Turbine blade, turbine, and method for adjusting natural frequency of turbine blade
阅读说明：本技术 涡轮叶片、涡轮及涡轮叶片的固有振动频率的调整方法 (Turbine blade, turbine, and method for adjusting natural frequency of turbine blade ) 是由 福井嘉夫 桑原正光 于 2019-03-22 设计创作，主要内容包括：涡轮叶片具备：平台；叶片形部,其从所述平台沿叶片高度方向延伸,并具有在前缘与后缘之间延伸的压力面及负压面；叶片根部,其隔着所述平台而与所述叶片形部位于所述叶片高度方向上的相反侧,并具有承载面；以及柄部,其位于所述平台与所述叶片根部之间,所述柄部具有如下剖面：与所述叶片形部的所述叶片高度方向正交,且将所述前缘侧的所述柄部的端部的宽度方向上的中央位置与所述后缘侧的所述柄部的端部的宽度方向上的中央位置连结而得到的线段相对于所述叶片根部的所述压力面侧的轮廓与所述叶片根部的所述负压面侧的轮廓的中心线倾斜。(The turbine blade is provided with: a platform; a blade-shaped portion extending from the platform in a blade height direction and having a pressure surface and a negative pressure surface extending between a leading edge and a trailing edge; a blade root portion located on the opposite side of the blade-shaped portion in the blade height direction with the platform interposed therebetween and having a bearing surface; and a shank between the platform and the blade root, the shank having a cross-section of: a line segment that is orthogonal to the blade height direction of the blade-shaped portion and connects a center position in the width direction of the end portion of the shank portion on the leading edge side and a center position in the width direction of the end portion of the shank portion on the trailing edge side is inclined with respect to a center line of a contour on the pressure surface side of the blade root and a contour on the suction surface side of the blade root.)
1. A turbine blade wherein, in the turbine blade,
the turbine blade is provided with:
a platform;
a blade-shaped portion extending from the platform in a blade height direction and having a pressure surface and a negative pressure surface extending between a leading edge and a trailing edge;
a blade root portion located on the opposite side of the blade-shaped portion in the blade height direction with the platform interposed therebetween and having a bearing surface; and
a shank located between the platform and the blade root,
the handle has the following cross-section:
orthogonal to the blade height direction of the blade-shaped portion,
and a line segment connecting a widthwise central position of the end of the shank portion on the leading edge side and a widthwise central position of the end of the shank portion on the trailing edge side is inclined with respect to a center line of a profile on the pressure surface side of the blade root and a profile on the suction surface side of the blade root.
2. The turbine blade of claim 1,
the shank has the cross section satisfying at least one of the conditions (a) and (b),
the region (a) on the trailing edge side in a first profile on the pressure surface side of the shank portion has a first convex portion bulging outward toward the pressure surface side than a region on the leading edge side in the first profile,
the region on the leading edge side in the second profile on the negative pressure surface side of the shank portion has a second convex portion bulging outward toward the negative pressure surface side than the region on the leading edge side in the second profile.
3. The turbine blade of claim 2,
the first profile of the pressure face side of the shank comprises:
a first leading edge side profile located on the leading edge side;
a first trailing edge side profile located on the trailing edge side; and
a first center profile located between the first leading edge-side profile and the first trailing edge-side profile,
the second profile of the negative pressure face side of the shank comprises:
a second leading edge side profile located on the leading edge side;
a second trailing edge side profile located on the trailing edge side; and
a second center profile located between the second leading edge-side profile and the second trailing edge-side profile,
at least one of the first protrusion and the second protrusion extends in the height direction of the shank in a blade height direction range including a blade height direction position of the shank at which a distance between the first center contour and the second center contour is minimized and including both sides of the blade height direction position.
4. The turbine blade of claim 3,
at least one of the first projection and the second projection extends over the entire range between the lower surface of the platform and the upper end of the bearing surface in the blade height direction of the shank.
5. The turbine blade of any one of claims 2 to 4,
at least one of the first convex portion and the second convex portion linearly extends in parallel with the center line in the cross section.
6. The turbine blade of claim 1,
the shank has the cross section satisfying at least one of the conditions (c) and (d),
the region on the trailing edge side in a first profile on the pressure surface side of the shank portion of (c) has a first recess recessed from the pressure surface side to the inner side as compared with a region on the leading edge side in the first profile,
the region on the leading edge side in the second profile on the negative pressure surface side of the shank portion in (d) has a second recess recessed inward from the negative pressure surface side as compared with the region on the leading edge side in the second profile.
7. The turbine blade of any one of claims 1-6,
for the shank, in the cross-section,
a first contour of the shank on the pressure surface side includes a first straight portion extending linearly in parallel with the center line of the blade root in a region other than a region on the trailing edge side,
the second contour of the shank on the negative pressure surface side includes a second linear portion extending linearly in parallel with the center line of the blade root in a region other than the region on the leading edge side.
8. The turbine blade of any one of claims 1-5,
the first profile of the pressure face side of the shank comprises:
a first leading edge side profile located on the leading edge side;
a first trailing edge side profile located on the trailing edge side; and
a first center profile located between the first leading edge-side profile and the first trailing edge-side profile,
the second profile of the negative pressure face side of the shank comprises:
a second leading edge side profile located on the leading edge side;
a second trailing edge side profile located on the trailing edge side; and
a second center profile located between the second leading edge-side profile and the second trailing edge-side profile,
the shank has the cross section satisfying at least one of the conditions (e) and (f),
wherein (e) is a distance from a reference line passing through a midpoint of the line segment and being parallel to the center line of the blade root, the distance being increased in the order of the first center profile, the first leading edge side profile, and the first trailing edge side profile,
the distance from the reference line in (f) is increased in the order of the second center profile, the second trailing edge side profile, and the second leading edge side profile.
