EP0176447A1 - Apparatus for the automatic control of the play of a labyrinth seal of a turbo machine - Google Patents

Apparatus for the automatic control of the play of a labyrinth seal of a turbo machine Download PDF

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Publication number
EP0176447A1
EP0176447A1 EP85401864A EP85401864A EP0176447A1 EP 0176447 A1 EP0176447 A1 EP 0176447A1 EP 85401864 A EP85401864 A EP 85401864A EP 85401864 A EP85401864 A EP 85401864A EP 0176447 A1 EP0176447 A1 EP 0176447A1
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EP
European Patent Office
Prior art keywords
seal
air
lining
turbomachine
wear
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
EP85401864A
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German (de)
French (fr)
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EP0176447B1 (en
Inventor
Robert Kervistin
Philippe Jean Lefebvre
Alain François Teissier
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.)
Safran Aircraft Engines SAS
Original Assignee
Societe Nationale dEtude et de Construction de Moteurs dAviation SNECMA
SNECMA SAS
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Publication of EP0176447A1 publication Critical patent/EP0176447A1/en
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Publication of EP0176447B1 publication Critical patent/EP0176447B1/en
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    • 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
    • F01D11/08—Preventing or minimising internal leakage of working-fluid, e.g. between stages for sealing space between rotor blade tips and stator
    • F01D11/14—Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing
    • F01D11/16—Adjusting or regulating tip-clearance, i.e. distance between rotor-blade tips and stator casing by self-adjusting means

Definitions

  • the invention relates to an automatic control device in operation of the clearance of a labyrinth type turbomachine seal.
  • the seals between fixed parts and rotating parts of a turbomachine frequently use labyrinth type seals composed, on the one hand, of elements in the form of wipers, in variable number according to the operating conditions and according to various technological parameters, and, on the other hand, on the fixed part opposite, of an element constituting a wear and sealing lining, called "abradable", that is to say usable by friction during possible contact with a wiper without causing significant damage thereto, this element being carried by an annular support connected to a fixed structure of the turbomachine.
  • Such seals can be arranged for example between different movable stages of compressor or turbine, and fixed parts (or rotating at a different speed) in the vicinity.
  • the wipers are in this case carried by spacers or rings and the lining is fixed on the stator (or on the mobile part rotating at the lowest speed preferably).
  • these seals are arranged between various turbomachine enclosures and are found in particular at the ends of the external enclosure of the combustion chamber housing, d on the one hand, on the side of the compressor outlet and, on the other hand, on the side of the turbine inlet.
  • the proper sealing function of the seal is more complex.
  • pressure balancing between various enclosures of the turbomachine is usually sought.
  • Controlled air circulation is also sought in the enclosures in order to create certain ventilation air streams which may be used in other areas of the turbomachine and thus it may be desirable to control the air flows with the best precision.
  • FR-A-2 437 544 in the name of the Applicant describes a seal in which the support of the wear lining is surrounded by an annular channel connected, at its downstream end, to an air intake provided in the wall of the combustion chamber casing while its other end opens upstream of the seal into the lower pressure air space surrounding the compressor shaft.
  • the adjustment of the circulation flow rate of the cooling air of the seal calls for an adjustable discharge valve controlled by an operating parameter of the turbomachine.
  • Another known device aims to obtain cooling of a labyrinth seal placed downstream of a turbomachine compressor and provides for this purpose passages passing through the stator of the seal through which air is sent between two teeth upstream of the seal rotor.
  • labyrinth seals are placed successively from upstream to downstream in three zones located under the downstream part of a combustion chamber and under an associated turbine distributor.
  • the device described collects the leaks coming from the first two seals and reintroduces this air into the third seal between teeth of the seal rotor from holes passing through the stator of this seal.
  • the invention combines new characteristics with these known elements while avoiding the drawbacks of the previous solutions and by new means obtains interesting results.
  • a rise to full throttle speed by rapid acceleration ensuring minimum clearance between the top of the wipers and the cooperating surface of the wear lining and sealing of the labyrinth seal and also, in the event of a sudden deceleration, to avoid any penetration of the wipers into the wear layer, which would cause, in addition to various mechanical drawbacks (vibratory phenomena, overheating inducing phenomena with divergent effect), the subsequent appearance of excessively large clear play that is detrimental to the yields.
  • a minimum of play must even be kept in order to allow that a phase of re-acceleration can follow quickly.
  • the device according to the invention of the aforementioned kind is characterized in that the wear and sealing lining is composed of two parts, a first part consisting of a honeycomb and a second part comprising a smooth surface, a series of holes peripherally distributed and passing through the annular support and the wear and sealing lining, being placed at the level of the separation between the two parts of said lining.
  • the first honeycomb part of the wear and sealing lining is located upstream, relative to the normal direction of gas flow of the turbomachine, from the second part with smooth surface.
  • the first honeycomb part of the wear lining and sealing is located downstream, relative to the normal direction of gas flow of the turbomachine, of the second part with smooth surface.
  • FIG. 1 there is shown schematically, in axial section, under stabilized operating conditions, a portion of a turbomachine comprising an embodiment of the invention.
  • a labyrinth seal according to the invention is disposed between a fixed part and a rotating part of the turbomachine.
  • the rotating part is shown schematically by a rotor part 1.
  • the fixed part comprises a stator element 2 connected in a known manner to the fixed structure of the turbomachine.
  • an annular chamber 3 schematically delimited by two radially spaced internal 4 and external 5 elements and by two axially spaced elements upstream 6 and downstream 7, upstream and downstream being defined with respect to the normal direction of gas flow of the turbomachine.
  • the radially external element 5 comprises one or more air inlet orifices 8. Inside the annular chamber 3, a short distance from the radially internal element 4, is disposed a thin sheet 9 pierced with series of multi-holes 10. This sheet divides the annular chamber 3 into two enclosures, one external 3a comprising the air inlets 8 and the other internal 3b.
  • the internal element 4 of the stator element 2 also constitutes an annular support on the radially internal face of which is fixed a lining 11 for wear and sealing which constitutes an element of the labyrinth seal according to the invention.
  • said wear and sealing lining 11 is composed of two parts, arranged axially and separated by a gap 12, an upstream part 11a and a downstream part 11b.
  • the internal element 4 comprises a series of peripherally distributed holes 12a which constitute air outlet orifices in the annular chamber 3.
  • the upstream part 11a of the wear and sealing lining 11 consists of a honeycomb and the downstream part 11b is a lining of known type and commonly used but necessarily having a smooth surface.
  • the rotor part 1 carries wipers 13 upstream and 14 downstream respectively, the shape and number of which are determined in a manner well known to those skilled in the art as a function of the operating parameters of the turbomachine.
  • the device according to the invention which has just been described makes it possible to obtain improved operation by ensuring in all operating conditions of the turbomachine, both in stabilized and transient conditions, a practically constant clearance guaranteeing a controlled value of the air flow rate passing through the labyrinth seal of the turbomachine on which said device is adapted without inadvertent variations being observed, the consequences of which are harmful for the yields or for the life of certain parts, in the leakage rates at the labyrinth seal.
  • the games jl and j2 may tend to increase.
  • the flow Dl tends to increase, but only according to a very small variation, while the flow D3 increases more quickly in a significant way, this consequently results in an increase in the flow D2 of cooling air.
  • the stator element 2 which centers cooling and therefore a contraction of this stator element 2 and, consequently, the clearances jl and j2 are restored to their initial value.
  • FIG. 2 represents an embodiment for an application of the invention to a labyrinth seal placed in line with the outlet of a combustion chamber on the radially internal side.
  • the internal jacket of an annular type combustion chamber 22 at 23, an annular envelope defining an enclosure 24 for external ventilation of the combustion chamber.
  • the jacket 21 is connected at its downstream end by a fixing means 25, for example of the bolt-on type, to a radial flange 26 of an internal part of stator vane 27.
  • the casing 23 carries a directed radial flange 28 towards the axis of the machine and to which are fixed by fixing means 29, for example of the bolt type, on the one hand, a radial flange 30 at the end of an annular support 31 and, on the other hand , a radial flange 32 at the end of an annular thin sheet 33 multi-perforated.
  • the annular support 31 carries on its radially internal face a wear and sealing lining 34 which comprises two parts arranged axially, an upstream part 34a consisting of a honeycomb and a downstream part 34b having a smooth external surface, these two parts being separated by an interval 34c.
  • the annular support 31 comprises at this interval 34c a series of holes 35.
  • the annular thin sheet 33 is slightly spaced radially outward relative to the support 31 on which it bears radially at 36 at its downstream end.
  • the support 31 carries a radial flange 37 directed radially outwards and making the connection with the internal part of the stator vane 27.
  • the rotary rotor part comprises a disc 38 carrying in the example shown five wipers 39 cooperating with the wear and sealing lining 34.
  • the internal enclosure is separated by the disc 38 into an upstream enclosure 40 where the air is at the pressure Pl and a downstream enclosure 41 where the air is at a pressure P2 lower than Pl.
  • a space provided between the annular support 31 and the chamber envelope 23 constitutes an annular chamber 42 allowing the ventilation of the annular support 31 and separated into two enclosures 42a and 42b by the annular sheet 33.
  • This thin sheet 33 has multi-perforations 43 for the impact ventilation of the support 31.
  • An opening 44 formed in the envelope 23 ensures the passage of a flow of air D2 from the combustion chamber enclosure 24 towards the chamber 42.
  • FIG. 3 schematically represents a part of a turbomachine similar to that which is represented in FIG. 1 and comprising a second embodiment of the invention.
  • the same references have been kept for identical parts as those which appear in FIG. 1 and reference will be made for more details to the complete description of the device which was made previously with reference to FIG. 1.
  • the wear and seal 111 entering the labyrinth seal is composed of two parts, arranged axially and separated by a gap 12, as before.
  • the upstream part IIIa of the wear and sealing lining 111 has a smooth surface and the downstream part IIIa consists of a honeycomb.
  • the device according to the invention according to the second embodiment which has just been described also makes it possible to ensure, as in the first mode, a practically constant clearance of the labyrinth seal, by guaranteeing a controlled value of the air flow passing through said joint and allowing to obtain the same advantages previously noted. Indeed, when a phase of rapid acceleration of climb to full throttle speed of the turbomachine, for example, as in the first embodiment, the clearances I 1 and I 2 may tend to decrease.
  • the flow rate D'3 tends to decrease but according to a very small variation whereas the flow rate D'1 decreases more quickly and in a more notable manner, it consequently results in an increase in the flow rate D'2 of air heating of the stator element 2 and therefore a dilation of this stator element 2 and consequently, the clearances I1 and J'2 are restored to their initial value.
  • the effects tending to decrease the games i1 and i2 are compensated and canceled and the games i1 and i2 are maintained at their objective value determined by the optimum results aimed for in stabilized operation of the turbomachine and it will be the same in all the operating conditions of the turbomachine tending to decrease the clearances i1 and i2.
  • the clearances I and I2 may tend to increase.
  • the flow rate D'3 tends to increase but only according to a very small variation whereas the flow rate D'1 increases more quickly in a significant way, this consequently results in a decrease in the flow rate D'2 air for heating the stator element 2, which causes this stator element 2 to contract and consequently the clearances I1 and J'2 are restored to their initial value.
  • the effects tending to increase the games i1 and i2 are compensated and canceled and the games i1 and i2 are again maintained at their objective value and so will be.
  • the device according to the invention also provides, in the second embodiment, a means of automatic correction, in real time, of variations in operation of the games I1 and I2 of the labyrinth to keep them at their chosen objective value.
  • FIG. 4 represents the same application of the second embodiment of the invention shown in FIG. 3.
  • the same references have again been kept for identical parts as those appearing in FIG. 2. We will limit our to indicating briefly the features arising from the application of the embodiment of Figure 3 to a labyrinth seal of the kind shown in Figure 2.
  • the identical annular support 31 carries on its radially inner face a wear lining and d seal 134 which has two parts arranged axially, an upstream part 134a having a smooth external surface and a downstream part 134b consisting of a honeycomb, these two parts being separated by a gap 134c. Furthermore, a flow of air D'2 for heating the annular support 31 is taken from the enclosure 24 of the combustion chamber.

