Active Aircraft Pylon Noise Control System

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(12) United States Patent (io) Patent No.: US 9,022,311 B2

Thomas et al. (45 ) Date of Patent :

May 5, 2015

(54) ACTIVE AIRCRAFT PYLON NOISE (56) References Cited CONTROL SYSTEM U.S. PATENT DOCUMENTS (75) Inventors: Russell H. Thomas, Yorktown, VA (US); 6,820,410 132 11/2004 Lair Michael J Czech, Issaquah, WA (US); 2008/0272228 Al 11/2008 Mengle et al.

Alaa A. Elmiligui, Virginia Beach, VA 2010/0257865 Al 10/2010 Mengle 2011/0000181 Al 1/2011 Oishi et al ...................... 60/39.5 (US) 2011/0155862 Al 6/2011 Mengle OT HER PU BLICATIONS (73) Assignee: The United States of America as represented by the Administrator of Steven J. Massey, Alaa A. Elmiligm, Craig A. Hunter, Russell H.

the National Aeronautics and Space Thomas, S. Paul Pao, and Vinod G. Mengle, "Computational Analy- Administration, Washington, DC (US) sis of a Chevron Nozzle Uniquely Tailored for Propulsion Airframe Aeroacoustics," 12thAIAA/CEAS Aeroacuoustics Conference (27th AIAA Aeroacoustics Conference) May 8-10, 2006, Cambridge, (*) Notice: Subject to any disclaimer, the term of this Massachusetts.

patent is extended or adjusted under 35 Craig A. Hunter, Russell H. Thomas, K. S. Abdol-Hamid, S. Paul Pao, U.S.C. 154(b) by 529 days.

AlaaA. Elmiligm, and Steven J. Massey, "Computational Analysis of the Flow and Acoustic Effects of Jet-Pylon Interaction," 11th AIAA/ (21) Appl. No.: 13/214,481 CEAS Aeroacoustics Conference May 23-25, 2005, Monterey, Cali- fornia.

(22) Filed: Aug. 22, 2011 * cited by examiner (65) Prior Publication Data Primary Examiner Valentina Xavier (74) Attorney, Agent, or Firm Robin W. Edwards; Helen US 2012/0068011 Al Mar. 22, 2012 M. Galus (57) ABSTRACT (51) Int. Cl.

B64C 1140 (2006.01) An active pylon noise control system for an aircraft includes B64C 23100 (2006.01) a pylon structure connecting an engine system with an air- B64D 27118 (2006.01) frame surface of the aircraft and having at least one aperture B64C 7102 (2006.01) to supply a gas or fluid therethrough, an intake portion B64C 21108 (2006.01) attached to the pylon structure to intake a gas or fluid, a regulator connected with the intake portion via a plurality of (52) U.S. Cl.

pipes, to regulate a pressure of the gas or fluid, a plenum CPC . B64C 7102 (2013.01); B64D 27118 (2013.01); chamber formed within the pylon structure and connected B64C 2230104 (2013.01); B64C 2230114 with the regulator, and configured to receive the gas or fluid as (2013.01); Y02T 50/166 (2013.01); B64C regulated by the regulator, and a plurality of injectors in 2230106 (2013.01); B64C 2230116 (2013.01); communication with the plenum chamber to actively inject B64C 21108 (2013.01) the gas or fluid through the plurality of apertures of the pylon (58) Field of Classification Search structure.

USPC ...................................... 244/1 N, 54; 60/39.5 See application file for complete search history.

