PITCH RANGE FOR A VARIABLE PITCH FAN

• US 20170138370A1
• Filed: 11/16/2015
• Published: 05/18/2017
• Est. Priority Date: 11/16/2015
• Status: Active Application

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Breeze-Stringfellow, Andrew, Miller, Brandon Wayne, Zatorski, Darek Tomasz, Kroger, Christopher James, Niergarth, Daniel Alan, Khalid, Syed Arif
• Granted Patent: US 10,288,083 B2
• Time in Patent Office: Days
• CPC Class Codes: B64C 11/30 Blade pitch-changing mechanisms
• CPC Class Codes: F01D 7/00 Rotors with blades adjustable in operation; Control thereof for reversing F01D1/30
• CPC Class Codes: F04D 27/002 by varying geometry within the pumps, e.g. by adjusting vanes
• CPC Class Codes: F04D 29/323 adjustable
• CPC Class Codes: F04D 29/325 for axial flow fans blade mountings F04D29/34, blades F04D29/38
• CPC Class Codes: F04D 29/36 adjustable flexible blades F04D29/382
• CPC Class Codes: F04D 29/522 especially adapted for elastic fluid pumps
• CPC Class Codes: F05D 2220/36 specially adapted for the fan of turbofan engines
• CPC Class Codes: F05D 2260/79 Bearing, support or actuation arrangements therefor
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A variable pitch fan for a propulsion device is provided. The variable pitch fan includes a plurality of fan blades coupled to a disk and a rotatable front hub covering the disk. Each fan blade is rotatable about a pitch axis to vary a pitch of the fan blade. The pitch is variable within a pitch range that is at least about 80° to about 130°. Each fan blade extends radially outward from the disk along a span from a root to a tip. A portion of the span adjacent the root defines a root span region, a portion of the span adjacent the tip defines a tip span region. A solidity of the variable pitch fan is at least 1.0 in the root span region.

Claims

1. A variable pitch fan for a propulsion device, the variable pitch fan comprising:

a plurality of fan blades coupled to a disk, each fan blade of the plurality of fan blades extending radially outward from the disk, each fan blade extending along a span from a root to a tip, a portion of the span adjacent the root defining a root span region, a portion of the span adjacent the tip defining a tip span region,

wherein each fan blade is rotatable about a pitch axis to vary a pitch of the fan blade, the pitch axis extending radially through the fan blade, the pitch variable within a pitch range, the pitch range being at least about 80°

to about 130°

, and

wherein a solidity of the variable pitch fan is at least 1.0 in the root span region.

2. The variable pitch fan of claim 1, further comprising a rotatable front hub covering the disk, wherein a fan hub radius ratio of the variable pitch fan is less than about 0.40.

3. The variable pitch fan of claim 1, wherein the plurality of fan blades comprises at least ten fan blades.

4. The variable pitch fan of claim 1, wherein a fan pressure ratio of the variable pitch fan is less than about 1.5.

5. The variable pitch fan of claim 1, wherein the solidity of the variable pitch fan is less than 1.0 in the tip span region.

6. The variable pitch fan of claim 1, wherein the pitch range corresponds to the variation in pitch between a feather pitch position and a reverse pitch position.

7. The variable pitch fan of claim 1, wherein the pitch range corresponds to the variation in pitch between a flat pitch position and a reverse pitch position.

8. The variable pitch fan of claim 1, wherein the pitch range is about 120°

.

9. The variable pitch fan of claim 1, further comprising a pitch change actuation assembly for varying the pitch of the plurality of fan blades, the actuation assembly comprising:

a scheduling ring rotatable relative to the disk and having a plurality of slots, and

a plurality of linkage arms, each linkage arm operatively coupled to one of the plurality of fan blades and to one of the plurality of slots,

wherein each of the plurality of fan blades rotates according to a blade pitch schedule defined by the slot to which it is operatively coupled, and wherein at least two of the plurality of slots define different blade pitch schedules.

10. The variable pitch fan of claim 1, further comprising a plurality of trunnion mechanisms for coupling each of the plurality of fan blades to the disk, each trunnion mechanism including a bearing having one or more components comprised of a nonferrous material.

11. The variable pitch fan of claim 1, wherein the propulsion device is a gas turbine engine.

12. A variable pitch fan for a propulsion device, the variable pitch fan comprising:

a plurality of fan blades coupled to a disk, each fan blade of the plurality of fan blades extending radially outward from the disk, each fan blade extending along a span from a root to a tip, a portion of the span adjacent the root defining a root span region, a portion of the span adjacent the tip defining a tip span region; and

a rotatable front hub covering the disk,

wherein a solidity of the variable pitch fan is at least 1.0 in the root span region,

wherein a fan pressure ratio of the variable pitch fan is less than about 1.5,

wherein a fan hub radius ratio of the variable pitch fan is less than about 0.40, and

wherein each fan blade is rotatable about a pitch axis to vary a pitch of the fan blade, the pitch axis extending radially through the fan blade, the pitch variable within a pitch range, the pitch range being at least about 80°

to about 130°

.

13. The variable pitch fan of claim 12, wherein the plurality of fan blades comprises at least ten fan blades.

14. The variable pitch fan of claim 13, wherein the solidity is less than 1.0 in the tip span region.

15. The variable pitch fan of claim 14, wherein the propulsion device is a gas turbine engine.

16. The variable pitch fan of claim 14, further comprising a pitch change actuation assembly for varying the pitch of the plurality of fan blades, the actuation assembly comprising:

a scheduling ring rotatable relative to the disk and having a plurality of slots, and

a plurality of linkage arms, each linkage arm operatively coupled to one of the plurality of fan blades and to one of the plurality of slots,

wherein each of the plurality of fan blades rotates according to a blade pitch schedule defined by the slot to which it is operatively coupled, and wherein at least two of the plurality of slots define different blade pitch schedules.

17. The variable pitch fan of claim 14, further comprising a plurality of trunnion mechanisms for coupling each of the plurality of fan blades to the disk, each trunnion mechanism including a bearing having one or more components comprised of a nonferrous material.

18. The variable pitch fan of claim 14, wherein the pitch range is about 120°

.

19. The variable pitch fan of claim 14, wherein the pitch range corresponds to the variation in pitch between a feather pitch position and a reverse pitch position.

20. The variable pitch fan of claim 14, wherein the pitch range corresponds to the variation in pitch between a flat pitch position and a reverse pitch position.