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

Abstract

Pour contrôler automatiquement le jeu d'un joint à labyrinthe de turbomachine, un élément de stator (2) comporte une chambre annulaire (3) alimentée sous un débit D2 par des orifices (8) et dont la partie radialement interne constitue le support annulaire (4) d'une garniture (11) d'usure et d'étanchéité formant ledit joint avec des léchettes (13, 14) portées par une pièce de rotor (1). Cette garniture (11) est en deux parties (11a, 11b) séparées par un intervalle (12) dans lequel débouchent des perçages (12a) dudit support (4), une partie (11a) étant constituée d'un nid d'abeilles et l'autre partie (11b) présentant une surface lisse. Les variations de débit D2 obtenues s'opposent aux variations des jeux j1 et j2 du joint. La position relative représentée des parties de garniture (11a, 11b) étant choisie dans le cas où le débit D2 est un air plus froid que celui qui alimente en D1 le joint et une position inverse étant choisie dans le cas où l'air d'alimentation en D2 est plus chaud que celui en D1.To automatically control the clearance of a labyrinth seal of a turbomachine, a stator element (2) comprises an annular chamber (3) supplied at a flow rate D2 by orifices (8) and the radially internal part of which constitutes the annular support ( 4) a seal (11) for wear and sealing forming said seal with wipers (13, 14) carried by a rotor part (1). This lining (11) is in two parts (11a, 11b) separated by a gap (12) into which openings (12a) of said support (4) open, a part (11a) consisting of a honeycomb and the other part (11b) having a smooth surface. The variations in flow D2 obtained are opposed to the variations in the clearances j1 and j2 of the joint. The relative position shown of the packing parts (11a, 11b) being chosen in the case where the flow D2 is cooler air than that which feeds the seal in D1 and a reverse position being chosen in the case where the air supply in D2 is hotter than that in D1.

Description

L'invention concerne un dispositif de contrôle automatique en fonctionnement du jeu d'un joint de turbomachine du type à labyrinthe.The invention relates to an automatic control device in operation of the clearance of a labyrinth type turbomachine seal.