12 Claims, 6 Drawing Sheets 300- 00000001 Dl~ n 351 3522 '04

US 9,022,311 B2 Sheet 1 of 6 May 5, 2015

U.S. Patent

1110--, v ~ 103 `/

FIG. 1

(Prior Art)

Patent Sheet 2 of 6 9,022,311 B2 U.S. May 5, 2015 US to FIG, 2 (Prior Art)

Patent 9,022,311 B2 U.S. May 5, 2015 Sheet 3 of 6 US M

Sheet 4 of 6 US 9,022,311 B2 U.S. Patent May 5, 2015 402 404

Regulator

Intake andlor pump

Portion

Plenum

Chamber

Switch

Injector Injector

c FIG. 4

Patent 9,022,311 B2 U.S. May 5, 2015 Sheet 5 of 6 US FIG. 5

US 9,022,311 B2 U.S. Patent May 5, 2015 Sheet 6 of 6 Inputting a gas or fluid in the pylon structure Controlling a pressure of a flow of the gas or fluid input Selectively injecting the gas or fluid through at least one aperture formed on the pylon structure FIG. 6

US 9,022,311 B2

ACTIVE AIRCRAFT PYLON NOISE system and the public. There are several factors that contrib- CONTROL SYSTEM ute to overall aircraft noise. These factors include the differ- ent operations (e.g., takeoff, approach, and cruise) of the ORIGIN OF THE INVENTION aircraft 100. The level of noise may vary depending on the 5 operation. For example, jet noise is typically higher during a The present invention was made in part by an employee of takeoff operation. Further, shock cell noise may occur during the United States Government and may be manufactured and a cruising operation of the aircraft 100 which may affect the used by or for the Government of the United States of passengers and crew aboard the aircraft 100. In addition, the America for governmental purposes without the payment of interaction of the engine jet exhaust with a deployed high-lift any royalties thereon or therefore. device (e.g., flaps 105 and 119, or ailerons 113 and 117) is another source of noise and is accentuated based upon a CROSS-REFERENCE TO RELATED configuration of the propulsion engine system 103.

APPLICATIONS Therefore, it is desirable to have an aircraft pylon noise control system capable of reducing jet-flap interaction noise This application claims the benefit of priority under 35 15 and redistributing noise sources within the aircraft to enhance U.S.C. §119 of U.S. Provisional Patent Application No.

acoustic shielding by the aircraft.

61/375,382, with a filing date of Aug. 20, 2010, the contents of which are incorporated by reference in their entirety. In SUMMARY OF THE INVENTION addition, this application is co-pending with related patent applications entitled `AIRCRAFT ENGINE EXHAUST 20 According to an embodiment of the present invention, an NOZZLE SYSTEM FOR JET NOISE REDUCTION" and active pylon noise system is provided. An active pylon noise "BLENDED CUTOUT FLAP FOR REDUCTION OF JET- control system for an aircraft includes a pylon structure con- FLAP INTERACTION NOISE" filed on the same day and necting an engine system with an airframe surface of the owned by the same assignee as this patent application. aircraft and having at least one aperture to supply a gas or fluid therethrough, an intake portion attached to the pylon structure BACKGROUND OF THE INVENTION to intake a gas or fluid, a regulator connected with the intake portion via a plurality of pipes, to regulate a pressure of the The present invention relates to an aircraft pylon noise gas or fluid, a plenum chamber formed within the pylon control system, and more specifically, to an active aircraft structure and connected with the regulator, and configured to pylon noise control system capable of reducing the overall 30 receive the gas or fluid as regulated by the regulator, and a noise of an aircraft by reducing noise associated with jet-flap plurality of injectors in communication with the plenum interaction where the engine exhaust flow interacts with a chamber to actively inject the gas or fluid through the plural- trailing edge device (e.g., flaps or ailerons) or by redistribut- ity of apertures of the pylon structure.

ing noise sources and reducing jet source noise or by enhanc- According to other embodiments of the present invention, ing acoustic shielding of jet noise by an airframe surface of 35 an aircraft system includes the above-mentioned active pylon the aircraft.

noise control system and a method for the same is also pro- FIGS. 1 and 2 illustrate a conventional aircraft and an vided.

