EP0937864A2 - Guidevane assembly for an axial turbomachine - Google Patents

Guidevane assembly for an axial turbomachine Download PDF

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Publication number
EP0937864A2
EP0937864A2 EP99103156A EP99103156A EP0937864A2 EP 0937864 A2 EP0937864 A2 EP 0937864A2 EP 99103156 A EP99103156 A EP 99103156A EP 99103156 A EP99103156 A EP 99103156A EP 0937864 A2 EP0937864 A2 EP 0937864A2
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EP
European Patent Office
Prior art keywords
housing
guide vane
vane ring
shroud
reinforcement
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
EP99103156A
Other languages
German (de)
French (fr)
Other versions
EP0937864A3 (en
EP0937864B1 (en
Inventor
Hermann Klingels
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MTU Aero Engines AG
Original Assignee
MTU Aero Engines GmbH
MTU Motoren und Turbinen Union Muenchen GmbH
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Publication of EP0937864A2 publication Critical patent/EP0937864A2/en
Publication of EP0937864A3 publication Critical patent/EP0937864A3/en
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Publication of EP0937864B1 publication Critical patent/EP0937864B1/en
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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
    • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
    • F01D5/12—Blades
    • F01D5/22—Blade-to-blade connections, e.g. for damping vibrations
    • F01D5/225—Blade-to-blade connections, e.g. for damping vibrations by shrouding
    • 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
    • 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
    • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
    • F01D25/24—Casings; Casing parts, e.g. diaphragms, casing fastenings
    • F01D25/246—Fastening of diaphragms or stator-rings
    • 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
    • F01D9/00—Stators
    • F01D9/02—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles
    • F01D9/04—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector
    • F01D9/042—Nozzles; Nozzle boxes; Stator blades; Guide conduits, e.g. individual nozzles forming ring or sector fixing blades to stators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05B—INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
    • F05B2230/00—Manufacture
    • F05B2230/60—Assembly methods
    • F05B2230/604—Assembly methods using positioning or alignment devices for aligning or centering, e.g. pins
    • F05B2230/606—Assembly methods using positioning or alignment devices for aligning or centering, e.g. pins using maintaining alignment while permitting differential dilatation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2230/00—Manufacture
    • F05D2230/60—Assembly methods
    • F05D2230/64—Assembly methods using positioning or alignment devices for aligning or centring, e.g. pins
    • F05D2230/642—Assembly methods using positioning or alignment devices for aligning or centring, e.g. pins using maintaining alignment while permitting differential dilatation

