EP0214393B1 - Antivibration device for turbo machine blades - Google Patents

Antivibration device for turbo machine blades Download PDF

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Publication number
EP0214393B1
EP0214393B1 EP86109040A EP86109040A EP0214393B1 EP 0214393 B1 EP0214393 B1 EP 0214393B1 EP 86109040 A EP86109040 A EP 86109040A EP 86109040 A EP86109040 A EP 86109040A EP 0214393 B1 EP0214393 B1 EP 0214393B1
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EP
European Patent Office
Prior art keywords
blades
magnet inserts
magnets
magnetic
cover plates
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP86109040A
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German (de)
French (fr)
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EP0214393A1 (en
Inventor
Peter Dipl.-Ing. Novacek
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BBC Brown Boveri AG Switzerland
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BBC Brown Boveri AG Switzerland
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Publication of EP0214393A1 publication Critical patent/EP0214393A1/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
    • 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
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2260/00—Function
    • F05D2260/96—Preventing, counteracting or reducing vibration or noise
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S416/00—Fluid reaction surfaces, i.e. impellers
    • Y10S416/50—Vibration damping features

Definitions

  • the invention relates to a device for damping blade vibrations in turbomachinery.
  • a common and long-established precaution to combat the vibrations that occur is that the blades within a row of blades are connected to each other in packages by a damper wire.
  • the invention seeks to remedy this.
  • the invention as characterized in the claims, is based on the object of achieving a stiffening of the blade assembly against occurring vibrations of various excitation orders in a device of the type mentioned.
  • the individual magnets are to be set and fixed in such a way that their end faces not only lie against one another in the installed state, but also press against one another. This can be done by an excess compared to the actual distance between two blades and / or by a pre-torsion of the blades before they are installed.
  • Fig. 1 shows individual blades 1, 2, n in a row of blades, as they are usually arranged on a rotor disk, not shown here.
  • the blades 1, 2, n themselves consist of blade root 3, transition part 4, blade 5 and cover plate 6.
  • the cover plate configuration shown here is provided where slim blades 5 are used.
  • an improvement in efficiency is sought by covering plate 6 bridging the space between the end of airfoil 5 and the stator, also not shown, so that the different thermal expansions of airfoil 5 in the radial direction between the inflow and outflow sides of blades 1, 2 , n no longer play a relevant role in the dimensioning of the gap.
  • the cover plate 6 is also designed such that it engages in the stator like a labyrinth, as a result of which the flow losses there can be minimized.
  • Such cover plates 6 are particularly suitable for holding magnets 7, 8, which bridge the individually designed space between two adjacent blades.
  • the magnets 7, 8 used here are of a round design; other geometric shapes can also be used.
  • the magnetic sections protruding from the cover plates 6 each have an alternating polarity to the other adjacent section, so that the individual cover plates 6 adhere to one another via the attractive force of the individual pair magnets 7, 8.
  • a further intermediate stage, formed by preferably identical magnets 7, 8, is provided approximately at half the height of the airfoil. This precaution should only be taken into account for soft blades, because this means that flow losses are involved.
  • the intermediate stage can have a thickening in the region of the penetration of the magnet 8 by the blades 1, 2, n.
  • Fig. 2 shows the top view of a cover plate design, in which at least the opposite end faces 9a of the cover plates 9 are magnetic.
  • the attraction available here is particularly great.
  • Such an embodiment is therefore preferably used for blades that are highly susceptible to vibration.
  • the force of attraction is only fully available if the required manufacturing accuracy of the blades in general and the cover plates 9 in particular are strictly observed.
  • cover plates 10 shown in FIG. 3 In contrast, the manufacturing accuracy of the cover plates 10 shown in FIG. 3 is no longer in the foreground.
  • the individual cover plates 10 carry magnetic inserts 11, 12 which lie against one another alone.
  • the cover plates 10 are also set back in this area. It can be provided that the individual magnet inserts 11, 12 can be adjusted so that their positioning can only be carried out after the assembly of the blades 1, 2, n.
  • the embodiment according to FIG. 4 pursues similar goals.
  • the individual magnetic inserts 14, 15 can be adjusted relative to one another in such a way that their magnetic head parts abut one another.
  • the rhomboidal shape of the cover plates 13 offers advantages when installing the blades 1, 2, n: since the plane of alignment of the cover plate flanks corresponds to that of the blade root, the blades 1, 2, ⁇ can be inserted into the rotor disk without subsequent alignment.
  • the variant shown in Fig. 5 is characterized in that the cover plates 16 at their edge zones with two magnetic inserts 17, 19 and. 18, 20 are equipped. While in the area of the blade flow, the magnetic inserts 19, 20 according to the conventional direction of polarity? / e are arranged, the other edge zone has magnetic inserts 17, 18 which abut one another with poles of the same name ⁇ / ⁇ or e / e.
  • This arrangement can also be used to achieve a circumferential bracing which, in combination with the force direction of the magnetic forces acting in reverse on the other side of the cover plates 16, results in good elasticity against shock-like vibrations.
  • uniform polarity e / e and / or e / e can also be provided in all the examples explained above.