aircraft wing of the aircraft, respectively. As shown in FIG. 1, Additional features and advantages are realized through the aircraft 100 includes a fuselage 101, wings 102, and a the techniques of the present invention. Other embodiments propulsion engine system 103. The propulsion engine system 40 and aspects of the invention are described in detail herein and 103 includes engines 106 at a lower surface of the wings 102.

are considered a part of the claimed invention. For a better Each engine 106 is housed in a nacelle 104 having an inlet 105 understanding of the invention with the advantages and the and a nozzle system 150 attached to the wing 102 via a pylon features, refer to the description and to the drawings.

structure 108. FIG. 2 shows high-lift devices included on the wing 102. The high lift devices may include deployable slats 45 BRIEF DESCRIPTION OF THE DRAWINGS 111 positioned toward a leading edge of the wing 102 and multiple trailing edge devices positioned toward a trailing The subject matter, which is regarded as the invention, is edge of the wing 102. The trailing edge devices include an particularly pointed out and distinctly claimed in the claims at outboard aileron 113, an outboard flap 105, an inboard aileron the conclusion of the specification. The forgoing and other 117, and an inboard flap 119. The outboard and inboard 50 features, and advantages of the invention are apparent from ailerons 113 and 117 are typically used for roll control of the the following detailed description taken in conjunction with aircraft 100 while the outboard and inboard flaps 105 and 119 the accompanying drawings in which: are used to control the lift of the aircraft 100 during takeoff FIG. 1 illustrates a conventional aircraft.

and landing operations. The ailerons 113 and 117 are hinged FIG. 2 illustrates a wing of the conventional aircraft shown devices that are un-gapped when in their deployed position. 55 in FIG. 1.

When the flaps 105 and 119 are deployed, they rotate and FIG. 3 is a partial schematic of a propulsion engine system move in an aft direction to open a gap relative to the wing 102 that can be implemented within embodiments of the present (as depicted by arrows 121 and 123). Since the motion path of invention.

the inboard flap 119 (as indicated by arrow 121) converges FIG. 4 is a diagram illustrating an active pylon noise con- with the motion path of the outboard flap 105, the inboard 60 trol system that can be implemented within embodiments of aileron 117 located between the flaps 105 and 119 may be a the present invention.

hinged device and does not move aft when deployed (as FIG. 5 is a schematic illustrating a heat shield formed on a indicated by arrow 125). When a flaperon is used in place of pylon structure that can be implemented within other embodi- the inboard aileron 117, it moves in an aft direction unlike the ments of the present invention.

inboard aileron 117. 65 FIG. 6 is a flowchart illustrating a method for injecting a Aircraft noise continues to have a significant negative gas or fluid into a pylon structure of an aircraft that can be impact on the environment, e.g., on the air transportation implemented within embodiments of the present invention.

US 9,022,311 B2

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DETAILED DESCRIPTION OF THE INVENTION may create an even higher pressure and also may control the pressure through the noise control system 400.

The present invention describes an active pylon noise con- A plenum chamber 406 is also formed within the pylon trol system that can be implemented within existing pylon structure 360 and is connected withthe regulator and/orpump structures or new pylon structures of an aircraft. The active 5 404, and configured to receive the gas or fluid as regulated by pylon noise control system of the present invention provides the regulator and/or pump 404. The plenum chamber 406 is • method for actively injecting gas or fluid such as air through connected with and communicates with a plurality of injec- • pylon structure of the aircraft. Details regarding the active tors 408 configured to actively inject the gas or fluid through pylon noise control system and the method will be discussed the apertures 365. The plenum chamber 406 distributes the below with reference to FIGS. 3 through 6. gas or fluid so that it can be delivered to the injectors 408 in a FIG. 3 is a partial schematic of a propulsion engine system uniform flow profile and pressure. The gas or fluid is then that can be implemented within embodiments of the present release from the injectors (Arrow Q.

