Suppression of part of the noise from a gas turbine engine

• US 20040088967A1
• Filed: 11/03/2003
• Published: 05/13/2004
• Est. Priority Date: 11/09/2002
• Status: Abandoned Application

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: Strange, Paul J. R, Webster, John R.
• Application Number:
  US10/698,493
• Publication Number:
  US 20040088967A1
• Time in Patent Office: Days
• US Class Current: 60/204
• CPC Class Codes: F02K 1/34 for attenuating noise

Abstract

A method and a system (10) for exhausting gas via a nozzle (19, 21) of a gas turbine engine, for example. The system (10) comprises a nozzle (19, 21) comprising a nozzle body portion (32, 33, 74) defining a nozzle exit (42, 43), characterised in that the nozzle body portion (32, 33, 74) comprises fluid injection means (60), positioned upstream of the exit (42, 43) relative to a fluid flow (F1, F2) created by the operation of the system, for injecting fluid (68) upstream of the exit (42, 43).

Claims

1. A system for exhausting gas via a nozzle, comprising:

a nozzle comprising a nozzle body portion defining a nozzle exit, characterised in that the nozzle body portion comprises fluid injection means, positioned upstream of the exit relative to a fluid flow created by the operation of the system, for injecting fluid upstream of the exit.

2. A system as claimed in claim 1 wherein the nozzle body portion further defines a nozzle flow channel leading to the nozzle exit, wherein the fluid injection means is positioned for injecting fluid within the nozzle flow channel.

3. A system as claimed in claim 1 wherein the nozzle has an exterior surface and the fluid injection means is positioned for injecting fluid at the exterior surface of the nozzle upstream of the exit.

4. A system as claimed in claim 1 wherein the fluid injection means comprises one or more apertures in the outer surface or surfaces of a nozzle body for providing one or more fluid jets.

5. A system as claimed in claim 4 wherein the aperture(s) are positioned upstream of the exit.

6. A system as claimed in claim 4 further comprising means for providing the fluid jet(s) via the aperture(s) during operation of the system.

7. A system as claimed in claim 4 further comprising pulsing means for pulsing the fluid jet(s).

8. A system as claimed in claim 7 wherein the pulsing means pulses the fluid jet(s) at a frequency of Hz and/or kHz.

9. A system as claimed in claim 7, wherein the pulsing means are controllable to vary the frequency at which one or more fluid jets are pulsed.

10. A system as claimed in claim 4, further comprising means for altering the mass flow of the fluid jet(s).

11. A system as claimed in claim 4 wherein the mass flow rate of the fluid jet(s), when operational, is fixed.

12. A system as claimed in claim 4, wherein the apertures have a fixed position and further comprising means for varying the position of fluid jets by providing fluid jets via selected apertures only.

13. A system as claimed in claim 1 wherein the fluid injection means creates microjets of fluid.

14. A system as claimed in claim 1 for use as an aeroplane engine, wherein the nozzle body tapers to an edge at an exit.

15. A system as claimed in claim 1, for use as an aeroplane engine, further comprising means for controlling the injection means to inject fluid during take-off of the aeroplane but not to inject fluid when cruising.

25. Any novel subject matter or combination including novel subject matter disclosed, whether or not within the scope of or relating to the same invention as any of the preceding claims.

16. A method of suppressing part of the noise of a gas exhausted from a nozzle comprising a nozzle body portion defining a nozzle exit, the method comprising the step of:

injecting fluid into a fluid flow created by the operation of the engine while the fluid flow is travelling adjacent the nozzle body portion.

17. A system for exhausting gas via a nozzle, comprising:

a nozzle comprising a nozzle body portion defining a nozzle exit, characterised in that the nozzle body portion comprises output means, positioned upstream of the exit relative to a fluid flow created by the operation of the system, for disturbing a boundary layer between the nozzle body portion and the fluid flow.

18. A system as claimed in claim 17, wherein the output means comprises fluid injection means for injecting fluid upstream of the exit or sound wave production means.

19. A system as claimed in claim 18, wherein the fluid injection means comprises a plurality of apertures for providing fluid microjets.

20. A system as claimed in claim 19, further comprising pulse means for pulsing the fluid microjets.

21. A method of suppressing part of the noise of a gas exhausted from a nozzle comprising a nozzle body portion defining a nozzle exit, the method comprising the step of:

disturbing a boundary layer between the nozzle body portion and a fluid flow created by the operation of the system.

22. A system for exhausting gas via a nozzle, comprising:

a nozzle, the nozzle comprising a nozzle body portion comprising fluid injection means for injecting fluid characterised in that the system further comprises control means for controlling the fluid injection means to inject fluid during a first phase of operation and to not inject fluid during a second phase of operation.

23. A system as claimed in claim 22 wherein the first phase is at least a part of the take-off phase of an aeroplane flight.

24. A system as claimed in claim 22 wherein the second phase is at least a part of the cruising phase of an aeroplane plane flight.