformation, thermal yield, and/or distortion of base sheet assembly 106 is also reduced. More specifically, relief cuts 200 permit base sheet assembly 106 to thermally expand relative to backbone 104 while facilitating reducing thermal stresses induced to base sheet assembly 106 and backbone 104.

    [0018] In the exemplary embodiments described herein, a divergent flap base sheet has been illustrated. However, the stress relief techniques described herein can be applied to a similarly constructed convergent flap base sheet.

    [0019] The above-described flap system is cost-effective and highly reliable. The flap system includes a base sheet assembly that is coupled to the backbone. The base sheet assembly includes a plurality of relief cuts that facilitate reducing thermal stresses induced to the base sheet assembly. Accordingly, deformation and/or distortion of the base sheet assembly is facilitated to be reduced in a cost-effective and reliable manner.


    Claims

    1. An assembly (100) for a gas turbine engine exhaust nozzle (30), said assembly comprising
    a backbone (104); and
    a base sheet (106) coupled to said backbone, said base sheet comprising at least one relief cut (200) and a pair of circumferentially-spaced sides (114 and 116) coupled together by an upstream side (110) and a downstream side (112), said at least one relief cut extends circumferentially inward from at least one of said circumferentially-spaced sides towards said other respective circumferentially-spaced side;
    characterized in that:

    said at least one relief cut comprises a plurality of long relief cuts (230) and a plurality of short relief cuts (232), wherein a length (LL) of each of said long relief cuts is longer than a length (LS) of each said short relief cuts.


     
    2. An assembly (100) in accordance with Claim 1, wherein said base sheet further comprises a flowpath side (120) and an opposite back side (122), said relief cut (200) extends from said flowpath side to said back side.
     
    3. An assembly (100) in accordance with Claim 1, wherein said base sheet (106) has a centerline axis (120), said at least one relief cut (200) oriented substantially perpendicularly to said centerline axis.
     
    4. An assembly (100) in accordance with Claim 1, wherein said at least one relief cut (200) further comprises at least one relief cut extending at least partially across said base sheet from each said circumferentially-spaced base sheet side (114 and 116).
     
    5. An assembly (100) in accordance with Claim 1, wherein said at least one relief cut (200) further comprises a plurality of relief cuts spaced axially between said base sheet upstream and downstream sides (110 and 112).
     
    6. An assembly (100) in accordance with Claim 1, wherein said base sheet upstream side (110) has a first width (W1) measured between said circumferentially-spaced sides (116 and 114), said base sheet downstream side (112) has a second width (W2) measured between said circumferentially-spaced sides, said first width different than said second width.
     
    7. A gas turbine engine (10) comprising a variable engine exhaust nozzle (30) comprising a flap system (100) coupled to said engine exhaust nozzle, said flap system comprising an assembly (100) in accordance with any of the preceding claims.
     
    8. A gas turbine engine (10) in accordance with Claim 7, wherein said flap system base sheet (106) comprises a flowpath side (120) and an opposite back side (122), said at least one base sheet relief cut (200) extending from said flowpath side to said back side.
     


    Ansprüche

    1. Anordnung (100) für eine Gasturbinentriebwerk-Auslassdüse (30), wobei die Anordnung Folgendes umfasst:

    ein Grundgerüst (104); und

    ein Grundblech (106), verbunden mit dem Grundgerüst, wobei das Grundblech mindestens einen Entlastungsschnitt (200) und ein Paar von um den Umfang beabstandeten Seiten (114 und 116) umfasst, die durch eine stromaufwärts liegende Seite (110) und eine stromabwärts liegende Seite (112) miteinander verbunden sind, wobei der mindestens eine Entlastungsschnitt sich am Umfang nach innen von mindestens einer der um den Umfang mit Abstand angeordneten Seiten in Richtung der jeweiligen anderen um den Umfang mir Abstand angeordneten Seite erstreckt;

    dadurch gekennzeichnet, dass:

    der mindestens eine Entlastungsschnitt mehrere lange Entlastungsschnitte (230) und mehrere kurze Entlastungsschnitte (232) umfasst, wobei eine Länge (LL) von jedem der langen Entlastungsschnitte länger als eine Länge (LS) von jedem der kurzen Entlastungsschnitte ist.


     
    2. Anordnung (100) nach Anspruch 1, wobei das Grundblech ferner eine Durchflusswegseite (120) und eine gegenüberliegende Rückseite (122) umfasst, wobei der Entlastungsschnitt (200) sich von der Durchflusswegseite zur Rückseite erstreckt.
     
    3. Anordnung (100) nach Anspruch 1, wobei das Grundblech (106) eine Mittellinienachse (120) aufweist, wobei der mindestens eine Entlastungsschnitt (200) im Wesentlichen senkrecht zur Mittellinienachse ausgerichtet ist.
     
