JP4061635B2 - Turbofan engine and its operation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a turbofan engine. In particular, the present invention relates to a turbofan engine characterized by a structure of a bypass portion.
[0002]
[Prior art]
The structure of a conventional turbofan engine will be described with reference to the drawings. FIG. 4 is a conceptual diagram of a conventional apparatus.
The turbofan engine 1 includes a core engine 10 and a bypass unit 20. The core engine 10 is provided at the center of the turbofan engine 1 and includes a core nacelle 11, a high-pressure compressor 12, a combustor 13, and a high-pressure turbine 14. The high-pressure compressor 12, the combustor 13, and the high-pressure turbine 14 are arranged in order from the front on the axis inside the core nacelle 11. The high-pressure compressor 12 compresses air that enters from the front of the core engine 10. The combustor 13 mixes the compressed air and fuel and burns them to produce combustion gas. The high-pressure turbine 14 expands the combustion gas and extracts rotational force. The high-pressure turbine 14 and the high-pressure compressor 12 are generally connected by a hollow rotating shaft. The coanacell 11 surrounds the high-pressure compressor 12, the combustor 13, and the high-pressure turbine 14, and forms the outer shape of the core engine 10.
[0003]
The bypass unit 20 of the turbofan engine 1 includes a fan nacelle 21, a front fan 22, an outlet guide vane 24, a low pressure compressor 26, and a low pressure turbine 27. The front fan 22 is provided so as to be rotationally driven in front of the core engine 10 and has fan rotor blades 23 provided at a predetermined pitch around the front fan 22. The fan nacelle 21 is a cylindrical duct provided so as to surround the front fan 22 and at least the tip of the core engine 10 in the circumferential direction. The fan nacelle 21 is supported by a plurality of support pillars 25 extending from the outer periphery of the core nacelle 11. A plurality of outlet guide vanes 24 are provided between the core nacelle 11 and the fan nacelle 21 and arranged in the circumferential direction in a cylindrical gap between the fan rotor blade 23 and the support column 25.
The low-pressure compressor 26 is provided between the front fan 22 and the high-pressure compressor 12 and sends low-pressure compressed air to the high-pressure compressor 12. The low pressure turbine 27 is provided behind the high pressure turbine 14 and is driven by the exhaust of the high pressure turbine 14. The low-pressure turbine 27, the front fan 22, and the low-pressure compressor 26 are connected by a drive shaft. The drive shaft passes through the center of the rotation shaft of the core engine.
[0004]
The operation of the conventional turbofan engine will be described. FIG. 5 is an explanatory diagram of a conventional bypass air flow.
The front fan 22 rotates and pushes forward air backward. The air flow is separated into a core engine air flow flowing through the core engine 11 and other bypass air flows.
The core engine air flow is sequentially compressed by the low-pressure compressor 26 and the high-pressure compressor 12, and the fuel is combusted by the combustor 13 to become high-pressure gas. The high-pressure gas expands to cause the high-pressure turbine 14 and the low-pressure turbine 27 to flow. The engine is rotated in order and exhausted from behind the turbofan engine 1.
The bypass air flow becomes a rotational flow when pushed rearward by the fan rotor blade 23, is guided by the outlet guide stationary blade 24, becomes a flow parallel to the axis, passes through the clearance of the support pillar 25, and then enters the fan nacelle. 21 blows backward from the rear part (referred to as a fan nozzle) to generate a propulsive force. In the case of an aircraft high bypass engine, the thrust of the bypass airflow accounts for the majority of the engine propulsion.
[0005]
Next, noise characteristics and aerodynamic characteristics of the bypass portion will be described with reference to the drawings. FIG. 3 is a graph of noise level and aerodynamic efficiency.
The aerodynamic characteristics combined with the fan blades of the front fan and the outlet guide vane greatly affect the efficiency of the turbofan engine 1. In particular, the outlet guide vane 24 plays an important role of changing the rotational flow generated by the fan rotor blade 23 into a linear flow parallel to the axis. The swirling flow remaining in the wake of the exit guide vane 24 is thrown back without generating a propulsive force, resulting in energy loss.