Les étanchéités entre parties fixes et parties tournantes de turbomachine font fréquemment appel à des joints du type à labyrinthe composés, d'une part, sur la partie tournante, d'éléments en forme de léchettes, en nombre variable selon les conditions de fonctionnement et suivant divers paramètres technologiques, et, d'autre part, sur la partie fixe située en regard, d'un élément constituant une garniture d'usure et d'étanchéité, dite "abradable", c'est-à-dire usable par frottement lors d'un contact éventuel avec une léchette sans entraîner d'endommagement notable de celle-ci, cet élément étant porté par un support annulaire relié à une structure fixe de la turbomachine. De tels joints peuvent être disposés par exemple entre différents étages mobiles de compresseur ou de turbine, et des parties fixes (ou tournant à une vitesse différente) avoisinantes. Les léchettes sont dans ce cas portées par des entretoises ou des anneaux et la garniture est fixée sur le stator (ou sur la partie mobile tournant à la vitesse la plus faible de préférence).The seals between fixed parts and rotating parts of a turbomachine frequently use labyrinth type seals composed, on the one hand, of elements in the form of wipers, in variable number according to the operating conditions and according to various technological parameters, and, on the other hand, on the fixed part opposite, of an element constituting a wear and sealing lining, called "abradable", that is to say usable by friction during possible contact with a wiper without causing significant damage thereto, this element being carried by an annular support connected to a fixed structure of the turbomachine. Such seals can be arranged for example between different movable stages of compressor or turbine, and fixed parts (or rotating at a different speed) in the vicinity. The wipers are in this case carried by spacers or rings and the lining is fixed on the stator (or on the mobile part rotating at the lowest speed preferably).

Dans une autre utilisation particulière de ces joints qui constitue une application plus directement visée par l'invention, ces joints sont disposés entre diverses enceintes de turbomachine et on les trouve en particulier aux extrémités de l'enceinte externe du carter de chambre de combustion, d'une part, du côté de la sortie de compresseur et, d'autre part, du côté de l'entrée de turbine. Dans ce cas la fonction propre d'étanchéité du joint est plus complexe. En effet, un équilibrage de pressions entre diverses enceintes de la turbomachine est habituellement recherchée. Une circulation d'air contrôlée est également recherchée dans les enceintes en vue de créer certains courants d'air de ventilation utilisable éventuellement dans d'autres zones de la turbomachine et ainsi il peut être souhaitable de contrôler avec la meilleure précision des débits d'air dits "débits de fuite" traversant ce type de joint à labyrinthe et dont la maîtrise se répercute sur divers résultats tels que les rendements de la turbomachine ou la durée de vie de différentes pièces. En dehors des diverses conditions de fonctionnement, telles que la pression dans les enceintes, l'un des paramètres fondamentaux dont dépend ce contrôle des débits d'air est le jeu en fonctionnement entre le sommet des léchettes et la garniture d'usure et d'étanchéité.In another particular use of these seals which constitutes an application more directly targeted by the invention, these seals are arranged between various turbomachine enclosures and are found in particular at the ends of the external enclosure of the combustion chamber housing, d on the one hand, on the side of the compressor outlet and, on the other hand, on the side of the turbine inlet. In this case the proper sealing function of the seal is more complex. In fact, pressure balancing between various enclosures of the turbomachine is usually sought. Controlled air circulation is also sought in the enclosures in order to create certain ventilation air streams which may be used in other areas of the turbomachine and thus it may be desirable to control the air flows with the best precision. so-called "leakage rates" passing through this type of labyrinth seal and whose control has repercussions on various results such as the efficiency of the turbomachine or the service life of different parts. Apart from the various operating conditions, such as the pressure in the chambers, one of the fundamental parameters on which this control of air flow rates depends is the clearance in operation between the top of the wipers and the wear and sealing.

Diverses solutions ont tenté de répondre à ces problèmes posés et en particulier de maintenir à une valeur contrôlée le jeu entre les léchettes et la garniture d'usure et d'étanchéité dans un joint à labyrinthe, quelles que soient les conditions de fonctionnement de la turbomachine, en régime stabilisé ou durant les phases de régime transitoire. Ainsi, FR-A-2 437 544 au nom de la Demanderesse décrit un joint dans lequel le support de la garniture d'usure est entouré d'un canal annulaire relié, à son extrémité aval, à une prise d'air prévue dans la paroi du carter de la chambre de combustion tandis que son autre extrémité débouche en amont du joint dans l'espace à air à pression plus faible entourant l'arbre du compresseur. Le réglage du débit de circulation de l'air de refroidissement du joint fait appel dans ce cas à une vanne de décharge réglable asservie à un paramètre de fonctionnement de la turbomachine. Ce mode de contrôle présente toutefois divers inconvénients inhérents à la méthode car il reste, d'une part, tributaire d'une chaîne complexe d'asservissement en multipliant les risques de panne ou de fonctionnement défectueux tenant aux vannes et autres accessoires et, d'autre part, les temps de réponse, notamment durant les phases de régime transitoire, risquent d'être trop longs pour assurer un fonctionnement pleinement satisfaisant.Various solutions have attempted to respond to these problems posed and in particular to maintain at a controlled value the clearance between the wipers and the wear and sealing lining in a labyrinth seal, whatever the operating conditions of the turbomachine. , in steady state or during transient state phases. Thus, FR-A-2 437 544 in the name of the Applicant describes a seal in which the support of the wear lining is surrounded by an annular channel connected, at its downstream end, to an air intake provided in the wall of the combustion chamber casing while its other end opens upstream of the seal into the lower pressure air space surrounding the compressor shaft. In this case, the adjustment of the circulation flow rate of the cooling air of the seal calls for an adjustable discharge valve controlled by an operating parameter of the turbomachine. However, this method of control has various drawbacks inherent in the method because it remains, on the one hand, dependent on a complex control chain by multiplying the risks of breakdown or faulty operation due to valves and other accessories and, on the other hand, response times, especially during the phases of transient regime, may be too long to ensure fully satisfactory operation.

Un autre dispositif connu selon FR-A-2 449 789 vise à obtenir un refroidissement d'un joint à labyrinthe placé en aval d'un compresseur de turbomachine et prévoit dans ce but des passages traversant le stator du joint par lesquels est envoyé un air de refroidissement arrivant entre deux dents amont du rotor du joint.Another known device according to FR-A-2 449 789 aims to obtain cooling of a labyrinth seal placed downstream of a turbomachine compressor and provides for this purpose passages passing through the stator of the seal through which air is sent between two teeth upstream of the seal rotor.

Selon GB-A-1 525 746, des joints à labyrinthe sont placés successivement d'amont en aval dans trois zones situées sous la partie aval d'une chambre de combustion et sous un distributeur de turbine associé. Afin de réduire globalement les fuites résultant de ces joints, le dispositif décrit collecte les fuites provenant des deux premiers joints et réintroduit cet air dans le troisième joint entre des dents du rotor du joint à partir de perçages traversant le stator de ce joint.According to GB-A-1 525 746, labyrinth seals are placed successively from upstream to downstream in three zones located under the downstream part of a combustion chamber and under an associated turbine distributor. In order to globally reduce the leaks resulting from these seals, the device described collects the leaks coming from the first two seals and reintroduces this air into the third seal between teeth of the seal rotor from holes passing through the stator of this seal.

L'invention associe des caractéristiques nouvelles à ces éléments connus en évitant les inconvénients des solutions antérieures et par des moyens nouveaux obtient des résultats intéressants. Il s'agit en particulier, lors d'une montée au régime plein gaz par une accélération rapide, d'assurer un jeu minimal entre le sommet des léchettes et la surface coopérante de la garniture d'usure et d'étanchéité du joint à labyrinthe et également, au cas d'une décélération brutale, d'éviter toute pénétration des léchettes dans la couche d'usure, ce qui entraînerait, outre divers inconvénients mécaniques (phénomènes vibratoires, échauffements induisant des phénomènes à effet divergent), l'apparition ultérieure de jeux trop importants nettement préjudiciables aux rendements. Durant cette dernière phase transitoire de décélération, en fait, un minimum de jeu doit même être conservé afin de permettre qu'une phase de réaccélération puisse suivre rapidement.The invention combines new characteristics with these known elements while avoiding the drawbacks of the previous solutions and by new means obtains interesting results. In particular, during a rise to full throttle speed by rapid acceleration, ensuring minimum clearance between the top of the wipers and the cooperating surface of the wear lining and sealing of the labyrinth seal and also, in the event of a sudden deceleration, to avoid any penetration of the wipers into the wear layer, which would cause, in addition to various mechanical drawbacks (vibratory phenomena, overheating inducing phenomena with divergent effect), the subsequent appearance of excessively large clear play that is detrimental to the yields. During this last transient phase of deceleration, in fact, a minimum of play must even be kept in order to allow that a phase of re-acceleration can follow quickly.

