Aircraft Engine Exhaust Nozzle System for Jet Noise Reduction

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(12) United States Patent (lo)

Patent No.: US 8,876,043 B2

Thomas et al. (45) Date of Patent : Nov. 4, 2014

(54) AIRCRAFT ENGINE EXHAUST NOZZLE (56) References Cited SYSTEM FOR JET NOISE REDUCTION U.S. PATENT DOCUMENTS (75) Inventors: Russell H. Thomas, Yorktown, VA (US); 6,820,410 132* 11/2004 Lair .............................. 244/1 N Michael J. Czech, Issaquah, WA (US); 6,969,028 132 * 11/2005 Dun ................................ 244/54 Ronen Elkoby, Los Angeles, CA (US) 2008/0272228 Al * 11/2008 Mengle et al . .................. 244/54 2010/0257865 Al 10/2010 Mengle (73) Assignee: The United States of America as 2011/0155862 Al 6/2011 Mengle represented by the Administrator of OTHER PUBLICATIONS the National Aeronautics and Space Administration, Washington, DC (US) Steven J. Massey, Alaa A. Elmiligui, Craig A. Hunter, Russell H.

Thomas, S. Paul Pao, and Vinod G. Mengle, "Computational Analy- (*) Notice: Subject to any disclaimer, the term of this sis of a Chevron Nozzle Uniquely Tailored for Propulsion Airframe patent is extended or adjusted under 35 Aeroacoustics," 12th AIAA/CEAS Aeroacuostics Conference (27th U.S.C. 154(b) by 0 days.

AIAA Aeroacoustics Conference) May 8-10, 2006, Cambridge, Massachusetts.

(21) Appl. No.: 13/214,469 Craig A. Hunter, Russell H. Thomas, K. S. Abdol-Hamid, S. Paul Pao, Alaa A. Elmligui, and Steven J. Massey, "Computational Analysis of (22) Filed: Aug. 22, 2011 the Flow and Acoustic Effects of Jet-Pylon Interaction," 11th AIAA/ CEAS Aeroacoustics Conference May 23-25, 2005, Monterey, Cali- (65) Prior Publication Data fornia.

US 2012/0061510 Al Mar. 15, 2012 * cited by examiner Related U.S. Application Data Primary Examiner Tien Dinh (60) Provisional application No. 61/375,386, filed on Aug.

Assistant Examiner Richard R Green 20, 2010.

(74) Attorney, Agent, or Firm Robin W. Edwards; Helen M. Galus (51) Int. Cl.

B64D 33104 (2006.01) (57) ABSTRACT B64D 27126 (2006.01) B64D 27100 (2006.01) The aircraft exhaust engine nozzle system includes a fan F02K 1134 (2006.01) nozzle to receive a fan flow from a fan disposed adjacent to an (52) U.S. Cl.

engine disposed above an airframe surface of the aircraft, a CPC ...................................... B64D 33106 (2013.01) core nozzle disposed within the fan nozzle and receiving an USPC ............................................. 244/54; 244/1 N engine core flow, and a pylon structure connected to the core (58) Field of Classification Search nozzle and structurally attached with the airframe surface to USPC ....... 244/1 N, 199.1, 200.1, 204, 204.1, 53 R, secure the engine to the aircraft.

244/54,55 See application file for complete search history. 20 Claims, 5 Drawing Sheets 36Gb ~ ~ 2

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US 8,876,043 B2 Nov. 4, 2014 Sheet 5 of 5 U.S. Patent FIG. 7

US 8,876,043 B2

AIRCRAFT ENGINE EXHAUST NOZZLE which simultaneously can reduce noise through three SYSTEM FOR JET NOISE REDUCTION approaches. The invention can reduce low frequency jet noise, a source which is more difficultto shieldby the aircraft.

CROSS-REFERENCE TO RELATED The invention can redistribute upstream toward the nozzle the APPLICATIONS 5 peak noise sources over a broad frequency range so that they can be more effectively shielded by the aircraft. Furthermore, This application claims the benefit of priority under 35 depending on the embodiment, the invention can redistribute U.S.C. §119 of U.S. Provisional Patent Application No.

jet noise sources in the azimuthal direction so that peak direc- 61/375,386, with a filing date of Aug. 20, 2010, the contents tion of propagation is away from the region of interest.

of which are incorporated by reference in their entirety. In 10 According to one embodiment of the present invention, an addition, this application is co-pending with related patent aircraft exhaust engine nozzle system is provided. The air- applications entitled "ACTIVE AIRCRAFT PYLON NOISE craft exhaust engine nozzle system includes a fan nozzle CONTROL SYSTEM" having U.S. patent application Ser.

configured to receive a fan flow from a fan disposed adjacent No. 13/214,481 and "BLENDED CUTOUT FLAP FOR to an engine disposed above an airframe surface of the air- REDUCTION OF JET-FLAP INTERACTION NOISE" hav- craft, a core nozzle disposed within the fan nozzle and con- ing U.S. patent application Ser. No. 13/214,453 filed on the same day and owned by the same assignee as this patent figured to receive an engine core flow, and a pylon structure application. connected to the core nozzle and structurally attached with the airframe surface to secure the engine to the aircraft.

