Steam turbine stator vane, steam turbine, and production method for steam turbine stator vane

1. A steam turbine stator vane, comprising:

a vane body portion which has a vane surface including a pressure surface and a suction surface;

a moisture removal channel disposed in the vane body portion;

at least one slit opening between a center of the pressure surface and a trailing edge in a direction orthogonal to a height direction from a base end portion toward a tip end portion which is connected to an annular member for supporting the steam turbine stator vane of the vane body portion to communicate with the moisture removal channel, and extending along the height direction; and

at least one groove portion disposed between the center of the pressure surface and the trailing edge in the direction orthogonal to the height direction and extending from the base end portion along the height direction, at least a part of the at least one groove portion overlapping the at least one slit along the height direction.

2. The steam turbine stator vane according to claim 1 ,

wherein the at least one groove portion is configured to be inclined to a side of the trailing edge from the tip end portion toward the base end portion.

3. The steam turbine stator vane according to claim 1 ,

wherein the at least one slit includes a plurality of slits disposed separately from each other in the height direction.

4. The steam turbine stator vane according to claim 3 ,

wherein the steam turbine stator vane further includes a recess which is disposed in the vane surface and to which the plurality of slits open.

5. The steam turbine stator vane according to claim 1 ,

wherein the at least one slit is disposed between the at least one groove portion and a leading edge.

6. The steam turbine stator vane according to claim 1 ,

wherein the at least one slit is disposed between the at least one groove portion and the trailing edge.

7. The steam turbine stator vane according to claim 1 ,

wherein the vane body portion includes a curved plate encompassing the moisture removal channel and configured such that a difference between a maximum value and a minimum value of a thickness of the curved plate falls within 40% of an average value of the thickness.

8. The steam turbine stator vane according to claim 7 ,

wherein the curved plate includes a pressure surface-side curved plate which has a surface including at least a part of the pressure surface, and a suction surface-side curved plate which has a surface including at least a part of the suction surface, and

wherein one of the at least one slit or the at least one groove portion is configured to include a joint where one end portion of the pressure surface-side curved plate and one end portion of the suction surface-side curved plate are joined by welding.

9. The steam turbine stator vane according to claim 8 ,

wherein the vane body portion further includes a trailing edge portion disposed between the joint and the trailing edge, the trailing edge portion having a trailing edge-side pressure surface connected to the trailing edge and a trailing edge-side wall surface extending from a front end portion on the trailing edge-side pressure surface along a direction intersecting with the trailing edge-side pressure surface, and

wherein the at least one groove portion includes the joint, and a part of the at least one groove portion is defined by the trailing edge-side wall surface.

10. The steam turbine stator vane according to claim 8 ,

wherein the vane body portion further includes a trailing edge portion disposed between the joint and the trailing edge, the trailing edge portion having a trailing edge-side pressure surface connected to the trailing edge and a trailing edge-side wall surface extending from a front end portion on the trailing edge-side pressure surface along a direction intersecting with the trailing edge-side pressure surface, and

wherein the at least one slit includes the joint, and a part of the at least one slit is defined by the trailing edge-side wall surface.

11. The steam turbine stator vane according to claim 8 ,

wherein the suction surface-side curved plate includes an extension portion extending from the trailing edge toward a leading edge, the extension portion having a surface including at least a part of the pressure surface,

wherein the one end portion of the suction surface-side curved plate includes a front end portion of the extension portion located on a side of the leading edge, and

wherein the at least one groove portion includes the joint, and a part of the at least one groove portion is defined by an end surface at the front end portion of the extension portion.

12. A steam turbine, comprising:

the steam turbine stator vane according to claim 1 ;

the annular member for supporting the steam turbine stator vane; and

a cavity disposed in the annular member and configured to receive a liquid from each of the moisture removal channel and the at least one groove portion in the vane body portion.

13. A production method for a steam turbine stator vane, the method comprising:

a slit forming step of forming at least one slit that opens between a center of the pressure surface and a trailing edge in a direction orthogonal to a height direction from a base end portion which is connected to an annular member for supporting the steam turbine stator vane toward a tip end portion of the vane body portion, which has the vane surface including a pressure surface and a suction surface, to communicate with a moisture removal channel disposed in the vane body portion, and extends along the height direction; and

a groove portion forming step of forming at least one groove portion extending from the base end portion along the height direction between the center of the pressure surface and the trailing edge in the direction orthogonal to the height direction, at least a part of the at least one groove portion overlapping the at least one slit along the height direction.