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

Description

Die Erfindung betrifft eine Einrichtung zur Dämpfung von Schaufelschwingungen bei Turbomaschinen.The invention relates to a device for damping blade vibrations in turbomachinery.

Bei Turbomaschinen werden die rotierenden Schaufeln unter anderem durch unregelmässige Anströmung erregt. Diese anregende Kraft verursacht oft unzulässige Wechselspannungen in den Schaufeln. Zur Bekämpfung dieser gefährlichen Schwingungen kann als naheliegende Massnahme die Verdickung des Schaufelprofiles in Betracht gezogen werden. Indessen verursacht diese Verstärkung eine wesentliche Verschlechterung des Wirkungsgrades, weshalb diese Massnahme in der Praxis eher nicht angewendet wird.In turbomachinery, the rotating blades are excited, among other things, by an irregular flow. This stimulating force often causes impermissible AC voltages in the blades. To combat these dangerous vibrations, the thickening of the blade profile can be considered as an obvious measure. However, this reinforcement causes a significant deterioration in efficiency, which is why this measure is rather not used in practice.

Eine häufige und seit langem praktizierte Vorkehrung zur Bekämpfung der auftretenden Schwingungen besteht darin, dass die Schaufelblätter innerhalb einer Schaufelreihe jeweils paketweise durch einen Dämpferdraht miteinander verbunden werden.A common and long-established precaution to combat the vibrations that occur is that the blades within a row of blades are connected to each other in packages by a damper wire.

Diese konventionelle Vorkehrung weist indessen einige Nachteile auf:

  • - Der Dämpferdraht innerhalb des Strömungskanals verschlechtert den Wirkungsgrad der Turbomaschine.
  • - Der Dämpferdraht wird stark durch Biegespannungen und Mediumtemperatur beansprucht.
  • - Der Dämpferdraht ist der Korrosion und Erosion ausgesetzt.
This conventional arrangement has several disadvantages:
  • - The damper wire within the flow channel deteriorates the efficiency of the turbomachine.
  • - The damper wire is heavily stressed by bending stresses and medium temperature.
  • - The damper wire is subject to corrosion and erosion.

Als jüngste Neuerung kann die Lösung mit Dämpferdrähten ausserhalb des Strömungskanals betrachtet werden, wie in der ASME-Publikation 81-DET-136 teilweise beschrieben ist. Diese Auslegungsart ermöglicht eine relative Bewegung zwischen Draht und Schaufeln. Indessen, wegen des gegenseitigen Ausgleichs der Kräfte am Dämpferdraht infolge Kopplung mehrerer Schaufeln, wird die Reibung nicht voll ausgenützt. Meistens verhält sich der Draht eher als ein nicht rutschendes Bindeglied statt als Dämpferdraht, und darum können auch nicht alle Erregungsordnungen unter Kontrolle gebracht werden. Um diese offensichtlichen Schwierigkeiten zu überwinden, ist deshalb in der obengenannten Publikation der Versuch unternommen worden, den Dämpferdraht durch kleine Drahtstücke zu ersetzen, welche irgendwie an der Rotorscheibe zu verankern wären. In der praktischen Ausführung lässt sich aber eine solche Lösung platzmässig nicht unterbringen.As a recent innovation, the solution with damper wires outside the flow channel can be considered, as is partially described in ASME publication 81-DET-136. This type of design allows relative movement between the wire and blades. However, due to the mutual balancing of the forces on the damper wire due to the coupling of several blades, the friction is not fully exploited. Most of the time, the wire behaves as a non-slipping link rather than a damper wire, and therefore not all excitation orders can be brought under control. In order to overcome these obvious difficulties, an attempt has therefore been made in the abovementioned publication to replace the damper wire with small pieces of wire which would somehow have to be anchored to the rotor disk. In practical terms, however, such a solution cannot be accommodated in terms of space.