9. The turbine blade of claim 8,
the shank has the cross section satisfying the condition of at least one of (e) and (f) at a height-direction position of the shank at which a distance between the first central contour and the second central contour is minimized.
10. The turbine blade of claim 1 or 6,
the first profile of the pressure face side of the shank comprises:
a first leading edge side profile located on the leading edge side;
a first trailing edge side profile located on the trailing edge side; and
a first center profile located between the first leading edge-side profile and the first trailing edge-side profile,
the second profile of the negative pressure face side of the shank comprises:
a second leading edge side profile located on the leading edge side;
a second trailing edge side profile located on the trailing edge side; and
a second center profile located between the second leading edge-side profile and the second trailing edge-side profile,
the shank has the cross section satisfying at least one of the conditions (g) and (h),
the distance from a reference line passing through a midpoint of the line segment and being parallel to the center line of the blade root increases in the order of the first center profile, the first trailing edge side profile, and the first leading edge side profile,
the distance from the reference line in (h) is increased in the order of the second center profile, the second leading edge profile, and the second trailing edge profile.
11. The turbine blade of claim 10,
the shank has the cross section satisfying the condition of at least one of (g) and (h) at a height-direction position of the shank at which a distance between the first central contour and the second central contour is minimized.
12. A turbine in which, in a turbine,
the turbine is provided with:
the turbine blade of any one of claims 1 to 11; and
and a rotor disk having a blade groove that engages with the blade root of the turbine blade.
13. A method for adjusting the natural frequency of a turbine blade, the turbine blade comprising:
a platform;
a blade-shaped portion extending from the platform in a blade height direction and having a pressure surface and a negative pressure surface extending between a leading edge and a trailing edge;
a blade root portion located on the opposite side of the blade-shaped portion in the blade height direction with the platform interposed therebetween and having a bearing surface; and
a shank located between the platform and the blade root,
the handle has the following cross-section:
orthogonal to the blade height direction of the blade-shaped portion,
and a line segment connecting a widthwise central position of an end of the shank portion on the leading edge side and a widthwise central position of an end of the shank portion on the trailing edge side is inclined with respect to a center line of a profile on the pressure surface side of the blade root and a profile on the suction surface side of the blade root,
wherein the content of the first and second substances,
the method for adjusting the natural frequency of the turbine blade includes the steps of: machining the profile of the shank such that the angle of the line segment relative to the centerline of the blade root changes.
14. The method of adjusting natural frequency of vibration of turbine blades according to claim 13,
the natural frequency of a mode in which the blade-shaped portion of the turbine blade vibrates along the center line is adjusted by machining the outer shape of the shank portion.
15. The method of adjusting natural frequency of vibration of turbine blades according to claim 13 or 14,
the shank portion satisfying at least one of the conditions (a) and (b) in the cross section,
the region (a) on the trailing edge side in a first profile on the pressure surface side of the shank portion has a first convex portion bulging outward toward the pressure surface side than a region on the leading edge side in the first profile,
the region on the leading edge side in the second profile on the negative pressure surface side of the shank portion has a second convex portion bulging outward toward the negative pressure surface side than the region on the leading edge side in the second profile,
in the step of processing the outer shape,
adjusting at least one of:
a size of a protruding amount of the first convex portion in the width direction of the shank portion or a range occupied by the first convex portion in the first profile; and
a protruding amount of the second convex portion in the width direction of the shank portion or a size of a range occupied by the second convex portion in the second profile.
16. The method of adjusting natural frequency of vibration of turbine blades according to claim 13 or 14,
the shank portion satisfying at least one of the conditions (c) and (d) in the cross section,
the region on the trailing edge side in a first profile on the pressure surface side of the shank portion of (c) has a first recess recessed from the pressure surface side to the inner side as compared with a region on the leading edge side in the first profile,
the region on the leading edge side in a second contour on the negative pressure surface side of the shank portion in (d) has a second recess recessed inward from the negative pressure surface side as compared with the region on the leading edge side in the second contour,
in the step of processing the outer shape,
adjusting at least one of:
a magnitude of a depression amount of the first concave portion in the width direction of the shank or a range occupied by the first concave portion in the first profile; and
a magnitude of a depression amount of the second recess in the width direction of the shank or a range occupied by the second recess in the second profile.
17. A method for adjusting the natural frequency of a turbine blade, the turbine blade comprising:
a platform;
a blade-shaped portion extending from the platform in a blade height direction and having a pressure surface and a negative pressure surface extending between a leading edge and a trailing edge;
a blade root portion located on the opposite side of the blade-shaped portion with the platform interposed therebetween and having a bearing surface; and
a shank located between the platform and the blade root,
wherein the content of the first and second substances,
the method for adjusting the natural frequency of the turbine blade includes the steps of: the outer shape of the shank is processed in at least one of a region on the trailing edge side in a first contour on the pressure surface side of the shank and a region on the leading edge side in a second contour on the suction surface side of the shank.
Technical Field
The present disclosure relates to a turbine blade, a turbine, and a method of adjusting natural frequency of the turbine blade.
