Patent Application
20240309886
The present disclosure relates generally to gas turbine engines, and more specifically to fan assemblies of gas turbine engines.
Gas turbine engines are used to power aircraft, watercraft, power generators, and the like. Gas turbine engines typically include an engine core having a compressor, a combustor, and a turbine. The compressor compresses air drawn into the engine and delivers high pressure air to the combustor. In the combustor, fuel is mixed with the high pressure air and is ignited. Products of the combustion reaction in the combustor are directed into the turbine where work is extracted to drive the compressor and, sometimes, an output shaft. Left-over products of the combustion are exhausted out of the turbine and may provide thrust in some applications.
Gas turbine engines also typically include a fan positioned within an inlet duct of the gas turbine engine. The fan includes rotating blades that that force air into the compressor section of the engine, as well as potentially providing additional thrust via forcing air around the engine core through bypass ducts. The fan blades may experience various operability issues due to factors such as variations in the intake airflow and pressure fluctuations within the inlet and the bypass ducts.
The present disclosure may comprise one or more of the following features and combinations thereof.
A fan assembly for a gas turbine engine according to the present disclosure includes a fan duct arranged circumferentially around a central axis, a fan comprising a plurality of fan blades that extend radially outward relative to the central axis and that are adapted to rotate about the central axis to force fan exit air toward an aft end of the fan duct, and an outlet guide vane assembly located in the fan duct axially downstream of the fan and configured to adjust a direction of incoming fan exit air received from the plurality of fan blades and reduce incidence between the outlet guide vane assembly and the fan exit air.
The outlet guide vane assembly includes a first variable leading edge outlet guide vane that extends radially relative to the central axis and includes a leading edge portion and a fixed aft portion, the leading edge portion including a first tip segment configured to rotate about a leading edge pitch axis and a first hub segment located radially inward of and separate from the first tip segment, the first hub segment configured to independently rotate about the leading edge pitch axis relative to the first tip segment, the first tip segment including a first plurality of gear teeth arranged thereon, the first hub segment including a second plurality of gear teeth arranged thereon, and a first actuation assembly including a first actuation rod, a first gear wheel assembly coupled to the first actuation rod and in engagement with the first plurality of gear teeth of the first tip segment, and a second gear wheel assembly coupled to the first actuation rod and in engagement with the second plurality of gear teeth of the first hub segment, wherein the first actuation rod is configured to be selectively rotated so as to rotate the first and second gear wheel assemblies, wherein rotation of the first gear wheel assembly causes rotation of the first tip segment about the leading edge pitch axis to a first pitch angle relative to the incoming fan exit air, and wherein rotation of the second gear wheel assembly causes rotation of the first hub segment about the leading edge pitch axis to a second pitch angle relative to the incoming fan exit air.
In some embodiments, the first actuation assembly is configured to rotate the first tip segment and the first hub segment to the first pitch angle and the second pitch angle which is different than the first pitch angle.
In some embodiments, the first gear assembly includes a first gear rotatably coupled to a first cavity formed in the fixed aft portion and in engagement with the first plurality of gear teeth of the first tip segment, the first gear assembly further includes a second gear fixedly coupled to the first actuation rod and in engagement with the first gear, and rotation of the second gear in a first rotational direction via the first actuation rod causes rotation of the first tip segment in the first rotational direction via engagement with the first gear.
In some embodiments, the second gear assembly is radially spaced apart from the first gear assembly and includes a third gear rotatably coupled to a second cavity formed in the fixed aft portion and in engagement with the second plurality of gear teeth of the first hub segment, the second gear assembly further includes a fourth gear fixedly coupled to the first actuation rod and in engagement with the third gear, and rotation of the fourth gear in the first rotational direction via the first actuation rod causes rotation of the first hub segment in the first rotational direction via engagement with the third gear.
In some embodiments, rotation of the second and fourth gears via the first actuation rod in a second rotational direction opposite the first rotational direction causes the first tip and hub segments to rotate in the second rotational direction.
In some embodiments, the second and fourth gears are smaller than and include fewer teeth than the first and third gears.
In some embodiments, the first actuation assembly is arranged radially generally outward of the fixed aft portion and includes a first actuation head, and the first actuation rod is fixedly coupled to the first actuation head such that rotation of the first actuation head causes rotation of the first cam rod.