On the other hand, the front rotor fan blade and the outlet guide vane are one of the main noise sources of the turbofan engine. Noise generated by the fan rotor blade 23 and the outlet guide vane 24 is radiated to the surroundings without being blocked from the front and rear openings of the fan nacelle 21.
[0006]
As shown in FIG. 3, noise is reduced when the axial distance between the fan rotor blade and the outlet guide vane is increased. During operation of the turbofan engine, a high pressure b is generated at the leading edge a where the bypass airflow of the outlet guide vane collides. Since the pressure in the gap between the adjacent outlet guide vanes 24 is low, a flow in which different pressures are arranged in the circumferential direction is generated behind the front fan. When the fan blade rotates in a direction orthogonal to the flow behind the front fan as the front fan rotates, a large noise is generated.
In the conventional design, the distance H between the fan rotor blade and the outlet guide stationary blade is determined so that the noise is within the range allowed by the environment. In this case, the distance H between the fan blade 23 and the outlet guide vane 24 is longer than the distance H between the fan blade 23 and the outlet guide vane 24 at which aerodynamic efficiency is maximized. As a result of the reduction of the aerodynamic efficiency of the bypass section, the fuel efficiency has deteriorated.
[0007]
[Problems to be solved by the invention]
In the case of the above-described turbofan engine, there is a tendency for noise to increase due to the higher output of the turbofan engine, and further noise reduction is required from environmental problems. In addition, an improvement in aerodynamic efficiency is required to improve fuel efficiency.
By the way, noise becomes a problem when an airplane is flying low, especially when taking off and landing to reduce the noise in order to improve the environment near the airport. Compared to that, turbofan engine noise is not a problem during high altitude cruises.
On the other hand, most of the aircraft's operating time is cruising at high altitude, and improving the aerodynamic efficiency of the turbofan engine during this time can reduce the overall fuel economy.
[0008]
The present invention has been devised in view of the above-described problems, and aims to provide a turbofan engine that can reduce noise problems and improve fuel efficiency in place of the conventional turbofan engine.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a turbofan engine according to the present invention is a turbofan engine, and includes a core engine in which a compressor, a combustor, and a turbine are arranged in order from the front to an axial center, and a tip of the core engine. A front fan that is rotatably provided around the axis and in which a plurality of fan rotor blades are arranged in a circumferential direction; a fan nacelle that surrounds the front fan and at least the tip of the core engine circumferentially; A plurality of outlet guide vanes arranged in the circumferential direction between the core engine and the fan nacelle, and a gap changing means capable of changing an axial interval between the fan rotor blade and the outlet guide vane, the gap changing means However, it has the movement drive mechanism which enables an exit guide stationary blade to move to an axial direction between a core engine and a fan nacelle .
[0010]
With the configuration of the present invention, the compressor, the combustor, and the turbine are arranged on the core of the core engine, and the front fan in which a plurality of fan blades are arranged in the circumferential direction is centered on the tip of the core engine. The fan nacelle surrounds the front fan and at least the tip of the core engine, and a plurality of outlet guide vanes are arranged circumferentially between the core engine and the fan nacelle. Because the interval changing means can change the axial interval between the fan rotor blade and the outlet guide vane,
Part of the air pushed back by the front fan enters the core engine and is exhausted through the compressor, combustion chamber and turbine, and other air passes between the core engine and the fan nacelle through the outlet guide vane. If the axial space between the fan blade and the outlet guide vane is widened, the aerodynamic interaction between the fan blade and the outlet guide vane is weakened and noise is reduced. If the interval between the outlet guide vanes in the axial direction is narrowed, the rectifying effect of the outlet guide vanes is increased and the air efficiency is improved. Therefore, it is possible to select when noise is desired to be reduced and when aerodynamic efficiency is desired to be improved.
