Engine nozzle and turbofan engine incorporating the same

Abstract

The present invention discloses an engine nozzle and a turbofan engine including the same. The engine nozzle includes an outer duct housing and an inner duct housing. The inner duct housing is disposed inside the outer duct housing. The engine nozzle further includes a plurality of noise reduction components, and the plurality of noise reduction components are arranged circumferentially along the tail of the outer duct housing and / or the inner duct housing. The noise reduction component includes a first wedge-shaped member and a second wedge-shaped member that can be controlled to rotate relative to each other. The first wedge-shaped member and the second wedge-shaped member extend out of the tail edge of the outer duct housing and / or the inner duct housing along the jet direction of the airflow. By circumferentially arranging a plurality of noise reduction components composed of two wedge-shaped members that can rotate relative to each other at the tail of the outer duct housing and / or the inner duct housing, the present invention increases the mixing effect of the inner and outer duct airflows or the mixing effect of the outer duct airflow and the outside atmosphere, thereby reducing the jet noise of the engine nozzle.

Description

Technical Field

[0001] The present invention relates to an engine nozzle and a turbofan engine including the same. Background Art

[0002] Noise airworthiness standards refer to the basic criteria stipulated by airworthiness departments for managing the noise levels of aircraft. Since noise affects human health and causes environmental pollution, airworthiness noise mainly focuses on the noise levels of aircraft during takeoff, overflight, and approach conditions. Engine noise is the main noise source of an aircraft, and jet noise, as one of the main noise sources of engine noise, has always been an important topic in the research of engine noise control.

[0003] The formation mechanism of jet noise is generally that when a jet of air flows into a stationary or slower-flowing air stream, the high-speed jet mixes sharply with the relatively stationary surrounding medium, resulting in strong turbulent pulsations in the jet boundary layer. Since the change in momentum in the gas needs to be balanced by a force, in a pure air stream without solid boundaries, the change in this force is caused by a change in pressure. The pressure in the flow region causes density fluctuations, which propagate to the medium outside the flow region, and this is the source of jet noise.

[0004] Increasing the bypass ratio of a turbofan engine can reduce the exhaust velocity of the engine, thereby reducing jet noise. Therefore, existing turbofan engines adopt a large bypass ratio design, significantly reducing jet noise. Currently, a serrated nozzle is a jet noise reduction scheme that is used more frequently. The serrated nozzle reduces jet noise by enhancing the mixing of the high-speed jet and the ambient atmosphere, but its disadvantage is that the serrated design will also cause a reduction in the aerodynamic performance of the nozzle, and the reduction in noise is achieved at the cost of thrust loss. Since jet noise only accounts for the main component when the turbofan engine is in the takeoff and overflight airworthiness conditions, and during the approach airworthiness condition and high-altitude cruise stage of the turbofan engine, fan noise is the main component and the proportion of jet noise is not high. However, the serrated nozzle will continuously cause thrust loss, thereby affecting the performance of the turbofan engine. Therefore, how to reduce jet noise while not affecting or slightly affecting the aerodynamic performance of the engine nozzle during airworthiness conditions and high-altitude cruise stage is a technical problem that needs to be solved in engine jet noise reduction. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the defect that using a serrated nozzle to reduce jet noise in the prior art will cause thrust loss in the airworthiness conditions and high-altitude cruise stage of a turbofan engine, and to provide an engine nozzle and a turbofan engine including the same.

[0006] The present invention solves the above technical problem through the following technical solutions:

[0007] The present invention discloses an engine nozzle. The engine nozzle includes an outer duct housing and an inner duct housing. The inner duct housing is disposed inside the outer duct housing. The engine nozzle further includes a plurality of noise reduction components, and the plurality of noise reduction components are arranged circumferentially along the tail of the outer duct housing and / or the inner duct housing.

[0008] The noise reduction component includes a first wedge and a second wedge that can be controlled to rotate relative to each other. The first wedge and the second wedge extend out of the tail edge of the outer duct housing and / or the inner duct housing along the jet direction of the air flow.

[0009] In this solution, by circumferentially arranging a plurality of noise reduction components composed of two relatively rotatable wedges at the tail of the outer duct housing and / or the inner duct housing, when the two wedges form a certain angle, an air flow pressure difference can be formed between the air flow ejected from the inner duct and the air flow ejected from the outer duct, or an air flow pressure difference can be formed between the air flow ejected from the outer duct and the external atmospheric air flow, increasing the mixing effect of the inner and outer duct air flows or the mixing effect of the outer duct air flow and the external atmosphere, thereby reducing the jet noise of the engine nozzle. The two wedges of the noise reduction component are arranged in a rotatable structure, and the two wedges can be set at a certain angle at different radial positions of the engine nozzle during aircraft takeoff and overflight of the airworthiness conditions as needed to reduce the jet noise. During the approach airworthiness conditions and the high-altitude cruise stage, the two wedges are overlapped without height difference to avoid affecting the aerodynamic performance of the engine nozzle during the airworthiness conditions and the high-altitude cruise stage, and further avoid thrust loss of the turbofan engine.