invention. As shown in FIG. 3, a portion 300 of an aircraft is According to an embodiment of the present invention, a provided. A wing 302 includes a propulsion engine system 15 switch 410 is provided and attached to the plurality of injec- 303 attached thereto. The engine system 303 includes an tors 408 to selectively direct the gas or fluid to at least one of engine (not shown) housed in a nacelle 304, and a nozzle the injectors 408.

system 350 for releasing exhaust flow from the engine. The According to an embodiment of the present invention, the nozzle system 350 includes a fan nozzle 351 configured to aperture 365 is formed within a shelf surface or a trailing edge receive a fan flow from a fan (not shown) disposed adjacent to 20 surface of the pylon structure 360. The gas or fluid is therefore an engine disposed above an airframe surface (e.g., the wing injected through the shelf surface or the trailing edge surface 302) of the aircraft and a core nozzle 352 disposed within the as indicated by the arrows A and B shown in FIG. 3. An fan nozzle 351 and configured to receive an engine core flow. injection angle of the gas or fluid injected from the injectors The nozzle system 350 further includes a plug 355 formed 408 may be angled perpendicular to the exhaust flow direc- within the core nozzle 352. According to an embodiment of 25 tion or angled in a downstream direction or at an angle ther- the present invention, a pylon structure 360 is connected to ebetween (Arrows B) if injected from the shelf surface or a the fan nozzle 351 and structurally attached with the wing 302 heat shield of the pylon structure 360, or a trailing edge to secure the engine system 303 to the aircraft. In this embodi- direction (i.e., a downstream direction) (Arrow A) if injected ment of the present invention, the engine system 303 is from the trailing edge surface of the pylon structure 360. The attached to a lower surface of the wing 302, however the 30 injection of the gas or fluid alters a trajectory of a flow of the present invention is not limited hereto and the engine system core nozzle 352 and a flow of the fan nozzle 351, and impacts 303 may be attached to an upper surface of the wing, the tail, a mixing process of the flow of the core nozzle 352 and the the fuselage or to an upper surface of a hybrid body-wing flow of the fan nozzle 351. At cruise conditions, the invention configuration of an aircraft. The pylon noise control system of can be used by adjusting the regulator and/or pump to inject the present invention supplies a gas or fluid through the pylon 35 very small levels of flow from the shelf, microblowing, in structure 360 of the aircraft. According to an embodiment of order to reduce drag associated with high-speed core flow the present invention, the fluid may be air or a gas mixture, scrubbing over the shelf surface.

water or other liquid. Details regarding the active pylon noise According to an embodiment of the present invention, control system will now be discussed below with reference to when an injector 408 is formed at the trailing edge surface of FIGS. 3 through 5. 40 the pylon structure 360, the wake of the pylon structure 360 is FIG. 4 is a diagram illustrating an active pylon noise con- affected by injecting a higher pressure and velocity of air trol system that can be implemented within embodiments of through the respective injector 408 (arrow A depicted in FIG.

the present invention. 3). Further, since the mixing of the flow of the core nozzle 352 As shown in FIG. 4, the active pylon noise control system and of the fan nozzle 351 is changed, the strength and distri- 400 includes the pylon structure 360 which comprises at least 45 bution of the aircraft noise sources is altered. The strengths of one aperture 365 (i.e., a slot or a plurality of apertures) to the aircraft noise sources are reduced and move upstream supply a gas or fluid therethrough. The noise control system instead of downstream. Further, the overall trajectory of the 400 further includes an intake portion 402 attached to the aircraft is altered away from the high-lift devices (i.e., the pylon structure 360 and configured to intake a gas or fluid. flaps or ailerons) included on the wing 302. The present According to an embodiment of the present invention, the 50 invention is not limited to the apertures 365 being formed on intake portion 402 may be formed on at least one junction a shelf surface or trailing edge surface of the pylon structure between the nacelle 304 and the pylon structure 360, on the 360. According to an embodiment of the present invention, side, upper surface or leading edge of the pylon structure 360, the apertures 365 may be formed on a heat shield of the pylon on the side or leading edge of the pylon structure that is structure. A detailed description will be discussed below with interior (e.g., an upper bifurcator, not shown) to the nacelle 55 reference to FIG. 5 304, or on an inner surface of the nacelle 304. The intake of FIG. 5 is a schematic illustrating a heat shield formed on fluid from these surfaces can also result in drag reduction, an the shelf of a pylon structure that can be implemented within additional desirable aspect of the present invention. other embodiments of the present invention. According to The noise control system 400 further includes a regulator another embodiment of the present invention, the pylon struc- and/or pump 404 connected with the intake portion 402 via a 60 ture 360 includes a heat shield 362. As shown in FIG. 5, an pipe(s) 405, and is configured to regulate a pressure of the gas inner surface of the heat shield facing the core nozzle 352 or fluid received from the intake portion 402. According to includes a perforated surface that includes a plurality of aper- other embodiments of the present invention, a regulator and/ tures 365. The gas or fluid is therefore injected through the or a pump is provided to control the pressure of the gas or perforated surface.