[0011]
Further, since the movable exit guide vanes axially between moving drive mechanism between the core engine and fan nacelle, moving the outlet guide vanes in the forward direction of the shaft the fan blades and outlet guide vanes The air gap between the fan blades and the outlet guide vane becomes wider and the noise is reduced and the noise is reduced. You can select when you want and when you want to improve aerodynamic efficiency.
[0012]
In the turbofan engine according to the present invention, the moving drive mechanism includes a linear guide mechanism that supports the outlet guide vane so as to be movable in the axial direction, and a linear drive mechanism that moves the outlet guide vane in the axial direction. It was.
With the configuration of the present invention, the linear guide mechanism supports the outlet guide vane so as to be axially movable, and the linear drive mechanism moves the outlet guide vane in the axial direction.
The linear drive mechanism can move the exit guide vane supported by the linear guide mechanism in the axial direction, and by operating the linear drive mechanism, it is possible to select when noise is desired to be reduced and when aerodynamic efficiency is desired to be improved.
[0013]
Further, in the turbofan engine according to the present invention, the moving drive mechanism includes a rotation support mechanism that supports the outlet guide vane so as to be tiltable in the axial direction, and a rotation drive mechanism that tilts the outlet guide vane in the axial direction. It was supposed to be.
With the configuration of the present invention, the rotation support mechanism supports the outlet guide vane so as to be tiltable in the axial direction, and the rotation drive mechanism tilts the exit guide vane in the axial direction.
The rotational drive mechanism can tilt the exit guide vane supported by the rotational support mechanism in the axial direction, and by operating the rotational drive mechanism, it is possible to select when noise is desired to be reduced and when aerodynamic efficiency is desired to be improved.
[0014]
Furthermore, a turbofan engine operating method according to the present invention provides the above-described turbofan engine, or a core engine in which a compressor, a combustor, and a turbine are arranged in order on the axis from the front, A front fan that is rotatably provided around the axis at the front end and has a plurality of fan rotor blades arranged in a circumferential direction, and a fan nacelle that surrounds the front fan and at least the front end of the core engine in a circumferential manner And a plurality of outlet guide vanes arranged in a circumferential direction between the core engine and the fan nacelle, and a space changing means capable of changing an axial interval between the fan rotor blade and the outlet guide vane. An engine was prepared, and the axial interval between the fan blade and the exit guide vane was increased during takeoff or landing, and the axial interval between the fan blade and the exit guide vane was narrowed during high altitude cruise. The configuration of the present invention described above increases the axial distance between the fan blade and the exit guide vane during takeoff or landing to reduce noise, and reduces the axial distance between the fan blade and the exit guide vane during high altitude cruise. Since the efficiency can be improved, a turbofan engine with high fuel efficiency can be realized without emitting noise to the environment.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a preferred first embodiment of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.
[0016]
The structure of the turbofan engine according to the first embodiment of the present invention will be described. FIG. 1 is a conceptual diagram of a first embodiment of the present invention.
[0017]
Since the structure of the core engine 10 is the same as the conventional one, the description thereof is omitted.
The bypass unit 20 of the turbofan engine 1 includes a fan nacelle 21, a front fan 22, an outlet guide vane 24, a low-pressure compressor 26, a low-pressure turbine 27, and a moving drive mechanism 30 (corresponding to an interval changing unit). The front fan 22 is provided so as to be rotationally driven in front of the core engine 10 and has fan rotor blades 23 provided at a predetermined pitch around the front fan 22. The fan nacelle 21 is a cylindrical duct provided so as to surround the front fan 22 and at least the tip of the core engine 10 in the circumferential direction. The fan nacelle 21 is supported by a plurality of support pillars 25 extending from the outer periphery of the core nacelle 11. Outlet guide vanes 24 are provided at a predetermined pitch in the circumferential direction in a cylindrical gap between the fan blade 23 and the support column 25 between the core nacelle 11 and the fan nacelle 21.