ORIGIN OF THE INVENTION According to another embodiment of the present invention, 20 an aircraft system includes a fuselage, a wing carried by the The present invention was made in part by an employee of fuselage, an engine formed above the wing; and the above- the United States Government and may be manufactured and mentioned engine exhaust nozzle system formed around the used by or for the Government of the United States of engine.

America for governmental purposes without the payment of Additional features and advantages are realized through any royalties thereon or therefore.

the techniques of the present invention. Other embodiments and aspects of the invention are described in detail herein and BACKGROUND OF THE INVENTION are considered a part of the claimed invention. For a better understanding of the invention with the advantages and the The present invention relates to an aircraft engine exhaust features, refer to the description and to the drawings.

nozzle system, and more specifically, to an aircraft engine exhaust nozzle system reducing jet noise by acoustic shield- BRIEF DESCRIPTION OF THE DRAWINGS ing.

Conventional aircraft typically include propulsion engines, The subject matter, which is regarded as the invention, is which are under the wing or tail surfaces. FIG.1 illustrates an aircraft including a conventional engine exhaust nozzle sys- particularly pointed out and distinctly claimed in the claims at tem. As shown in FIG. 1, the aircraft 100 includes a fuselage 35 the conclusion of the specification. The forgoing and other 101, wings 102, and a propulsion engine system 103. The features, and advantages of the invention are apparent from propulsion engine system 103 is attached underneath the the following detailed description taken in conjunction with wing 102 by a pylon structure 107. Each propulsion engine the accompanying drawings in which: system 103 includes an engine 106 housed in a nacelle 104 FIG. 1 illustrates an aircraft including a conventional and having an inlet 105 and a nozzle system 150. The nozzle 40 engine exhaust nozzle system.

system 150 releases a jet exhaust from the engine into the FIG. 2 illustrates an aircraft including an engine exhaust atmosphere. Primary component noise sources from the nozzle system installed above an aircraft wing that can be engine system 103 include the noise associated with each of implemented within embodiments of the present invention.

the fan, compressor, turbine, combustor, and that noise asso- FIG. 3 is a partial schematic of an engine exhaust nozzle ciated with the high velocity jet exhaust flow. There are many system that can be implemented within embodiments of the methods for reducing the various noise sources from the present invention.

aircraft 100 including those noise sources from the engine FIG. 4 is partial schematic illustrating the effect on engine system 103. One method that has the potential of significant exhaust flow of the pylon structure included in the engine noise reduction includes the use of the aircraft itself as an exhaust nozzle system shown in FIG. 3 that can be imple- acoustic shield for the noise sources associated with the mented within embodiments of the present invention.

engines 106. This approach requires a new configuration of FIG. 5 is a partial schematic of an engine exhaust nozzle aircraft with the engines installed on the upper surface of the system having a plurality of pylon structures that can be wing 102, fuselage 101, or an aircraft that has a hybrid wing implemented within other embodiments of the present inven- and fuselage. Of the engine noise sources, the jet exhaust tion.

noise source is a particular challenge due to the fact that the FIG. 6 is a partial schematic of the engine exhaust nozzle noise sources are in the exhaust flow itself and therefore system shown in FIG. 5 including an additional pylon struc- originate throughout the jet exhaust flow as many as ten ture having a perforated surface that can be implemented engine diameters downstream of the nozzle system 150 exit within embodiments of the present invention.

plane. FIG. 7 is a partial schematic of an engine exhaust nozzle Therefore, it is desirable to have an improved aircraft 60 system having a chevron-formed nozzles that can be imple- nozzle system that is capable of much more noise reduction mented within other embodiments of the present invention.

when installed on the upper surface of the aircraft.

