Nozzle vane with two slopes

1. A nozzle vane for a turbomachine, the vane presenting mutually orthogonal longitudinal, tangential, and radial axes, and having pressure side and suction side surfaces extending radially between a base and a tip, and longitudinally between a leading edge and a trailing edge, and a plurality of vane sections having centers of gravity in alignment along a stacking axis, said vane presenting a lower portion, an intermediate portion, and an upper portion, said lower portion extending radially between the base of the vane and a lower limit of the intermediate portion, and said upper portion extending radially between an upper limit of the intermediate portion and the tip of the vane, wherein the stacking axis presents, in the lower and upper portions, a tangent line that is substantially radial, and in the intermediate portion, at least two tangent lines having different slopes.

2. A vane according to claim 1 , wherein the tangential component of the stacking axis, in said intermediate portion, comprises a first slope in the direction opposite to the direction of rotation of the disk, and a second slope in the direction of rotation of said disk.

3. A vane according to claim 2 , wherein said first slope presents an angle of inclination with respect to the radial direction lying in the range 5° to 45°.

4. A vane according to claim 2 , wherein said second slope presents an angle of inclination with respect to the radial direction lying in the range 5° to 45°.

5. A vane according to claim 2 , wherein said first slope extends radially between the lower limit of the intermediate portion and a bend point situated between the lower and upper limits of said intermediate portion, and said second slope extends radially between said bend point and said upper limit.

6. A vane according to claim 5 , wherein the tangential component of the stacking axis of the intermediate portion occupies a radial height lying in the range 35% to 65% of a total radial height between the base and the tip of said vane.

7. A vane according to claim 1 , wherein the tangential component of the stacking axis of the lower portion occupies a radial height lying in the range 10% to 25% of a total radial height between the base and the tip of said vane.

8. A vane according to claim 1 , wherein the tangential component of the stacking axis of the upper portion occupies a radial height lying in the range 10% to 25% of a total radial height between the base and the tip of said vane.

9. A vane according to claim 1 , wherein the vane is a stationary vane of a compressor of the turbomachine, the vane is only connected to the turbomachine at the upper portion of the vane, and the upper portion of the vane is connected to an outer shroud of a stator of the compressor.

10. A vane according to claim 1 , wherein the lower portion of the vane extends to a location proximate an inner shroud of a rotor disk of a compressor of the turbomachine without being connected to the inner shroud, and the rotor disk is configured to rotate around the longitudinal axis of the turbomachine.

11. A nozzle vane for a turbomachine, the vane presenting mutually orthogonal longitudinal, tangential, and radial axes, and having pressure side and suction side surfaces extending radially between a base and a tip, and longitudinally between a leading edge and a trailing edge, and a plurality of vane sections having centers of gravity in alignment along a stacking axis, said vane presenting a lower portion, an intermediate portion, and an upper portion, said lower portion extending radially between the base of the vane and a lower limit of the intermediate portion, and said upper portion extending radially between an upper limit of the intermediate portion and the tip of the vane, wherein the stacking axis presents, in the lower and upper portions, a tangent line which extends parallel to the radial axis of the vane, and in the intermediate portion, at least two tangent lines having different slopes, said intermediate portion having a C-shaped form.

12. A vane according to claim 11 , wherein the tangential component of the stacking axis, in said intermediate portion, comprises a first slope in the direction opposite to the direction of rotation of the disk, and a second slope in the direction of rotation of said disk.

13. A vane according to claim 12 , wherein said first slope presents an angle of inclination with respect to the radial direction lying in the range 5° to 45°.

14. A vane according to claim 12 , wherein said second slope presents an angle of inclination with respect to the radial direction lying in the range 5° to 45°.

15. A vane according to claim 12 , wherein said first slope extends radially between the lower limit of the intermediate portion and a bend point situated between the lower and upper limits of said intermediate portion, and said second slope extends radially between said bend point and said upper limit.

16. A vane according to claim 15 , wherein the tangential component of the stacking axis of the intermediate portion occupies a radial height lying in the range 35% to 65% of a total radial height between the base and the tip of said vane.

17. A vane according to claim 11 , wherein the tangential component of the stacking axis of the lower portion occupies a radial height lying in the range 10% to 25% of a total radial height between the base and the tip of said vane.

18. A vane according to claim 11 , wherein the tangential component of the stacking axis of the upper portion occupies a radial height lying in the range 10% to 25% of a total radial height between the base and the tip of said vane.

19. A vane according to claim 11 , wherein the vane is a stationary vane of a compressor of the turbomachine, the vane is only connected to the turbomachine at the upper portion of the vane, and the upper portion of the vane is connected to an outer shroud of a stator of the compressor.

20. A vane according to claim 11 , wherein the lower portion of the vane extends to a location proximate an inner shroud of a rotor disk of a compressor of the turbomachine without being connected to the inner shroud, and the rotor disk is configured to rotate around the longitudinal axis of the turbomachine.