The low-pressure compressor 26 is provided between the front fan 22 and the high-pressure compressor 12 and sends low-pressure compressed air to the high-pressure compressor 12. The low pressure turbine 27 is provided behind the high pressure turbine 14 and is driven by the exhaust of the high pressure turbine. The low pressure turbine 27, the front fan 22, and the low pressure compressor 26 are connected by a drive shaft. The drive shaft passes through the center of the rotation shaft of the core engine.
[0018]
The moving drive mechanism 30 is a means that can change the axial interval between the fan rotor blade 23 and the outlet guide vane 24, and can move the outlet guide vane 24 in the axial direction between the core nacelle 11 and the fan nacelle 21. is there.
The movement drive mechanism 30 includes a linear guide mechanism 31 and a linear drive mechanism 32. The linear guide mechanism 31 is a mechanism that supports the outlet guide vane 24 so as to be axially movable between the core nacelle 11 and the fan nacelle 21. For example, the linear guide mechanism 31 is a linear guide 31. The linear guide 31 includes a fan linear guide and a core linear guide. The fan linear guide is installed in the fan nacelle and supports the outer peripheral end of the outlet guide vane so as to be movable in the axial direction. The core linear guide is installed in the core nacelle, and supports the inner peripheral end of the outlet guide vane so as to be movable in the axial direction.
The linear drive mechanism 32 is a mechanism that can move the outlet guide vane 24 in the axial direction, and is, for example, a feed screw and an electric motor that drives the feed screw. The linear drive mechanism 32 is arrange | positioned in the fan nacelle 21, for example. When the electric motor rotates the feed screw, the outlet guide vane 24 guided by the linear guide 31 is moved in the axial direction. For example, when the electric motor rotates in the forward direction, the outlet guide vane 24 moves in the forward direction of the shaft, and the interval between the fan rotor blade 23 and the outlet guide vane 24 becomes narrow. When the electric motor is reversed, the outlet guide vane 24 moves in the rearward direction of the shaft, and the distance between the fan rotor blade 23 and the outlet guide vane 24 is widened.
[0019]
Next, the operation of the turbofan engine will be described according to the operation procedure.
At the time of take-off or landing of the airplane, the electric motor is reversed so that the exit guide vane 24 is positioned rearward in the axial direction. Since the gap between the fan blade 23 and the outlet guide vane 24 is wide, the aerodynamic interaction between the fan blade 23 and the outlet guide vane 24 is weakened, and the noise of the bypass unit 20 is reduced. On the other hand, since the rectification effect by the exit guide vane 24 is reduced, the aerodynamic efficiency is lowered, and a lot of fuel is used for a short time of takeoff and landing.
At the time of altitude cruise of the airplane, the electric motor is rotated forward so that the exit guide vane 24 is positioned forward in the axial direction. Since the gap between the fan rotor blade 23 and the outlet guide vane 24 is narrow, the rectifying effect of the outlet guide vane 24 is increased, aerodynamic efficiency is improved, and fuel efficiency is improved. On the other hand, the aerodynamic interaction between the fan blade 23 and the outlet guide vane 24 is weakened, and the noise in the bypass section is increased, but it does not adversely affect the environment because it is cruising altitude.
[0020]
Next, a second preferred embodiment of the present invention will be described with reference to the drawings. In each figure, common portions are denoted by the same reference numerals, and redundant description is omitted.
[0021]
A structure of a turbofan engine according to a second embodiment of the present invention will be described. FIG. 2 is a conceptual diagram of the second embodiment of the present invention.
[0022]
Since the structure of the core engine 10 is the same as the conventional one, the description thereof is omitted.
Since the structure of the bypass unit 20 of the turbofan engine 1 is the same except for the movement drive mechanism, the description of the same part is omitted.
[0023]
The movement drive mechanism 40 is a means capable of changing the axial interval between the fan rotor blade 23 and the outlet guide vane 24 and is capable of moving the outlet guide vane 24 in the axial direction between the core nacelle 11 and the fan nacelle 21. .