Definitions

  • the invention relates to a fluid flow machine with a rotor and stator in fluidic terms single or multi-stage design, according to the preamble of the claim 1.
  • Such a turbomachine is known for example from DE-PS 27 45 130, this document specifically relates to axial turbines with labyrinth seals.
  • the flow channel of the working medium alternately leads through guide vanes and rotating vane rings, the static components protruding radially from the outside and the rotating ones radially from the inside.
  • Figure 1 of this document clearly shows, there are both radially inside seals between the rotor and the vane rings ( Inner Airseal ”) as well as seals arranged radially on the outside between the rotor blades and the stator ( Outer Airseal ").
  • the sealing fins are the Inner Airseal "is attached to the rotor (item 4), so that their dimensions or dimensional deviations depend on the conditions on the rotor (temperature, speed).
  • the associated sealing lining (item 7), on the other hand, is on the inner cover band (item 20)
  • the guide vane segments are mounted on the housing (pos. 13, 14), so that the dimensions or dimensional deviations of the sealing layer are ultimately determined by the conditions on the outside of the housing on the other hand, the housing often does not change conformingly at the same time, so that there are gap-changing relative movements between the sealing elements (item 7.8) Outer Airseal "(item 11, 12).
  • each segment of a guide vane ring is a mechanical unit on - in the longitudinal section hook-shaped housing elements (item 14 At the upstream end of the outer shroud, each guide vane segment has an edge bead with a groove which engages around the hook-shaped housing element (item 14, 22) in a claw-like manner (see FIG. 3).
  • each guide vane segment there is an angled section in longitudinal section with a radially outwardly facing contact surface, which during operation is caused by a flow-induced tilting moment around the upstream one Claw bearing "is pressed against the corresponding hook-shaped housing element (see FIG. 1).
  • the hook-shaped housing elements also as Hook rings “identifiable -flows of high density heat flow to the colder housing, the "Hook rings” especially in the area of Claw bearings "can be increasingly plastically deformed by crawling. The only remedy here is permanent cooling of the Hook rings ".
  • DE-PS 35 40 943 describes such a gap control system especially for one Dual-flow engine.
  • the secondary air duct extends at least up to to the end of the turbine area and has openings (item 11) in its inner wall on, through the secondary air from the outside targeted to areas of the turbine housing can be blown.
  • This simplified ACC system may have the problem that the low excess pressure of the secondary air flow is not sufficient to in locally narrow housing zones due to correspondingly small flow cross sections To generate cooling air flows with sufficient mass flow.
  • an ACC compressor air from the booster or low pressure compressor branched off as coolant, routed in separate channels and via valves specifically blown out.
  • guide vane rings In the case of smaller gas turbine engines, it is known to design guide vane rings as self-supporting, integral components with closed shrouds and to center them in the housing. This is for manufacturing and strength reasons (thermal stresses) monolithic "solution limited to blade rings with relatively small dimensions.
  • DE-OS 33 36 420 describes a mechanism for protection against overtightening of a gas turbine rotor in the event of a shaft break.
  • the mechanism works in the Way that the guide vane segments axially at least one vane ring pivoted and brought into contact / engagement with adjacent blades become. The mutual mechanical blade friction and destruction slows down the rotor quickly and effectively.
  • the vane segments belonging to the mechanism each have a pivot bearing on the outer shroud segment and are on their inner circumference by means of a form-fitting, ring-like reinforcement element connected so that the segments together form a rigid, self-supporting Form the guide vane ring.
  • the swivel bearings (positions 36, 56, 58 and 64) provide spoke centering for the intrinsically stable guide vane ring, which contributes to precise positioning / centering reduced thermal voltages.
  • a disadvantage is the heat transfer from Hot gas area to the housing (item 34), which also affects the bearing elements are. The resulting high temperatures and temperature gradients in the components this area can significantly reduce the service life.
  • the US-PS 3,588,267 protects a guide vane ring construction in plastic construction, in which the blades are attached to a closed, inner torus and form a self-supporting wreath with it.
  • the outer blade tips are designed without a cover tape and directly in the recesses of a metallic one Glued housing, the elasticity of the bond small relative shifts balances / absorbs. It is obvious that this design is for higher temperatures is completely unusable and at best in the fan or low pressure compressor area Can be used.
  • the invention thus lies in the thermal decoupling of the housing and guide vanes by means of a special design and storage / centering of at least one guide vane ring and by means of air cooling of the housing.
  • the - at least one - guide vane ring is designed as a self-supporting component with a reinforcement on the inner shroud, which stiffens it against slipping axial deformation. Starting from an approximately flat, radial alignment of the blade axes in the unloaded state, these are offset by the static pressure difference in front of / behind the guide blade ring during deflection Zero "axially deflected towards the middle of the rim and possibly also curved.
  • the guide vane rim is therefore mechanically comparable to a disc spring, the inner edge (hole edge) of which forms the inner cover band and the outer edge of which forms the outer cover band.
  • the inner cover band is both axially displaced as well as twisted / inverted due to the blade-induced moments, which means that the material cross-sections of the shroud visible in radial-axial sections are rotated more or less around imaginary axes perpendicular to the cutting surface depending on the rigidity / reinforcement.
  • the inventive reinforcement of the inner shroud against said inversion also reduces the axial deflection of the blade axes and thus the overall deformation of the guide vane ring under load. This improves the dimensional stability of the static component Inner Airseal ".
  • the at least triple bearing which allows radial movements ( Spoke centering ") of the shroud segments practically does not hinder thermal expansion / contraction and thus also contributes to minimizing tension. In addition, exact centering in the housing is achieved.
  • the combination of the guide vane ring construction and bearing arrangement and cooling air ducting according to the invention has the result that the deformation behavior of the ring is mainly determined by the conditions / temperatures in the hot gas, which are also decisive for the rotor behavior. Since the static components of the Inner "- and Outer Airseal "are carried by the guide vane rings and behave in conformity with them, the best possible adaptation of the deformations of the static and rotary sealing components with regard to time course, size and direction is achieved with changing operating conditions (unsteady operation). Thus, the machine can consistently with approximately constant, minimal gaps or leakage losses and thus high efficiency can be achieved, especially in the guide vane area there is no risk of premature component fatigue. The use of brush seals is promoted or even made possible by the conformal behavior of the seal carrier (slight gap change, low eccentricity etc.).
  • the present invention is generally for turbomachines with a rotor and stator, i.e. suitable for compressors and turbines, which at least in sections in Axial design, i.e. with predominantly axial flow.
  • Axial design i.e. with predominantly axial flow.
  • Thermodynamic and due to their size, low-pressure turbines are likely to be medium to large Gas turbine engines are preferred applications, which is why the figure Example from this area shows.
  • the first two stages are from the low-pressure turbine 1 and from this in turn the relevant elements of the top half are shown, with the turbine / engine axis would run horizontally below the representation.
  • the flow direction of the working gas runs from left to right, i.e. first through the guide vane ring 14, then through the area of the blades 3, then through the guide vane ring 15 and through the area of the moving blades 4, whereby further stages (leading, running) can follow.
  • the outer engine casing forms the housing 13 in which the guide vane rings 14, 15 are radially centered and are axially fixed. Both the blades 3,4 and the vane rings 14, 15 are designed with inner and outer cover bands 5 to 8 and 16 to 19, the inner and outer blade shrouds between each the blades have gaps, including damaged blades can be replaced individually are.
  • the guide vane rings 14, 15 are designed as self-supporting components, their mechanical stability being achieved predominantly in the area of the inner shrouds 16, 17. There are closed in the circumferential direction, ie circumferential ", reinforcements 20, 21 arranged, which also decisively influence the thermal behavior (changes in shape and shape) of the guide vane rings 14, 15.
  • the gas forces during operation cause, among other things, an inverting axial deformation of the guide vane rings, ie an axial deflection increasing from the outer to the inner shroud with some twisting of the shrouds plate spring-like "deformation can be significantly reduced by the reinforcements on the inner cover bands.
  • the reinforcements shown are, for example, the toroidal hollow bodies shown, axially spaced rings, combinations of hollow and solid profiles, etc., the space conditions also playing a role.
  • the reinforcements should play a role.
  • the reinforcements should in any case - in the axial / radial section - have as large a moment of inertia as possible about a radial axis, for example through the center of gravity, which can be achieved by sufficient, axially spaced area portions.
  • the area portions of the shroud are to be taken into account here.
  • the determination of the stresses and deformations in the Stülpen is possible using relevant calculation methods.
  • the reinforcement 20 is positively connected to the shroud 16, the Guide vane ring 14 can consist of several segments, which on the reinforcement be held together.
  • the reinforcement 21, however, is in the shroud 17 integrated, i.e. integrally joined with this.
  • Guide vane segments are the starting parts, which by welding or Solder in the area of the inner shroud / reinforcement.
  • outer shrouds 18, 19 should still be segmented in the installed state be, i.e. have several joints on the circumference to prevent thermal stress minimize.
  • the Inner Airseal is - at least predominantly - designed with brush seals, brushes 22, 23 fastened in the area of the guide vane ring reinforcements running against rings 11, 12 connected to the rotor 2, which form axial stops for the rotor blades 3, 4.
  • the honeycomb carriers 28, 29 are in turn mounted on the guide vane rings 14, 15 and are therefore adapted to the deformation behavior thereof.
  • air cooling is used for the housing and the bearing units the guide vane rings provided, which is not so constructively is complex, like an ACC system.
  • an air guide shell 30 is arranged at a radial distance, so that between this and the housing cooling air can flow in the longitudinal direction of the engine.
  • the admission the cooling air, which is usually branched off from the compressor, is carried out via bores 35 into a first chamber 33.
  • the air guide shell has in the area of the bearing journals 26 and 27 30 deliberately gas-permeable openings 31,32, so that part of the cooling air along the journals 26, 27 in the area of the outer shrouds 18, 19 of the guide vane rings 14.15 can flow, a corresponding pressure drop (Cooling air overpressure) provided.
  • This cools the bearings and Heat flows from the vane rings to the housing are minimized.
  • the wall element 37 has - not shown - restrictors or forms itself with corresponding ones Throttle columns a restrictor for the cooling air, so that this in the subsequent Chamber 34 enters with reduced pressure. It is sufficient if the cooling air only a moderate overpressure in relation to the working gas in the adjacent one Has flow channel.
  • the pressure of the working gas decreases axially, it makes sense to also to reduce the cooling air pressure at least in a few stages, which is here is achieved by the chamber design mentioned with restrictors. High pressures the cooling air would also have a high compressive strength of the air guide shell 30 require, i.e. larger wall thicknesses and more weight.
  • Wall elements 36, 38 There are more between the flow channel of the working gas and the cooling air channel Wall elements 36, 38 arranged, which secondary gas flows, i.e. -losses, to prevent through these passages. For cooling reasons, these are also Wall elements 36, 38 deliberately designed or fastened somewhat gas-permeable.

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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

The machine has at least one blade ring (14,15) formed as a self-supporting component with a mainly rotary-symmetrical stiffening (20,21) along the inner cover plate (16,17), to protect it against axial deformation. The outer cover plate (18,19) is segmented and has several joints. The blade ring is positioned in the housing (13) via at least three segments of the outer plate using a bearing unit (24,25,26,27), which permits a local relative movement. An air guide shell (3) between housing and outer cover plate guides a cooling air flow along the inside of the housing. It has openings (31,32) for the housing-fastened bearings (26,27) of the blade ring. The openings permit passage of the part of the air flow towards the cover plate.

