Low noise permeable airfoil

• US 6,139,259 A
• Filed: 10/29/1998
• Issued: 10/31/2000
• Est. Priority Date: 10/29/1998
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Ho, Patrick Y., Gliebe, Philip R.
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): WOO, RICHARD SUKYOON
• Application Number:
  US09/181,904
• Time in Patent Office: 733 Days
• Field of Search: 415/119, 415/115, 415/208.1, 415/209.1, 415/142, 416/224, 416/229 A, 416/230, 416/500, 244/1 N, 244/209
• US Class Current: 415/119
• CPC Class Codes: B64C 11/20 Constructional features
• CPC Class Codes: F01D 5/145 Means for influencing boundary layers or secondary circulations for compressors F04D29/68
• CPC Class Codes: F01D 5/148 Blades with variable camber, e.g. by ejection of fluid
• CPC Class Codes: F01D 5/18 Hollow blades, i.e. blades with cooling or heating channels or cavities structure of hollow blades in general F01D5/147; Heating, heat-insulating or cooling means on blades
• CPC Class Codes: F01D 9/065 Fluid supply or removal conduits traversing the working fluid flow, e.g. for lubrication-, cooling-, or sealing fluids see also F01D25/16, F01D25/24 and F01D25/26
• CPC Class Codes: F02C 7/045 having provisions for noise suppression
• CPC Class Codes: F04D 29/542 Bladed diffusers fixing blades to stators F01D9/042
• CPC Class Codes: F04D 29/667 by influencing the flow pattern, e.g. suppression of turbulence
• CPC Class Codes: F04D 29/681 especially adapted for elastic fluid pumps
• CPC Class Codes: F04D 29/682 by fluid extraction
• CPC Class Codes: F04D 29/684 by fluid injection
• CPC Class Codes: F05D 2240/121 related to the leading edge of a stator vane
• CPC Class Codes: F05D 2260/96 Preventing, counteracting or reducing vibration or noise
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A stator airfoil is subject to wake fluid from rotor blades in a gas turbine engine. The airfoil includes a plurality of cross channels extending therethrough between opposite sides thereof for bleeding the wake fluid therebetween to reduce differential pressure thereacross and reduce noise.

Claims

1. A stator airfoil subject to wake fluid from rotor blades in a gas turbine engine comprising:

a leading edge, an opposite trailing edge, an inner root, an opposite outer tip, and opposite first and second sides extending therebetween; and

a plurality of cross channels extending through said airfoil from said first side to said second side for bleeding said wake fluid therebetween to reduce differential pressure thereacross.

2. An airfoil according to claim 1 wherein said cross channels are disposed adjacent said leading edge for first receiving said wake fluid and reducing differential pressure thereof between said first and second sides.

3. An airfoil according to claim 2 wherein said cross channels are spaced apart both radially between said root and tip and axially between said leading and trailing edges in a pattern to distribute said differential pressure reduction thereacross.

4. An airfoil according to claim 3 wherein said cross channels are disposed solely adjacent said leading edge, and said first and second sides are otherwise imperforate.

5. An airfoil according to claim 3 being solid from said root to said tip between said first and second sides, with said cross channels extending therethrough.

6. An airfoil according to claim 3 being hollow from said root to said tip, and including a septum defining forward and aft chambers to fluidly separate said cross channels in said forward chamber from said aft chamber.

7. An airfoil according to claim 6 further comprising an acoustic damping fiber inside said forward chamber.

8. An airfoil according to claim 3 wherein said cross channels are sized in diameter to reduce unsteady-state differential pressure in said wake fluid between said first and second sides to a greater extent than steady state differential pressure therein.

9. An airfoil according to claim 3 in the form of a fan strut disposed in combination with a row of fan blades upstream therefrom for reducing fan noise.

10. An airfoil according to claim 3 in the form of a fan outlet guide vane disposed in combination with a row of fan blades upstream therefrom for reducing fan noise.

11. An airfoil according to claim 3 in the form of a turbine rear frame strut disposed in combination with a row of turbine blades upstream therefrom for reducing turbine exhaust noise.

12. A method of reducing noise from wake fluid interaction between a row of rotor blades and row of stator airfoils comprising bleeding said wake fluid circumferentially through said airfoils from a first side thereof to an opposite second side to reduce differential pressure therebetween.

13. A method according to claim 12 further comprising bleeding said wake fluid solely adjacent a leading edge of said airfoils.

14. A method according to claim 12 further comprising bleeding said wake fluid to reduce unsteady-state differential pressure in said wake fluid between said first and second sides to a greater extent than steady state differential pressure therein.

15. A method according to claim 12 further comprising bleeding said wake fluid through a fan strut disposed downstream of a fan blade in a gas turbine engine to reduce fan noise.

16. A method according to claim 12 further comprising bleeding said wake fluid through a fan outlet guide vane disposed downstream of a fan blade in a gas turbine engine to reduce fan noise.

17. A method according to claim 12 further comprising bleeding said wake fluid through a turbine rear frame strut disposed downstream of a turbine blade in a gas turbine engine to reduce turbine exhaust noise.

18. A stator airfoil including cross channels extending between opposite sides thereof for bleeding external fluid across said opposite sides to reduce differential pressure.

19. A stator airfoil comprising:

opposite first and second sides extending between opposite leading and trailing edges; and

a plurality of cross channels extending between said opposite sides for bleeding external fluid from said first side to said second side to reduce differential pressure thereacross.

20. An airfoil according to claim 19 wherein said cross channels are disposed solely adjacent said leading edge, and are sized in diameter to reduce unsteady-state differential pressure in said fluid between said first and second sides to a greater extent than steady state differential pressure therein.