Le dispositif selon l'invention du genre précité est caractérisé en ce que la garniture d'usure et d'étanchéité est composée de deux parties, une première partie constituée d'un nid d'abeilles et une deuxième partie comportant une surface lisse, une série de perçages périphériquement répartis et traversant le support annulaire et la garniture d'usure et d'étanchéité, étant placés au niveau de la séparation entre les deux parties de ladite garniture.The device according to the invention of the aforementioned kind is characterized in that the wear and sealing lining is composed of two parts, a first part consisting of a honeycomb and a second part comprising a smooth surface, a series of holes peripherally distributed and passing through the annular support and the wear and sealing lining, being placed at the level of the separation between the two parts of said lining.

Avantageusement, lorsque l'air alimentant les perçages de ladite garniture à partir de la chambre ménagée dans le stator du joint est un air de refroidissement plus froid que l'air débitant directement à travers le joint à partir de son extrémité amont située du côté des plus fortes pressions, la première partie en nid d'abeilles de la garniture d'usure et d'étanchéité est située en amont, par rapport au sens normal de circulation des gaz de la turbomachine, de la deuxième partie à surface lisse.Advantageously, when the air supplying the holes in said seal from the chamber formed in the stator of the seal is cooler air than the air flowing directly through the seal from its upstream end situated on the side of the at higher pressures, the first honeycomb part of the wear and sealing lining is located upstream, relative to the normal direction of gas flow of the turbomachine, from the second part with smooth surface.

Par contre et avantageusement, lorsque l'air alimentant les perçages de ladite garniture est plus chaud que l'air débitant directement à travers le joint à partir de son côté amont, la première partie en nid d'abeilles de la garniture d'usure et d'étanchéité est située en aval, par rapport au sens normal de circulation des gaz de la turbomachine, de la deuxième partie à surface lisse.On the other hand and advantageously, when the air supplying the holes in said lining is warmer than the air flowing directly through the seal from its upstream side, the first honeycomb part of the wear lining and sealing is located downstream, relative to the normal direction of gas flow of the turbomachine, of the second part with smooth surface.

D'autres caractéristiques et avantages de l'invention seront mieux compris à l'aide de la description qui va suivre en référence aux dessins annexés dans lesquels :

  • - la figure 1 représente une vue schématique en coupe longitudinale d'une partie de turbomachine comportant un dispositif conforme à l'invention dans le cas où le stator du joint est alimenté par de l'air froid ;
  • - la figure 2 représente en coupe longitudinale une partie de turbomachine comportant un joint à labyrinthe sous le distributeur de turbine et muni selon l'invention d'un dispositif de contrôle automatique en fonctionnement du jeu du joint à labyrinthe, dans le cas où le stator du joint est alimenté par de l'air froid ;
  • - la figure 3 représente une vue schématique en coupe longitudinale d'une partie de turbomachine comportant un dispositif conforme à l'invention dans le cas où le stator du joint est alimenté par de l'air chaud ;
  • - la figure 4 représente en coupe longitudinale une partie de turbomachine comportant un joint à labyrinthe sous le distributeur de turbine et muni selon l'invention d'un dispositif de contrôle automatique en fonctionnement du jeu du joint à labyrinthe, dans le cas où le stator du joint est alimenté par de l'air chaud.
Other characteristics and advantages of the invention will be better understood with the aid of the description which follows with reference to the appended drawings in which:
  • - Figure 1 shows a schematic view in longitudinal section of a part of a turbomachine comprising a device according to the invention in the case where the stator of the seal is supplied with cold air;
  • - Figure 2 shows in longitudinal section a portion of a turbomachine comprising a labyrinth seal under the turbine distributor and provided according to the invention with an automatic control device in operation of the clearance of the labyrinth seal, in the case where the stator the seal is supplied with cold air;
  • - Figure 3 shows a schematic view in longitudinal section of a part of a turbomachine comprising a device according to the invention in the case where the stator of the seal is supplied with hot air;
  • - Figure 4 shows in longitudinal section a portion of a turbomachine comprising a labyrinth seal under the turbine distributor and provided according to the invention with an automatic control device in operation of the clearance of the labyrinth seal, in the case where the stator of the seal is supplied by hot air.

Sur la figure 1, on a représenté schématiquement, en coupe axiale, dans des conditions de fonctionnement stabilisé, une partie de turbomachine comportant un mode de réalisation de l'invention. Un joint à labyrinthe conforme à l'invention est disposé entre une partie fixe et une partie tournante de la turbomachine. La partie tournante est représentée schématiquement par une pièce de rotor 1. La partie fixe comporte un élément de stator 2 relié d'une manière connue à la structure fixe de la turbomachine. Dans cet élément de stator 2 est ménagée une chambre annulaire 3 schématiquement délimitée par deux éléments radialement espacés interne 4 et externe 5 et par deux éléments axialement espacés amont 6 et aval 7, amont et aval étant définis par rapport au sens normal de circulation des gaz de la turbomachine. L'élément radialement externe 5 comporte un ou plusieurs orifices 8 d'arrivée d'air. A l'intérieur de la chambre annulaire 3, à courte distance de l'élément radialement interne 4, est disposée une tôle de faible épaisseur 9 percée de séries de multitrous 10. Cette tôle divise la chambre annulaire 3 en deux enceintes, l'une externe 3a comportant les arrivées d'air 8 et l'autre interne 3b. L'élément interne 4 de l'élément de stator 2 constitue également un support annulaire sur la face radialement interne duquel est fixée une garniture 11 d'usure et d'étanchéité qui constitue un élément du joint à labyrinthe conforme à l'invention. Selon l'invention, ladite garniture 11 d'usure et d'étanchéité est composée de deux parties, disposées axialement et séparées par un intervalle 12, une partie amont lla et une partie aval llb. Au niveau de l'intervalle 12, l'élément interne 4 comporte une série de perçages 12a périphériquement répartis qui constituent des orifices de sortie d'air de la chambre annulaire 3. Dans le mode de réalisation de l'invention représenté à la figure 1, la partie amont lla de la garniture d'usure et d'étanchéité 11 est constituée d'un nid d'abeilles et la partie aval llb est une garniture de type connu et couramment utilisé mais présentant obligatoirement une surface lisse. En regard de chaque partie lla et llb de la garniture d'usure et d'étanchéité 11, la pièce de rotor 1 porte des léchettes respectivement 13 en amont et 14 en aval dont la forme et le nombre sont déterminés de manière bien connue de l'homme du métier en fonction des paramètres de fonctionnement de la turbomachine.In Figure 1, there is shown schematically, in axial section, under stabilized operating conditions, a portion of a turbomachine comprising an embodiment of the invention. A labyrinth seal according to the invention is disposed between a fixed part and a rotating part of the turbomachine. The rotating part is shown schematically by a rotor part 1. The fixed part comprises a stator element 2 connected in a known manner to the fixed structure of the turbomachine. In this stator element 2 is formed an annular chamber 3 schematically delimited by two radially spaced internal 4 and external 5 elements and by two axially spaced elements upstream 6 and downstream 7, upstream and downstream being defined with respect to the normal direction of gas flow of the turbomachine. The radially external element 5 comprises one or more air inlet orifices 8. Inside the annular chamber 3, a short distance from the radially internal element 4, is disposed a thin sheet 9 pierced with series of multi-holes 10. This sheet divides the annular chamber 3 into two enclosures, one external 3a comprising the air inlets 8 and the other internal 3b. The internal element 4 of the stator element 2 also constitutes an annular support on the radially internal face of which is fixed a lining 11 for wear and sealing which constitutes an element of the labyrinth seal according to the invention. According to the invention, said wear and sealing lining 11 is composed of two parts, arranged axially and separated by a gap 12, an upstream part 11a and a downstream part 11b. At the interval 12, the internal element 4 comprises a series of peripherally distributed holes 12a which constitute air outlet orifices in the annular chamber 3. In the embodiment of the invention shown in FIG. 1 , the upstream part 11a of the wear and sealing lining 11 consists of a honeycomb and the downstream part 11b is a lining of known type and commonly used but necessarily having a smooth surface. Opposite each part 11a and 11b of the wear and sealing lining 11, the rotor part 1 carries wipers 13 upstream and 14 downstream respectively, the shape and number of which are determined in a manner well known to those skilled in the art as a function of the operating parameters of the turbomachine.