DETAILED DESCRIPTION OF THE INVENTION SUMMARY OF THE INVENTION 65 The present invention is an engine exhaust nozzle system The present invention accomplishes the above stated for an aircraft. Several embodiments of the present invention objective by providing an aircraft engine exhaust system, include the nozzle system as being a separate flow, round or

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chevron-formed nozzle system installed above the wing, tail pylon structure 260a aerodynamically closes out before an surfaces, or fuselage of the aircraft or within a hybrid wing exit plane of the fan nozzle 251, ideally, but could also be body aircraft where the engine is installed above the wing. closed out before the exit of the core nozzle 252. A second Embodiments of the present invention further include the use pylon structure 260b is formed at an upper surface (i.e., a of pylon technology to increase the effectiveness of acoustic 5 crown position) of the fan nozzle 251 opposite the first pylon shielding in the aircraft and modifying the orientation of the structure 260a formed at the airframe surface 201 (e.g., in a nozzle system and the pylon technology to even further keel position). The second pylon structure 260b extends increase the effectiveness of acoustic shielding. downstream longer than the core nozzle exit and similar to the FIG. 2 illustrates an aircraft including an engine exhaust pylon 260 of FIG. 3. According to an embodiment of the nozzle system installed above an aircraft wing that can be io present invention, the first pylon structure 260a and the sec- implemented within embodiments of the present invention. ond pylon structure 260b are formed at approximately 180 As shown in FIG. 2, a hybrid wing-body aircraft 200 is degrees apart however the present invention is not limited provided. The aircraft 200 includes a hybrid wing-body 201 hereto and may vary as needed. That is, the first pylon struc- and a plurality of engines 202. Each engine 202 is housed in ture 260a and the second pylon structure 260b may be ori- a nacelle 204 and includes an inlet 205 and a nozzle system 15 ented at a different angle other than 180 degrees. This orien- 250. The present invention is not limited to a particular num- tation is made to take advantage of the strong azimuthal ber of engines 202 and may vary accordingly. In addition, the directivity created by the second pylon structure 260b to nozzle system 250 may be formed in any manner necessary to better orient peak noise away from directions of interest implement the purpose set forth herein. Additional details (people on the ground, for example). According to an embodi- regarding the nozzle system 250 will now be discussed below 20 ment of the present invention, the first pylon structure 260a with reference to FIGS. 3 through 6. may be fixed since it structurally attaches the engine 202 to FIG. 3 is a partial schematic of an engine exhaust nozzle the airframe surface and the second pylon structure 260b may system that can be implemented within embodiments of the be oriented at an orientation other than 180 degrees from the present invention. As shown in FIG. 3, the nozzle system 250 first pylon structure 260a. The present invention is not limited includes a fan nozzle 251, which directs fan flow away from 25 to any particular type of pylon structure in the keel position an upstream engine along a predetermined path. The nozzle and may be implemented within any type of pylon structure.

system 250 further includes a core nozzle 252 that directs core A pylon structure in the keel position according to another flow away from the engine 202 (as depicted in FIG. 2). The embodiment of the present invention will now be discussed nozzle system 250 further includes a plug 255 at a center of below with reference to FIG. 6.

the core nozzle 252. According to an embodiment of the 30 FIG. 6 is a partial schematic of the engine exhaust nozzle present invention, the nozzle system 250 further includes a system shown in FIG. 5 including a pylon structure having a pylon structure 260 formed at an upper surface (i.e., a crown perforated surface that can be implemented within other portion) of the fan nozzle 251 opposite an airframe surface embodiments of the present invention.

(e.g., the wing body portion 201). The pylon structure 260 As shown in FIG. 6, the nozzle system 250 further includes further controls and direct exhaust airflow in an upstream 35 a pylon structure 360a integrally formed with a lower surface direction away from the nozzle system 250 as discussed of the core nozzle 252. The pylon structure 360a is longer below with reference to FIG. 4. than the pylon structure 260a shown in FIG. 5. The pylon FIG. 4 is partial schematic illustrating the effect on engine structure 360a extends downstream of the exits for the fan and exhaust flow of the pylon structure included in the engine core nozzles 251 and 252 (as depicted in FIG. 7). A pylon exhaust nozzle system shown in FIG. 3 that can be imple- 40 structure 360b is also provided and is the same as pylon mented within embodiments of the present invention. As structure 260b shown in FIG. 5 thus a description thereof is indicated by the arrows A and B shown in FIG. 4, the fan flow being omitted. According to an embodiment of the present (as indicated by Arrow A) and the core flow (as indicated by invention, the pylon structure 360a may include a perforated Arrow B) travel in an downstream direction away from the surface 280 having a plurality of apertures 282 formed to flow nozzle system 250. The aerodynamic shape of the pylon 45 air, for example, therethrough (as indicated by arrows C) as structure 260 alters what would otherwise be an axisymmet- described in the copending commonly assigned application ric and concentric jet exhaust flow. Because of the curvature entitled "Active Pylon Noise Control System" having Ser. No.