[0010] Preferably, the first wedge can be controlled to tilt towards the central axis direction of the engine nozzle, and the second wedge can be controlled to tilt away from the central axis direction of the engine nozzle.

[0011] In this solution, by tilting the first wedge towards the central axis direction of the engine nozzle and tilting the second wedge away from the central axis direction of the engine nozzle, the jet air flows at different duct positions of the first wedge and the second wedge can be made, further enhancing the mixing effect of the inner and outer duct air flows.

[0012] Preferably, a plurality of through holes are distributed on the first wedge and / or the second wedge.

[0013] In this solution, by arranging a plurality of through holes on the first wedge and the second wedge, the noise generated enters the small holes and the sound energy can be consumed by friction, enabling the wedge itself to have a certain noise reduction performance and achieving the effect of secondary noise reduction.

[0014] Preferably, the first wedge and the second wedge are arranged at intervals in the circumferential direction of the engine nozzle.

[0015] In this solution, the first wedge-shaped member and the second wedge-shaped member are circumferentially spaced apart from each other in the engine nozzle, so that there is a certain gap between the two wedge-shaped members for the airflow to pass through, enhancing the airflow mixing effect.

[0016] Preferably, the extending end of the second wedge-shaped member is farther away from the central axis of the engine nozzle than the extending end of the first wedge-shaped member. Through holes are distributed on the first wedge-shaped member and the second wedge-shaped member, and the through holes on the first wedge-shaped member face the through holes on the second wedge-shaped member.

[0017] In this solution, after the noise generated by the airflow injection obliquely enters through the through holes on the first wedge-shaped member, it will enter the through holes on the second wedge-shaped member again at a certain refraction angle. Part of this noise is transmitted to the atmosphere through the through holes on the second wedge-shaped member. After two refractions, not only can the noise be attenuated, but also the noise propagation path can be changed to make it propagate upward, so that less noise is received at the ground noise airworthiness observation point.

[0018] Preferably, the extending end of the second wedge-shaped member is filled with a porous medium material.

[0019] In this solution, part of the noise generated by the airflow injection will be absorbed by the porous medium material on the second wedge-shaped member, which can reduce the noise.

[0020] Preferably, along the injection direction of the airflow, the cross-sections of the first wedge-shaped member and the second wedge-shaped member gradually decrease.

[0021] Preferably, the first wedge-shaped member and the second wedge-shaped member rotate relative to each other to form a V-shaped opening, and the opening angle of the V-shaped opening is less than 45°.

[0022] The present invention also discloses a turbofan engine, and the turbofan engine includes the above-mentioned engine nozzle.

[0023] The positive and progressive effects of the present invention are as follows: By circumferentially arranging a plurality of noise reduction components composed of two wedge-shaped parts that can rotate relative to each other at the tail of the outer casing and / or the inner casing, when the two wedge-shaped parts form a certain angle, an air flow pressure difference can be formed between the air flow ejected from the inner duct and the air flow ejected from the outer duct, or an air flow pressure difference can be formed between the air flow ejected from the outer duct and the external atmospheric air flow, increasing the mixing effect of the internal and external duct air flows or the mixing effect of the outer duct air flow and the external atmosphere, thereby reducing the jet noise of the engine nozzle. The two wedge-shaped parts of the noise reduction component are arranged in a rotatable structure, and can be set at a certain angle at different radial positions of the engine nozzle according to needs during aircraft takeoff and overflight of the airworthiness conditions to reduce the jet noise, and the two wedge-shaped parts are made to coincide with no height difference during the approach airworthiness conditions and the high-altitude cruise stage to avoid affecting the aerodynamic performance of the engine nozzle during the airworthiness conditions and the high-altitude cruise stage, and further avoid thrust loss of the turbofan engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 FIG. is a schematic structural view of an engine nozzle in a preferred embodiment of the present invention.

[0025] Figure 2 FIG. is a schematic structural view of a noise reduction component in a preferred embodiment of the present invention.

[0026] Figure 3 FIG. is a schematic diagram of the noise reduction principle of a noise reduction component in a preferred embodiment of the present invention.