Description

Die Erfindung betrifft eine Strömungsmaschine mit Rotor und Stator in strömungstechnisch ein- oder mehrstufiger Ausführung, gemäß dem Oberbegriff des Patentanspruches 1.The invention relates to a fluid flow machine with a rotor and stator in fluidic terms single or multi-stage design, according to the preamble of the claim 1.

Eine derartige Strömungsmaschine ist beispielsweise aus der DE-PS 27 45 130 bekannt, wobei diese Schrift sich speziell auf Axialturbinen mit Labyrinthdichtungen bezieht. Der Strömungskanal des Arbeitsmediums führt abwechselnd durch Leit- und Laufschaufelkränze wobei die statischen Bauteile radial von außen, die rotierenden radial von innen in diesen hineinragen. Wie Figur 1 dieser Schrift deutlich zeigt, gibt es sowohl radial innen angeordnete Dichtungen zwischen dem Rotor und den Leitschaufelkränzen (

Figure 00010001
Inner Airseal") als auch radial außen angeordnete Dichtungen zwischen den Laufschaufeln und dem Stator ( Outer Airseal").Such a turbomachine is known for example from DE-PS 27 45 130, this document specifically relates to axial turbines with labyrinth seals. The flow channel of the working medium alternately leads through guide vanes and rotating vane rings, the static components protruding radially from the outside and the rotating ones radially from the inside. As Figure 1 of this document clearly shows, there are both radially inside seals between the rotor and the vane rings (
Figure 00010001
Inner Airseal ") as well as seals arranged radially on the outside between the rotor blades and the stator ( Outer Airseal ").

Bei der Axialturbine gemäß der DE-PS sind die Dichtfins (Pos.8) der Inner Airseal" am Rotor (Pos.4) befestigt, so daß deren Maße bzw. Maßabweichungen von den Verhältnissen am Rotor (Temperatur, Drehzahl) abhängen. Der zugehörige Dichtungsbelag (Pos.7) ist demgegenüber am inneren Deckband (Pos. 20) der Leitschaufelsegmente (Pos. 1,5) befestigt. Die Leitschaufelsegmente sind am Gehäuse (Pos. 13,14) gelagert, so daß die Maße bzw. Maßabweichungen des Dichtungsbelages letztlich von den Verhältnissen außen am Gehäuse wesentlich mitbestimmt werden. Die Verhältnisse am Rotor einerseits und am Gehäuse andererseits ändern sich oft weder konform nach zeitgleich, so daß sich spaltverändernde Relativbewegungen zwischen den Dichtungselementen (Pos.7,8) ergeben. Das Gleiche gilt für die Outer Airseal" (Pos. 11,12). Die spezielle Art der Leitschaufelbefestigung am Gehäuse wird so bzw. in vergleichbarer Ausführung bei größeren Triebwerken häufig verwendet. Jedes Segment eines Leitschaufelkranzes ist als mechanische Einheit an - im Längsschnitt- hakenförmigen Gehäuseelementen (Pos.14) gelagert, welche in Umfangsrichtung ringförmig geschlossen sind. Am stromaufwärtigen Ende des äußeren Deckbandes weist jedes Leitschaufelsegment einen Randwulst mit Nut auf, welcher das hakenförmige Gehäuseelement (Pos. 14,22) klauenartig umgreift (siehe Fig. 3). In the axial turbine according to DE-PS, the sealing fins (item 8) are the Inner Airseal "is attached to the rotor (item 4), so that their dimensions or dimensional deviations depend on the conditions on the rotor (temperature, speed). The associated sealing lining (item 7), on the other hand, is on the inner cover band (item 20) The guide vane segments are mounted on the housing (pos. 13, 14), so that the dimensions or dimensional deviations of the sealing layer are ultimately determined by the conditions on the outside of the housing on the other hand, the housing often does not change conformingly at the same time, so that there are gap-changing relative movements between the sealing elements (item 7.8) Outer Airseal "(item 11, 12). The special type of guide vane attachment to the housing is often used in this way or in a comparable version for larger engines. Each segment of a guide vane ring is a mechanical unit on - in the longitudinal section hook-shaped housing elements (item 14 At the upstream end of the outer shroud, each guide vane segment has an edge bead with a groove which engages around the hook-shaped housing element (item 14, 22) in a claw-like manner (see FIG. 3).

Am stromabwärtigen Ende des äußeren Deckbandes jedes Leitschaufelsegmentes ist eine -im Längsschnitt- abgewinkelteAnlagestufe mit einer radial nach außen weisenden Anlagefläche vorhanden, welche im Betrieb infolge eines strömungsinduzierten Kippmomentes um das stromaufwärtige Klauenlager" gegen das korrespondierende hakenförmige Gehäuseelement gedrückt wird (siehe Fig. 1). Durch die hakenförmigen Gehäuseelemente - auch als Hakenringe" bezeichenbar -fließen Wärmeströme hoher Dichte zum kälteren Gehäuse, wobei die ,Hakenringe" speziell im Bereich der Klauenlager" durch Kriechen zunehmend plastisch verformt werden können. Abhilfe schafft hier meist nur eine permanente Kühlung der Hakenringe". Falls vorhanden, kann hierzu ein aktives Spaltkontrollsystem ( Aktive Clearence Control"= ACC) mit herangezogen werden, welches dann allerdings permanent in Betrieb sein muß.At the downstream end of the outer shroud of each guide vane segment there is an angled section in longitudinal section with a radially outwardly facing contact surface, which during operation is caused by a flow-induced tilting moment around the upstream one Claw bearing "is pressed against the corresponding hook-shaped housing element (see FIG. 1). Through the hook-shaped housing elements - also as Hook rings "identifiable -flows of high density heat flow to the colder housing, the "Hook rings" especially in the area of Claw bearings "can be increasingly plastically deformed by crawling. The only remedy here is permanent cooling of the Hook rings ". If available, an active gap control system ( A ctive C learence C ontrol "= ACC) with used be, which must then, however, be permanently in operation.

Die DE-PS 35 40 943 beschreibt ein solches Spaltkontrollsystem speziell für ein Zweistromtriebwerk. Bei diesem erstreckt sich der Sekundärluftkanal zumindest bis zum Ende des Turbinenbereiches und weist Öffnungen (Pos. 11) in seiner Innenwand auf, durch die Sekundärluft von außen gezielt auf Bereiche des Turbinengehäuses geblasen werden kann. Bei diesem vereinfachten ACC-System besteht ggf. das Problem, daß der geringe Überdruck des Sekundärluftstromes nicht ausreicht, um in örtlich eng begrenzten Gehäusezonen durch entsprechend kleine Strömungsquerschnitte Kühlluftströme mit ausreichendem Massendurchsatz zu erzeugen. Üblicherweise wird bei einem ACC Verdichterluft aus dem Booster bzw. Niederdruckverdichter als Kühlmittel abgezweigt, in separaten Kanälen geführt und über Ventile gezielt ausgeblasen.DE-PS 35 40 943 describes such a gap control system especially for one Dual-flow engine. In this, the secondary air duct extends at least up to to the end of the turbine area and has openings (item 11) in its inner wall on, through the secondary air from the outside targeted to areas of the turbine housing can be blown. This simplified ACC system may have the problem that the low excess pressure of the secondary air flow is not sufficient to in locally narrow housing zones due to correspondingly small flow cross sections To generate cooling air flows with sufficient mass flow. Usually with an ACC compressor air from the booster or low pressure compressor branched off as coolant, routed in separate channels and via valves specifically blown out.