Dort wo die Schaufeln mit Deckplatten ausgebildet sind, werden diese zur Dämpfung herangezogen: Die Flanken der Deckplatten werden so bearbeitet, dass sie zueinander Kontaktflächen verschiedener Ausgestaltung bilden. Diese Deckplattenkonstruktionen weisen aber verschiedene Nachteile auf:

  • - Teure Bearbeitung und Ausführung der Kontaktflächen.
  • - Aufwendige Montage.
  • - Unterschiedliche Kontaktflächenkräfte, je nach Betriebszustand.
  • - Mechanische Abnützung der Kontaktflächen, worauf die angestrebte Dämpfung sich fortlaufend verschlechtert.
Where the blades are formed with cover plates, these are used for damping: the flanks of the cover plates are processed in such a way that they form contact surfaces of different designs. However, these cover plate designs have several disadvantages:
  • - Expensive machining and execution of the contact surfaces.
  • - Elaborate assembly.
  • - Different contact surface forces, depending on the operating state.
  • - Mechanical wear of the contact surfaces, whereupon the desired damping continuously deteriorates.

Hier will die Erfindung Abhilfe schaffen. Der Erfindung, wie sie in den Ansprüchen gekennzeichnet ist, liegt die Aufgabe zugrunde bei einer Einrichtung der eingangs genannten Art eine Versteifung des Schaufelverbundes gegen auftretende Schwingungen verschiedenster Erregungsordnung zu erreichen.The invention seeks to remedy this. The invention, as characterized in the claims, is based on the object of achieving a stiffening of the blade assembly against occurring vibrations of various excitation orders in a device of the type mentioned.

Die wesentlichen Vorteile der Erfindung sind darin zu sehen, dass sobald die während des Betriebes auftretenden Schwingungskräfte die vorgegebene Magnetkraft übersteigen, löst sich die durch Magnetkraft zusammengehaltene Verbindung ziemlich schlagartig auf. Dieser Unterbruch in der Versteifung wirkt sich schwingungsunterdrückend aus, was sofort zu einer Beruhigung des Systems führt.The main advantages of the invention can be seen in the fact that as soon as the vibrational forces that occur during operation exceed the predetermined magnetic force, the connection held together by magnetic force dissolves quite suddenly. This interruption in the stiffening has a vibration-suppressing effect, which immediately calms down the system.

Beim Abklingen der Schwingungen ziehen sich die Magnete bei ungleicher Polarität wieder an. Die beim Aufschlagen freiwerdende Energie wird voll in Wärme umgewandelt, da sich kein Rückprallen und keine elastische Ausschwingung einstellt, womit eine augenblickliche dämpfungswirksame Fixierung vonstatten geht. Die erneute Fixierung läuft somit ohne Nebeneffekte ab, das bedeutet, dass die remanenten Schwingungen im System abrupt neutralisiert werden, gleich der Berührung der Trommelfläche einer durch Schlag angeregten Trommel.When the vibrations decay, the magnets attract each other if the polarity is different. The energy released on impact is fully converted into heat, since there is no rebounding and no elastic oscillation, which means that the cushioning is instantly effective. The re-fixation thus takes place without side effects, which means that the retentive vibrations in the system are abruptly neutralized, just like touching the drum surface of a drum excited by impact.