Background
Blades of a turbine such as a gas turbine or a steam turbine receive an exciting force generated by a fluctuation or rotation of a flow of combustion gas or a flow of steam during operation of the turbine. The resonance phenomenon caused by such an exciting force can cause damage to the turbine blade, the rotor disk, and the like.
Therefore, in order to avoid the resonance of the turbine blade, it is proposed to adjust the natural frequency of the turbine blade.
For example,
Disclosure of Invention
Problems to be solved by the invention
However, there are a plurality of vibration modes of the turbine blade, and the resonance frequency differs for each vibration mode.
Therefore, it is desirable to selectively adjust the natural frequency of the turbine blade without causing resonance phenomenon, while deviating from the resonance frequency of the specific vibration mode.
In view of the above-described circumstances, an object of at least one embodiment of the present invention is to provide a turbine blade capable of selectively adjusting the natural frequency away from the resonance frequency of a specific vibration mode, a turbine provided with the turbine blade, and a method of adjusting the natural frequency of the turbine blade.
Means for solving the problems
(1) A turbine blade according to at least one embodiment of the present invention includes:
a platform;
a blade-shaped portion extending from the platform in a blade height direction and having a pressure surface and a negative pressure surface extending between a leading edge and a trailing edge;
a blade root portion located on the opposite side of the blade-shaped portion in the blade height direction with the platform interposed therebetween and having a bearing surface; and
a shank located between the platform and the blade root,
the handle has the following cross-section:
orthogonal to the blade height direction of the blade-shaped portion,
and a line segment connecting a widthwise central position of the end of the shank portion on the leading edge side and a widthwise central position of the end of the shank portion on the trailing edge side is inclined with respect to a center line of a profile on the pressure surface side of the blade root and a profile on the suction surface side of the blade root.
According to the structure of the above (1), the shank has the following cross section at any position in the blade height direction: a line segment that is orthogonal to the blade height direction and that connects the widthwise central position of the end of the shank on the leading edge side and the widthwise central position of the end of the shank on the trailing edge side is inclined with respect to a center line of a contour on the pressure surface side of the blade root and a contour on the negative pressure surface side of the blade root (hereinafter, also referred to as "center line of the blade root"). That is, in this cross section, since the shank has a shape that protrudes or is recessed in the width direction at least one of a pair of diagonal positions, the rigidity of the shank at that position is increased or decreased as compared with the case where the above-described line segment is parallel to the center line of the blade root. This makes it possible to selectively increase or decrease the natural frequency of the vibration mode in which relatively large stress is generated at the pair of diagonal positions. In this way, the natural frequency of the specific vibration mode can be selectively adjusted while suppressing the influence on the natural frequencies of the other vibration modes. This can suppress damage caused by vibration of the turbine blade.
(2) In some embodiments, in addition to the structure of the above (1),
the shank has the cross section satisfying at least one of the conditions (a) and (b),
the region (a) on the trailing edge side in a first profile on the pressure surface side of the shank portion has a first convex portion bulging outward toward the pressure surface side than a region on the leading edge side in the first profile,
the region on the leading edge side in the second profile on the negative pressure surface side of the shank portion has a second convex portion bulging outward toward the negative pressure surface side than the region on the leading edge side in the second profile.
According to the configuration of the above (2), in the cross section at any position in the blade height direction, since the convex portion (the first convex portion or the second convex portion) is provided at least one of the pair of diagonal positions (regions) including the region on the pressure surface side and the trailing edge side and the region on the negative pressure surface side and the leading edge side, the rigidity at the position where the convex portion is provided can be improved. As a result, the natural frequency of the vibration mode in which the blade-shaped portion vibrates along the center line (i.e., the vibration mode in which relatively large stress is generated at the pair of diagonal positions) can be selectively adjusted.
(3) In some embodiments, in addition to the structure of the above (2),
the first profile of the pressure face side of the shank comprises:
a first leading edge side profile located on the leading edge side;
a first trailing edge side profile located on the trailing edge side; and
a first center profile located between the first leading edge-side profile and the first trailing edge-side profile,
the second profile of the negative pressure face side of the shank comprises:
a second leading edge side profile located on the leading edge side;
a second trailing edge side profile located on the trailing edge side; and
a second center profile located between the second leading edge-side profile and the second trailing edge-side profile,
at least one of the first protrusion and the second protrusion extends in the height direction of the shank in a height direction range including a height direction position of the shank at which a distance between the first center contour and the second center contour is minimized and including both sides of the height direction position.
According to the structure of the above (3), the cross section of the above (2) is provided in a range in the blade height direction including a position where the distance (the thickness of the shank) between the first center contour on the pressure surface side and the second center contour on the negative pressure surface side is minimized. That is, in this cross section, since the convex portion (the first convex portion or the second convex portion) is provided at least at one of a pair of diagonal positions (regions) including the region on the pressure surface side and the trailing edge side and the region on the negative pressure surface side and the leading edge side, the stiffness at the position where the convex portion is provided can be increased, and the natural frequency of the vibration mode in which the blade-shaped portion vibrates along the center line can be selectively adjusted. This can more effectively suppress damage to the turbine blade.
(4) In some embodiments, in addition to the structure of the above (3),
at least one of the first projection and the second projection extends in the entire range between the lower surface of the platform and the upper end of the bearing surface in the height direction of the shank.