fluid. Thus, the noise control system 400 may operate pas- 65 FIG. 6 is a flowchart illustrating a method for injecting a sively based on a higher pressure of gas or fluid from the gas or fluid into a pylon structure of an aircraft that can be intake flowing through the pipes 405 and where the pump implemented within embodiments of the present invention.

US 9,022,311 B2

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As shown in FIG. 6, at operation 600, a gas or fluid is input 2. The active pylon noise control system of claim 1, further into the pylon structure 360 via the intake portion 402. From comprising: operation 600, the process continues to operation 610, where a switch attached to the plurality of injectors to selectively a pressure of the flow of the gas or fluid input in the pylon direct the gas or fluid to at least one injector of the structure 360 is controlled via the regulator and/or pump 404.

5 plurality of injectors.

The gas or fluid is selectively injected, at operation 615, 3. The active pylon noise control system of claim 1, through at least one aperture 365 formed on the pylon struc- wherein the at least one aperture is formed within a shelf ture 360, via the switch 410. This selection may involve surface or a trailing edge surface of the pylon structure such injecting the gas or fluid through the shelf surface or the that the gas or fluid is injected through the shelf surface or the trailing edge surface of the pylon structure 360. 10 trailing edge surface.

Embodiments of the present invention provide an active 4. The active pylon noise control system of claim 3, pylon noise control system that is capable of reducing overall wherein an injection angle of the gas or fluid injected from the aircraft noise by injecting air, for example, through a pylon plurality of injectors is at an angle perpendicular to an exhaust structure attaching the engine system to the airframe surface 15 flow direction or in a downstream direction or at an angle of the aircraft. In this system, the flow rate of the air is therebetween if injected from the shelf surface or a heat shield adjustable at different operating points of the aircraft, and the of the pylon structure, or in a downstream direction if injected system operates at relatively low pressures, typically less than from the trailing edge surface of the pylon structure.

approximately two atmospheres of pressure. The system is 5. The active noise control system of claim 4, wherein the applicable to different aircraft configurations and may be intake portion is formed on at least one junction between a implemented within existing pylon structures. 20 The terminology used herein is for the purpose of describ- nacelle housing the engine system and the pylon structure, on ing particular embodiments only and is not intended to be a side surface, upper surface or leading edge surface of the limiting of the invention. As used herein, the singular forms pylon structure, on a side surface or leading edge surface of "a," "an," and "the" are intended to include the plural forms as the pylon structure which is interior to the nacelle or on an well, unless the context clearly indicates otherwise. It will be 25 inner surface of the nacelle.

further understood that the terms "comprises" and/or "com- 6. The active noise control system of claim 5, wherein the prising," when used in this specification, specify the presence pylon further comprises a heat shield, wherein an inner sur- of stated features, integers, steps, operations, elements, and/ face of the heat shield facing the core nozzle comprises the at or components, but do not preclude the presence or addition least one aperture.

