Periodic stator airfoils

• US 6,439,838 B1
• Filed: 12/18/1999
• Issued: 08/27/2002
• Est. Priority Date: 12/18/1999
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Crall, David W., Manwaring, Steven R.
• Primary Examiner(s): Ryznic, John E.
• Application Number:
  US09/466,157
• Time in Patent Office: 983 Days
• Field of Search: 415/119, 415/194, 415/195
• US Class Current: 415/119
• CPC Class Codes: F01D 5/26 Antivibration means not restricted to blade form or construction or to blade-to-blade connections or to the use of particular materials
• CPC Class Codes: F01D 9/02 Nozzles; Nozzle boxes; Stator blades; Guide conduits , e.g. individual nozzles nozzle boxes F01D9/047
• CPC Class Codes: F04D 29/544 Blade shapes
• CPC Class Codes: F04D 29/563 specially adapted for elastic fluid pumps
• CPC Class Codes: F04D 29/668 damping or preventing mechanical vibrations
• CPC Class Codes: F05D 2240/10 Stators
• CPC Class Codes: F05D 2250/184 sinusoidal
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A stator includes a row of airfoils extending inwardly from a casing. The airfoils are spaced apart circumferentially from each other at a spacing varying in turn around the perimeter of the casing for reducing vibratory excitation of a downstream rotor stage.

Claims

1. A stator configured for channeling inlet air through an inlet end of a gas turbine engine into a row of fan rotor blades, and comprising a row of airfoils extending radially inwardly from a casing for channeling said air to said fan rotor blades, and spaced circumferentially apart from each other at a periodic spacing varying in turn around the perimeter of said casing for reducing wake excitation of said fan rotor blades from said airfoils.

2. A stator according to claim 1 wherein said airfoils have a greater circumferential spacing varying in turn on one side of said casing than on an opposite side thereof having a lesser circumferential spacing varying in turn.

3. A stator according to claim 2 wherein said airfoils vary in circumferential spacing around said casing in a period corresponding with said casing perimeter.

4. A stator according to claim 3 wherein said circumferential spacing is sinusoidal.

5. A stator according to claim 3 wherein said greater circumferential spacing is up to about 10% greater than a uniform nominal spacing of the total number of airfoils in said casing, and said lesser circumferential spacing is up to about 10% less than said nominal spacing.

6. A stator according to claim 3 in the form of a fan front frame wherein said airfoils comprise struts configured for directing air to said row of fan rotor blades downstream therefrom.

7. A frame according to claim 6 wherein said airfoils further comprise inlet guide vanes mounted to said casing in alignment with corresponding ones of said struts.

8. A fan frame comprising a row of struts extending radially between an outer casing and inner hub, and spaced circumferentially apart from each other at a periodic spacing varying in turn around the perimeter of said casing.

9. A frame according to claim 8 wherein said struts have a greater circumferential spacing varying in turn on one side of said casing than on an opposite side thereof having a lesser circumferential spacing varying in turn.

10. A frame according to claim 9 wherein said struts vary in circumferential spacing around said casing in a period corresponding with said casing perimeter.

11. A frame according to claim 10 wherein said circumferential spacing is sinusoidal.

12. A frame according to claim 10 wherein said greater circumferential spacing is up to about 10% greater than a uniform nominal spacing of the total number of airfoils in said casing, and said lesser circumferential spacing is up to about 10% less than said nominal spacing.

13. A fan frame comprising a row of aligned struts and vanes extending radially between an outer casing and an inner hub, and spaced circumferentially apart from each other at a periodic spacing varying in turn around the perimeter of said casing.

14. A frame according to claim 13 wherein said struts and vanes have a greater circumferential spacing varying in turn on one side of said casing than on an opposite side thereof having a lesser circumferential spacing varying in turn.

15. A frame according to claim 14 wherein said struts and vanes vary in circumferential spacing around said casing in a period corresponding with said casing perimeter.

16. A frame according to claim 15 wherein said circumferential spacing is sinusoidal.

17. A frame according to claim 15 wherein said greater circumferential spacing is up to about 10% greater than a uniform nominal spacing of the total number of airfoils in said casing, and said lesser circumferential spacing is up to about 10% less than said nominal spacing.

18. A frame according to claim 14 further comprising a rotor supported at one end in said hub, and including a row of fan rotor blades disposed directly downstream of said vanes.

19. A frame according to claim 18 wherein said vanes are variable in angular position.

20. A frame according to claim 19 wherein said struts have a streamlined profile.