The movement drive mechanism 40 includes a rotation support mechanism 41 and a rotation drive mechanism 42. The rotation support mechanism 41 is a mechanism that rotatably supports the outlet guide vane 24 so as to be tiltable in the axial direction between the core nacelle 11 and the fan nacelle 21, for example, a pin support portion. The pin support portion fixedly supports one end of the outlet guide vane 24 on the core nacelle 11 in a rotatable manner.
The rotation drive mechanism 42 is a mechanism that can tilt the outlet guide vane 24 in the axial direction, and is, for example, an electric cylinder. The rod tip of the electric cylinder is connected to the outer end of the outlet guide vane 24. When the electric cylinder is operated, the outlet guide vane 24 that is rotatably fixed to the pin support portion is tilted in the axial direction. For example, when the electric cylinder extends the rod, the outlet guide vane 24 tilts in the forward direction of the shaft, and the distance between the fan rotor blade 23 and the outlet guide vane 24 becomes narrow. When the electric cylinder contracts the rod, the outlet guide vane 24 tilts in the rearward direction of the shaft, and the distance between the fan rotor blade 23 and the outlet guide vane 24 increases.
[0024]
Next, the operation of the turbofan engine will be described according to the operation procedure.
When the airplane takes off and landing, the electric cylinder contracts the rod, and the exit guide vane 25 is tilted rearward in the axial direction. Since the gap between the fan blade 23 and the outlet guide vane 24 is wide, the aerodynamic interaction between the fan blade 23 and the outlet guide vane 24 is weakened, and the noise of the bypass unit 20 is reduced. On the other hand, since the rectification effect by the exit guide vane 24 is reduced, the aerodynamic efficiency is lowered, and a lot of fuel is used for a short time of takeoff and landing.
During altitude cruising of the airplane, the electric cylinder extends the rod and tilts the exit guide vane 24 forward in the axial direction. Since the gap between the fan rotor blade 23 and the outlet guide vane 24 is narrow, the rectifying effect of the outlet guide vane 24 is increased, aerodynamic efficiency is improved, and fuel efficiency is improved. On the other hand, the aerodynamic interaction between the fan blade 23 and the outlet guide vane 24 is weakened, and the noise in the bypass section is increased, but it does not adversely affect the environment because it is cruising altitude.
[0025]
If the turbofan engine of the above-mentioned embodiment is used, it is possible to freely select the interval between the exit guide vanes of the fan rotor blades according to the operational status of the aircraft, and does not emit noise to the environment, and also has good fuel efficiency. You can drive.
Further, the distance between the outlet guide vane and the fan rotor blade can be easily selected by a mechanism for moving the exit guide vane in the axial direction between the core nacelle and the fan nacelle. In addition, the mobile drive mechanism can be set inside the core nacelle or the fan nacelle, and a predetermined effect can be exhibited without affecting the other aerodynamic performance of the turbofan engine.
[0026]
The present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention.
The moving drive mechanism is not limited to the structure described, but may adopt other types. For example, the fan rotor blade may be movable back and forth.
In the drawing, the movement drive mechanism and the rotation drive mechanism are installed in the fan nacelle, but the present invention is not limited to this, and may be placed in the core nacelle, for example.
[0027]
【The invention's effect】
As described above, the turbofan engine of the present invention has the following effects due to its configuration.
Part of the air pushed back by the front fan enters the core engine and is exhausted through the compressor, combustion chamber and turbine, and other air passes between the core engine and the fan nacelle through the outlet guide vane. If the axial space between the fan blade and the outlet guide vane is widened, the aerodynamic interaction between the fan blade and the outlet guide vane is weakened and noise is reduced. If the axial distance between the outlet guide vanes is reduced, the rectifying effect of the outlet guide vanes is increased and the air efficiency is improved, so that it is possible to select when noise is desired to be reduced and when aerodynamic efficiency is desired.
In addition, if the outlet guide vane is moved in the forward direction of the shaft, the axial interval between the fan rotor blade and the outlet guide vane is increased, improving air efficiency. The axial distance between the blade and the exit guide vane becomes wider, reducing the noise, and it is possible to select when noise is desired to be reduced and when aerodynamic efficiency is desired.