[0027] DESCRIPTION OF REFERENCE NUMERALS:

[0028] Outer casing 100

[0029] Outer duct 110

[0030] Inner casing 200

[0031] Inner duct 210

[0032] Noise reduction component 300

[0033] First wedge-shaped part 310

[0034] Second wedge-shaped part 320

[0035] Through hole 330

[0036] Filling layer 340

[0037] Rotating shaft 350 DETAILED DESCRIPTION OF THE INVENTION

[0038] The present invention will be more clearly and completely described below by way of examples in conjunction with the drawings, but the present invention is not limited thereto within the scope of the examples.

[0039] AsFigures 1-3 As shown, an engine nozzle disclosed in this embodiment is for a turbofan engine. The engine nozzle includes an outer duct housing 100 and an inner duct housing 200, and the inner duct housing 200 is disposed inside the outer duct housing 100. The inner cavity of the inner duct housing 200 forms an inner duct 210, and an outer duct 110 is formed between the outer duct housing 100 and the inner duct housing 200. The engine nozzle of this embodiment further includes a plurality of noise reduction components 300. As Figure 1 shown, the plurality of noise reduction components 300 are circumferentially arranged along the tail of the inner duct housing 200. As Figure 2 and Figure 3 shown, the noise reduction component 300 includes a first wedge member 310 and a second wedge member 320 that can be controlled to rotate relative to each other. The first wedge member 310 and the second wedge member 320 extend out of the tail edges of the outer duct housing 100 and / or the inner duct housing 200 along the jet direction of the air flow.

[0040] In this embodiment, by circumferentially arranging a plurality of noise reduction components 300 composed of two wedge members that can rotate relative to each other at the tail of the outer duct housing 100 and / or the inner duct housing 200, when the two wedge members form a certain angle, an air flow pressure difference can be formed between the air flow ejected from the inner duct and the air flow ejected from the outer duct, or an air flow pressure difference can be formed between the air flow ejected from the outer duct and the external atmospheric air flow, increasing the mixing effect of the inner and outer duct air flows or the mixing effect of the outer duct air flow and the external atmosphere, thereby reducing the jet noise of the engine nozzle. The two wedge members of the noise reduction component 300 are arranged in a rotatable structure, and the two wedge members can be arranged at different radial positions of the engine nozzle at a certain angle according to needs during takeoff and overflight of the aircraft to reduce the jet noise. During the approach airworthiness condition and the high-altitude cruise stage, the two wedge members are overlapped without height difference to avoid affecting the aerodynamic performance of the engine nozzle during the airworthiness condition and the high-altitude cruise stage, and further avoid thrust loss of the turbofan engine.

[0041] In other embodiments, a plurality of noise reduction components 300 may also be circumferentially arranged only along the tail of the outer duct housing 100. Or, a plurality of noise reduction components 300 are circumferentially arranged on the tails of both the outer duct housing 100 and the inner duct housing 200. Circumferentially arranging a plurality of noise reduction components 300 along the tail of the outer duct housing 100 can form an air flow pressure difference between the air flow ejected from the outer duct and the external atmospheric air flow, increasing the mixing effect of the outer duct air flow and the external atmosphere, thereby reducing the jet noise of the engine nozzle.

[0042] In this embodiment, the first wedge member 310 can be controlled to tilt towards the central axis direction of the engine nozzle, and the second wedge member 320 can be controlled to tilt away from the central axis direction of the engine nozzle. Tilting the first wedge member 310 towards the central axis direction of the engine nozzle and the second wedge member 320 away from the central axis direction of the engine nozzle can cause the jet airflows at different duct positions of the first wedge member 310 and the second wedge member 320, further enhancing the mixing effect of the inner and outer duct airflows.

[0043] In this embodiment, both the first wedge member 310 and the second wedge member 320 are wedge plate structures, made of metal, plastic or other composite materials, preferably lightweight rigid materials.

[0044] The first wedge member 310 and the second wedge member 320 are installed through a rotating shaft 350. The relative rotation of the first wedge member 310 and the second wedge member 320 is controlled by a rotating mechanism, and the control of the rotating mechanism can be through remote operation. The relative rotation of the first wedge member 310 and the second wedge member 320 can be that only the first wedge member 310 rotates, or only the second wedge member 320 rotates, or the first wedge member 310 and the second wedge member 320 rotate simultaneously.

[0045] The rotating mechanism is a common mechanical structure, as long as it can drive the first wedge member 310 and the second wedge member 320 to have relative rotation, and the specific structure will not be described here.