Le dispositif conforme à l'invention qui vient d'être décrit permet d'obtenir un fonctionnement amélioré en assurant dans toutes conditions de fonctionnement de la turbomachine, aussi bien en régime stabilisé qu'en régime transitoire un jeu pratiquement constant garantissant une valeur contrôlée du débit d'air traversant le joint à labyrinthe de turbomachine sur lequel est adapté ledit dispositif sans que l'on observe des variations intempestives, dont les conséquences sont néfastes pour les rendements ou pour la durée de vie de certaines pièces, dans les débits de fuites au niveau du joint à labyrinthe. En effet, si l'on désigne par jl le jeu entre le sommet des léchettes 13 et la surface coopérante de la partie amont lla de la garniture d'usure et d'étanchéité 11 et par j2 le jeu entre le sommet des léchettes 14 et la surface coopérante de la partie aval llb de ladite garniture, lors d'une phase d'accélération rapide de montée au régime plein gaz de la turbomachine, par exemple, par suite des effets combinés des dilatations notamment d'origine mécanique par effet centrifuge et d'origine thermique appliquées aux différents éléments de structure, les jeux jl et j2 peuvent avoir tendance à diminuer. Si l'on désigne par Dl le débit d'air entrant à l'extrémité amont dans l'espace séparant la pièce de rotor 1 et l'élément de stator 2, par D2 le débit d'air entrant dans la chambre annulaire 3 par les orifices 8 de l'élément de stator 2, le point de prélèvement de cet air dans la turbomachine étant choisi de telle sorte que cet air soit plus froid que celui Dl entrant à l'amont du joint, par D3 le débit d'air sortant du joint à labyrinthe, dans la phase d'accélération concernée, le débit Dl a tendance à diminuer mais suivant une variation très faible alors que le débit D3 diminue plus rapidement et de manière plus notable, il en résulte par conséquent une diminution du débit D2 d'air de refroidissement de l'élément de stator 2, ce qui entraîne un réchauffement et donc une dilatation de cet élément de stator 2 et, par suite, les jeux jl et j2 sont rétablis à leur valeur initiale. De cette façon, les effets tendant à diminuer les jeux jl et j2 sont compensés et annulés et les jeux jl et j2 sont maintenus à leur valeur objective déterminée pour les résultats optimaux visés en fonctionnement stabilisé de la turbomachine et il en sera de même dans toutes les conditions de fonctionnement de la turbomachine tendant à diminuer les jeux jl et j2.The device according to the invention which has just been described makes it possible to obtain improved operation by ensuring in all operating conditions of the turbomachine, both in stabilized and transient conditions, a practically constant clearance guaranteeing a controlled value of the air flow rate passing through the labyrinth seal of the turbomachine on which said device is adapted without inadvertent variations being observed, the consequences of which are harmful for the yields or for the life of certain parts, in the leakage rates at the labyrinth seal. Indeed, if we denote by jl the clearance between the top of the wipers 13 and the cooperating surface of the upstream portion lla of the wear and sealing lining 11 and by j2 the clearance between the top of the wipers 14 and the cooperating surface of the downstream part 11b of said lining, during a phase of rapid acceleration of the rise to full throttle speed of the turbomachine, for example, as a result of the combined effects of expansions, in particular of mechanical origin by centrifugal effect, and of thermal origin applied to the various structural elements, the clearances jl and j2 may tend to decrease. If we denote by Dl the air flow entering the upstream end in the space separating the rotor part 1 and the stator element 2, by D2 the air flow entering the annular chamber 3 by the orifices 8 of the stator element 2, the point of sampling of this air in the turbomachine being chosen so that this air is cooler than that Dl entering upstream of the joint, by D3 the air flow leaving the labyrinth seal, in the acceleration phase concerned, the flow Dl tends to decrease but depending a very small variation while the flow D3 decreases more quickly and in a more noticeable manner, this consequently results in a reduction in the flow D2 of cooling air of the stator element 2, which leads to heating and therefore expansion of this stator element 2 and, consequently, the sets jl and j2 are restored to their initial value. In this way, the effects tending to decrease the games jl and j2 are compensated and canceled and the games jl and j2 are maintained at their objective value determined for the optimal results aimed at in stabilized operation of the turbomachine and it will be the same in all the operating conditions of the turbomachine tending to reduce the clearances jl and j2.

De manière similaire, si on passe par exemple à un régime de décélération de la turbomachine, les jeux jl et j2 peuvent avoir tendance à augmenter. Dans ce cas, le débit Dl a tendance à augmenter, mais uniquement suivant une variation très faible, alors que le débit D3 augmente plus rapidement d'une façon sensible, il en résulte par conséquent une augmentation du débit D2 d'air de refroidissement de l'élément de stator 2, ce qui entraxe un refroidissement et donc une contraction de cet élément de stator 2 et, par suite, les jeux jl et j2 sont rétablis à leur valeur initiale. De cette façon, les effets tendant à accroître les jeux jl et j2 sont compensés et annulée et les jeux jl et j2 sont à nouveau maintenus à leur valeur objective et il en sera de même dans toutes les conditions de fonctionnement de la turbomachine tendant à accroître les jeux jl et j2.Similarly, if one goes for example to a deceleration regime of the turbomachine, the games jl and j2 may tend to increase. In this case, the flow Dl tends to increase, but only according to a very small variation, while the flow D3 increases more quickly in a significant way, this consequently results in an increase in the flow D2 of cooling air. the stator element 2, which centers cooling and therefore a contraction of this stator element 2 and, consequently, the clearances jl and j2 are restored to their initial value. In this way, the effects tending to increase the games jl and j2 are compensated for and canceled and the games jl and j2 are again maintained at their objective value and it will be the same in all the operating conditions of the turbomachine tending to increase the games jl and j2.