Bei gleicher Polarität der benachbarten Magnete findet an sich kein Aufschlagen der Magnetflächen gegeneinander im Sinne obiger Ausführungen bei ungleichpoligen Magnetflächen. Gleichwohl ist aber die potentielle Energie der Magnete, wenn auch in umgekehrter Richtung, vorhanden. Da es sich hier um ein geschlossenes System handelt (Schaufelverbund), erzeugt eine durch Schwingungen bedingte Abstossung zweier benachbarter Magnete (Spreizung) eine von der Versteifung des restlichen Schaufelverbundes ausgehende Gegenkraft.With the polarity of the adjacent magnets being the same, there is no percussion of the magnetic surfaces against one another in the sense of the above statements for non-polar magnetic surfaces. Nevertheless, the potential energy of the magnets is present, albeit in the opposite direction. Since this is a closed system (vane assembly), a vibration-induced repulsion of two adjacent magnets (expansion) creates a counterforce from the stiffening of the rest of the vane assembly.

Die einzelnen Magnete sind so einzustellen und zu fixieren, dass deren Stirnflächen im eingebauten Zustand nicht nur aneinander anliegen, sondern auch gegeneinander drücken. Dies kann durch ein Übermass gegenüber dem tatsächlichen Abstand zweier Schaufeln und/oder durch eine Vortorsion der Schaufeln vor deren Einbau geschehen.The individual magnets are to be set and fixed in such a way that their end faces not only lie against one another in the installed state, but also press against one another. This can be done by an excess compared to the actual distance between two blades and / or by a pre-torsion of the blades before they are installed.

Vorteilhafte und zweckmässige Weiterbildungen der erfindungsgemässen Aufgabenlösung sind des weitem in den übrigen abhängigen Ansprüchen gekennzeichnet.Advantageous and expedient developments of the task solution according to the invention are further characterized in the remaining dependent claims.

Im folgenden sind anhand der Zeichnung Ausführungsbeispiele des Erfindungsgegenstandes vereinfacht dargestellt und näher erläutert. Alle für das unmittelbare Verständnis der Erfindung unwesentlichen Elemente sind nicht dargestellt. Gleiche Elemente sind in den Figuren mit den gleichen Bezugszeichen versehen. Es zeigt:

  • Fig. 1 eine Teilansicht einer Schaufelreihe mit eingebauten Magneten,
  • Fig. 2 die Draufsicht auf eine Deckplattenausführung,
  • Fig. 3 eine weitere Deckplattenausführung mit eingebauten Magneten,
  • Fig. 4 eine weitere Deckplattenausführung mit einer weiteren Variante eines Magneteneinbaues und
  • Fig. 5 eine weitere Deckplattenausführung mit einer weiteren Variante eines Magneteneinbaues.
Exemplary embodiments of the subject matter of the invention are shown in simplified form and explained in more detail below with reference to the drawing. All elements which are not essential for the direct understanding of the invention are not shown. Identical elements are provided with the same reference symbols in the figures. It shows:
  • 1 is a partial view of a row of blades with built-in magnets,
  • 2 is a top view of a cover plate design,
  • 3 shows a further cover plate design with built-in magnets,
  • Fig. 4 shows another cover plate design with egg ner another variant of a magnet installation and
  • Fig. 5 shows a further cover plate design with a further variant of a magnet installation.