of the pylon shelf (as shown in FIG. 3) combined with the 13/214,481 filed on Aug. 20, 2011 and incorporated by ref- wake of the pylon structure 260, the flow of core nozzle 252 erence herein in its entirety.

has a tendency to move off of the centerline of the nozzle 50 The present invention is not limited to the fan nozzle 251 system 250 and into the wake of the pylon structure 260. The and the core nozzle 252 being formed in a round design.

effect of this subtle relative movement between the flows of These nozzles 251 and 252 may be formed with an exit the fan nozzle 251 and the core nozzle 252 can be to redis- perimeter thereof having projections formed thereon. Addi- tribute jet noise sources in the azimuthal direction and, to tional details regarding this embodiment will be discussed some extent intheaxial direction as well. Embodiments ofthe 55 below with reference to FIG. 7.

present invention further include a plurality of pylon struc- FIG. 7 is a partial schematic of an engine exhaust nozzle tures to increase the effectiveness of acoustic shielding of the system having chevron-formed nozzles that can be imple- aircraft 200. Additional details will now be discussed with mented within other embodiments of the present invention.

reference to FIGS. 5 and 6. As shown in FIG. 7, the fan nozzle 251 and/or the core nozzle FIG. 5 is a partial schematic of an engine exhaust nozzle 60 252 may be formed with a plurality of projections 251a and system having a plurality of pylon structures that can be 252a formed at an exit perimeter thereof and extending in an implemented within other embodiments of the present inven- aft direction. The projections 251a and 252a are spaced apart tion. As shown in FIG. 5, the nozzle system includes a plu- from each other by a predetermined gap as shown. According rality of pylon structures 260a and 260b. The first pylon to one embodiment of the present invention, the plurality of structure 260a is connected to the core nozzle 252, and struc- 65 projections 251a and 251a may be circumferentially formed, turally attached with the airframe surface 201, at a keel posi- uniform in size, along the exit perimeter of the fan nozzle 251 tion, to secure the engine 202 to the aircraft 200. The first and/or the core nozzle 252. The uniform, in size, projections

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may be either uniform or varying, circumferentially, in • first pylon structure connected to the core nozzle and immersion into the flow. According to yet another embodi- structurally attached with the airframe surface to secure ment of the present invention, the plurality of projections the engine to the aircraft; and 251a and 252a may be azimuthally varied in size as shown in • second pylon structure formed at an upper surface of the FIG. 7. 5 fan nozzle opposite the first pylon structure formed at the According to yet another embodiment of the present inven- airframe surface, wherein the second pylon structure tion, as further shown in FIG. 7, a number of the projections extends downstream of exits for the fan nozzle and the 251a and 252a on a side of the fan nozzle 251 and the core core nozzle.

nozzle 252, adjacent to the pylon structure 360a are greater in 2. The engine exhaust nozzle system of claim 1, wherein at l0 size than a remainder of the plurality of the projections 251a least one of the fan nozzle and the core nozzle further com- and 252a. prises a plurality of projections formed at an exit perimeter Embodiments of the present invention provide an aircraft thereof and extending in an aft direction, the projections engine exhaust nozzle system capable of redistributing being spaced apart from each other by a predetermined gap.

engine noise sources upstream where they can be shielded by 15 3. The engine exhaust nozzle system of claim 2, wherein a surface of the aircraft. Therefore, the present invention the plurality of projections are circumferentially formed.

provides the advantage of further reducing noise associated 4. The engine exhaust nozzle system of claim 2, wherein with the engine exhaust by increasing the effectiveness of the plurality of projections are azimuthally varying projec- acoustic shielding by the aircraft. Embodiments of the present tions.

invention, further implement an aircraft pylon technology 20 5. The engine exhaust nozzle system of claim 4, wherein a and a method for varying of an orientation of the nozzles of number of the projections on a side of the at least one of the the aircraft nozzle system, and the pylon structures in a crown fan nozzle and the core nozzle, adjacent to the first pylon position and a keel position relative to the airframe surface of structure are greater in size than a remainder of the plurality of the aircraft, to further increase shielding effectiveness.

the proj ections of the at least one of the fan nozzle and the core The present invention is not limited to being used in an 25 nozzle.

aircraft. It may be applied to other industries, for example, a 6. The engine exhaust nozzle system of claim 1, wherein high pressure exhaust duct from a factory, machinery, or other the first pylon structure and the second pylon structure are applications to thereby reduce associated noise.

formed at approximately 180 degrees apart.

