ROTOR BLADE FOR A NINTH PHASE OF A COMPRESSOR

Abstract

The invention relates to a blade (10) 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 (10) having a 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 (10) also comprising a thickening (30), substantially parallel to a base portion (12) of the blade (10) itself, fixable to said rotor, said thickening (30) being substantially situated half-way up the blade (10) and being suitable for shifting the natural resonance frequencies of the blade (10) itself outside a functioning frequency range of said rotor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics and advantages of a rotor blade of a ninth phase of a compressor according to the present invention will appear more evident from the following illustrative and non-limiting description, referring to the enclosed schematic drawings in which:

FIG. 1 is a raised view of a rotor blade of a compressor produced with an aerodynamic profile according to the present invention;

FIG. 2 is a raised view of the opposite side of the blade of FIG. 1; and

FIG. 3 is a diagram of the maximum thickness trend of a blade according to the present invention, with respect to its height.

Claims

1. A blade (10) 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 (10) having a 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 (10) being characterized in that it comprises a thickening (30), substantially parallel to a base portion (12) of the blade (10) itself, fixable to said rotor, said thickening (30) being substantially situated halfway up the blade (10) and being suitable for shifting the natural resonance frequencies of the blade (10) itself outside a functioning frequency range of said rotor.

2. The blade (10) according to claim 1, characterized in that it comprises a further thickening, substantially parallel to said base portion (12) and situated in particular close to a free end (14).

3. The blade (10) according to claim 1, characterized in that it comprises a profile which is identified by a first substantially concave surface (3), which is pressurized, and a second substantially convex surface (5) which is in depression and which is opposite to the first, said two surfaces (3, 5) being continuous and joined to each other to form the profile of said blade 10.

4. The blade (10) according to claim 3, characterized in that each closed curve has a maximum thickness determined by the maximum distance between said first surface (3) and said second surface (5), said maximum thickness of each closed curve, along the height of the blade 10 in the direction of a free end (14) of the blade (10), 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.

5. The blade (10) according to claim 4, characterized in that along the height of the blade (10) in the direction of its free end (14), said maximum thickness has a trend according to the following equations, wherein h represents the height of the blade (10), expressed as a percentage of the total height of the blade (10), and wherein Tmax is the maximum adimensionalized thickness relating to the closed curve corresponding to the height: Tmax=−34.522*h4+36.4*h3−8.4113*h2−0.7259*h+0.9961

6. The blade (10) according to claim 5, characterized in that said closed curves are defined according to Table I, whose values, expressed in millimeters, refer to a profile at room temperature.

7. The blade (10) according to claim 6, characterized in that the profile of each blade (10) has a tolerance of ±2 mm in a normal direction with respect to the profile of the blade 10 itself.

8. The blade (10) according to claim 7, characterized in that the profile of each blade (10) comprises an antiwear coating.

9. The blade (10) according to claim 8, characterized in that said coating has a thickness ranging from 0 to 0.5 mm.

10. A rotor of a ninth phase of a compressor, characterized in that it comprises a series of blades (10) according to claim 1.

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

12. A compressor characterized in that it comprises a rotor according to claim 10.