of one or more other features, integers, steps, operations, so 7. An aircraft system comprising: element components, and/or groups thereof. • fuselage; The corresponding structures, materials, acts, and equiva- • wing carried by the fuselage; lents of all means or step plus function elements in the claims an engine system comprising: below are intended to include any structure, material, or act an engine formed above or beneath the wing, for performing the function in combination with other 35 a nacelle housing the engine therein, and claimed elements as specifically claimed. The description of an engine exhaust nozzle system formed around the the present invention has been presented for purposes of engine, and comprising: illustration and description, but is not intended to be exhaus- • fan nozzle configured to receive a fan flow from a fan tive or limited to the invention in the form disclosed. Many disposed adjacent to an engine disposed above an modifications and variations will be apparent to those of 40 airframe surface of the aircraft; ordinary skill in the art without departing from the scope and • core nozzle disposed within the fan nozzle and config- spirit of the invention. The embodiment was chosen and ured to receive an Engine core flow; described in order to best explain the principles of the inven- a pylon structure connected to the fan nozzle and structur- tion and the practical application, and to enable others of ally attached with an airframe surface to secure the ordinary skill in the art to understand the invention for various 45 engine system to the aircraft; and embodiments with various modifications as are suited to the an active pylon noise control system comprising: particular use contemplated. It is therefore to be understood at least one aperture formed on the pylon structure to that, within the scope of the appended claims, the invention supply a gas or fluid therethrough; may be practiced other than as specifically described. an intake portion attached to the pylon structure and What is claimed as new and desired to be secured by 50 configured to intake the gas or fluid; Letters Patent of the United States is: a regulator connected with the intake portion via a plu- 1. An active pylon noise control system for an aircraft, rality of pipes and configured to regulate a pressure of comprising: the gas or fluid; a pylon structure connecting an engine system with an a plenum chamber formed within the pylon structure and airframe surface of the aircraft and comprising at least 55 connected with the regulator and configured to one aperture to supply a gas or fluid therethrough; receive the gas or fluid as regulated by the regulator; an intake portion attached to the pylon structure and con- a plurality of injectors in communication with the ple- figured to intake a gas or fluid; num chamber, and configured to actively inject the • regulator connected with the intake portion via a plurality gas or fluid through the at least one aperture of the of pipes, and configured to regulate a pressure of the gas 60 pylon structure.

or fluid; 8. The aircraft system of claim 7, wherein the active pylon • plenum chamber formed within the pylon structure and noise control system further comprises: connected with the regulator, and configured to receive a switch attached to the plurality of injectors to selectively the gas or fluid as regulated by the regulator; direct the gas or fluid to at least one injector of the • plurality of injectors in communication with the plenum 65 plurality of injectors.

chamber and configured to actively inject the gas or fluid 9. The aircraft system of claim 7, wherein the at least one through the plurality of apertures of the pylon structure. aperture is formed within a shelf surface or a trailing edge

US 9,022,311 B2

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surface of the pylon structure such that the gas or fluid is injected through the shelf surface or the trailing edge surface.

10. The aircraft system of claim 9, wherein an injection angle of the gas or fluid injected from the plurality of injectors is at an angle perpendicular to an exhaust flow direction or in s a downstream direction or at an angle therebetween if injected from the shelf surface or a heat shield of the pylon structure, or in a downstream direction if injected from the trailing edge surface of the pylon structure.

11. The aircraft system of claim 7, wherein the intake io portion is formed on at least one junction between the nacelle and the pylon structure, on a side surface, upper surface or leading edge surface of the pylon structure, on a side surface or leading edge surface of the pylon structure which is interior to the nacelle, or on an inner surface of the nacelle. is 12. The aircraft system of claim 7, wherein the pylon further comprises a heat shield, wherein an inner surface of the heat shield facing the core nozzle comprises the at least one aperture.

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