Apparatus and method for reducing aircraft noise and acoustic fatigue
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
B64F-001/26
B64F-001/00
출원번호
US-0792941
(2004-03-04)
등록번호
US-7484589
(2009-02-03)
발명자
/ 주소
Guo,Yueping
출원인 / 주소
The Boeing Company
대리인 / 주소
Evan Law Group LLC
인용정보
피인용 횟수 :
10인용 특허 :
24
초록▼
An apparatus and method is provided for attenuating aerospace engine noise and unsteady pressure fluctuations associated with high velocity exhaust flows. The apparatus and method reduce acoustic fatigue damage to aerospace vehicles that may be caused by the reflection of exhaust energy from landing
An apparatus and method is provided for attenuating aerospace engine noise and unsteady pressure fluctuations associated with high velocity exhaust flows. The apparatus and method reduce acoustic fatigue damage to aerospace vehicles that may be caused by the reflection of exhaust energy from landing and/or launch platforms. The apparatus includes a passive treatment area associated with the platform operable for reducing the magnitude of the reflected sound waves and unsteady pressure fluctuations from the high velocity exhaust mass flow exiting from the engine. The passive treatment area may include a layer of sound absorptive material, at least one set of roughness elements for disrupting high velocity flow structures. A protective cover may be positioned over the passive treatment area for permitting exhaust flow to pass therethrough while still providing adequate structure to support the weight of the aerospace vehicle.
대표청구항▼
What is claimed: 1. A platform for an aerospace vehicle for reducing unsteady pressure fluctuations of high velocity exhaust mass flow exiting from an aerospace vehicle to reduce fatigue, the platform comprising: a passive treatment area positioned adjacent said platform, passive treatment area ope
What is claimed: 1. A platform for an aerospace vehicle for reducing unsteady pressure fluctuations of high velocity exhaust mass flow exiting from an aerospace vehicle to reduce fatigue, the platform comprising: a passive treatment area positioned adjacent said platform, passive treatment area operable for reducing the unsteady pressure fluctuations generated by the high velocity exhaust mass flow exiting from an exhaust nozzle of said aerospace vehicle and impinging on a surface of said platform and reflecting therefrom in order to reduce the fatigue of the platform, said passive treatment area comprising at least one roughness element for disrupting high velocity structures of said exhaust flow to attenuate said unsteady pressure fluctuations, said passive treatment area further operable to attenuate reflective sound waves, wherein said at least one roughness element comprises at least one of a plurality of elements of varying sizes, elements of irregular shapes, and elements of both varying sizes and irregular shapes. 2. The platform of claim 1, wherein said passive treatment area comprises: a layer of sound absorptive material to provide noise attenuation. 3. The platform of claim 1, wherein the high velocity exhaust mass flow has a jet Mach number within range of 1.3 jet Mach. 4. The platform of claim 1, wherein a layer of sound absorbing material is positioned under said at least one roughness element. 5. The platform of claim 1 further comprising: a cover positioned over said passive treatment area. 6. The platform of claim 5, wherein said cover permits said exhaust flow to pass therethrough and provides adequate structure to support the weight of said aerospace vehicle. 7. The platform of claim 6, wherein said protective cover is formed from a wire mesh faceplate. 8. The platform of claim 2, wherein said sound absorptive material is formed from a honeycomb structure. 9. The platform of claim 2, wherein said sound absorptive material is formed from a composite structure. 10. The platform of claim 1, wherein at least one of the elements is a sphere. 11. The platform of claim 1, wherein at least one of the elements is a cylinder. 12. The platform of claim 1, wherein at least one of the elements is a cube. 13. The platform of claim 1, wherein at least one of the elements is a tetrahedron. 14. The platform of claim 1, wherein said at least one roughness element is formed from one of a plurality of materials. 15. The platform of claim 14, wherein said material is metal. 16. The platform of claim 14, wherein said material is composite. 17. The platform of claim 14, wherein said material is ceramic. 18. A passive treatment area for reducing unsteady pressure fluctuations of high velocity exhaust mass flow exiting from an aerospace vehicle to reduce fatigue, the passive treatment area comprising: means for attenuating the unsteady pressure fluctuations caused by the high velocity exhaust mass flow existing from an exhaust nozzle of the aerospace vehicle to reduce fatigue, the means also attenuating reflected noise, said means comprising: a layer of sound absorptive material to provide noise attenuation; a plurality of roughness elements positioned adjacent said sound absorptive layer, wherein said roughness elements comprise at least one of elements of varying sizes, elements of irregular shapes, and elements of both varying sizes and irregular shapes; and a covering positioned over said passive treatment area operable for permitting sound waves to pass through to said roughness elements and sound absorption material. 