    4. Anordnung (100) nach Anspruch 1, wobei der mindestens eine Entlastungsschnitt (200) ferner mindestens einen Entlastungsschnitt umfasst, der sich zumindest teilweise von jeder um den Umfang mit Abstand angeordneten Grundblechseite (114 und 116) quer über das Grundblech erstreckt.
     
    5. Anordnung (100) nach Anspruch 1, wobei der mindestens eine Entlastungsschnitt (200) ferner mehrere Entlastungsschnitte umfasst, die in Axialrichtung zwischen der stromaufwärts liegenden und der stromabwärts liegenden Seite (110 und 112) des Grundblechs mit Abstand angeordnet sind.
     
    6. Anordnung (100) nach Anspruch 1, wobei das Grundblech auf der stromaufwärts liegenden Seite (110) eine erste Breite (W1) aufweist, die zwischen den um den Umfang beabstandeten Seiten (116 und 114) gemessen wird, das Grundblech auf der stromabwärts liegenden Seite (112) eine zweite Breite (W2) aufweist, die zwischen den um den Umfang beabstandeten Seiten gemessen wird, wobei die erste Breite von der zweiten Breite abweicht.
     
    7. Gasturbinentriebwerk (10), das eine variable Triebwerksauslassdüse (30) umfasst, welche ein Klappensystem (100) umfasst, das mit der Triebwerksauslassdüse verbunden ist, wobei das Klappensystem eine Anordnung (100) nach einem der vorhergehenden Ansprüche umfasst.
     
    8. Gasturbinentriebwerk (10) nach Anspruch 7, wobei das Grundblech des Klappensystems (106) eine Durchlasswegseite (120) und eine gegenüberliegende Rückseite (122) umfasst, wobei sich der mindestens eine Grundblechentlastungsschnitt (200) von der Durchlasswegseite zur Rückseite erstreckt.
     


    Revendications

    1. Ensemble (100) pour une tuyère d'échappement de moteur à turbine à gaz (30), l'ensemble comprenant :

    une ossature (104) ; et

    une tôle de base (106) couplée à ladite ossature, ladite tôle de base comprenant au moins une découpe en dépouille (200) et une paire de côtés circonférentiellement espacés (114 et 116) couplés conjointement par un côté amont (110) et un côté aval (112), ladite au moins une découpe en dépouille s'étendant sur la circonférence vers l'intérieur d'au moins l'un desdits côtés circonférentiellement espacés vers ledit autre côté circonférentiellement espacé respectif ;

    caractérisé en ce que :

    ladite au moins une découpe en dépouille comprend une pluralité de longues découpes en dépouille (230) et une pluralité de courtes découpes en dépouille (232), dans lequel une longueur (LL) de chacune desdites longues découpes en dépouille est plus longue qu'une longueur (LS) de chacune desdites courtes découpes en découpe.


     
    2. Ensemble (100) selon la revendication 1, dans lequel ladite tôle de base comprend en outre un côté de voie d'écoulement (120) et un côté arrière opposé (122), ladite découpe en dépouille (200) s'étendant dudit côté de voie d'écoulement audit côté arrière.
     
    3. Ensemble (100) selon la revendication 1, dans lequel ladite tôle de base (106) présente un axe central (120), ladite au moins une découpe en dépouille (200) étant orientée sensiblement perpendiculairement audit axe central.
     
    4. Ensemble (100) selon la revendication 1, dans lequel ladite au moins une découpe en dépouille (200) comprend en outre au moins une découpe en dépouille s'étendant au moins en partie en travers de ladite tôle de base à partir de chaque dit côté de tôle de base circonférentiellement espacé (114 et 116).
     
    5. Ensemble (100) selon la revendication 1, dans lequel ladite au moins une découpe en dépouille (200) comprend en outre une pluralité de découpes en dépouille axialement espacées entre les côtés amont et aval (110 et 112) de ladite tôle de base.
     
    6. Ensemble (100) selon la revendication 1, dans lequel ledit côté amont (110) de la tôle de base a une première largeur (W1) mesurée entre lesdits côtés circonférentiellement espacés (116 et 114), tandis que ledit côté aval (112) de la tôle de base a une seconde largeur (W2) mesurée entre lesdits côtés circonférentiellement espacés, ladite première largeur étant différente de ladite seconde largeur.
     
    7. Moteur à turbine à gaz (10) comprenant une tuyère d'échappement de moteur variable (30) comprenant un système de volets (100) couplé à ladite tuyère d'échappement de moteur, ledit système de volets comprenant un ensemble (100) selon l'une quelconque des revendications précédentes.
     
    8. Moteur à turbine à gaz (10) selon la revendication 7, dans lequel ladite tôle de base (106) du système de volets comprend un côté de voie d'écoulement (120) et un côté arrière opposé (122), ladite au moins une découpe en dépouille (200) de la tôle de base s'étendant dudit côté de voie d'écoulement audit côté arrière.
     




    Drawing














    Cited references

    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description