According to the structure of the above (4), since at least one of the first projection and the second projection is provided so as to extend over the entire range between the lower surface of the platform and the upper end of the bearing surface in the height direction of the shank, the rigidity can be more reliably increased at the position of the first projection or the second projection. This makes it possible to more effectively adjust the natural frequency of the vibration mode in which the blade-shaped portion vibrates along the center line.
(5) In several embodiments, in addition to any one of the structures (2) to (4) above,
at least one of the first convex portion and the second convex portion linearly extends in parallel with the center line in the cross section.
According to the configuration of the above (5), since at least one of the first convex portion and the second convex portion is formed to linearly extend in parallel to the center line in the cross section, the configuration of the above (2) can be realized without largely changing the shape of the shank portion as compared with a case where these convex portions are not provided.
(6) In some embodiments, in addition to the structure of the above (1),
the shank has the cross section satisfying at least one of the conditions (c) and (d),
the region on the trailing edge side in a first profile on the pressure surface side of the shank portion of (c) has a first recess recessed from the pressure surface side to the inner side as compared with a region on the leading edge side in the first profile,
the region on the leading edge side in the second profile on the negative pressure surface side of the shank portion in (d) has a second recess recessed inward from the negative pressure surface side as compared with the region on the leading edge side in the second profile.
According to the configuration of the above (6), in the above cross section at any position in the blade height direction, since the recess (the first recess or the second recess) is provided at least one of the pair of diagonal positions (regions) including the region on the pressure surface side and the trailing edge side and the region on the negative pressure surface side and the leading edge side, the rigidity at the position where the recess is provided can be reduced. This makes it possible to selectively adjust the natural frequency of the vibration mode in which the blade-shaped portion vibrates along the center line.
(7) In several embodiments, in the cross section of the shank portion, on the basis of any one of the structures (1) to (6) described above,
a first contour of the shank on the pressure surface side includes a first straight portion extending linearly in parallel with the center line of the blade root in a region other than a region on the trailing edge side,
the second contour of the shank on the negative pressure surface side includes a second linear portion extending linearly in parallel with the center line of the blade root in a region other than the region on the leading edge side.
According to the structure of the above (7), the shank has the cross section (first cross section) described below at any height direction position. That is, in this cross section (first cross section), at a pair of diagonal positions at which the natural frequency of the vibration mode in which the blade-shaped portion vibrates along the center line can be adjusted, there are portions that protrude (for example, the first convex portion or the second convex portion described above) or portions that are recessed (for example, the first concave portion or the second concave portion described above) with reference to the first linear portion or the second linear portion that is parallel to the center line. This makes it possible to selectively adjust the natural frequency of the vibration mode in which the blade-shaped portion vibrates along the center line.
(8) In several embodiments, in addition to any one of the above-described structures (1) to (5), the first contour of the pressure surface side of the shank includes:
a first leading edge side profile located on the leading edge side;
a first trailing edge side profile located on the trailing edge side; and
a first center profile located between the first leading edge-side profile and the first trailing edge-side profile,
the second profile of the negative pressure face side of the shank comprises:
a second leading edge side profile located on the leading edge side;
a second trailing edge side profile located on the trailing edge side; and
a second center profile located between the second leading edge-side profile and the second trailing edge-side profile,
the shank has the cross section satisfying at least one of the conditions (e) and (f),
wherein (e) is a distance from a reference line passing through a midpoint of the line segment and being parallel to the center line of the blade root, the distance being increased in the order of the first center profile, the first leading edge side profile, and the first trailing edge side profile,
the distance from the reference line in (f) is increased in the order of the second center profile, the second trailing edge side profile, and the second leading edge side profile.
According to the structure of the above item (8), the shank has the cross section (second cross section) described below at any height position. That is, in this cross section (second cross section), the trailing edge side bulges out to the leading edge side in the first contour on the pressure surface side, or the leading edge side bulges out to the trailing edge side in the second contour on the suction surface side. Accordingly, the stiffness at the diagonal positions can be increased by the bulging portions provided at the pair of diagonal positions at which the natural frequency of the above-described vibration mode in which the blade-shaped portion vibrates along the center line can be adjusted, and the natural frequency of the turbine blade can be selectively adjusted.
(9) In some embodiments, in addition to the structure of the above (8),
the shank has the cross section satisfying the condition of at least one of (e) and (f) at a height-direction position of the shank at which a distance between the first central contour and the second central contour is minimized.
According to the configuration of the above (9), since the shank portion has the cross section (second cross section) described in the above (8) at the height direction position of the shank portion where the thickness of the shank portion is minimized, as described in the above (8), the stiffness at the above diagonal position where the bulge portion is provided can be improved, and the natural frequency of the vibration mode in which the blade-shaped portion vibrates along the above-mentioned center line can be adjusted.
(10) In some embodiments, in addition to the structure of (1) or (6), the first contour of the pressure surface side of the shank includes:
a first leading edge side profile located on the leading edge side;
a first trailing edge side profile located on the trailing edge side; and
a first center profile located between the first leading edge-side profile and the first trailing edge-side profile,
the second profile of the negative pressure face side of the shank comprises:
a second leading edge side profile located on the leading edge side;
a second trailing edge side profile located on the trailing edge side; and
a second center profile located between the second leading edge-side profile and the second trailing edge-side profile,
the shank has the cross section satisfying at least one of the conditions (g) and (h),
the distance from a reference line passing through a midpoint of the line segment and being parallel to the center line of the blade root increases in the order of the first center profile, the first trailing edge side profile, and the first leading edge side profile,
the distance from the reference line in (h) is increased in the order of the second center profile, the second leading edge profile, and the second trailing edge profile.