In some embodiments, first actuation assembly further includes a first actuation arm coupled to the first actuation head and extending generally axially aft therefrom, pivoting of the first actuation arm about a rotation axis of the first actuation head causes rotation of the first actuation head which causes rotation of the first actuation rod.
In some embodiments, the fixed aft portion includes an actuation rod receiving cavity formed therethrough, and the first actuation head is circumferentially aligned with the fixed aft portion such that the first actuation rod extends through the actuation rod receiving cavity.
In some embodiments, the first actuation head is circumferentially offset from the fixed aft portion such that the first actuation rod radially extends circumferentially adjacent to the fixed aft portion.
In some embodiments, the outlet guide vane assembly further includes a first annular ring extending circumferentially about the central axis, an axially aft end of the first actuation arm is connected to the first annular ring, and circumferential movement of the first annular ring causes movement of the first actuation arm generally circumferentially relative to the first actuation head which causes the first actuation arm to pivot about the rotation axis of the first actuation head which causes rotation of the first actuation head which causes rotation of the first actuation rod.
In some embodiments, the first variable leading edge outlet guide vane further includes a central segment arranged between the first tip segment and the first hub segment such that the first tip segment and the first hub segment are radially spaced apart.
In some embodiments, the central segment is coupled to and extends axially away from an axially forward side of the fixed aft portion.
According to a further aspect of the present disclosure, a fan assembly for a gas turbine engine includes a fan duct arranged circumferentially around a central axis, a fan adapted to rotate about the central axis to force fan exit air toward an aft end of the fan duct, and an outlet guide vane assembly located in the fan duct axially downstream of the fan and configured to adjust a direction of incoming fan exit air received from the plurality of fan blades and reduce incidence between the outlet guide vane assembly and the fan exit air.
The outlet guide vane assembly includes a first variable leading edge outlet guide vane including a leading edge portion and a fixed aft portion, the leading edge portion including a first tip segment configured to rotate about a leading edge pitch axis, the first tip segment including a first plurality of gear teeth arranged thereon, and a first actuation assembly including a first actuation rod and a first gear wheel assembly coupled to the first actuation rod and in engagement with the first plurality of gear teeth of the first tip segment, wherein the first actuation rod is configured to be selectively rotated so as to rotate the first gear wheel assembly, and wherein rotation of the first gear wheel assembly causes rotation of the first tip segment about the leading edge pitch axis to a first pitch angle relative to the incoming fan exit air.
In some embodiments, the leading edge portion further includes a first hub segment located radially inward of and separate from the first tip segment, the first hub segment configured to independently rotate about the leading edge pitch axis relative to the first tip segment, and wherein the first hub segment includes a second plurality of gear teeth arranged thereon.
In some embodiments, the first actuation assembly further includes a second gear wheel assembly coupled to the first actuation rod and in engagement with the second plurality of gear teeth of the first hub segment, the selective rotation of the first actuation rod rotates the second gear wheel assembly, and rotation of the second gear wheel assembly causes rotation of the first hub segment about the leading edge pitch axis to a second pitch angle relative to the incoming fan exit air.
In some embodiments, the first gear assembly includes a first gear rotatably coupled to a first cavity formed in the fixed aft portion and in engagement with the first plurality of gear teeth of the first tip segment, the first gear assembly further includes a second gear fixedly coupled to the first actuation rod and in engagement with the first gear, and rotation of the second gear in a first rotational direction via the first actuation rod causes rotation of the first tip segment in the first rotational direction via engagement with the first gear.
In some embodiments, the second gear assembly is radially spaced apart from the first gear assembly and includes a third gear rotatably coupled to a second cavity formed in the fixed aft portion and in engagement with the second plurality of gear teeth of the first hub segment, the second gear assembly further includes a fourth gear fixedly coupled to the first actuation rod and in engagement with the third gear, and rotation of the fourth gear in the first rotational direction via the first actuation rod causes rotation of the first hub segment in the first rotational direction via engagement with the third gear.
In some embodiments, rotation of the second and fourth gears via the first actuation rod in a second rotational direction opposite the first rotational direction causes the first tip and hub segments to rotate in the second rotational direction.
