METHOD FOR INFLUENCING, DAMPING, OR SUPPRESSING MECHANICAL VIBRATIONS OCCURRING DURING OPERATION IN A TURBOMACHINE BLADE, A TURBOMACHINE BLADE USEFUL FOR CARRYING OUT THE METHOD, AND A PIEZOELECTRIC DAMPING ELEMENT

• US 20120126665A1
• Filed: 11/17/2011
• Published: 05/24/2012
• Est. Priority Date: 11/24/2010
• Status: Active Grant

• Current Assignee: Ansaldo Energia Switzerland AG (Ansaldo Energia SPA)
• Original Assignee: Alstom Technology Ltd. (Alstom SA)
• Inventors: SZWEDOWICZ, Jaroslaw Leszek, KAPPIS, Wolfgang, PANNING, Lars, SCHWARZENDAHL, Sebastian Marc, NEUBAUER, Marcus, HOHL, Andreas, WALLASCHEK, Jörg
• Granted Patent: US 8,569,928 B2
• Time in Patent Office: Days
• US Class Current: 310/319
• CPC Class Codes: F01D 25/06 for preventing blade vibration means on blade-carrying members or blades F01D5/00
• CPC Class Codes: F01D 5/16 for counteracting blade vibration
• CPC Class Codes: F04D 29/324 Blades
• CPC Class Codes: F04D 29/668 damping or preventing mechanical vibrations
• CPC Class Codes: F05D 2260/96 Preventing, counteracting or reducing vibration or noise
• CPC Class Codes: F16F 15/005 using electro- or magnetostrictive actuation means generating of mechanical vibrations operating with electrostriction B06B1/06, with magnetostriction B06B1/08; vehicle suspension arrangements characterised by use of piezoelectric elements B60G17/01941; piezoelectric, electrostrictive and magnetostrictive devices per se H10N30/00
• CPC Class Codes: Y02E 10/72 Wind turbines with rotation axis in wind direction
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

In a method for influencing, in particular damping or suppressing, mechanical vibrations occurring during operation in a turbomachine blade (10), the mechanical vibratory energy of the turbomachine blade (10) is first converted into electrical energy and the electrical energy generated is then converted into heat loss. Effective damping which can be used especially simply and in a versatile way is achieved in that the piezoelectric effect is used in order to convert mechanical vibratory energy into electrical energy.

Claims

1. A method for suppressing mechanical vibrations occurring during operation in a turbomachine blade, the method comprising:

converting mechanical vibratory energy of the turbomachine blade into electrical energy; and

piezoelectrically converting said electrical energy into heat loss.

2. The method as claimed in claim 1, further comprising:

installing at least one piezoelectric damping element firmly in the turbomachine blade;

wherein piezoelectrically converting comprises deforming said damping element as a result of the mechanical vibrations of the turbomachine blade and generating an electrical voltage; and

ohmically losing heat from the generated electrical voltage in a connected electrical network.

3. The method as claimed in claim 2, wherein:

said electrical network comprises a shunt including a series connection of an inductance and an ohmic resistance;

the piezoelectric damping element comprises a capacitance including a piezo body arranged between electrodes; and

further comprising tuning a resonant frequency of an oscillatory circuit formed by said electrical network to a mechanical vibration to be damped of the turbomachine blade.

4. The method as claimed in claim 3, further comprising:

measuring and evaluating electrical oscillations in the piezoelectric damping element to determine and monitor the mechanical vibrations in the turbomachine blade.

5. The method as claimed in claim 2, further comprising:

forming a cavity in the turbomachine blade configured and arranged to receive the piezoelectric damping element; and

inserting the piezoelectric damping element into the cavity and firmly coupling the piezoelectric damping element to the turbomachine blade.

6. The method as claimed in claim 5, wherein coupling comprises forming a materially integral connection or mechanical bracing.

7. The method as claimed in claim 1, wherein the turbomachine blade comprises a turbine blade.

8. A turbomachine blade comprising:

a blade leaf; and

at least one piezoelectric damping element installed firmly in the blade leaf.

9. The turbomachine blade as claimed in claim 8, wherein said blade comprises a turbine blade.

10. The turbomachine blade as claimed in claim 8, wherein the at least one piezoelectric damping element comprises a piezo element and an electrical network connected to the piezo element.

11. The turbomachine blade as claimed in claim 10, wherein the electrical network comprises a shunt containing an ohmic resistance connected to electrically dampen the piezo element.

12. The turbomachine blade as claimed in claim 10, wherein the electrical network or the shunt comprises a series connection comprising said ohmic resistance and an inductance.

13. The turbomachine blade as claimed in claim 10, wherein the electrical network or the shunt comprises a coil.

14. The turbomachine blade as claimed in claim 10, wherein the piezo element comprises a stack of piezo bodies and electrodes.

15. The turbomachine blade as claimed in claim 8, further comprising:

a cavity in the blade leaf, the at least one piezoelectric damping element being positioned in said cavity.

16. The turbomachine blade as claimed in claim 15, further comprising:

a dedicated casing surrounding the at least one piezoelectric damping element.

17. The turbomachine blade as claimed in claim 16, wherein the dedicated casing comprises an upper subcasing and a lower subcasing.

18. The turbomachine blade as claimed in claim 8, wherein the at least one piezoelectric damping element is firmly coupled to the blade leaf.

19. The turbomachine blade as claimed in claim 8, wherein the at least one piezoelectric damping element is coupled to the blade leaf with a materially integral connection or by mechanical bracing.

20. The turbomachine blade as claimed in claim 8, wherein the at least one piezoelectric damping element comprises a plurality of piezoelectric damping elements arranged in and distributed over the blade leaf.

21. The turbomachine blade as claimed in claim 8, further comprising:

a measuring device configured and arranged to receive and evaluate signals occurring at the piezoelectric damping element;

wherein the at least one piezoelectric damping element is wirelessly connected to the measuring device.

22. A piezoelectric damping element useful for installation in a turbomachine blade, the piezoelectric damping element comprising:

a piezo element; and

an electrical network connected to the piezo element.

23. The piezoelectric damping element as claimed in claim 22, wherein the electrical network comprises a shunt including an ohmic resistance, wherein the piezo element is electrically damped by the shunt.

24. The piezoelectric damping element as claimed in claim 22, wherein the piezo element comprises a stack of piezo bodies and electrodes.

25. The piezoelectric damping element as claimed in claim 23, wherein the electrical network or the shunt comprises a series connection including said ohmic resistance and an inductance.

26. The piezoelectric damping element as claimed in claim 25, wherein the electrical network or the shunt comprises a coil.

27. The piezoelectric damping element as claimed in claim 22, further comprising:

a casing surrounding the piezoelectric damping element.

28. The piezoelectric damping element as claimed in claim 22, wherein the casing comprises an upper subcasing and a lower subcasing.

29. The piezoelectric damping element as claimed in claim 22, wherein the electrical network comprises a time-variable resistance.