According to the structure of the above item (10), the shank has the cross section (third cross section) described below at any height position. That is, in this cross section (third cross section), the trailing edge side is recessed from the leading edge side in the first contour on the pressure surface side, or the leading edge side is recessed from the trailing edge side in the second contour on the suction surface side. Accordingly, the rigidity at the diagonal positions can be reduced by the dimples provided at the pair of diagonal positions at which the natural frequency of the above-described vibration mode in which the blade-shaped portion vibrates along the above-described center line can be adjusted, and the natural frequency of the turbine blade can be selectively adjusted.
(11) In some embodiments, in addition to the structure of (10) above,
the shank has the cross section satisfying the condition of at least one of (g) and (h) at a height-direction position of the shank at which a distance between the first central contour and the second central contour is minimized.
According to the configuration of the above (11), since the shank portion has the cross section (third cross section) described in the above (10) at the height direction position of the shank portion where the thickness of the shank portion is minimized, as described in the above (10), the stiffness at the above diagonal position where the depression is provided can be reduced, and the natural frequency of the vibration mode in which the blade-shaped portion vibrates along the above-described center line can be adjusted.
(12) A turbine according to at least one embodiment of the present invention includes:
the turbine blade of any one of (1) to (11) above; and
and a rotor disk having a blade groove that engages with the blade root of the turbine blade.
According to the structure of the above item (12), the shank has the following cross section at any position in the blade height direction: a line segment which is orthogonal to the blade height direction and connects the center position in the width direction of the end of the shank on the leading edge side and the center position in the width direction of the end of the shank on the trailing edge side is inclined with respect to the center line of the outline on the pressure surface side of the blade root and the outline on the negative pressure surface side of the blade root. That is, in this cross section, since the shank has a shape that protrudes or is recessed in the width direction at least one of a pair of diagonal positions, the rigidity of the shank at that position is increased or decreased as compared with the case where the line segment is parallel to the center line. This makes it possible to selectively increase or decrease the natural frequency of the vibration mode in which relatively large stress is generated at the pair of diagonal positions. In this way, the natural frequency of the specific vibration mode can be selectively adjusted while suppressing the influence on the natural frequencies of the other vibration modes. This can suppress damage caused by vibration of the turbine blade.
(13) In accordance with at least one embodiment of the present invention, there is provided a method for adjusting a natural frequency of a turbine blade, the turbine blade including:
a platform;
a blade-shaped portion extending from the platform in a blade height direction and having a pressure surface and a negative pressure surface extending between a leading edge and a trailing edge;
a blade root portion located on the opposite side of the blade-shaped portion in the blade height direction with the platform interposed therebetween and having a bearing surface; and
a shank located between the platform and the blade root,
the handle has the following cross-section:
orthogonal to the blade height direction of the blade-shaped portion,
and a line segment connecting a widthwise central position of an end of the shank portion on the leading edge side and a widthwise central position of an end of the shank portion on the trailing edge side is inclined with respect to a center line of a profile on the pressure surface side of the blade root and a profile on the suction surface side of the blade root,
wherein the content of the first and second substances,
the method for adjusting the natural frequency of the turbine blade includes the steps of: machining the profile of the shank such that the angle of the line segment relative to the centerline of the blade root changes.
According to the method of the above (13), the shank is processed so that the shank has an outer shape at any position in the blade height direction, the outer shape being orthogonal to the blade height direction, and an angle of a line segment connecting a widthwise central position of an end of the shank on the leading edge side and a widthwise central position of an end of the shank on the trailing edge side with respect to a center line of the blade root is changed. That is, in this cross section, the outer shape of the shank is processed by appropriately changing the angle of the line segment with respect to the center line of the blade root so that the shank has a shape that protrudes or dents in the width direction at least at one of a pair of diagonal positions, and therefore the rigidity of the shank at that position is increased or decreased as compared with the case where the line segment is parallel to the center line of the blade root. This makes it possible to selectively increase or decrease the natural frequency of the vibration mode in which relatively large stress is generated at the pair of diagonal positions. In this way, the natural frequency of the specific vibration mode can be selectively adjusted while suppressing the influence on the natural frequencies of the other vibration modes. This can suppress damage caused by vibration of the turbine blade.
(14) In several embodiments, in addition to the method of (13) above,
the natural frequency of a mode in which the blade-shaped portion of the turbine blade vibrates along the center line is adjusted by machining the outer shape of the shank portion.
According to the method of the above (14), since the outer shape of the shank portion is processed so as to have a shape protruding or recessed in the width direction at least at one of a pair of diagonal positions to adjust the natural frequency of the vibration mode in which the blade portion vibrates along the above-mentioned center line, the natural frequency of the vibration mode in which the blade portion vibrates along the above-mentioned center line can be selectively adjusted.
(15) In several embodiments, in addition to the method of (13) or (14) above,
the shank portion satisfying at least one of the conditions (a) and (b) in the cross section,
the region (a) on the trailing edge side in a first profile on the pressure surface side of the shank portion has a first convex portion bulging outward toward the pressure surface side than a region on the leading edge side in the first profile,
the region on the leading edge side in the second profile on the negative pressure surface side of the shank portion has a second convex portion bulging outward toward the negative pressure surface side than the region on the leading edge side in the second profile,
in the step of processing the outer shape,
adjusting at least one of:
a size of a protruding amount of the first convex portion in the width direction of the shank portion or a range occupied by the first convex portion in the first profile; and
a protruding amount of the second convex portion in the width direction of the shank portion or a size of a range occupied by the second convex portion in the second profile.