Fig. 1 zeigt einzelne Schaufeln 1, 2, n einer Schaufelreihe, wie sie üblicherweise auf einer hier nicht dargestellten Rotorscheibe angeordnet sind. Die Schaufeln 1, 2, n selbst bestehen aus Schaufelfuss 3, Uebergangsteil 4, Schaufelblatt 5 und Deckplatte 6. Die hier dargestellte Deckplattenkonfiguration wird dort vorgesehen, wo schlanke Schaufelblätter 5 zum Einsatz kommen. In erster Linie wird damit eine Verbesserung des Wirkungsgrades angestrebt, indem die Deckplatte 6 den Zwischenraum zwischen Ende Schaufelblattes 5 und dem ebenfalls nicht dargestellten Stator überbrückt, so dass die unterschiedlichen Wärmedehnungen des Schaufelblattes 5 in radialer Richtung zwischen Anströmungs- und Abströmungsseite der Schaufeln 1, 2, n für die Spaltbemessung des genannten Zwischenraumes keine relevante Rolle mehr spielen. Auch ist die Deckplatte 6 dergestalt ausgebildet, dass sie labyrinthartig in den Stator hineingreift, wodurch die dortigen Strömungsverluste minimiert werden können. Solche Deckplatten 6 eignen sich vorzüglich zur Aufnahme von Magneten 7, 8, die den individuell gestalteten Zwischenraum aus zwie benachbarten Schaufeln überbrücken. Die hier zur Anwendung gelangenden Magnete 7, 8 sind von runder Ausführungsart; andere geometrische Formen sind ebenso einsetzbar. Die aus den Deckplatten 6 herausragenden Magnetteilstücke weisen jeweils zum anderen benachbarten Teilstück eine wechselnde Polarität eie auf, so dass die einzelnen Deckplatten 6 über die Anziehungskraft der einzelnen Paarmagneten 7, 8 zueinander haften. Etwa auf halber Schaufelblatthöhe ist eine weitere, durch vorzugsweise gleiche Magnete 7, 8 gebildete Zwischenstufe vorgesehen. Diese Vorkehrung soll sinnvollerweise nur bei weichen Schaufeln in Betracht gezogen werden, denn mithin handelt man sich Strömungsverluste ein. Selbstverständlich kann die Zwischenstufe im Bereich des Durchstosses des Magnetes 8 durch die Schaufeln 1, 2, n eine Verdickung aufweisen.Fig. 1 shows individual blades 1, 2, n in a row of blades, as they are usually arranged on a rotor disk, not shown here. The blades 1, 2, n themselves consist of blade root 3, transition part 4, blade 5 and cover plate 6. The cover plate configuration shown here is provided where slim blades 5 are used. First and foremost, an improvement in efficiency is sought by covering plate 6 bridging the space between the end of airfoil 5 and the stator, also not shown, so that the different thermal expansions of airfoil 5 in the radial direction between the inflow and outflow sides of blades 1, 2 , n no longer play a relevant role in the dimensioning of the gap. The cover plate 6 is also designed such that it engages in the stator like a labyrinth, as a result of which the flow losses there can be minimized. Such cover plates 6 are particularly suitable for holding magnets 7, 8, which bridge the individually designed space between two adjacent blades. The magnets 7, 8 used here are of a round design; other geometric shapes can also be used. The magnetic sections protruding from the cover plates 6 each have an alternating polarity to the other adjacent section, so that the individual cover plates 6 adhere to one another via the attractive force of the individual pair magnets 7, 8. A further intermediate stage, formed by preferably identical magnets 7, 8, is provided approximately at half the height of the airfoil. This precaution should only be taken into account for soft blades, because this means that flow losses are involved. Of course, the intermediate stage can have a thickening in the region of the penetration of the magnet 8 by the blades 1, 2, n.

Fig. 2 zeigt die Draufsicht auf eine Deckplattenausführung, bei der mindestens die gegenliegenden Stirnflächen 9a der Deckplatten 9 magnetisch sind. Die hier zur Verfügung stehende Anziehungskraft ist besonders gross. Eine solche Ausführungsart kommt demnach vorzugsweise bei stark schwingungsanfälligen Schaufeln zum Einsatz. Allerdings steht die Anziehungskraft nur dann voll zur Verfügung, wenn die geforderte Herstellungsgenauigkeit der Schaufeln allgemein und der Deckplatten 9 insbesondere genau eingehalten wird.Fig. 2 shows the top view of a cover plate design, in which at least the opposite end faces 9a of the cover plates 9 are magnetic. The attraction available here is particularly great. Such an embodiment is therefore preferably used for blades that are highly susceptible to vibration. However, the force of attraction is only fully available if the required manufacturing accuracy of the blades in general and the cover plates 9 in particular are strictly observed.

