STATIONARY BLADE AND STEAM TURBINE

• US 20100329847A1
• Filed: 10/24/2008
• Published: 12/30/2010
• Est. Priority Date: 10/31/2007
• Status: Active Grant

• Current Assignee: Mitsubishi Power Limited (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Mitsubishi Heavy Industries, Ltd.
• Inventors: Yamashita, Hiroyuki, Kaneko, Yasutomo, Ooyama, Hiroharu
• Granted Patent: US 8,851,844 B2
• Time in Patent Office: Days
• US Class Current: 415/115
• CPC Class Codes: F01D 5/16 for counteracting blade vibration
• CPC Class Codes: F01D 9/041 using blades F01D5/148 takes precedence
• CPC Class Codes: F05D 2220/31 in steam turbines
• CPC Class Codes: Y10S 416/50 Vibration damping features

Abstract

A stationary blade and a steam turbine capable of reducing self-excited vibrations with a simple configuration are provided. A stationary blade has a cavity, extending in a blade-width direction, formed therein and slits communicating between the cavity and the outside. A wave-shaped plate spring that is in sliding contact with at least one of a pressure-side member and a suction-side member is provided between the pressure-side member, which is a portion on the pressure side of the cavity, and the suction-side member, which is a portion on the suction side of the cavity. When the stationary blade is elastically deformed, the wave-shaped plate spring causes friction between itself and at least one of the pressure-side member and the suction-side member. This friction attenuates relative positional displacement between the pressure-side member and the suction-side member. Thus, self-excited vibrations occurring at the stationary blade can be reduced.

Claims

1. A stationary blade used in a steam turbine, having a cavity formed therein and having a slit formed for communicating between the cavity and the outside, the stationary blade comprising a sliding-contact member capable of contacting a blade inner face from the cavity in a slidable manner.

2. The stationary blade according to claim 1, comprising a pressure-side portion, which is a portion on the pressure side of the cavity, and a suction-side portion, which is a portion on the suction side of the cavity,

wherein the sliding-contact member is provided between the pressure-side portion and the suction-side portion and is in contact with at least one of the pressure-side portion and the suction-side portion.

3. The stationary blade according to claim 2,

wherein the sliding-contact member is an urging member that urges the pressure-side portion and the suction-side portion outward in a blade-thickness direction.

4. The stationary blade according to claim 3,

wherein the urging member is a plate-like spring member that has a plate shape extending in a blade-width direction and presses the pressure-side portion and the suction-side portion with an elasticity caused by distortion.

5. The stationary blade according to claim 4,

wherein the plate-like spring member has a wave-shaped cross section and is in contact with the pressure-side portion and the suction-side portion at crests of the wave shape.

6. The stationary blade according to claim 4,

wherein the plate-like spring member has a substantially C-shaped cross section and is in contact with one of the pressure-side portion and the suction-side portion at open-end portions of the C shape and is in contact with the other at a base portion of the C shape.

7. The stationary blade according to claim 4,

wherein the plate-like spring member has a bow-shaped cross section and is in contact with one of the pressure-side portion and the suction-side portion at end portions of the bow shape and is in contact with the other at a base portion of the bow shape.

8. The stationary blade according to claim 4,

wherein two plate-like spring members having a bow-shaped cross section are disposed in the blade-thickness direction, and rear faces of base portions of the plate-like spring members are configured to be in sliding contact with each other.

9. The stationary blade according to claim 7,

wherein an end portion of the plate-like spring member has a divided structure or a slit structure in which the end portion is divided into a plurality of plates in a plate-thickness direction.

10. The stationary blade according to claim 4,

wherein the plate-like spring member has an angular U-shaped cross section and is in contact with the pressure-side portion and the suction-side portion at arm portions of the angular U shape.

11. The stationary blade according to claim 4,

wherein the pressure-side portion and the suction-side portion are bonded to each other at a front edge and a rear edge, and

wherein the plate-like spring member is bonded to one of the pressure-side portion and the suction-side portion.

12. The stationary blade according to claim 4,

wherein, among cavities divided by the plate-like spring member, a cavity not communicating with the outside via a slit is provided with a damping material.

14. A steam turbine in which the stationary blades according to claim 1 are arranged at predetermined intervals in a circumferential direction of a rotor shaft.

15. The steam turbine according to claim 14,

wherein solid stationary blades are arranged in a mixed manner.

16. The steam turbine according to the claim 15,

wherein the stationary blades and the solid stationary blades are alternately arranged.

17. The steam turbine according to claim 14,

wherein a plurality of types of stationary blades having different natural frequencies are arranged.

18. The stationary blade according to claim 8,

wherein an end portion of the plate-like spring member has a divided structure or a slit structure in which the end portion is divided into a plurality of plates in a plate-thickness direction.

13. A stationary blade comprising:

a plate-like partition wall provided substantially perpendicular to a mean camber line of the blade to divide the cavity formed therein into a front-edge-side cavity and a rear-edge-side cavity, the rear-edge-side cavity being filled with a damping material.

19. A steam turbine in which the stationary blades according to claim 13 are arranged at predetermined intervals in a circumferential direction of a rotor shaft.

20. The steam turbine according to claim 19,

wherein solid stationary blades are arranged in a mixed manner.

21. The steam turbine according to the claim 20,

wherein the stationary blades and the solid stationary blades are alternately arranged.

22. The steam turbine according to claim 19,

wherein a plurality of types of stationary blades having different natural frequencies are arranged.