Rotor blade for a ninth phase of a compressor

1. A blade of a rotor of a ninth phase of a compressor, which can be defined by coordinates of a discreet combination of points, in a Cartesian reference system (X, Y, Z), wherein the axis (Z) is a radial axis intersecting the central axis of the compressor, said blade having an aerodynamic profile which can be identified by means of a series of closed intersection curves between the profile itself and planes (X, Y) lying at distances (Z) from the central axis, said blade comprising:

a base portion fixable to said rotor,

the aerodynamic profile extending from a foot at said base portion to a free end distal from said base portion,

a first thickening, substantially parallel to said base portion, said first thickening being substantially situated halfway up the blade, and

a further thickening, substantially parallel to said base portion and situated close to said free end, said further thickening having a maximum thickness less than a thickness of the blade at said foot,

said first thickening and said further thickening being suitable for shifting the natural resonance frequencies of the blade itself outside a functioning frequency range of said rotor.

2. The blade according to claim 1 , wherein said blade further comprises:

the aerodynamic profile identified by a first substantially concave surface, which is pressurized, and a second substantially convex surface which is in depression and which is opposite to the first,

said two surfaces being continuous and joined to each other to form the aerodynamic profile of said blade.

3. The blade according to claim 2 , wherein each closed curve has a maximum thickness determined by the maximum distance between said first surface and said second surface, said maximum thickness of each closed curve, along the height of the blade in the direction of a free end of the blade, first having a decreasing and then an increasing trend, followed again by a decreasing and finally increasing trend, with a discontinuity point of the slope.

4. The blade according to claim 3 , wherein along the height of the blade in the direction of its free end, said maximum thickness has a trend according to the following equations, wherein h represents the height of the blade, expressed as a percentage of the total height of the blade, and wherein Tmax is the maximum adimensionalized thickness relating to the closed curve corresponding to the height:

T max=−34.522 *h 4 +36.4 *h 3 −8.4113*h 2 −0.7259 *h+ 0.9961

for height values ranging from 0 to 45%;

T max=−1.3509 *h+ 1.4459

for a height ranging from 45% to 58%;

T max=0.2074 *h+ 0.5443

for a height ranging from 58% to 86%;

T max=0.9058 *h− 0.0518

for a height ranging from 86% to 100%.

5. A blade of a rotor of a ninth phase of a compressor, which can be defined by coordinates of a discreet combination of points, in a Cartesian reference system (X, Y, Z), wherein the axis (Z) is a radial axis intersecting the central axis of the compressor, said blade having an aerodynamic profile which can be identified by means of a series of closed intersection curves between the profile itself and planes (X, Y) lying at distances (Z) from the central axis, said blade comprising:

a base portion fixable to said rotor,

the aerodynamic profile having a surface extending from a foot at said base portion to a free end distal from said base portion,

a first thickening, substantially parallel to said base portion, said first thickening being substantially situated halfway up the blade,

a further thickening, substantially parallel to said base portion and situated close to said free end, said further thickening having a maximum thickness less than a thickness of the blade at said foot, and

said first thickening and said further thickening being suitable for shifting the natural resonance frequencies of the blade itself outside a functioning frequency range of said rotor;

wherein said closed curves are defined according to Table I, whose values, expressed in millimeters, refer to a profile at room temperature.

6. The blade according to claim 5 , wherein the profile of said blade has a tolerance of +/−2 mm in a normal direction with respect to the profile of the blade itself.

7. The blade according to claim 6 , further comprising an antiwear coating on the surface.

8. The blade according to claim 7 , wherein said coating has a thickness ranging from 0 to 0.5 mm.

9. A rotor of a ninth phase of a compressor, comprising a series of blades according to claim 1 .

10. The rotor according to claim 9 , wherein said series of blades is constrained to an outer surface of said rotor and said series of blades is also uniformly distributed thereon in order to maximize the efficiency of the rotor itself.

11. A compressor characterized in that it comprises a rotor according to claim 9 .

12. A blade of a rotor of a compressor, which can be defined by coordinates of a discreet combination of points, in a Cartesian reference system (X, Y, Z), wherein the axis (Z) is a radial axis intersecting the central axis of the compressor, said blade having a profile defining the surface of the blade which can be identified by means of a series of closed intersection curves between the profile itself and planes (X, Y) lying at distances (Z) from the central axis, said blade comprising said closed curves defined according to Table I, whose values, expressed in millimeters, refer to a profile at room temperature.

13. The blade according to claim 12 , wherein the profile of said blade has a tolerance of +/−2 mm in a normal direction with respect to the profile of the blade itself.

14. The blade according to claim 13 , further comprising an antiwear coating on the blade surface.

15. The blade according to claim 14 , wherein said coating has a thickness ranging from 0 to 0.5 mm.

16. The blade according to claim 12 wherein the values of the coordinates of Table 1 are multiplied by a corrective constant to obtain a scaled profile maintaining the same form.

17. A rotor of a ninth phase of a compressor, the rotor comprising a series of blades according to claim 12 .

18. The rotor according to claim 12 , wherein said series of blades is constrained to an outer surface of said rotor and said series of blades is also uniformly distributed thereon in order to maximize the efficiency of the rotor itself.

19. A compressor that comprises a rotor according to claim 12 .