Bei kleineren Gasturbinentriebwerken ist es bekannt, Leitschaufelkränze als selbsttragende, integrale Bauelemente mit geschlossenen Deckbändern auszuführen und im Gehäuse zu zentrieren.Aus fertigungstechnischen sowie festigkeitstechnischen Gründen (Thermospannungen) ist diese monolithische" Lösung auf Schaufelkränze mit relativ kleinen Abmessungen beschränkt.In the case of smaller gas turbine engines, it is known to design guide vane rings as self-supporting, integral components with closed shrouds and to center them in the housing. This is for manufacturing and strength reasons (thermal stresses) monolithic "solution limited to blade rings with relatively small dimensions.

Die DE-OS 33 36 420 beschreibt einen Mechanismus zum Schutz gegen ein Überdrehen eines Gasturbinenrotors bei Wellenbruch. Der Mechanismus wirkt in der Weise daß die Leitschaufelsegmente mindestens eines Leitschaufelkranzes axial verschwenkt und in Berührung/Eingriff mit benachbarten Laufschaufeln gebracht werden. Die wechselseitige mechanische Schaufelreibung und -zerstörung bremst den Rotor schnell und effektiv ab. Die zu dem Mechanismus gehörenden Leitschaufelsegmente weisen je ein Schwenklager am äußeren Deckbandsegment auf und sind an ihrem Innenumfang mittels eines formschlüssigen, ringartigen Verstärkungs-elementes verbunden, so daß die Segmente zusammen einen steifen, selbsttragenden Leitschaufelkranz bilden. Bei der Ausführung gemäß Figur 2 und 3 bilden die Schwenklager (Positionen 36,56,58 und 64) eine Speichenzentrierung für den eigenstabilen Leitschaufelkranz, was eine genaue Positionierung/Zentrierung bei reduzierten Thermospannungen ermöglicht. Nachteilig ist der Wärmeübergang vom Heißgasbereich zum Gehäuse (Pos. 34), von dem auch die Lagerelemente betroffen sind. Die resultierenden hohen Temperaturen und Temperaturgradienten in den Bauteilen dieses Bereiches können die Standzeit/Lebensdauer erheblich reduzieren.DE-OS 33 36 420 describes a mechanism for protection against overtightening of a gas turbine rotor in the event of a shaft break. The mechanism works in the Way that the guide vane segments axially at least one vane ring pivoted and brought into contact / engagement with adjacent blades become. The mutual mechanical blade friction and destruction slows down the rotor quickly and effectively. The vane segments belonging to the mechanism each have a pivot bearing on the outer shroud segment and are on their inner circumference by means of a form-fitting, ring-like reinforcement element connected so that the segments together form a rigid, self-supporting Form the guide vane ring. Form in the embodiment according to Figures 2 and 3 the swivel bearings (positions 36, 56, 58 and 64) provide spoke centering for the intrinsically stable guide vane ring, which contributes to precise positioning / centering reduced thermal voltages. A disadvantage is the heat transfer from Hot gas area to the housing (item 34), which also affects the bearing elements are. The resulting high temperatures and temperature gradients in the components this area can significantly reduce the service life.

Die US-PS 3,588,267 schützt eine Leitschaufelkranzkonstruktion in Kunststoffbauweise, bei welcher die Schaufeln an einem geschlossenen, inneren Torus befestigt sind und mit diesem einen selbsttragenden Kranz bilden. Die äußeren Schaufelspitzen sind deckbandlos ausgeführt und direkt in Aussparungen eines metallischen Gehäuses eingeklebt, wobei die Elastizität der Klebung kleine Relativverschiebungen ausgleicht/aufnimmt. Es ist offensichtlich, daß diese Konstruktion für höhere Temperaturen völlig unbrauchbar ist und bestenfalls im Fan- bzw. Niederdruckverdichterbereich Verwendung finden kann.The US-PS 3,588,267 protects a guide vane ring construction in plastic construction, in which the blades are attached to a closed, inner torus and form a self-supporting wreath with it. The outer blade tips are designed without a cover tape and directly in the recesses of a metallic one Glued housing, the elasticity of the bond small relative shifts balances / absorbs. It is obvious that this design is for higher temperatures is completely unusable and at best in the fan or low pressure compressor area Can be used.

Angesichts dieser bekannten Lösungen und ihrer Nachteile besteht die Aufgabe der Erfindung darin, eine Strömungsmaschine mit Rotor und Stator sowie mit mindestens einem, je ein äußeres und ein inneres Deckband aufweisenden Leitschaufelkranz zu schaffen, welche sich in allen Betriebszuständen durch eine optimale Spalthaltung, d.h. durch besonders niedrige, wenig variierende und rechnerisch gut erfaßbare Leckageverluste, somit einen hohen Wirkungsgrad, sowie durch eine relativ einfache, kosten- und gewichtsgünstige, langlebige und wartungsfreundliche Konstruktion ohne die Erfordernis eines aktiven Spaltkontrollsystems (ACC's) auszeichnet und auch mit großen Leistungen und Abmessungen ausführbar sowie funktionstüchtig ist.In view of these known solutions and their disadvantages, there is the task of Invention in a turbomachine with rotor and stator and at least one, each having an outer and an inner cover band guide vane ring to create, which is in all operating conditions by an optimal gap, i.e. due to particularly low, little varying and computationally easy to understand Leakage losses, thus a high efficiency, as well as by a relative simple, cost-effective, low-weight, durable and maintenance-friendly construction without the need for an active gap control system (ACC's) and can also be carried out with large capacities and dimensions and is functional is.

Diese Aufgabe wird durch die im Anspruch 1 gekennzeichnete Kombination der Merkmale A bis D gelöst, in Verbindung mit den gattungsbildenden Merkmalen in dessen Oberbegriff.This object is achieved by the combination of Features A to D solved, in connection with the generic features in its generic term.

