Transonic blade

1. A transonic blade used in a flow field through which an overall or partial flow passes at a transonic speed or higher,

wherein the transonic blade is formed such that:

a cross-sectional surface at each of spanwise positions of the blade is shifted parallel to a line connecting a leading edge with a trailing edge of the blade;

a stacking line is shifted toward an upstream side of working fluid, the stacking line connecting together gravity center positions of blade cross-sectional surfaces at respective spanwise positions in a range from a hub cross-sectional surface joined to a rotating shaft or an outer circumferential side casing of a rotating machine to a tip cross-sectional surface lying at a position most remote from the hub cross-sectional surface in a spanwise direction; and

a maximum thickness position of the cross-sectional surface of the blade at each of the spanwise positions are shifted toward a trailing edge side of the blade in a range from the hub cross-sectional surface to the tip cross-sectional surface.

2. The transonic blade according to claim 1 ,

wherein the stacking line is located on the upstream side of the working fluid at all spanwise positions and is monotonously shifted toward the upstream side from the hub cross-sectional surface to the tip cross-sectional surface.

3. The transonic blade according to claim 1 ,

wherein the maximum blade-thickness position is located on a leading edge side at the hub cross-sectional surface and is monotonously shifted toward a trailing edge side in a range from the hub cross-sectional surface to the tip cross-sectional surface.

4. The transonic blade according to claim 1 ,

wherein the maximum blade-thickness position lies on the upstream side of an average axial position between the leading edge and the trailing edge at the hub cross-sectional surface and lies on the downstream side of an average axial position between the leading edge and the trailing edge at the tip cross-sectional surface.

5. The transonic blade according to claim 1 ,

wherein a cross-sectional shape at each of the spanwise positions is formed of a circular arc forming a leading edge portion of the blade, a circular arc forming a trailing edge portion, an upper surface of the blade and a lower surface of the blade, and a shape of a camber line defined by a midpoint between the upper and lower surfaces of the blade is a multi circular arc formed of two or more circular arcs.

6. The transonic blade according to claim 1 ,

wherein a change rate of the stacking line toward the upstream side is maximized at the tip cross-sectional surface.

7. A axial-flow rotating machine comprising:

a plurality of stator blades mounted in axial and circumferential directions on the inner circumferential surface side of a casing; and

a plurality of rotor blades mounted in the circumferential direction on an outer circumferential surface side of a rotating shaft;

wherein the transonic blade of claim 1 is used for all or part of the stator blades.

8. A transonic blade used in a flow field through which an overall or partial flow passes at a transonic speed or higher,

wherein the transonic blade is formed such that:

a cross-sectional surface at each of spanwise positions of the blade is shifted parallel to a line connecting a leading edge with a trailing edge of the blade;

a stacking line connecting together gravity center positions of the cross-sectional surfaces of the blade at respective spanwise positions has a constant axial position on a hub cross-sectional surface side of a certain spanwise position between a hub cross-sectional surface joined to a rotating shaft or an outer circumferential side casing of a rotating machine and a mean cross-sectional surface located at a center in a spanwise direction and is shifted toward the upstream side of working fluid from the certain spanwise position to the tip cross-sectional surface side; and

a maximum thickness position of the cross-sectional surface of the blade at each of the spanwise positions is shifted toward a trailing edge side of the blade in a range from the hub cross-sectional surface to the tip cross-sectional surface.

9. The transonic blade according to claim 8 ,

wherein the maximum blade-thickness position is located on a leading edge side at the hub cross-sectional surface and is monotonously shifted toward a trailing edge side in a range from the hub cross-sectional surface to the tip cross-sectional surface.

10. The transonic blade according to claim 8 ,

wherein the maximum blade-thickness position lies on the upstream side of an average axial position between the leading edge and the trailing edge at the hub cross-sectional surface and lies on the downstream side of an average axial position between the leading edge and the trailing edge at the tip cross-sectional surface.

11. The transonic blade according to claim 8 ,

wherein a cross-sectional shape at each of the spanwise positions is formed of a circular arc forming a leading edge portion of the blade, a circular arc forming a trailing edge portion, an upper surface of the blade and a lower surface of the blade, and a shape of a camber line defined by a midpoint between the upper and lower surfaces of the blade is a multi circular arc formed of two or more circular arcs.

12. The transonic blade according to claim 8 ,

wherein a change rate of the stacking line toward the upstream side is maximized at the tip cross-sectional surface.

13. A axial-flow rotating machine comprising:

a plurality of stator blades mounted in axial and circumferential directions on the inner circumferential surface side of a casing; and

a plurality of rotor blades mounted in the circumferential direction on an outer circumferential surface side of a rotating shaft;

wherein the transonic blade of claim 8 is used for all or part of the stator blades.