The terminology used herein is for the purpose of describ- 7. The engine exhaust nozzle system of claim 1, wherein ing particular embodiments only and is not intended to be 30 the airframe surface comprises at least one of a wing, a tail, a limiting of the invention. As used herein, the singular forms fuselage and a hybrid body-wing configuration of the aircraft.

"a," "an," and "the" are intended to include the plural forms as 8. The engine exhaust nozzle system of claim 1, wherein well, unless the context clearly indicates otherwise. It will be the first pylon structure is integrally formed with a lower further understood that the terms "comprises" and/or "com- surface of the core nozzle and extends downstream of exits for prising," when used in this specification, specify the presence 35 the fan nozzle and the core nozzle.

of stated features, integers, steps, operations, elements, and/ 9. The engine exhaust nozzle system of claim 8, wherein or components, but do not preclude the presence or addition the first pylon structure comprises a perforated surface of one ore more other features, integers, steps, operations, including a plurality of apertures formed to flow air there- element components, and/or groups thereof.

through.

The corresponding structures, materials, acts, and equiva- 40 10. The engine exhaust nozzle system of claim 1, wherein lents of all means or step plus function elements in the claims the first pylon structure is integrally formed with a lower below are intended to include any structure, material, or act surface of the core nozzle and closes out before the exit of the for performing the function in combination with other core nozzle.

claimed elements as specifically claimed. The description of 11. An aircraft system comprising: the present invention has been presented for purposes of 45 a fuselage; illustration and description, but is not intended to be exhaus- a wing carried by the fuselage; tive or limited to the invention in the form disclosed. Many an engine formed above the wing; and modifications and variations will be apparent to those of an engine exhaust nozzle system formed around the ordinary skill in the art without departing from the scope and engine, and comprising: spirit of the invention. The embodiments were chosen and 50 a fan nozzle configured to receive a fan flow from a fan described in order to best explain the principles of the inven- disposed adjacent to an engine disposed above an tion and the practical application, and to enable others of airframe surface of the aircraft; ordinary skill in the art to understand the invention for various a core nozzle disposed within the fan nozzle and config- embodiments with various modifications as are suited to the ured to receive an engine core flow; particular use contemplated. It is therefore to be understood 55 a first pylon structure connected to the core nozzle and that, within the scope of the appended claims, the invention structurally attached with the airframe surface to may be practiced other than as specifically described.

secure the engine to the aircraft; and a second pylon structure formed at an upper surface of What is claimed as new and desired to be secured by the fan nozzle opposite the first pylon structure Letters Patent of the United States is: 60 formed at the airframe surface, wherein the second 1. An engine exhaust nozzle system for an aircraft com- pylon structure extends downstream of exits for the prising: fan nozzle and the core nozzle.

• fan nozzle configured to receive a fan flow from a fan 12. The aircraft system of claim 11, wherein at least one of disposed adjacent to an engine disposed above an air- the fan nozzle and the core nozzle further comprises a plural- frame surface of the aircraft; 65 ity of projections formed at an exit perimeter thereof and • core nozzle disposed within the fan nozzle and configured extending in an aft direction, the projections being spaced to receive an engine core flow; apart from each other by a predetermined gap.

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13. The aircraft system of claim 12, wherein a number of the projections on a side of the at least one of the fan nozzle and the core nozzle, adjacent to the first pylon structure are greater in size than a remainder of the plurality of the projec- tions of the at least one of the fan nozzle and the core nozzle. 5 14. The aircraft system of claim 11, wherein the plurality of projections are circumferentially formed.

15. The aircraft system of claim 11, wherein the plurality of projections are azimuthally varied in size.

16. The aircraft system of claim 11, wherein the airframe io surface comprises at least one of a wing, a tail, and a fuselage of the aircraft.

17. The aircraft system of claim 11, wherein the first pylon structure and the second pylon structure are formed at approximately 180 degrees apart. 15 18. The aircraft system of claim 11, wherein the first pylon structure is integrally formed with a lower surface of the core nozzle and extends downstream of exits of the fan nozzle and the core nozzle.

19. The aircraft system of claim 18, wherein the first pylon 20 structure comprises a perforated surface including a plurality of apertures formed to flow air therethrough.

20. The aircraft system of claim 11, wherein the first pylon structure is integrally formed with a lower surface of the core nozzle and closes out before the exit of the core nozzle. 25