19. The passive treatment are of claim 18, wherein the means is for attenuating the unsteady pressure fluctuations caused by the high velocity exhaust mass flow having a jet Mach number within range of 1.3 jet Mach. 20. The passive treatment area of claim 18, wherein said protective covering provides a structural support surface for walking, aircraft landing and take off, and storing equipment thereon. 21. The passive treatment area of claim 18, wherein said roughness elements are operable for disrupting the high velocity exhaust mass flow and dispersing said unsteady pressure fluctuations and said attenuated sound waves. 22. The passive treatment area of claim 18, wherein said cover is formed from a wire mesh faceplate. 23. The passive treatment area of claim 18, wherein said sound absorptive material is formed from a honeycomb structure. 24. The passive treatment area of claim 18, wherein said sound absorptive material is formed from a composite structure. 25. The passive treatment area of claim 18, wherein at least one of the elements is a sphere. 26. The passive treatment area of claim 18, wherein at least one of the elements is a cylinder. 27. The passive treatment area of claim 18, wherein at least one of the elements is a cube. 28. The passive treatment area of claim 18, wherein at least one of the elements is a tetrahedron. 29. The passive treatment area of claim 18, wherein said roughness elements are formed from one of a plurality of materials. 30. The passive treatment area of claim 29, wherein said material is metal. 31. The passive treatment area of claim 29, wherein said material is composite. 32. The passive treatment area of claim 29, wherein said material is ceramic. 33. The passive treatment area of claim 18, wherein said roughness elements are fixed with respect to said sound absorbing layer. 34. The passive treatment area of claim 18, wherein said roughness elements are movable with respect to said sound absorbing layer. 35. The passive treatment area of claim 18, wherein said treatment area is operably associated with a support platform for short takeoff and vertical landing vehicles (STOVL). 36. The passive treatment area of claim 18, wherein said treatment area is operably associated with a rocket launch facility. 37. The passive treatment area of claim 18, wherein said treatment area is operably associated with a support platform for research and test facilities having engine test stands. 38. A method of reducing acoustic fatigue of an aerospace vehicle having high velocity exhaust mass flow exiting from the aerospace vehicle, the method comprising: positioning a passive treatment area in a path of the high velocity exhaust flow exiting from the aerospace vehicle, wherein said passive treatment area comprises at least one roughness element comprising at least one of a plurality of elements of varying sizes, elements of irregular shapes, and elements of both varying sizes and irregular shapes; attenuating unsteady pressure fluctuations generated by said high velocity exhaust flow, and further attenuating sound waves; reflecting said attenuated pressure and sound waves omni-directionally from said passive treatment area; and impinging said attenuated pressure fluctuations on said aerospace vehicle. 39. The method of claim 38, wherein the attenuating step comprises: destroying large scale vertical flow structures; and breaking large scale vortices into incoherent flow. 40. The method of claim 39, wherein the destroying and breaking steps comprise: positioning the at least one roughness element in said flow path of said high velocity exhaust flow for interfering with said flow structure. 41. The method of claim 38, wherein the attenuating step further comprises: absorbing unsteady pressure fluctuations and sound waves from said high velocity exhaust flow. 42. The method of claim 41, wherein the absorbing step further comprises: positioning a layer of acoustical absorptive material in said flow path of said high velocity exhaust flow. 43. A method of attenuating and reflecting unsteady pressure fluctuations and sound waves of an aerospace vehicle having high velocity exhaust mass flow existing from the aerospace vehicle using a passive treatment area located on an aircraft support platform, the method comprising: forming a passive treatment area adjacent said platform, in which said forming further comprises: positioning a layer of sound absorption material in said passive treatment area; embedding at least one roughness element in said sound absorbing layer, wherein said at least one roughness element comprises at least one of a plurality of elements of varying sizes, elements of irregular shapes, and elements of both varying sizes and irregular shapes; and directing high velocity exhaust flow from an engine of the aerospace vehicle toward said passive treatment area. 44. The method of claim 43, wherein the forming step further comprises: covering said treatment area with a cover formed of material operable for permitting high velocity exhaust flow to pass therethrough and of sufficient strength to support the weight of an aircraft. 45. The method of claim 43 wherein the high velocity exhaust mass flow has a jet Mach number within range of 1.3 jet Mach. 46. The method of claim 38 wherein the high velocity exhaust mass flow has a jet Mach number within range of 1.3 jet Mach.
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