Die Erfindung liegt somit in der thermischen Entkoppelung von Gehäuse und Leitschaufeln mittels einer speziellen Ausführung und Lagerung/Zentrierung mindestens eines Leitschaufelkranzes sowie mittels Luftkühlung des Gehäuses. Der - mindestens eine - Leitschaufelkranz ist als selbsttragendes Bauteil mit einer Verstärkung am inneren Deckband ausgeführt, welche ihn gegen stülpende Axialverformung versteift. Ausgehend von einer etwa ebenen, radialen Ausrichtung der Schaufelachsen im unbelasteten Zustand werden diese durch die statische Druckdifferenz vor/hinter dem Leitschaufelkranz bei Auslenkung Null" am Gehäuse zur Kranzmitte hinzunehmend axial ausgelenkt und dabei u.U. auch gekrümmt. Somit ist der Leitschaufelkranz mechanisch mit einer Tellerfeder vergleichbar, deren inneren Rand (Lochrand) das innere Deckband, und deren äußeren Rand das äußere Deckband bildet. Das innere Deckband wird dabei sowohl axial verschoben als auch durch die schaufelinduzierten Momente in sich verdreht/verstülpt. Das heißt, die in Radial-Axialschnitten sichtbaren Materialquerschnitte des Deckbandes werden um gedachte, zur Schnittfläche jeweils senkrechte Achsen je nach Steifigkeit/Verstärkung mehr oder weniger verdreht.The invention thus lies in the thermal decoupling of the housing and guide vanes by means of a special design and storage / centering of at least one guide vane ring and by means of air cooling of the housing. The - at least one - guide vane ring is designed as a self-supporting component with a reinforcement on the inner shroud, which stiffens it against slipping axial deformation. Starting from an approximately flat, radial alignment of the blade axes in the unloaded state, these are offset by the static pressure difference in front of / behind the guide blade ring during deflection Zero "axially deflected towards the middle of the rim and possibly also curved. The guide vane rim is therefore mechanically comparable to a disc spring, the inner edge (hole edge) of which forms the inner cover band and the outer edge of which forms the outer cover band. The inner cover band is both axially displaced as well as twisted / inverted due to the blade-induced moments, which means that the material cross-sections of the shroud visible in radial-axial sections are rotated more or less around imaginary axes perpendicular to the cutting surface depending on the rigidity / reinforcement.

Die erfindungsgemäße Verstärkung des inneren Deckbandes gegen besagte Verstülpung reduziert auch die axiale Auslenkung der Schaufelachsen und somit die gesamte Verformung des Leitschaufelkranzes unter Last. Dies verbessert die Maßhaltigkeit der statischen Komponente der Inner Airseal".The inventive reinforcement of the inner shroud against said inversion also reduces the axial deflection of the blade axes and thus the overall deformation of the guide vane ring under load. This improves the dimensional stability of the static component Inner Airseal ".

Durch die wenigen, kleinen Wärmebrücken/Lagereinheiten zwischen äußerem Deckband und Gehäuse sowie durch die Kühlluftführung in diesem Bereich wird ein Wärmetransport vom Gaskanal in das Gehäuse weitestgehend vermieden, wodurch sich u. a. geringe Temperaturgradienten im äußeren Deckband einstellen, was in Kombination mit der Segmentierung des äußeren Deckbandes die Thermospannungen im Leitkranz verringert. Das luftgekühlte Gehäuse bleibt auf einem niedrigen Temperaturniveau, wogegen der Leitkranz insgesamt etwa die Heißgastemperatur annimmt.Due to the few, small thermal bridges / storage units between the outside Cover band and housing as well as through the cooling air duct in this area Heat transfer from the gas duct into the housing is largely avoided, which means yourself u. a. set low temperature gradients in the outer shroud, which in Combined with the segmentation of the outer shroud the thermal stresses reduced in the wreath. The air-cooled case remains low Temperature level, whereas the lead ring as a whole is about the hot gas temperature assumes.

Die mindestens dreifache, jeweils radiale Bewegungen zulassende Lagerung ( Speichenzentrierung") der Deckbandsegmente behindert die thermische Dehnung/Kontraktion praktisch nicht und trägt somit auch zu einer Spannungsminimierung bei. Außerdem wird eine exakte Zentrierung im Gehäuse erreicht.The at least triple bearing, which allows radial movements ( Spoke centering ") of the shroud segments practically does not hinder thermal expansion / contraction and thus also contributes to minimizing tension. In addition, exact centering in the housing is achieved.

Die erfindungsgemäße Kombination aus Leitschaufelkranzkonstruktion und -lagerung sowie Kühlluftführung hat zur Folge, daß das Verformungsverhalten des Kranzes überwiegend durch die Verhältnisse/Temperaturen im Heißgas, welche auch für das Rotorverhalten maßgeblich sind, bestimmt wird. Da die statischen Komponenten der Inner"- und Outer Airseal" von den Leitschaufelkränzen getragen werden und sich zu diesen konform verhalten, wird eine bestmögliche Angleichung der Verformungen der statischen und rotatorischen Dichtungskomponenten hinsichtlich Zeitverlauf, Größe und Richtung bei wechselnden Betriebsverhältnissen (instationärer Betrieb) erreicht. Somit kann die Maschine durchgehend mit etwa gleichbleibenden, minimalen Spalten bzw. Leckageverlusten und damit hohem Wirkungsgrad gefahren werden, wobei speziell im Leitschaufelbereich keine vorzeitige Bauteilermüdung zu befürchten ist. Die Anwendung von Bürstendichtungen wird durch das konforme Verhalten der Dichtungsträger (geringe Spaltänderung, geringe Exzentrizität etc.) begünstigt bzw. sogar erst ermöglicht.The combination of the guide vane ring construction and bearing arrangement and cooling air ducting according to the invention has the result that the deformation behavior of the ring is mainly determined by the conditions / temperatures in the hot gas, which are also decisive for the rotor behavior. Since the static components of the Inner "- and Outer Airseal "are carried by the guide vane rings and behave in conformity with them, the best possible adaptation of the deformations of the static and rotary sealing components with regard to time course, size and direction is achieved with changing operating conditions (unsteady operation). Thus, the machine can consistently with approximately constant, minimal gaps or leakage losses and thus high efficiency can be achieved, especially in the guide vane area there is no risk of premature component fatigue. The use of brush seals is promoted or even made possible by the conformal behavior of the seal carrier (slight gap change, low eccentricity etc.).

In den Unteransprüchen sind bevorzugte Ausgestaltungen der Strömungsmaschine nach dem Hauptanspruch gekennzeichnet.Preferred embodiments of the turbomachine are in the subclaims marked according to the main claim.

Die Erfindung wird anschließend anhand der Figur noch näher erläutert. Diese zeigt einen Teillängsschnitt durch die Niederdruckturbine eines Turboluftstrahltriebwerkes. The invention is explained in more detail with reference to the figure. This shows a partial longitudinal section through the low pressure turbine of a turbo air jet engine.

Die vorliegende Erfindung ist generell für Strömungsmaschinen mit Rotor und Stator, d.h. für Verdichter und Turbinen, geeignet, welche zumindest abschnittsweise in Axialbauart, d.h. mit vorwiegend axialer Durchströmung, ausgeführt sind. Thermodynamisch und abmessungsbedingt dürften Niederdruckturbinen mittlerer bis großer Gasturbinentriebwerke bevorzugte Anwendungsfälle darstellen, weshalb die Figur ein Beispiel aus diesem Bereich zeigt.The present invention is generally for turbomachines with a rotor and stator, i.e. suitable for compressors and turbines, which at least in sections in Axial design, i.e. with predominantly axial flow. Thermodynamic and due to their size, low-pressure turbines are likely to be medium to large Gas turbine engines are preferred applications, which is why the figure Example from this area shows.