According to a further aspect of the present disclosure, a method comprises arranging a fan duct circumferentially around a central axis, providing a fan comprising a plurality of fan blades that extend radially outward relative to the central axis and that are adapted to rotate about the central axis to force fan exit air toward an aft end of the fan duct, arranging an outlet guide vane assembly in the fan duct axially downstream of the fan and configured to adjust a direction of incoming fan exit air received from the plurality of fan blades and reduce incidence between the outlet guide vane assembly and the fan exit air, the outlet guide vane assembly including a first variable leading edge guide vane that extends radially relative to the central axis and includes a leading edge portion and a fixed aft portion, the leading edge portion including a first tip segment configured to rotate about a leading edge pitch axis and a first hub segment located radially inward of and separate from the first tip segment, the first hub segment configured to independently rotate about the leading edge pitch axis relative to the first tip segment, the first tip segment including a first plurality of gear teeth arranged thereon, the first hub segment including a second plurality of gear teeth arranged thereon, arranging a first actuation assembly relative to the first variable leading edge guide vane, the first actuation assembly including a first actuation rod, coupling a first gear assembly to the first actuation rod, the first gear assembly in engagement with the first plurality of gear teeth arranged on the first tip segment, and selectively coupling a second gear assembly to the first actuation rod radially spaced apart from the first gear assembly, the second gear assembly in engagement with the second plurality of gear teeth arranged on the first hub segment.
The first actuation rod is configured to be selectively rotated so as to rotate the first and second gear wheel assemblies, wherein rotation of the first gear wheel assembly causes rotation of the first tip segment about the leading edge pitch axis to a first pitch angle relative to the incoming fan exit air, and wherein rotation of the second gear wheel assembly causes rotation of the first hub segment about the leading edge pitch axis to a second pitch angle relative to the incoming fan exit air.
These and other features of the present disclosure will become more apparent from the following description of the illustrative embodiments.
For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to a number of illustrative embodiments illustrated in the drawings and specific language will be used to describe the same.
An illustrative aerospace gas turbine engine 10 includes a fan assembly 12 and an engine core 13 having a compressor 14, a combustor 16, and a turbine 18, as shown in
The fan assembly 12 includes a fan 21 having a plurality of fan blades 22 that extend radially outward relative to the central axis 11 and that are located in the inlet of the gas turbine engine 10, as shown in
In the illustrative embodiment, the fan assembly 12 further includes outlet guide vane assembly 28 located in the fan duct 20 axially downstream of the plurality of fan blades 22 that is configured to reduce the incidence between the outlet guide vane assembly 28 and the fan exit air 15 received from the plurality of fan blades 22 and return the flow to generally axial flow, as shown in
The first variable leading edge outlet guide vane 30 extends radially outward relative to the central axis 11, as shown in
As shown in
Together, the first tip and hub segments 32, 42 form the leading edge portion 31. As shown in
The first tip and hub segments 32, 42 are configured to rotate about the leading edge pitch axis 39, as shown in
The first hub segment 42 is configured to independently rotate about the leading edge pitch axis 39 relative to the first tip segment 32, and may include a small radial gap therebetween. In some embodiments, the first hub segment 42 can include a hinge rod 47 extending radially outwardly from the radially outer side 45 of the first hub segment 42 and rotatably received within the radially inner side 36 of the first tip segment 32 to add stability to the rotation of the two segments 32, 42 relative to each other while allowing for independent rotation. The hinge rod 47 of the first hub segment 42 can be cylindrical and aligned with the leading edge pitch axis 39. In some embodiments in which the first tip and hub segments 32, 42 are formed of a sufficiently stiff material, a hinge rod may be omitted.
