ROTOR FOR A GAS TURBINE ENGINE

• US 20150322803A1
• Filed: 04/28/2015
• Published: 11/12/2015
• Est. Priority Date: 05/07/2014
• Status: Active Grant

• Current Assignee: Rolls-Royce Corporation (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce Corporation (Rolls-Royce Holdings Plc)
• Inventors: Fulayter, Roy D., Rivers, Jonathan M., Jordan, Matthew, Molnar, Daniel E.
• Granted Patent: US 9,932,840 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F01D 5/027 Arrangements for balancing for balancing rotating bodies in general F16F15/32; for compensating unbalance G01M1/36
• CPC Class Codes: F01D 5/10 Anti- vibration means specially adapted for radial flow machines or engines F01D5/04
• CPC Class Codes: F01D 5/146 of blades with tandem configuration, split blades or slotted blades
• CPC Class Codes: F01D 5/16 for counteracting blade vibration
• 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: F05D 2220/32 in gas turbines
• 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 rotor for a gas turbine engine includes a central wheel and a plurality of blades that extend outwardly from the central wheel. The blades are non-uniform to reduce flutter and forced response effects induced during operation of a gas turbine engine including the rotor.

Claims

1. A rotor for use in a gas turbine engine, the rotor comprising

a central wheel arranged around a central axis,

a plurality of first frequency blades that extend outward from the central wheel in a radial direction away from the central axis, each of the first frequency blades formed to include at least one first-frequency-modification slot that extends inward in the radial direction from a radially-outward tip of the first frequency blade toward the central wheel, and

a plurality of second frequency blades that extend outward from the central wheel in the radial direction away from the central axis, each of the second frequency blades arranged circumferentially between two first frequency blades and formed to include at least one second-frequency-modification slot, different from the at least one first-frequency-modification slot, that extends inward in the radial direction from a radially-outward tip of the second frequency blade toward the central wheel.

2. The rotor of claim 1, wherein the at least one first-frequency-modification slot and the at least one second-frequency-modification slot are sized and located so that the natural frequency of one low order mode of each of the first frequency blades is not equal to the natural frequency of the same low order mode of each of the second frequency blades and so that the natural frequency of the other low order modes of each of the first frequency blades is substantially equal to the natural frequency of the same low order modes of each of the second frequency blades.

3. The rotor of claim 2, wherein the at least one first-frequency-modification slot and the at least one second-frequency-modification slot are sized and located so that the natural frequency of the first torsional mode of each of the first frequency blades is not equal to the natural frequency of the first torsional mode of each of the second frequency blades.

4. The rotor of claim 2, wherein the at least one first-frequency-modification slot and the at least one second-frequency-modification slot are sized and located so that the natural frequency of the first bend mode of each of the first frequency blades is not equal to the natural frequency of the first bend mode of each of the second frequency blades.

5. The rotor of claim 1, wherein each of the first frequency blades includes a first airfoil having a first aerodynamic profile between a leading edge and a trailing edge of the first airfoil, each of the second frequency blades includes a second airfoil having a second aerodynamic profile between a leading edge and a trailing edge of the second airfoil, and the first aerodynamic profile is substantially the same as the second aerodynamic profile.

6. The rotor of claim 5, wherein each of the first frequency blades and each of the second frequency blades are substantially identical except for the first-frequency-modification slots and the second-frequency-modification slots.

7. The rotor of claim 1, wherein the at least one first-frequency-modification slot of each first frequency blade is spaced apart from a leading edge and from a trailing edge of the first frequency blade.

8. The rotor of claim 7, wherein the at least one second-frequency-modification slot of each second frequency blade is spaced apart from a leading edge and a trailing edge of the second frequency blade.

9. The rotor of claim 1, wherein each of the first frequency blades formed to include two first-frequency-modification slots that are spaced-apart from one another.

10. The rotor of claim 1, wherein the first-frequency-modification slots and the second-frequency-modification slots are blind slots with one open end and one closed end.

11. The rotor of claim 10, wherein the closed ends of the first-frequency-modification slots and the second-frequency-modification slots are contoured.

12. A rotor for use in a gas turbine engine, the rotor comprising

a central wheel arranged around a central axis,

a plurality of first frequency blades that extend outward from the central wheel in a radial direction away from the central axis, each of the first frequency blades formed to include at least one first-frequency-modification slot that extends inward in the radial direction from a radially-outward tip of the first frequency blade toward the central wheel, and

a plurality of second frequency blades that extend outward from the central wheel in the radial direction away from the central axis, each of the second frequency blades arranged circumferentially between two first frequency blades,

wherein the at least one first-frequency-modification slots are sized and located so that the natural frequency of one low order mode of each of the first frequency blades is not equal to the natural frequency of the same low order mode of each of the second frequency blades.

13. The rotor of claim 12, wherein the first-frequency-modification slots are blind slots with one open end and one closed end.

14. The rotor of claim 14, wherein the closed ends of the first-frequency-modification voids are contoured.

15. A rotor for use in a gas turbine engine, the rotor comprising

a central wheel arranged around a central axis,

a plurality of first frequency blades that extend outward from the central wheel in a radial direction away from the central axis, each of the first frequency blades formed to include at least one first-frequency-modification void, and

a plurality of second frequency blades that extend outward from the central wheel in the radial direction away from the central axis, each of the second frequency blades are formed to include at least one second-frequency-modification void, different from the at least one first-frequency-modification void,

wherein the at least one first-frequency-modification void and the at least one second-frequency-modification void are sized and located so that the natural frequency of one low order mode of each of the first frequency blades is not equal to the natural frequency of the same low order mode of each of the second frequency blades.

16. The rotor of claim 15, wherein the at least one first-frequency-modification void and the at least one second-frequency-modification void are sized and located so that the natural frequency of the other low order modes of each of the first frequency blades is substantially equal to the natural frequency of the same low order modes of each of the second frequency blades.

17. The rotor of claim 15, wherein the first-frequency-modification voids are blind slots with one open end and one closed end.

18. The rotor of claim 17, wherein the closed ends of the first-frequency-modification voids are contoured.

19. The rotor of claim 17, wherein the open ends of the first-frequency-modification voids are arranged along tips of the corresponding first frequency blades.

20. The rotor of claim 19, wherein the first frequency blades each include two first-frequency-modification voids.