On note ainsi que pour toute variation des conditions de fonctionnement de la turbomachine, on observe une variation du débit d'air froid D2 alimentant la chambre annulaire 3 de l'élément de stator 2 de telle sorte que l'incidence sur les jeux jl et j2 du labyrinthe est en sens inverse de la variation des jeux qui résulterait de cette variation des conditions. Dans tous les cas, les effets se compensent et le dispositif selon l'invention procure un moyen de correction automatique, en temps réel, des variations en fonctionnement des jeux jl et j2 du labyrinthe pour les maintenir à leur valeur objective choisie.It is thus noted that for any variation in the operating conditions of the turbomachine, there is a variation in the flow of cold air D2 supplying the chamber annular 3 of the stator element 2 so that the impact on the games jl and j2 of the labyrinth is in the opposite direction to the variation of the games which would result from this variation of the conditions. In all cases, the effects compensate each other and the device according to the invention provides a means of automatic correction, in real time, of variations in operation of the games jl and j2 of the labyrinth to maintain them at their chosen objective value.

La figure 2 représente un mode de réalisation pour une application de l'invention à un joint de labyrinthe placé au droit de la sortie d'une chambre de combustion du côté radialement interne. On a représenté sur cette figure, en 21, la chemise interne d'une chambre de combustion de type annulaire 22, en 23, une enveloppe annulaire définissant une enceinte 24 de ventilation externe de la chambre de combustion. La chemise 21 est reliée à son extrémité aval par un moyen de fixation 25, par exemple du type à boulonnage, à une bride radiale 26 d'une partie interne d'aubage de stator 27. L'enveloppe 23 porte une bride radiale 28 dirigée vers l'axe de la machine et sur laquelle sont fixées par des moyens de fixation 29, par exemple du type à boulonnage, d'une part, une bride radiale 30 d'extrémité d'un support annulaire 31 et, d'autre part, une bride radiale 32 d'extrémité d'une tôle mince annulaire 33 multi- perforée. Le support annulaire 31 porte sur sa face radialement interne une garniture d'usure et d'étanchéité 34 qui comporte deux parties disposées axialement, une partie amont 34a constituée d'un nid d'abeilles et une partie aval 34b présentant une surface externe lisse, ces deux parties étant séparées par un intervalle 34c. Le support annulaire 31 comporte au niveau de cet intervalle 34c une série de perçages 35. La tôle mince annulaire 33 est légèrement écartée radialement vers l'extérieur par rapport au support 31 sur lequel elle est en appui radial en 36 à son extrémité aval. A son extrémité aval, le support 31 porte une bride radiale 37 dirigée radialement vers l'extérieur et effectuant la liaison avec la partie interne de l'aubage de stator 27. Au droit de la partie fixe statorique de la machine qui vient d'être décrite, la partie tournante rotorique comporte un disque 38 portant dans l'exemple représenté cinq léchettes 39 coopérant avec la garniture d'usure et d'étanchéité 34. L'enceinte interne est séparée par le disque 38 en une enceinte amont 40 où l'air est à la pression Pl et une enceinte aval 41 où l'air est à une pression P2 inférieure à Pl. Un espace ménagé entre le support annulaire 31 et l'enveloppe de chambre 23 constitue une chambre annulaire 42 permettant la ventilation du support annulaire 31 et séparée en deux enceintes 42a et 42b par la tôle annulaire 33. Cette tôle mince 33 comporte des multiperforations 43 pour la ventilation par impacts du support 31. Une ouverture 44 ménagée dans l'enveloppe 23 assure le passage d'un débit d'air D2 de l'enceinte 24 de chambre de combustion vers la chambre 42.FIG. 2 represents an embodiment for an application of the invention to a labyrinth seal placed in line with the outlet of a combustion chamber on the radially internal side. There is shown in this figure, at 21, the internal jacket of an annular type combustion chamber 22, at 23, an annular envelope defining an enclosure 24 for external ventilation of the combustion chamber. The jacket 21 is connected at its downstream end by a fixing means 25, for example of the bolt-on type, to a radial flange 26 of an internal part of stator vane 27. The casing 23 carries a directed radial flange 28 towards the axis of the machine and to which are fixed by fixing means 29, for example of the bolt type, on the one hand, a radial flange 30 at the end of an annular support 31 and, on the other hand , a radial flange 32 at the end of an annular thin sheet 33 multi-perforated. The annular support 31 carries on its radially internal face a wear and sealing lining 34 which comprises two parts arranged axially, an upstream part 34a consisting of a honeycomb and a downstream part 34b having a smooth external surface, these two parts being separated by an interval 34c. The annular support 31 comprises at this interval 34c a series of holes 35. The annular thin sheet 33 is slightly spaced radially outward relative to the support 31 on which it bears radially at 36 at its downstream end. At its downstream end, the support 31 carries a radial flange 37 directed radially outwards and making the connection with the internal part of the stator vane 27. In line with the fixed stator part of the machine which has just been described, the rotary rotor part comprises a disc 38 carrying in the example shown five wipers 39 cooperating with the wear and sealing lining 34. The internal enclosure is separated by the disc 38 into an upstream enclosure 40 where the air is at the pressure Pl and a downstream enclosure 41 where the air is at a pressure P2 lower than Pl. A space provided between the annular support 31 and the chamber envelope 23 constitutes an annular chamber 42 allowing the ventilation of the annular support 31 and separated into two enclosures 42a and 42b by the annular sheet 33. This thin sheet 33 has multi-perforations 43 for the impact ventilation of the support 31. An opening 44 formed in the envelope 23 ensures the passage of a flow of air D2 from the combustion chamber enclosure 24 towards the chamber 42.

Dans cette application, on obtient un contrôle automatique en temps réel des variations en fonctionnement du jeu du joint à labyrinthe pour le maintenir à une valeur objective choisie et le fonctionnement permettant d'obtenir ce résultat est identique à celui qui a été décrit précédemment en référence à la figure 1. Comme précédemment exposé, les variations du débit D2 d'air de refroidissement vont dans le même sens que les variations du jeu du joint à labyrinthe, ce qui dans chaque cas permet de ramener le jeu à sa valeur initiale obtenue en fonctionnement stabilisé.In this application, automatic control in real time of the variations in operation of the clearance of the labyrinth seal is obtained in order to maintain it at a chosen objective value and the operation making it possible to obtain this result is identical to that which was described previously with reference in FIG. 1. As previously explained, the variations in the flow rate D2 of cooling air go in the same direction as the variations in the clearance of the labyrinth seal, which in each case makes it possible to bring the clearance to its initial value obtained by stabilized operation.