As shown in
To rotate independently, the illustrative embodiment of the outlet guide vane assembly 28 includes a first actuation assembly 70 associated with the first tip and hub segments 32, 42, as shown in
Illustratively, the first actuation arm 74 and the first actuation head 76 are arranged radially outward of the fixed aft portion 50, as shown in
In some embodiments, the first actuation arm 74 extending axially away from the first actuation head 76, as shown in
In some embodiments, the actuation head 76 is cylindrical having a central axis 76C that aligns with a central axis 78C of the of the first actuation rod 78. The first actuation head 76 is fixedly arranged within an opening 77 formed at a first end 74A of the first actuation arm 74. As a result, pivoting movement of the first actuation arm 74 about the actuation head 76 central axis 76C rotates the first actuation head 76, which in turn rotates the first actuation rod 78. In some embodiments, the first actuation arm 74 is arranged radially outward of the vane 30 and the outer fan duct casing 19, as shown in
As shown in
The first gear assembly 56 can further include a second gear 58 arranged axially aft of the first gear 57 within the cavity 51, as shown in
The second gear assembly 59 can include third and fourth gears 60, 61 similarly configured as the first gear assembly 56, the third and fourth gears 60, 61 being radially spaced apart from the first and second gears 57, 58 along the first actuation rod 78, as shown in
The second gear assembly 59 can further include the fourth gear 61 arranged axially aft of the third gear 60 within the cavity 54, as shown in
As can be seen in
As can be seen in
Similarly, a single gear in the second gear assembly 59 could be used to rotate the hub segment 42, although again, directionality would be reversed. For example, as shown in
In some embodiments, the second gear 58 can be smaller than and includes fewer teeth than the first gear 57, and the fourth gear 61 is larger than and includes more teeth than the third gear 60. In some embodiments, both the second and fourth gears 58, 61 are smaller than and include fewer teeth than the first and third gears 57, 60. In some embodiments, both the second and fourth gears 58, 61 are larger than and include more teeth than the first and third gears 57, 60, such the configurations of these gears shown in
In operation in embodiments including two gears for each assembly 56, 59, rotation of the first actuation rod 78 in the first rotational direction rotates the first tip and hub segments 32, 42 in the first rotational direction. Opposingly, rotation of the second and fourth gears 58, 61 via the first actuation rod 78 in the opposite second rotational direction causes the first tip and hub segments 32, 42 to rotate in the second rotational direction.
The amount of rotation of the first tip and hub segments 32, 42, or in other words the range of pitch angles that the first tip and hub segments 32, 42 can be rotated to, is dependent on the configuration of the gears 57, 58, 60, 61, in addition to the number of teeth length of the first and second pluralities of gear teeth 55, 66. For example, a smaller range of pitch angles of the first tip and hub segments 32, 42 can be achieved by utilizing a smaller gear with less teeth, or teeth that are more spaced apart about the circumference of the gear. This would lead to less precise rotation of the first tip and hub segments 32, 42 such that the pitch angle that the first tip and hub segments 32, 42 are movable to based on each per tooth movement of the gear is large. In some embodiments, a larger range of pitch angles of the first tip and hub segments 32, 42 can be achieved by utilizing a larger gear with more teeth, or teeth that are more tightly spaced about the circumference of the gear. This would lead to more precise rotation of the first tip and hub segments 32, 42 such that the pitch angle that the first tip and hub segments 32, 42 are movable to based on each per tooth movement of the gear is smaller.
By selectively arranging specific gears with specific size and tooth configurations, the first tip and hub segments 32, 42 can be individually controlled with respect to each other to the same or differing angles, thus allowing for a multitude of segment positions and arrangements to be achieved. For example, the same sized gears can be used such that the first tip and hub segments 32, 42 are rotated to the same pitch angles when the actuation rod 78 is rotated. In other embodiments, differently sized gears with differing tooth arrangements can be used such that the first tip and hub segments 32, 42 are rotated to different pitch angles when the actuation rod 78 is rotated. For example, the first gear 57 can be larger than and include more teeth than the third gear 60. Conversely, the first gear 57 can be smaller than and include fewer teeth than the third gear 60. This provides for great flexibility in managing incoming airflows which may include distortions and disturbances. This can be particularly useful in embedded engine applications with complex intake and inlet duct geometries. In such scenarios, the distortion flows have more significant gradients and vortices, even in flight, so accommodation is necessary to maintain fan operability and performance.
In some embodiments, such as that shown in
In other embodiments, a vane 30″ may include an additional gear 58B″ that is configured to rotate the first tip segment 32″ (although not shown, may also be applicable to the gears associated with the first hub segment) in a direction opposite of other vanes that do not include the additional gear, as shown in
With regard to the first actuation assembly 70 described above, the first actuation arm 74 is configured to be moved generally circumferentially relative to the first actuation head 76 by annular rings (such as annular ring 62 shown in
As shown in
As can be seen in
In some scenarios, it may be beneficial to have more control over individual sections of the plurality of variable leading edge outlet guide vanes 30 or individual vanes 30. This may be particular useful when the engine experiences more significantly distorted flows, such as in embedded engine applications. Sectional control or individual control would provide additional flexibility to accommodate as much flow variation as possible to recover operability and performance margins. For example, as an aircraft maneuvers through ground crosswind or variations of flight orientations such as sideslip and pitch variations, the plurality of variable leading edge outlet guide vanes 30 can be rotationally moved in sections or independently to best reset the inlet angles and maximize the fan operability envelope. The optimized rest of the inlet angles improves stall margin, improves efficiency and performance, and reduces fan forcing debits.