Von der Niederdruckturbine 1 sind die ersten beiden Stufen und hiervon wiederum die relevanten Elemente der oberen Hälfte dargestellt, wobei die Turbinen/Triebwerksachse horizontal unterhalb der Darstellung verlaufen würde. Die Strömungsrichtung des Arbeitsgases verläuft von links nach rechts, d.h. zunächst durch den Leitschaufelkranz 14, dann durch den Bereich der Laufschaufeln 3, anschließend durch den Leitschaufelkranz 15 und durch den Bereich der Laufschaufeln 4, wobei noch weitere Stufen (Leit-, Lauf-) folgen können. Die äußere Triebwerkshülle bildet das Gehäuse 13, in welchem die Leitschaufelkränze 14,15 radial zentriert und axial fixiert gelagert sind. Sowohl die Laufschaufeln 3,4 als auch die Leitschaufelkränze 14,15 sind mit inneren und äußeren Deckbändern 5 bis 8 und 16 bis 19 ausgeführt, wobei die inneren und äußeren Laufschaufeldeckbänder jeweils zwischen den Schaufeln Trennfugen aufweisen, u.a. damit beschädigte Schaufeln einzeln auswechselbar sind.The first two stages are from the low-pressure turbine 1 and from this in turn the relevant elements of the top half are shown, with the turbine / engine axis would run horizontally below the representation. The flow direction of the working gas runs from left to right, i.e. first through the guide vane ring 14, then through the area of the blades 3, then through the guide vane ring 15 and through the area of the moving blades 4, whereby further stages (leading, running) can follow. The outer engine casing forms the housing 13 in which the guide vane rings 14, 15 are radially centered and are axially fixed. Both the blades 3,4 and the vane rings 14, 15 are designed with inner and outer cover bands 5 to 8 and 16 to 19, the inner and outer blade shrouds between each the blades have gaps, including damaged blades can be replaced individually are.

Die Leitschaufelkränze 14,15 sind als selbsttragende Bauelemente ausgeführt, wobei ihre mechanische Stabilität überwiegend im Bereich der inneren Deckbänder 16,17 erzielt wird. Dort sind in Umfangsrichtung geschlossene, d.h. umlaufende", Verstärkungen 20,21 angeordnet, welche auch das thermische Verhalten (Maß- und Formänderungen) der Leitschaufelkränze 14,15 entscheidend beeinflussen. Die Gaskräfte im Betrieb bewirken u.a. eine stülpende Axialverformung der Leitschaufelkränze, d.h. eine vom äußeren zum inneren Deckband zunehmende axiale Auslenkung mit einer gewissen Verdrehung der Deckbänder in sich. Diese tellerfederartige" Verformung läßt sich über die Verstärkungen an den inneren Deckbändern erheblich reduzieren. Als Verstärkungen sind beispielsweise die dargestellten, torusartigen Hohlkörper, axial beabstandete Ringe, Kombinationen von Hohl- und Vollprofilen usw. geeignet, wobei auch die Platzverhältnisse eine Rolle spielen. Die Verstärkungen sollten jedenfalls - im Axial-/Radialschnitt - ein möglichst großes Flächenträgheitsmoment um eine radiale Achse z.B. durch den Flächenschwerpunkt aufweisen, was durch ausreichende, axial beabstandete Flächenanteile erreichbar ist. Die Flächenanteile des Deckbandes sind hier mit zu berücksichtigen. Vorteilhaft ist ein Verstärkungswerkstoff mit hohem E-Modul. Insgesamt sollte bei möglichst kleiner Massenerhöhung ein Optimum an Steifigkeitserhöhung erzielt werden. Die Ermittlung der Spannungen und Verformungen beim Stülpen" ist über einschlägige Berechnungsverfahren möglich.The guide vane rings 14, 15 are designed as self-supporting components, their mechanical stability being achieved predominantly in the area of the inner shrouds 16, 17. There are closed in the circumferential direction, ie circumferential ", reinforcements 20, 21 arranged, which also decisively influence the thermal behavior (changes in shape and shape) of the guide vane rings 14, 15. The gas forces during operation cause, among other things, an inverting axial deformation of the guide vane rings, ie an axial deflection increasing from the outer to the inner shroud with some twisting of the shrouds plate spring-like "deformation can be significantly reduced by the reinforcements on the inner cover bands. The reinforcements shown are, for example, the toroidal hollow bodies shown, axially spaced rings, combinations of hollow and solid profiles, etc., the space conditions also playing a role. The reinforcements should play a role. The reinforcements should in any case - in the axial / radial section - have as large a moment of inertia as possible about a radial axis, for example through the center of gravity, which can be achieved by sufficient, axially spaced area portions. The area portions of the shroud are to be taken into account here. A reinforcing material with a high E- Overall, an optimum increase in stiffness should be achieved with the smallest possible increase in mass. The determination of the stresses and deformations in the Stülpen "is possible using relevant calculation methods.

Die Verstärkung 20 ist mit dem Deckband 16 formschlüssig verbunden, wobei der Leitschaufelkranz 14 aus mehreren Segmenten bestehen kann, welche über die Verstärkung zusammengehalten werden. Die Verstärkung 21 ist hingegen in das Deckband 17 integriert, d.h. stoffschlüssig mit diesem zusammengefügt. Auch hier können Leitschaufelsegmente die Ausgangsteile sein, welche durch Schweißen oder Löten im Bereich des inneren Deckbandes/ der Verstärkung verbunden werden.The reinforcement 20 is positively connected to the shroud 16, the Guide vane ring 14 can consist of several segments, which on the reinforcement be held together. The reinforcement 21, however, is in the shroud 17 integrated, i.e. integrally joined with this. Here too Guide vane segments are the starting parts, which by welding or Solder in the area of the inner shroud / reinforcement.

Die äußeren Deckbänder 18,19 sollen jedoch im Einbauzustand noch segmentiert sein, d.h. mehrere Trennfugen am Umfang aufweisen, um Thermospannungen zu minimieren.However, the outer shrouds 18, 19 should still be segmented in the installed state be, i.e. have several joints on the circumference to prevent thermal stress minimize.

Die Zentrierung und Fixierung der Leitschaufelkränze 14,15 im Gehäuse 13 erfolgt
   über

  • jeweils mindestens drei Lagereinheiten mit je einem gehäusefesten Lagerzapfen
       26,27 und
  • je einer deckbandfesten Lagerbuchse 24,25. Die Kontaktflächen der Zapfen sind
       ballig, die
  • der Buchsen zylindrisch ausgeführt, so daß über eine freie radiale Beweglichkeit hin
       aus
  • auch kleine allseitige Schwenkbewegungen nach Art eines Kugelgelenkes möglich
       sind. All
  • dies minimiert Zwangskräfte und somit Bauteilspannungen, was wiederum die Lebensdauer erhöht.
    • The guide vane rings 14, 15 are centered and fixed in the housing 13
    about
  • at least three bearing units each with a bearing journal fixed to the housing
    26.27 and
  • one bearing bush 24.25 fixed to the shroud. The contact surfaces of the pegs are
    crowned, the
  • the bushings are cylindrical, so that there is free radial mobility
    out
  • even small all-round swivel movements in the manner of a ball joint are possible
    are. Alles
  • this minimizes constraining forces and thus component stresses, which in turn increases the service life.