La figure 3 représente schématiquement une partie de turbomachine analogue à celle qui est représentée à la figure 1 et comportant un second mode de réalisation de l'invention. On a conservé pour des pièces identiques les mêmes repères que ceux qui figurent sur la figure 1 et on se reportera pour plus de détails à la description complète du dispositif qui a été faite précédemment en référence à la figure 1. On se bornera à indiquer brièvement les particularités propres au mode de réalisation représenté à la figure 3. La garniture d'usure et d'étanchéité 111 entrant dans le joint à labyrinthe est composée de deux parties, disposées axialement et séparées par un intervalle 12, comme précédemment. Mais, dans le présent mode de réalisation, la partie amont llla de la garniture d'usure et d'étanchéité 111 présente une surface lisse et la partie aval lllb est constituée d'un nid d'abeilles. Par ailleurs, si l'on désigne par D'1 le débit d'air entrant à l'extrémité amont dans l'espace séparant la pièce de rotor 1 et l'élément de stator 2, par D'2 le débit d'air entrant dans la chambre annulaire 3 par les orifices 8 de l'élément de stator 2, le point de prélèvement de cet air dans la turbomachine est choisi de telle sorte que cet air D'2 est plus chaud que D'l. On désigne par D'3 le débit d'air sortant du joint à labyrinthe, par j'1 le jeu entre le sommet des léchettes 13 et la surface coopérante de la partie amont llla de la garniture d'usure et d'étanchéité et par j'2 le jeu entre le sommet des léchettes 14 et la surface coopérante de la partie aval lllb de ladite garniture. Le dispositif conforme à l'invention selon le second mode de réalisation qui vient d'être décrit permet également d'assurer comme dans le premier mode un jeu pratiquement constant du joint à labyrinthe, en garantissant une valeur contrôlée du débit d'air traversant ledit joint et permettant d'obtenir les mêmes avantages précédemment relevés. En effet, lors d'une phase d'accélération rapide de montée au régime plein gaz de la turbomachine, par exemple, comme dans le premier mode de réalisation, les jeux j'l et j'2 peuvent avoir tendance à diminuer. Par suite, le débit D'3 a tendance à diminuer mais suivant une variation très faible alors que le débit D'1 diminue plus rapidement et de manière plus notable, il en résulte par conséquent une augmentation du débit D'2 d'air de réchauffement de l'élément de stator 2 et donc une dilatation de cet élément de stator 2 et par suite, les jeux j'1 et j'2 sont rétablis à leur valeur initiale. Comme dans le premier mode, les effets tendant à diminuer les jeux j'1 et j'2 sont compensés et annulés et les jeux j'1 et j'2 sont maintenus à leur valeur objective déterminée par les résultats optimaux visés en fonctionnement stabilisé de la turbomachine et il en sera de même dans toutes les conditions de fonctionnement de la turbomachine tendant à diminuer les jeux j'1 et j'2.FIG. 3 schematically represents a part of a turbomachine similar to that which is represented in FIG. 1 and comprising a second embodiment of the invention. The same references have been kept for identical parts as those which appear in FIG. 1 and reference will be made for more details to the complete description of the device which was made previously with reference to FIG. 1. We will limit ourselves to indicating briefly the specific features of the embodiment shown in Figure 3. The wear and seal 111 entering the labyrinth seal is composed of two parts, arranged axially and separated by a gap 12, as before. However, in the present embodiment, the upstream part IIIa of the wear and sealing lining 111 has a smooth surface and the downstream part IIIa consists of a honeycomb. Furthermore, if one designates by D'1 the air flow entering at the upstream end in the space separating the rotor part 1 and the stator element 2, by D'2 the air flow entering the annular chamber 3 through the orifices 8 of the stator element 2, the point of sampling this air in the turbomachine is chosen so that this air D'2 is hotter than D'l. We denote by D'3 the air flow leaving the labyrinth seal, by i1 the clearance between the top of the wipers 13 and the cooperating surface of the upstream part IIIa of the wear and sealing lining and by I2 the clearance between the top of the wipers 14 and the cooperating surface of the downstream part IIIb of said lining. The device according to the invention according to the second embodiment which has just been described also makes it possible to ensure, as in the first mode, a practically constant clearance of the labyrinth seal, by guaranteeing a controlled value of the air flow passing through said joint and allowing to obtain the same advantages previously noted. Indeed, when a phase of rapid acceleration of climb to full throttle speed of the turbomachine, for example, as in the first embodiment, the clearances I 1 and I 2 may tend to decrease. Consequently, the flow rate D'3 tends to decrease but according to a very small variation whereas the flow rate D'1 decreases more quickly and in a more notable manner, it consequently results in an increase in the flow rate D'2 of air heating of the stator element 2 and therefore a dilation of this stator element 2 and consequently, the clearances I1 and J'2 are restored to their initial value. As in the first mode, the effects tending to decrease the games i1 and i2 are compensated and canceled and the games i1 and i2 are maintained at their objective value determined by the optimum results aimed for in stabilized operation of the turbomachine and it will be the same in all the operating conditions of the turbomachine tending to decrease the clearances i1 and i2.

De manière similaire, si on passe par exemple à un régime de décélération de la turbomachine, les jeux j'1 et j'2 peuvent avoir tendance à augmenter. Dans ce cas, le débit D'3 a tendance à augmenter mais uniquement suivant une variation très faible alors que le débit D'1 augmente plus rapidement d'une façon sensible, il en résulte par conséquent une diminution du débit D'2 d'air de réchauffement de l'élément de stator 2, ce qui entraîne une contraction de cet élément de stator 2 et par suite, les jeux j'1 et j'2 sont rétablis à leur valeur initiale. De cette façon, comme dans le premier mode, les effets tendant à accroître les jeux j'1 et j'2 sont compensés et annulés et les jeux j'1 et j'2 sont à nouveau maintenus à leur valeur objective et il en sera de même dans toutes les conditions de fonctionnement de la turbomachine tendant à accroître les jeux j'1 et j'2. Ainsi, dans tous les cas, le dispositif selon l'invention procure également dans le second mode de réalisation un moyen de correction automatique, en temps réel, des variations en fonctionnement des jeux j'1 et j'2 du labyrinthe pour les maintenir à leur valeur objective choisie.Similarly, if we pass for example to a deceleration regime of the turbomachine, the clearances I and I2 may tend to increase. In this case, the flow rate D'3 tends to increase but only according to a very small variation whereas the flow rate D'1 increases more quickly in a significant way, this consequently results in a decrease in the flow rate D'2 air for heating the stator element 2, which causes this stator element 2 to contract and consequently the clearances I1 and J'2 are restored to their initial value. In this way, as in the first mode, the effects tending to increase the games i1 and i2 are compensated and canceled and the games i1 and i2 are again maintained at their objective value and so will be. likewise in all the operating conditions of the turbomachine tending to increase the clearances i1 and i2. Thus, in all cases, the device according to the invention also provides, in the second embodiment, a means of automatic correction, in real time, of variations in operation of the games I1 and I2 of the labyrinth to keep them at their chosen objective value.

De manière analogue à la représentation sur la figure 2 d'une application du premier mode de réalisation de l'invention représenté à la figure 1, application à un joint de labyrinthe placé au droit de la sortie d'une chambre de combustion du côté radialement interne, la figure 4 représente la même application du second mode de réalisation de l'invention représenté à la figure 3. On a à nouveau conservé pour des pièces identiques les mêmes repères que ceux figurant à la figure 2. On se bornera à indiquer brièvement les particularités découlant de l'application du mode de réalisation de la figure 3 à un joint à labyrinthe du genre représenté à la figure 2. Dans ce cas, le support annulaire identique 31 porte sur sa face radialement interne une garniture d'usure et d'étanchéité 134 qui comporte deux parties disposées axialement, une partie amont 134a présentant une surface externe lisse et une partie aval 134b constituée d'un nid d'abeilles, ces deux parties étant séparées par un intervalle 134c. Par ailleurs, un débit d'air D'2 de réchauffement du support annulaire 31 est prélevé dans l'enceinte 24 de chambre de combustion.Analogously to the representation in FIG. 2 of an application of the first embodiment of the invention shown in FIG. 1, application to a labyrinth seal placed in line with the exit of a combustion chamber on the radially side internal, FIG. 4 represents the same application of the second embodiment of the invention shown in FIG. 3. The same references have again been kept for identical parts as those appearing in FIG. 2. We will limit ourselves to indicating briefly the features arising from the application of the embodiment of Figure 3 to a labyrinth seal of the kind shown in Figure 2. In this case, the identical annular support 31 carries on its radially inner face a wear lining and d seal 134 which has two parts arranged axially, an upstream part 134a having a smooth external surface and a downstream part 134b consisting of a honeycomb, these two parts being separated by a gap 134c. Furthermore, a flow of air D'2 for heating the annular support 31 is taken from the enclosure 24 of the combustion chamber.