[0046] Such as Figure 2 and Figure 3 As shown, in this embodiment, a plurality of through holes 330 are distributed on the first wedge member 310 and the second wedge member 320. By providing a plurality of through holes 330 on the first wedge member 310 and the second wedge member 320, the noise generated can enter the small holes and the sound energy can be consumed by friction, enabling the wedge members themselves to have certain noise reduction performance and achieving the effect of secondary noise reduction.

[0047] In some embodiments, only a plurality of through holes 330 are distributed on the first wedge member 310 or the second wedge member 320. Or, no through holes 330 are provided on both wedge members.

[0048] In this embodiment, the first wedge member 310 and the second wedge member 320 are arranged at intervals in the circumferential direction of the engine nozzle. Arranging the first wedge member 310 and the second wedge member 320 at intervals in the circumferential direction of the engine nozzle can provide a certain gap between the two wedge members for the airflow to pass through, enhancing the airflow mixing effect.

[0049] In this embodiment, the extending end of the second wedge member 320 is away from the central axis of the engine nozzle relative to the extending end of the first wedge member 310. The through holes 330 distributed on the first wedge member 310 and the second wedge member 320 are inclined, and the through holes 330 on the first wedge member 310 face the through holes 330 on the second wedge member 320.

[0050] As Figure 3 shown, with the above structure, after the noise generated by the airflow injection obliquely enters through the through holes 330 on the first wedge member 310, it will enter the through holes 330 on the second wedge member 320 again at a certain refraction angle. Part of this noise is transmitted to the atmosphere through the through holes 330 on the second wedge member 320. After two refractions, not only can the noise be attenuated, but also the noise propagation path can be changed to make it propagate upward, so that less noise is received at the ground noise airworthiness observation point.

[0051] As Figure 1 shown, the extending end of the second wedge member 320 has a filling layer 340, and the filling layer 340 is composed of a porous medium material.

[0052] By providing the filling layer 340 of the porous medium material, the noise generated by the airflow injection will be absorbed by the porous medium material on the second wedge member 320, and the noise can be reduced.

[0053] In this embodiment, along the injection direction of the airflow, the cross-sections of the first wedge member 310 and the second wedge member 320 gradually decrease. The first wedge member 310 and the second wedge member 320 rotate relative to each other to form a V-shaped opening, and the opening angle of the V-shaped opening is less than 45°. The best effect is achieved when the opening angle is within 5° - 15°.

[0054] The present invention also discloses a turbofan engine, and the turbofan engine includes the above-mentioned engine nozzle.

[0055] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that this is only for illustration. The protection scope of the present invention is defined by the appended claims. Without departing from the principles and essence of the present invention, those skilled in the art can make various changes or modifications to these embodiments, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. An engine nozzle, the engine nozzle comprising an outer casing and an inner casing, the inner casing being disposed inside the outer casing, characterized in that, The engine nozzle further includes a plurality of noise reduction components, and the plurality of noise reduction components are arranged circumferentially along the tail of the outer casing and / or the inner casing; The noise reduction component includes a first wedge-shaped member and a second wedge-shaped member that can be controlled to rotate relative to each other. The first wedge-shaped member and the second wedge-shaped member extend out of the tail edge of the outer casing and / or the inner casing along the jet direction of the airflow; a plurality of through holes are distributed on the first wedge-shaped member and / or the second wedge-shaped member.

2. The engine nozzle according to claim 1, characterized in that, The first wedge-shaped member can be controlled to tilt towards the central axis direction of the engine nozzle, and the second wedge-shaped member can be controlled to tilt away from the central axis direction of the engine nozzle.

3. The engine nozzle according to claim 1, characterized in that, The first wedge-shaped member and the second wedge-shaped member are arranged at intervals in the circumferential direction of the engine nozzle.

4. The engine nozzle according to claim 3, characterized in that, The extension end of the second wedge-shaped member is farther away from the central axis of the engine nozzle than the extension end of the first wedge-shaped member. Through holes are distributed on the first wedge-shaped member and the second wedge-shaped member, and the through holes on the first wedge-shaped member face the through holes on the second wedge-shaped member.

5. The engine nozzle according to claim 4, characterized in that, The extension end of the second wedge-shaped member is filled with a porous medium material.

6. The engine nozzle according to claim 1, characterized in that, Along the jet direction of the airflow, the cross-sections of the first wedge-shaped member and the second wedge-shaped member both gradually decrease.

7. The engine nozzle according to claim 1, characterized in that The first wedge-shaped member and the second wedge-shaped member rotate relative to each other to form a V-shaped opening, and the opening angle of the V-shaped opening is less than 45°.

8. A turbofan engine, characterized in that, The turbofan engine includes the engine nozzle according to any one of claims 1-7.

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