According to the method of the above (15), in the shank portion, when the convex portion (the first convex portion or the second convex portion) is provided at least one of a pair of diagonal positions (regions) including the region on the pressure surface side and the trailing edge side and the region on the suction surface side and the leading edge side in the cross section at any position in the blade height direction, the amount of protrusion of the convex portion or the size of the range occupied by the convex portion in the width direction is adjusted by machining. Thus, the shank portion is processed so that the amount of protrusion of the convex portion or the size of the occupied range becomes an appropriate value, and the rigidity at the position where the convex portion is provided is increased, whereby the natural frequency can be adjusted to a desired value. This makes it possible to selectively adjust the natural frequency of the vibration mode in which the blade-shaped portion vibrates along the center line.
(16) In several embodiments, in addition to the method of (13) or (14) above,
the shank portion satisfying at least one of the conditions (c) and (d) in the cross section,
the region on the trailing edge side in a first profile on the pressure surface side of the shank portion of (c) has a first recess recessed from the pressure surface side to the inner side as compared with a region on the leading edge side in the first profile,
the region on the leading edge side in a second contour on the negative pressure surface side of the shank portion in (d) has a second recess recessed inward from the negative pressure surface side as compared with the region on the leading edge side in the second contour,
in the step of processing the outer shape,
adjusting at least one of:
a magnitude of a depression amount of the first concave portion in the width direction of the shank or a range occupied by the first concave portion in the first profile; and
a magnitude of a depression amount of the second recess in the width direction of the shank or a range occupied by the second recess in the second profile.
According to the method of the above (16), in the shank portion, when the recess (the first recess or the second recess) is provided at least one of a pair of diagonal positions (regions) including the region on the pressure surface side and the trailing edge side and the region on the suction surface side and the leading edge side in the cross section at any position in the blade height direction, the amount of recess of the recess in the width direction or the size of the range occupied by the recess is adjusted by machining. Thus, the shank is machined so that the amount of recess or the size of the occupied range of the recess becomes an appropriate value, and the rigidity at the position where the recess is provided is lowered, whereby the natural frequency can be adjusted to a desired value. This makes it possible to selectively adjust the natural frequency of the vibration mode in which the blade-shaped portion vibrates along the center line.
(17) In accordance with at least one embodiment of the present invention, there is provided a method for adjusting a natural frequency of a turbine blade, the turbine blade including:
a platform;
a blade-shaped portion extending from the platform in a blade height direction and having a pressure surface and a negative pressure surface extending between a leading edge and a trailing edge;
a blade root portion located on the opposite side of the blade-shaped portion with the platform interposed therebetween and having a bearing surface; and
a shank located between the platform and the blade root,
wherein the content of the first and second substances,
the method for adjusting the natural frequency of the turbine blade includes the steps of: the outer shape of the shank is processed in at least one of a region on the trailing edge side in a first contour on the pressure surface side of the shank and a region on the leading edge side in a second contour on the suction surface side of the shank.
According to the method of the above (17), since the outer shape of the shank is processed in at least one of the region on the trailing edge side on the pressure surface side of the shank and the region on the leading edge side on the negative pressure surface side of the shank, the shank is processed into a shape protruding or recessed in the width direction at least one of a pair of diagonal positions. Thus, the stiffness of the shank portion at the diagonal positions is increased or decreased, whereby the natural frequency of the vibration mode in which relatively large stress is generated at the pair of diagonal positions can be selectively increased or decreased. In this way, the natural frequency of the specific vibration mode can be selectively adjusted while suppressing the influence on the natural frequencies of the other vibration modes. This can suppress damage caused by vibration of the turbine blade.
Effects of the invention
According to at least one embodiment of the present invention, there are provided a turbine blade capable of selectively adjusting the natural frequency of a specific vibration mode, a turbine provided with the turbine blade, and a method of adjusting the natural frequency of the turbine blade.
Drawings
Fig. 1 is a schematic configuration diagram of a gas turbine according to an embodiment.
Fig. 2 is a view of the turbine blade according to the embodiment as viewed from the leading edge toward the trailing edge.
Fig. 3 is a view of the turbine blade shown in fig. 2 as viewed from the negative pressure surface toward the pressure surface.
Fig. 4 is a view showing a section IV-IV of fig. 3.
Fig. 5 is a cross-sectional view (cross-section a-a in fig. 3) of the shank of the turbine blade according to the embodiment.
Fig. 6 is a cross-sectional view (cross-section B-B in fig. 3) of the shank of the turbine blade according to the embodiment.
Fig. 7 is a cross-sectional view (cross-section C-C in fig. 3) of the shank of the turbine blade according to the embodiment.
Fig. 8 is a cross-sectional view (cross-section D-D in fig. 3) of the shank of the turbine blade according to the embodiment.
Fig. 9 is a cross-sectional view (cross-section E-E in fig. 3) of the shank of the turbine blade according to the embodiment.
Fig. 10 is a cross-sectional view (cross-section D-D in fig. 3) of the shank of the turbine blade according to the embodiment.
Fig. 11 is a cross-sectional view (cross-section D-D in fig. 3) of the shank of the turbine blade according to the embodiment.