Dans cette application, on obtient à nouveau un contrôle automatique en temps réel des variations en fonctionnement du jeu du joint à labyrinthe pour le maintenir à une valeur objective choisie et le fonctionnement permettant d'obtenir ce résultat est identique à celui qui a été décrit précédemment en référence à la figure 3. Comme précédemment exposé, les variations du débit D'2 d'air de réchauffement vont dans le sens inverse des variations du jeu du joint à labyrinthe, ce qui dans chaque cas permet de ramener le jeu à sa valeur initiale obtenue en fonctionnement stabilisé.In this application, automatic control is again obtained in real time of the variations in operation of the clearance of the labyrinth seal to maintain it at a chosen objective value and the operation making it possible to obtain this result is identical to that which has been described previously. with reference to Figure 3. As previously exposed, the variations in the flow rate of heating air D'2 go in the opposite direction to the variations in the clearance of the labyrinth seal, which in each case makes it possible to bring the clearance to its initial value obtained in stabilized operation.

Claims (3)

1. Dispositif de contrôle automatique en fonctionnement du jeu d'un joint de turbomachine du type à labyrinthe du genre dans lequel des éléments en forme de léchettes (13, 14;39) sont portés par une pièce de rotor (1;38) et une garniture (11; 34; 111; 134) d'usure et d'étanchéité placée en regard desdites léchettes (13,14;39) est portée par un support annulaire (4;31) constituant la partie radialement interne de stator, ledit stator comportant une chambre annulaire (3:42) munie sur son diamètre externe d'orifices (8:44) d'arrivée d'air, une tôle mince (9;33) percée de multitrous (10) étant disposée à l'intérieur de ladite chambre (3;42) à faible distance dudit support annulaire (4;31), caractérisé en ce que ladite garniture (11; 34; 111; 134) d'usure et d'étanchéité est composée de deux parties (11a, 11b; 34a,34b; 111a, 111b; 134a, 134b), une première partie (lla;34a;lllb;134b) constituée d'un nid d'abeilles et une deuxième partie (11b; 34b; 111a; 134a) comportant une surface lisse, une série de perçages (12a; 35) périphériquement répartis et traversant ledit support annulaire (4;31) et ladite garniture (11; 34; 111; 134) d'usure et d'étanchéité, étant placés au niveau de l'intervalle (12;34c;134c) séparant les deux parties (lla et 11b; 34a et 34b;llla et 111b; 134a et 134b) de ladite garniture (11; 34; 111; 134).1. Device for automatically controlling the operation of the play of a labyrinth-type turbomachine seal of the type in which wiper-shaped elements (13, 14; 39) are carried by a rotor part (1; 38) and a seal (11; 34; 111; 134) for wear and sealing placed opposite said wipers (13,14; 39) is carried by an annular support (4; 31) constituting the radially internal part of the stator, said stator comprising an annular chamber (3:42) provided with air intake orifices (8:44) on its external diameter, a thin sheet (9; 33) pierced with multi-holes (10) being placed inside from said chamber (3; 42) at a short distance from said annular support (4; 31), characterized in that said wear and sealing lining (11; 34; 111; 134) is composed of two parts (11a, 11b; 34a, 34b; 111a, 111b; 134a, 134b), a first part (lla; 34a; lllb; 134b) consisting of a honeycomb and a second part (11b; 34b; 111a; 134a) comprising a smooth surface, a e series of holes (12a; 35) peripherally distributed and passing through said annular support (4; 31) and said seal (11; 34; 111; 134) of wear and sealing, being placed at the level of the interval (12; 34c; 134c) separating the two parts (11a and 11b; 34a and 34b; IIIa and 111b; 134a and 134b) of said lining (11; 34; 111; 134). 2. Dispositif de contrôle automatique du jeu d'un joint à labyrinthe selon la revendication 1, caractérisé en ce que la première partie (lla;34a) en nid d'abeilles de la garniture (11;34) d'usure et d'étanchéité est située en amont, par rapport au sens normal de circulation des gaz de la turbomachine, de la deuxième partie (11b; 34b) à surface lisse et lesdits perçages (12a;35) de ladite garniture sont alimentés par de l'air de refroidissement à partir de ladite chambre (3;42) ménagée dans le stator du joint, cet air étant plus froid que l'air débitant directement à travers le joint à partir de son extrémité amont située du côté des plus fortes pressions.2. Device for automatically controlling the play of a labyrinth seal according to claim 1, characterized in that the first part (lla; 34a) of honeycomb of the lining (11; 34) of wear and sealing is located upstream, with respect to the normal direction of circulation of the gases of the turbomachine, of the second part (11b; 34b) with smooth surface and said bores (12a; 35) of said lining are supplied with air from cooling from said chamber (3; 42) formed in the stator of the seal, this air being cooler than the air flowing directly through the seal from its upstream end situated on the side of the highest pressures. 3. Dispositif de contrôle automatique du jeu d'un joint à labyrinthe selon la revendication 1, caractérisé en ce que la première partie (lllb;134b) en nid d'abeilles de la garniture (111;134) d'usure et d'étanchéité est située en aval, par rapport au sens normal de circulation des gaz de la turbomachine, de la deuxième partie (llla;134a) à surface lisse et lesdits perçages (12a;35) de ladite garniture (111;134) sont alimentés par de l'air chaud à partir de ladite chambre (3;42) ménagée dans le stator du joint, cet air étant plus chaud que l'air débitant directement à travers le joint à partir de son extrémité amont située du côté des plus fortes pressions.3. Device for automatically controlling the play of a labyrinth seal according to claim 1, characterized in that the first part (IIIb; 134b) of the lining (111; 134) of wear and sealing is located downstream, relative to the normal direction of gas flow of the turbomachine, of the second part (IIIa; 134a) with a smooth surface and said holes (12a; 35) of said lining (111; 134) are supplied by hot air from said chamber (3; 42) formed in the stator of the seal, this air being hotter than the air flowing directly through the seal from its upstream end situated on the side of the highest pressures .
EP85401864A 1984-09-27 1985-09-25 Apparatus for the automatic control of the play of a labyrinth seal of a turbo machine Expired EP0176447B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8414819 1984-09-27
FR8414819A FR2570764B1 (en) 1984-09-27 1984-09-27 DEVICE FOR AUTOMATICALLY CONTROLLING THE PLAY OF A TURBOMACHINE LABYRINTH SEAL

Publications (2)

Publication Number Publication Date
EP0176447A1 true EP0176447A1 (en) 1986-04-02
EP0176447B1 EP0176447B1 (en) 1987-11-04

Family

ID=9308118

Family Applications (1)

Application Number Title Priority Date Filing Date
EP85401864A Expired EP0176447B1 (en) 1984-09-27 1985-09-25 Apparatus for the automatic control of the play of a labyrinth seal of a turbo machine

Country Status (5)

Country Link
US (1) US4662821A (en)
EP (1) EP0176447B1 (en)
JP (1) JPS6185504A (en)
DE (1) DE3560917D1 (en)
FR (1) FR2570764B1 (en)

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CN112065511B (en) * 2020-08-31 2021-10-26 南京航空航天大学 Injection type honeycomb bush-labyrinth sealing structure

Also Published As

Publication number Publication date
JPS6185504A (en) 1986-05-01
JPH0350082B2 (en) 1991-07-31
EP0176447B1 (en) 1987-11-04
DE3560917D1 (en) 1987-12-10
FR2570764B1 (en) 1986-11-28
FR2570764A1 (en) 1986-03-28
US4662821A (en) 1987-05-05

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