ROTOR BLADE FOR A SECOND PHASE OF A COMPRESSOR

• US 20080044288A1
• Filed: 02/16/2007
• Published: 02/21/2008
• Est. Priority Date: 02/27/2006
• Status: Active Grant

• Current Assignee: Nuovo Pignone Tecnologie SRL (Nuovo Pignone International SRL)
• Original Assignee: General Electric Company
• Inventors: Arinci, Paolo, Novori, Alessio, Lorusso, Salvatore
• Granted Patent: US 7,785,074 B2
• Time in Patent Office: Days
• US Class Current: 416/223R
• CPC Class Codes: F01D 5/141 Shape, i.e. outer, aerodynamic form F01D5/148 - F01D5/20 take precedence; blade construction F01D5/147
• CPC Class Codes: F01D 5/288 Protective coatings for blades
• CPC Class Codes: F04D 29/324 Blades
• CPC Class Codes: F04D 29/668 damping or preventing mechanical vibrations
• CPC Class Codes: F05D 2250/74 given by a set or table of xyz-coordinates
• CPC Class Codes: F05D 2260/96 Preventing, counteracting or reducing vibration or noise
• CPC Class Codes: Y10S 416/50 Vibration damping features

Abstract

The invention relates to a blade (10) of a rotor of a second 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 midway up the blade (10) and being suitable for shifting the natural resonance frequencies of the blade (10) itself outside a functioning velocity range of said rotor.

Claims

1. A blade of a rotor of a second 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 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 comprising:

a thickening, substantially parallel to a base portion of the blade itself, fixable to said rotor, said thickening being substantially situated halfway up the blade and being suitable for shifting one or more natural resonance frequencies of the blade itself outside a functioning velocity range of said rotor.

2. The blade according to claim 1, further comprising:

a profile which is 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 profile of said blade 10.

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 10 in the direction of a free end of the blade, having a non-linearly variable trend.

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 a polynomial function of the sixth degree.

5. The blade according to claim 4, wherein said polynomial function of the sixth degree is:

Tmax=−

21.119*h⁶+70.467*h⁵−

85.603*h⁴+44.523*h³−

7.8323*h²−

1.1541*h+0.997

wherein h represents the percentage of the height of the blade, and wherein Tmax is the maximum adimensionalized thickness relating to the closed curve corresponding to that percentage of the height of the blade.

6. The blade according to claim 1, wherein said closed curves are defined according to Table I, whose values, expressed in millimeters, refer to a profile at room temperature.

7. The blade according to claim 1, wherein the profile of each blade has a tolerance of +/−

2 mm in a normal direction with respect to the profile of the blade itself.

8. The blade according to claim 1, wherein the profile of each blade comprises an antiwear coating.

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

10. A rotor of a second phase of a compressor, wherein the rotor comprises:

a series of blades according to claim 1.

11. The rotor according to claim 10, characterized in that said series of blades 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.

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