Fig. 12 is a cross-sectional view (cross-section E-E in fig. 3) of the shank of the turbine blade according to the embodiment.
Fig. 13 is a cross-sectional view (cross-section D-D in fig. 3) of the shank of the turbine blade according to the embodiment.
Fig. 14 is a cross-sectional view (cross-section D-D in fig. 3) of the shank of the turbine blade according to the embodiment.
Detailed Description
Hereinafter, several embodiments of the present invention will be described with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the constituent members described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention to these, but are merely illustrative examples.
First, a gas turbine, which is an example of an application object of the turbine blade according to the several embodiments, will be described with reference to fig. 1. Fig. 1 is a schematic configuration diagram of a gas turbine according to an embodiment.
As shown in fig. 1, a
The compressor 2 includes a plurality of stationary blades 16 fixed to the compressor casing 10 side, and a plurality of rotor blades 18 implanted in the rotor 8 so as to be alternately arranged with respect to the stationary blades 16.
The air taken in from the air intake port 12 is sent to the compressor 2, and the air is compressed by the plurality of stationary blades 16 and the plurality of rotor blades 18, thereby becoming high-temperature and high-pressure compressed air.
The fuel and the compressed air generated by the compressor 2 are supplied to the combustor 4, and the fuel is combusted in the combustor 4 to generate combustion gas as a working fluid of the
The
The
In the
Next, a turbine blade according to several embodiments will be described. In the following description, the moving blades 26 (see fig. 1) of the
Fig. 2 is a view of the
As shown in fig. 2 to 4, a turbine blade 40 (rotor blade 26) according to one embodiment includes a
The blade-shaped
The blade-shaped
As shown in fig. 2, in the
As shown in fig. 4, the pressure
That is, the center line Lc is a straight line including a line segment connecting the widthwise central positions of the
The blade-shaped
In several embodiments, the
In the present specification, the "width direction" of the
Several embodiments of the
Fig. 5 to 9 are cross-sectional views showing the
Fig. 5 to 7 are views corresponding to the section a-a, the section B-B, and the section C-C in fig. 3, respectively, and show a cross section (a cross section viewed from the horizontal direction) in the blade height direction and the width direction of the
Fig. 8 and 9 are views corresponding to the D-D section and the E-E section of fig. 3, respectively, and show a section perpendicular to the blade height direction of the
As shown in fig. 8 and 9, in the
As shown in the drawing, in the
In the above cross section, the phrase "outward in the pressure surface side" and "outward in the negative pressure surface side" refers to the outer sides in the circumferential direction of the pressure surface side and the negative pressure surface side, respectively, with reference to the widthwise center position of the
The broken lines in fig. 5, 6, 8, and 9 show the
Therefore, as shown in fig. 8 and 9, in the
In the above-described embodiment, the
Therefore, at a pair of diagonal positions where the convex portion is provided, the rigidity of the
In a certain type of
In the
As shown in fig. 8, the
In this way, when the
As shown in fig. 7, in the present embodiment, the
The thinned portion 70 may also be provided at an upper portion (a side close to the platform 42) of the
The blade height direction position shown in the section E-E of fig. 3 is the height direction position at which the above-described thinned portion 70 is provided. That is, in the present embodiment, the first
In this case, a cross section (second cross section; see fig. 9) perpendicular to the blade height direction at the position of the section E-E in fig. 3 has the following features.
That is, the
The
In the second cross section (see fig. 9), a distance D1D in the circumferential direction from the reference line Lo passing through the midpoint Pc of the line segment S1 and parallel to the center line Lc of the
Further, a distance D2D in the circumferential direction from the reference line Lo to the second center contour 86D, a distance D2a in the circumferential direction from the reference line Lo to the second leading
According to the above relation, the cross section shown in fig. 9 shows: since the thinned portion 70 is provided at the center portion in the front-rear direction (axial direction) and is largely hollowed out, the distances between the first center contour 84d and the second center contour 86d located at the center portion in the front-rear direction and the reference line Lo are smaller than the distances between the front edge side end portion and the rear edge side end portion. At the blade height position where the thinned portion 70 is provided, the bulged portions (the first
The
In this way, since the second cross-section is provided at the blade height direction position of the
As shown in fig. 3, 8, and 9, the
As shown in fig. 5 and 6, the
The
In this case, since the
As shown in fig. 8 and 9, the first
That is, the
In this case, compared to the case where the
Fig. 10 is a cross-sectional view of the
In the above-described embodiment, the
For example, as shown in fig. 10, in the cross section described above, the
That is, as shown in fig. 10, in the
Therefore, at a pair of diagonal positions where the convex portion is provided, the rigidity of the
Fig. 11 and 12 are sectional views of turbine blades according to an embodiment other than the turbine blades shown in fig. 5 to 9.
Fig. 11 and 12 are views corresponding to the D-D section and the E-E section of fig. 3, respectively, and show a section of the
As shown in fig. 11 and 12, in the
As shown in the drawing, in the
In the cross section, the terms "from the pressure surface side to the inside" and "from the negative pressure surface side to the inside" mean the side toward the center position in the width direction of the
The broken lines in fig. 11 and 12 represent the contours (
Therefore, as shown in fig. 11 and 12, in the
In the above-described embodiment, the
Therefore, at a pair of diagonal positions where the recess is provided, the rigidity of the
As shown in fig. 11, the
In this way, when the
The height direction position shown in the section E-E of fig. 3 is the blade height direction position where the above-described thinned portion 70 is provided. In the present embodiment, the first recess 78 and the second recess 88 are provided at the blade height direction positions where the thinned portions 70 are provided.