    • Die Inner Airseal" ist hier - zumindest überwiegend - mit Bürstendichtungen ausgeführt, wobei im Bereich der Leitschaufelkranzverstärkungen befestigte Bürsten 22,23 gegen mit dem Rotor 2 verbundene Ringe 11,12 laufen, welche axiale Anschläge für die Laufschaufeln 3,4 bilden.The Inner Airseal "is - at least predominantly - designed with brush seals, brushes 22, 23 fastened in the area of the guide vane ring reinforcements running against rings 11, 12 connected to the rotor 2, which form axial stops for the rotor blades 3, 4.

    Die Outer Airseal" ist hier mit Labyrinthdichtungen verwirklicht, wobei ringschneidenartige Dichtspitzen 9,10 gegen Wabenstrukturen laufen, welche auf Wabenträger 28,29 aufgebracht sind. Die Wabenträger 28,29 sind ihrerseits an den Leitschaufelkränzen 14,15 gelagert und dadurch im Verformungsverhalten an diese angeglichen.The Outer Airseal "is realized here with labyrinth seals, ring-shaped sealing tips 9, 10 running against honeycomb structures which are applied to honeycomb carriers 28, 29. The honeycomb carriers 28, 29 are in turn mounted on the guide vane rings 14, 15 and are therefore adapted to the deformation behavior thereof.

    Im Sinne der Erfindung ist eine Luftkühlung für das Gehäuse und die Lagereinheiten der Leitschaufelkränze vorgesehen, welche konstruktiv jedoch bei weitem nicht so aufwendig ist, wie ein ACC-System. Zu diesem Zweck ist auf der Innenseite des Gehäuses 13 in radialem Abstand eine Luftleitschale 30 angeordnet, so daß zwischen dieser und dem Gehäuse Kühlluft in Triebwerkslängsrichtung strömen kann. Der Zutritt der in der Regel vom Verdichter abgezweigten Kühlluft erfolgt über Bohrungen 35 in eine erste Kammer 33. Im Bereich der Lagerzapfen 26 und 27 besitzt die Luftleitschale 30 bewußt gasdurchlässige Öffnungen 31,32, so daß ein Teil der Kühlluft längs der Lagerzapfen 26,27 in den Bereich der äußeren Deckbänder 18,19 der Leitschaufelkränze 14,15 strömen kann, ein entsprechendes Druckgefälle (Kühlluftüberdruck) vorausgesetzt. Dadurch werden die Lagerstellen gekühlt und Wärmeströme von den Leitschaufelkränzen zum Gehäuse minimiert. Das Wandelement 37 weist - nicht dargestellte - Restriktoren auf oder bildet selbst mit entsprechenden Drosselspalten einen Restriktor für die Kühlluft, so daß diese in die nachfolgende Kammer 34 mit reduziertem Druck eintritt. Es reicht aus, wenn die Kühlluft jeweils nur einen mäßigen Überdruck gegenüber dem Arbeitsgas im angrenzenden Strömungskanal aufweist. Da der Druck des Arbeitsgases axial abnimmt, ist es sinnvoll, auch den Kühlluftdruck zumindest in wenigen Stufen zu reduzieren, was hier durch die genannte Kammerbauweise mit Restriktoren erreicht wird. Hohe Überdrücke der Kühlluft würden auch eine hohe Druckfestigkeit der Luftleitschale 30 erfordern, d.h. größere Wanddicken und mehr Gewicht. For the purposes of the invention, air cooling is used for the housing and the bearing units the guide vane rings provided, which is not so constructively is complex, like an ACC system. For this purpose is on the inside of the case 13 an air guide shell 30 is arranged at a radial distance, so that between this and the housing cooling air can flow in the longitudinal direction of the engine. The admission the cooling air, which is usually branched off from the compressor, is carried out via bores 35 into a first chamber 33. The air guide shell has in the area of the bearing journals 26 and 27 30 deliberately gas-permeable openings 31,32, so that part of the cooling air along the journals 26, 27 in the area of the outer shrouds 18, 19 of the guide vane rings 14.15 can flow, a corresponding pressure drop (Cooling air overpressure) provided. This cools the bearings and Heat flows from the vane rings to the housing are minimized. The wall element 37 has - not shown - restrictors or forms itself with corresponding ones Throttle columns a restrictor for the cooling air, so that this in the subsequent Chamber 34 enters with reduced pressure. It is sufficient if the cooling air only a moderate overpressure in relation to the working gas in the adjacent one Has flow channel. Since the pressure of the working gas decreases axially, it makes sense to also to reduce the cooling air pressure at least in a few stages, which is here is achieved by the chamber design mentioned with restrictors. High pressures the cooling air would also have a high compressive strength of the air guide shell 30 require, i.e. larger wall thicknesses and more weight.

    Zwischen dem Strömungskanal des Arbeitsgases und dem Kühlluftkanal sind weitere Wandelemente 36, 38 angeordnet, welche Arbeitsgasnebenströme, d.h. -verluste, durch diese Passagen verhindern sollen. Aus Kühlungsgründen sind auch diese Wandelemente 36,38 bewußt etwas gasdurchlässig ausgeführt bzw. befestigt.There are more between the flow channel of the working gas and the cooling air channel Wall elements 36, 38 arranged, which secondary gas flows, i.e. -losses, to prevent through these passages. For cooling reasons, these are also Wall elements 36, 38 deliberately designed or fastened somewhat gas-permeable.

    Claims (6)