Further, the linear drive mechanism can move the exit guide vane supported by the linear guide mechanism in the axial direction, and by operating the linear drive mechanism, it is possible to select when noise is desired to be reduced and when aerodynamic efficiency is desired to be improved.
In addition, the rotational drive mechanism can tilt the outlet guide vane supported by the rotational support mechanism in the axial direction, and by operating the rotational drive mechanism, it is possible to select when noise is desired to be reduced and when aerodynamic efficiency is desired.
Also, during takeoff or landing, widen the axial distance between the fan blade and exit guide vane to reduce noise, and narrow the axial distance between the fan blade and exit guide vane during high altitude cruise to improve aerodynamic efficiency. Therefore, it is possible to realize a turbo fan engine with good fuel efficiency without emitting noise to the environment.
Accordingly, it is possible to provide a turbofan engine that can reduce noise problems and can further improve fuel efficiency, and a driving method thereof.
[0028]
[Brief description of the drawings]
FIG. 1 is a conceptual diagram of a first embodiment of the present invention.
FIG. 2 is a concept of a second embodiment of the present invention.
FIG. 3 is a graph of noise level and aerodynamic efficiency.
FIG. 4 is a conceptual diagram of a conventional apparatus.
FIG. 5 is an explanatory view of a conventional bypass air flow.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Turbofan engine 10 Core engine 11 Coana cell 12 High pressure compressor 13 Combustor 14 High pressure turbine 20 Bypass part 21 Fan nacelle 22 Front fan 23 Fan rotor blade 24 Outlet guide vane 25 Support pillar 26 Low pressure compressor 27 Low pressure turbine 30 Movement Drive mechanism 31 Guide mechanism 32 Linear drive mechanism 40 Movement drive mechanism 41 Rotation support mechanism 42 Rotation drive mechanism

Claims (5)

A turbofan engine, which is a core engine in which a compressor, a combustor, and a turbine are arranged in order on the axis from the front, and a plurality of fan rotor blades provided at the tip of the core engine so as to be rotatable around the axis Are arranged in a circumferential direction between the core engine and the fan nacelle, the front fan arranged circumferentially, the fan nacelle that surrounds the front fan and at least the tip of the core engine circumferentially A plurality of outlet guide vanes, and interval changing means capable of changing an axial interval between the fan rotor blade and the outlet guide vane,
A turbofan engine characterized in that the interval changing means has a moving drive mechanism that allows the outlet guide vane to move in the axial direction between the core engine and the fan nacelle . 2. The turbo according to claim 1 , wherein the moving drive mechanism includes a linear guide mechanism that supports the outlet guide vane so as to be axially movable, and a linear drive mechanism that moves the outlet guide vane in the axial direction. Fan engine. Movement driving mechanism, according to claim 1, characterized in that it comprises a rotary support mechanism for tiltably supporting the outlet guide vanes in the axial direction, and a rotary driving mechanism for tilting the exit guide vanes in the axial direction Turbofan engine. A core engine in which a compressor, a combustor, and a turbine are arranged in order on the axis from the front, and a plurality of fan rotor blades arranged in a circumferential direction at the tip of the core engine so as to be rotatable around the axis. A front fan, a fan nacelle that circumferentially surrounds the front fan and at least the tip of the core engine, and a plurality of outlet guide vanes arranged circumferentially between the core engine and the fan nacelle A turbofan engine comprising a gap changing means capable of changing an axial gap between the fan rotor blade and the outlet guide vane ,
A turbofan engine operating method characterized in that the axial interval between the fan rotor blade and the exit guide vane is widened during takeoff or landing, and the axial interval between the fan rotor blade and the exit guide vane is narrowed during high-air cruise. A turbofan engine according to any one of claims 1 to 3 is prepared, the axial interval between the fan blade and the exit guide vane is widened during takeoff or landing, and the fan blade and the exit guide vane during high altitude cruise. A method of operating a turbofan engine, characterized by narrowing the axial spacing of the blades.

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