In this case, a cross section (third cross section; see fig. 12) perpendicular to the blade height direction at the position of the E-E cross section in fig. 3 has the following features.
That is, the
The
In the third cross-section (see fig. 12), a distance D1D in the circumferential direction from the reference line Lo passing through the midpoint Pc of the line segment s1 and parallel to the center line Lc of the
Further, a distance D2D in the circumferential direction from the reference line Lo to the second center contour 86D, a distance D2a in the circumferential direction from the reference line Lo to the second leading
According to the above relation, the cross section shown in fig. 12 shows: since the thinned portion 70 is provided at the center portion in the front-rear direction (axial direction) and is largely hollowed out, the distance between the first center contour 84d and the second center contour 86d located at the center portion in the front-rear direction and the reference line Lo is relatively smaller than the distance between the leading edge side end portion and the trailing edge side end portion. In addition, recessed portions (first recessed portions 78 and second recessed portions 88) are provided on the trailing edge side on the pressure surface side and the leading edge side on the negative pressure surface side with respect to the prototype outlines 57 and 67 at the blade height direction positions where the thinned portions 70 are provided.
The
As described above, since the third cross-sectional surface is provided at the blade height direction position of the
As shown in fig. 3, 11, and 12, the
Although not particularly shown, the first recess 78 and/or the second recess 88 may extend over the entire range between the
In this case, since the first recess 78 and/or the second recess 88 extend over the entire range between the
As shown in fig. 11 and 12, the first concave portion 78 and/or the second concave portion 88 linearly extend in parallel with the center line Lc in the cross section (for example, the first cross section or the third cross section).
That is, the first recess 78 and/or the second recess 88 (notch) are provided within a certain range in the front-rear direction.
In this case, the natural frequency of the
Fig. 13 is a cross-sectional view of the
In the above-described embodiment, the
For example, as shown in fig. 13, in the cross section described above, the
That is, as shown in fig. 13, in the
Therefore, at a pair of diagonal positions where the convex portion is provided, the rigidity of the
Fig. 14 is a cross-sectional view showing a cross section of the
In the above embodiment, the shapes of the first
Therefore, similarly to the embodiment shown in fig. 8, at a pair of diagonal positions where the first
In the first
Here, in the present specification, the "end" of the
Note that, even when the position of the starting point of the first
By defining the "end portion" in such a range, it becomes easy to determine whether or not the specific vibration mode (for example, a1 mode) in which the blade-shaped
Therefore, even if the line segment S1(P1P2) connecting the widthwise central position P1 of the
In the above-described end portion, when the length of the
Next, a method of adjusting the natural frequency of the
In some embodiments, the
That is, the
The adjusting method of some embodiments comprises the following steps: the outer shape of the
In some embodiments, as described above, the natural frequency of the mode in which the blade-shaped
More specifically, for example, in the case of the
For example, in the case of the
Thus, the rigidity of the
As described above, in the
In some embodiments, the
The adjusting method according to this embodiment includes a step of machining the outer shape of the
According to the method of the above embodiment, since the outer shape of the
While the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and includes a mode in which the above embodiments are modified and a mode in which these modes are appropriately combined.
In the present specification, expressions such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "central", "concentric", or "coaxial" which indicate relative or absolute arrangements mean not only such an arrangement as is strictly described, but also a state in which the relative displacement is achieved with a tolerance, or an angle or a distance to the extent that the same function can be obtained.
For example, expressions indicating states of equality such as "equal", and "homogeneous" indicate not only states of strict equality but also states of tolerance or difference in degree to obtain the same function.
In the present specification, the expressions indicating shapes such as a square shape and a cylindrical shape indicate not only shapes such as a square shape and a cylindrical shape in a strict geometrical sense but also shapes including a concave-convex portion, a chamfered portion, and the like within a range in which similar effects can be obtained.
In the present specification, the expression "including", "including" or "having" one constituent element is not an exclusive expression excluding the presence of other constituent elements.
Description of reference numerals:
1 gas turbine
2 compressor
4 burner
6 turbine
8 rotor
10 compressor chamber
12 air intake
16 stationary blade
18 moving blade
20 outer casing
22 turbine chamber
24 stationary blade
26 moving blade
28 passage for combustion gas
30 air exhaust chamber
32 rotor disk
33 blade groove
34 cooling passage
36 Ribs
38 inner wall surface
40 turbine blade
42 platform
43 lower surface
44 blade-shaped part
46 leading edge
48 trailing edge
50 pressure surface
51 blade root
52 negative pressure surface
53P Profile
53S profile
54 bearing surface
55 upper end
56 handle part
57 prototype outline
58 first projection
67 prototype contour
68 second projection
70 thinned part
78 first recess
80 end of the pipe
82 end portion
84 first profile
84a first leading edge profile (leading edge side zone)
84b first trailing edge side contour (trailing edge side area)
84c first straight line part
84d first center profile
86 second profile
86a second leading edge profile (leading edge side zone)
86b second trailing edge side contour (trailing edge side area)
86c second straight line part
86d second center profile
88 second recess
100 foremost end face
100a foremost extension
101 rearmost end face
101a rearmost extension
Lc center line
Lo reference line
P1 center position
P2 center position
Pc midpoint
And S1 line segment.
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