Demgegenüber steht die Herstellungsgenäuigkeit bei den in Fig. 3 ersichtlichen Deckplatten 10 nicht mehr so im Vordergrunde. Die einzelnen Deckplatten 10 tragen Magneteinsätze 11,12 die allein gegeneinander anliegen. In diesem Bereich sind die Deckplatten 10 auch zurückversetzt. Es kann vorgesehen werden, dass die einzelnen Magneteinsätze 11, 12 verstellt werden können, so dass deren Positionierung erst nach der Montage der Schaufeln 1, 2, n vorgenommen werden kann.In contrast, the manufacturing accuracy of the cover plates 10 shown in FIG. 3 is no longer in the foreground. The individual cover plates 10 carry magnetic inserts 11, 12 which lie against one another alone. The cover plates 10 are also set back in this area. It can be provided that the individual magnet inserts 11, 12 can be adjusted so that their positioning can only be carried out after the assembly of the blades 1, 2, n.

Aehnliche Ziele verfolgt die Ausführungsform nach Fig. 4. Auch hier können die einzelnen Magneteinsätze 14, 15 gegeneinander so verstellt werden, dass ihre magnetischen Kopfpartien aufeinanderstossen. Die rhomboide Form der Deckplatten 13 bietet Vorteile bei der Montage der Schaufeln 1, 2, n: Indem die Fluchtebene der Deckplattenflanken mit derjenigen des Schaufelfusses übereinstimmt, lassen sich die Schaufeln 1, 2, η ohne nachträgliches Ausrichten in die Rotorscheibe einschieben.The embodiment according to FIG. 4 pursues similar goals. Here, too, the individual magnetic inserts 14, 15 can be adjusted relative to one another in such a way that their magnetic head parts abut one another. The rhomboidal shape of the cover plates 13 offers advantages when installing the blades 1, 2, n: since the plane of alignment of the cover plate flanks corresponds to that of the blade root, the blades 1, 2, η can be inserted into the rotor disk without subsequent alignment.

Bei allen vorangegangenen Beispielen ist es möglich, die beschriebenen Ausführungsformen durch folgende Vorkehrungen funktionsmässig zu erweitern:

  • - Die Magnetkräfte können mit anderen Vorspannkräften kombiniert werden. In Frage kommt beispielsweise eine Vortorsion der Schaufeln 1, 2, n vor deren Einbau.
  • - Die Magneteinsätze erfassen die Schaufeln einer Reihe paketweise von beispielsweise 5-7 Einheiten. Paketweise kann die Polaritätsrichtung der Magnete auch gewechselt werden. Der daraus resultierende Verstimmeffekt kann zusätzlich verstärkt werden, indem die Stärke der Magneten von Paket zu Paket oder in Umfangsrichtung variiert wird.
  • - Magnetbestückte Schaufeln können mit mechanisch starr verbundenen Schaufeln abwechseln. Auch bei dieser Konfiguration geht es darum, den Verstimmeffekt zu verstärken.
  • - Anstelle von Permanentmagneten können Elektromagnete vorgesehen werden. Ihre Steuerung wird vorzugsweise von aussen, induktiv oder über Schleifringe bewerkstelligt.
In all the preceding examples, it is possible to extend the functionality of the described embodiments by taking the following precautions:
  • - The magnetic forces can be combined with other preload forces. For example, a pre-torsion of the blades 1, 2, n before they are installed.
  • - The magnetic inserts capture the blades of a row in packets of, for example, 5-7 units. The polarity direction of the magnets can also be changed in packages. The resulting detuning effect can be further enhanced by varying the strength of the magnets from package to package or in the circumferential direction.
  • - Magnetically equipped blades can alternate with mechanically rigidly connected blades. This configuration is also about increasing the detuning effect.
  • - Instead of permanent magnets, electromagnets can be provided. Your control is preferably carried out from the outside, inductively or via slip rings.