    Strömungsmaschine mit Rotor und Stator in strömungstechnisch zumindest abschnittsweise axialer Bauart, deren Rotor Laufschaufeln, und deren Stator ein Gehäuse mit Leitschaufeln aufweist, wobei die Leitschaufeln als mindestens ein Leitschaufelkranz mit einem radial inneren und einem radial äußeren Deckband angeordnet, sind, insbesondere axiale Niederdruckturbine, gekennzeichnet durch die Kombination folgender Merkmale: (A) Mindestens ein Leitschaufelkranz (14,15) ist als selbsttragendes Bauteil mit einer in Umfangsrichtung geschlossenen, zumindest weitgehend rotationssymmetrischen, das Bauteil gegen stülpende Axialverformung versteifenden Verstärkung (20,21) am inneren Deckband (16,17) ausgeführt, (B) der mindestens eine Leitschaufelkranz (14,15) weist ein segmentiertes äußeres Deckband (18,19) mit mehreren über seinen Umfang verteilten Trennfugen auf und (C) er ist über mindestens drei Segmente des äußeren Deckbandes (18,19) mittels jeweils einer örtlich radiale Relativbewegungen zulassenden Lagereinheit (24,25,26,27), d.h. insgesamt über eine sog. Speichenzentrierung mit mindestens drei Speichen, im Gehäuse (13) positioniert, und (D) zwischen dem Gehäuse (13) und dem äußeren Deckband (18,19) des mindestens einen Leitschaufelkranzes (14,15) ist eine Luftleitschale (30) angeordnet, welche einen Kühlluftstrom längs der Gehäuseinnenseite führt und mit Öffnungen (31,32) für die gehäusefesten Lagerelemente (26,27) des mindestens eine Leitschaufelkranzes (14,15) versehen ist, wobei die Öffnungen (31,32) einen Teil des Kühlluftstromes zum Deckband (18,19) hin durchtreten lassen. Turbomachine with rotor and stator in fluidic at least sectionally axial design, the rotor blades and the stator of which have a housing with guide vanes, the guide vanes being arranged as at least one guide vane ring with a radially inner and a radially outer shroud, in particular axial low-pressure turbine by combining the following features: (A) At least one guide vane ring (14, 15) is designed as a self-supporting component with a reinforcement (20, 21) on the inner shroud (16, 17) that is closed in the circumferential direction and is at least largely rotationally symmetrical, stiffening the component against slipping axial deformation, (B) the at least one guide vane ring (14, 15) has a segmented outer shroud (18, 19) with a plurality of separating joints distributed over its circumference and (C) it is in the housing over at least three segments of the outer shroud (18, 19) by means of a respective bearing unit (24, 25, 26, 27) that allows radial relative relative movements, that is, overall via a so-called spoke centering with at least three spokes 13) positioned, and (D) an air guide shell (30) is arranged between the housing (13) and the outer shroud (18, 19) of the at least one guide vane ring (14, 15), which guides a cooling air flow along the inside of the housing and with openings (31, 32) for the bearing elements (26, 27) fixed to the housing of the at least one guide vane ring (14, 15), the openings (31, 32) allowing part of the cooling air flow to pass through to the shroud (18, 19). Strömungsmaschine nach Anspruch 1, dadurch gekennzeichnet, daß die Verstärkung (20,21) des mindestens einen Leitschaufelkranzes (14,15) als torusförmiger Hohlkörper oder in Form mindestens zweier axial beabstandeter Ringe ausgeführt und stoffschlüssig in das innere Deckband (17) integriert oder formschlüssig mit diesem (16) verbunden ist.Fluid machine according to claim 1, characterized in that the reinforcement (20, 21) of the at least one guide vane ring (14, 15) as a toroidal one Hollow body or in the form of at least two axially spaced rings and integrated into the inner shroud (17) or with a positive fit this (16) is connected. Strömungsmaschine nach Anspruch 2 mit formschlüssiger Verbindung zwischen der Verstärkung und dem inneren Deckband des mindestens einen Leitschaufelkranzes, dadurch gekennzeichnet, daß der mindestens eine Leitschaufelkranz (14) aus mehreren Leitschaufelsegmenten besteht, welche mittels der Verstärkung (20) zu einem selbsttragenden Bauteil zusammengefügt sind.Fluid machine according to claim 2 with a positive connection between the reinforcement and the inner shroud of the at least one guide vane ring, characterized in that the at least one vane ring (14) consists of several guide vane segments, which by means of the reinforcement (20) are assembled into a self-supporting component. Strömungsmaschine nach einem oder mehreren der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß die Verstärkung (20,21) des mindestens einen Leitschaufelkranzes (14,15) das statische Element einer Wellendichtung trägt, insbesondere die Bürste (22,23) einer Bürstendichtung oder den Einlaufbelag bzw. die Wabenstruktur einer Labyrinthdichtung.Fluid machine according to one or more of claims 1 to 3, characterized characterized in that the reinforcement (20, 21) of the at least one guide vane ring (14,15) carries the static element of a shaft seal, in particular the brush (22, 23) of a brush seal or the inlet covering or the honeycomb structure a labyrinth seal. Strömungsmaschine nach einem oder mehreren der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß jede Lagereinheit des mindestens einen Leitschaufelkranzes (14,15) aus einem gehäusefesten Lagerzapfen (26,27) mit balliger Kontaktfläche und einer deckbandfesten Lagerbuchse (24,25) mit zylindrischer Kontaktfläche besteht.Fluid machine according to one or more of claims 1 to 4, characterized characterized in that each bearing unit of the at least one vane ring (14,15) from a housing-fixed bearing journal (26,27) with a spherical contact surface and a shroud-fixed bearing bush (24, 25) with a cylindrical contact surface consists. Strömungsmaschine nach einem oder mehreren der Ansprüche 1 bis 5, dadurch gekennzeichnet, daß der Strömungskanal des Kühlluftstromes zwischen Gehäuse (13) und Luftleitschale (30) in mehrere, nacheinander durchströmte Kammern (33,34) mit von Kammer zu Kammer abnehmendem Innendruck aufgeteilt ist, wobei jede Kammer (33,34) für einen Betriebsdruck ausgelegt ist, welcher zumindest geringfügig höher ist als der Druck im jeweils benachbarten Strömungskanalbereich des Arbeitsmediums.Fluid machine according to one or more of claims 1 to 5, characterized characterized in that the flow channel of the cooling air flow between the housing (13) and air guide shell (30) in several successively flowed through chambers (33,34) with internal pressure decreasing from chamber to chamber, whereby each chamber (33, 34) is designed for an operating pressure which is at least is slightly higher than the pressure in the adjacent flow channel area of the working medium.
    EP99103156A 1998-02-20 1999-02-18 Guidevane assembly for an axial turbomachine Expired - Lifetime EP0937864B1 (en)

    Applications Claiming Priority (2)

    Application Number Priority Date Filing Date Title
    DE19807247A DE19807247C2 (en) 1998-02-20 1998-02-20 Turbomachine with rotor and stator
    DE19807247 1998-02-20

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    EP0937864A2 true EP0937864A2 (en) 1999-08-25
    EP0937864A3 EP0937864A3 (en) 2000-10-25
    EP0937864B1 EP0937864B1 (en) 2003-08-13

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    US (1) US6139263A (en)
    EP (1) EP0937864B1 (en)
    JP (1) JP4230040B2 (en)
    DE (2) DE19807247C2 (en)

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    EP2796667A1 (en) * 2013-04-24 2014-10-29 MTU Aero Engines GmbH Slip ring seal
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    WO2011018072A3 (en) * 2009-08-14 2011-09-15 Mtu Aero Engines Gmbh Fastening element for a guide blade ring of a turbomachine
    EP2719869A1 (en) * 2012-10-12 2014-04-16 MTU Aero Engines GmbH Axial sealing in a housing structure for a turbomachine
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    EP2796667A1 (en) * 2013-04-24 2014-10-29 MTU Aero Engines GmbH Slip ring seal
    US9835039B2 (en) 2013-04-24 2017-12-05 MTU Aero Engines AG Slide ring seal
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    Also Published As

    Publication number Publication date
    JP4230040B2 (en) 2009-02-25
    JPH11294103A (en) 1999-10-26
    EP0937864A3 (en) 2000-10-25
    DE19807247A1 (en) 1999-09-09
    DE59906550D1 (en) 2003-09-18
    DE19807247C2 (en) 2000-04-20
    US6139263A (en) 2000-10-31
    EP0937864B1 (en) 2003-08-13

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