Die in Fig. 5 dargestellte Variante zeichnet sich dadurch aus, dass die Deckplatten 16 an ihren Randzonen mit je zwei Magneteinsätzen 17, 19 resp. 18, 20 bestückt sind. Während im Bereich der Schaufelanströmung die Magneteinsätze 19, 20 nach der konventionellen Poiaritätsrichtung ? / e angeordnet sind, weist die andere Randzone Magneteinsätze 17, 18 auf, die mit gleichnamigen PoIe ε /⊕ oder e / e aufeinanderstossen. Auch durch diese Anordnung lässt sich eine Umfangsverspannung erreichen, die in Kombination mit der auf der anderen Seite der Deckplatten 16 umgekehrt wirkenden Kraftrichtung der Magnetkräfte eine gute Elastizität gegen stossartig auftretende Schwingungen ergibt.The variant shown in Fig. 5 is characterized in that the cover plates 16 at their edge zones with two magnetic inserts 17, 19 and. 18, 20 are equipped. While in the area of the blade flow, the magnetic inserts 19, 20 according to the conventional direction of polarity? / e are arranged, the other edge zone has magnetic inserts 17, 18 which abut one another with poles of the same name ε / ⊕ or e / e. This arrangement can also be used to achieve a circumferential bracing which, in combination with the force direction of the magnetic forces acting in reverse on the other side of the cover plates 16, results in good elasticity against shock-like vibrations.

Selbstverständlich kann die gleichmässige Polarität e / e und/oder e / e bei allen vorgängig erläuterten Beispielen ebenfalls vorgesehen werden.Of course, the uniform polarity e / e and / or e / e can also be provided in all the examples explained above.

Falls Vibrationskräfte zum Abheben der Deckplatten führen, tragen die Magnetkräfte durch ihr Dämpfungsvermögen zur Schwingungstilgung bei.If vibration forces cause the cover plates to lift off, the magnetic forces contribute to vibration damping through their damping ability.

Die beschriebene Technik findet Anwendung bei Leit- und Laufschaufeln.The technique described is used for guide and rotor blades.

Claims (5)

1. Device for damping blade vibrations in turbomachines, characterized in that the blades (1, 2, n) carry magnet inserts (7, 8, 9a,11,12, 14, 15,17, 18, 19, 20), which butt together non-positively on the rotor through a positive allowance with respect to the separation of the two blades and/or through pretor- sion of the blades in the blade combination.
2. Device according to Claim 1, characterized in that the magnet inserts (7, 8, 9a, 11,12,14, 15, 17,18, 19, 20) are integrated in the shroud plates (6, 9, 10, 12, 16) of the blades (1, 2, n).
3. Device according to Claim 1, characterized in that neighbouring magnet inserts (7/8, 11/12, 19/20) are of opposite polarity.
4. Device according to Claim 1, characterized in that neighbouring magnet inserts (17/18) are of the same polarity.
5. Device according to Claim 2, characterized in that neighbouring shroud plates (16) are equipped in the region of the inlet flow with magnet inserts (19/20) of opposite polarity, and in the region of the outlet flow with magnet inserts (17/18) of the same polarity.
EP86109040A 1985-08-31 1986-07-02 Antivibration device for turbo machine blades Expired EP0214393B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH373085 1985-08-31
CH3730/85 1985-08-31

Publications (2)

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EP0214393A1 EP0214393A1 (en) 1987-03-18
EP0214393B1 true EP0214393B1 (en) 1989-12-13

Family

ID=4262270

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86109040A Expired EP0214393B1 (en) 1985-08-31 1986-07-02 Antivibration device for turbo machine blades

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US (1) US4722668A (en)
EP (1) EP0214393B1 (en)
JP (1) JP2574257B2 (en)
DE (1) DE3667521D1 (en)
HR (1) HRP920469B1 (en)
PL (1) PL152331B1 (en)
YU (1) YU45358B (en)

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Also Published As

Publication number Publication date
HRP920469B1 (en) 1996-04-30
JP2574257B2 (en) 1997-01-22
JPS6255401A (en) 1987-03-11
PL152331B1 (en) 1990-12-31
US4722668A (en) 1988-02-02
EP0214393A1 (en) 1987-03-18
YU45358B (en) 1992-05-28
PL260782A1 (en) 1987-08-24
DE3667521D1 (en) 1990-01-18
YU148086A (en) 1990-04-30

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