As can be seen in
In this configuration, the first and second annular ring segments 62S1, 62S2 can be configured to independently rotate about the central axis 11 so as to move each actuation arm 74 coupled thereto generally circumferentially relative to the first actuation head 76, or in other words, to pivot each actuation arm 74 coupled thereto about the actuation head 76 central axis 76C. The first and second annular ring segments 62S1, 62S2 are circumferentially spaced apart a great enough distance to allow maximum movement relative to each other. For example, in some scenarios, the first annular ring segment 62S1 may be moved in an opposing circumferential direction to the second annular ring segment 62S2 such that the respective tip segments 32 of their associated vanes 30 are rotated in opposing rotational directions.
The outlet guide vane assembly 28 can include multiple annular ring segments similar to the segments 62S1, 62S2 disposed around the entire circumferential extent of the assembly 28. As such, the multiple annular ring segments can define groups of vanes 30, the tip and hub segments 32, 42 of each being able to be rotated to unique pitch angles based on the circumferential movement and position of their respective annular ring segment. As will be described in detail below, the annular ring segments 62 may be controlled by a control system 99.
In some embodiments, the control system 99 is configured to rotate each segment 32, 42 of each vane 30 of the first plurality of variable leading edge outlet guide vanes 30 individually relative to each other vane's 30 segments 32, 42, as shown in
In another example, if the rotation of the first plurality of guide vanes 30 causes more undesirable flow effects in certain circumferential sectors, only vanes 30 located in those certain circumferential sectors may be rotated to specific pitch angles to reduce losses from said flow effects, while other vanes 30 may be rotated to different pitch angles. Then, if the flow dynamically encounters different distortions during operation, different circumferential sectors may require vane 30 adjustment. The individual controllability allows for the option to adjust these different circumferential sectors dynamically.
In order to carry out the individual control, the second end 74B of the actuation arm 74 may include a control member 75 coupled to an external actuator (not shown) that moves the actuation arm 74 generally circumferentially relative to the first actuation head 76, as shown in
As touched on above, by controlling at least one vane 30 of the plurality of variable leading edge outlet guide vanes 30, the control system 99 is configured to control at least some of the flow of the fan exit air 15 after it passes over and exits the fan blades 22. By controlling the entirety of the plurality of variable leading edge outlet guide vanes 30, the control system 99 can accommodate the overall flow of the fan exit air 15, in particular distorted flow, after it passes over and exits the fan blades 22 in order to control fan blade 22 response to forces acting on the fan blades 22, as well as to reduce losses created by undesirable variations in the air flow. Moreover, because the fan exit air 15 may not be uniform as it exits the fan blades 22, the plurality of variable leading edge outlet guide vanes 30 or the axial passage between the vanes 30 and the fan blades 22 operate further from their ideal design conditions. By adjusting the plurality of variable leading edge outlet guide vanes 30, parameters such as incidence are improved, and detrimental flow conditions and losses in the vanes 30 or the axial passage between the vanes 30 and the fan blades 22 such as vortices and stall are reduced.
In some embodiments, the control system 99 is configured to rotate the segments 32, 42 of each vane 30 of the first plurality of variable leading edge outlet guide vanes 30 to pitch angles in response to the gas turbine engine 10 operating at a given operating condition so as to reduce the incidence between the outlet guide vane assembly 28 and the fan exit air 15 received from the plurality of fan blades 22 and redirect the fan exit air 15 in a first direction, in particular a generally axial direction. In particular, the operating condition in which the fan assembly 12 and gas turbine engine 10 are operating in may include at least one of take-off, climb, cruise, descent, landing, and aircraft maneuvers of an aircraft having the engine 10 equipped. In each of these operating conditions, the plurality of fan blades 22 and/or the vanes 30 of the fan assembly 12 may experience various undesirable operability issues such as forcing, stall, and flutter. For example, the engine 10 may operate in particular speed ranges for each of the operating conditions, and as result, the fan blades 22 may experience greater or lower levels of forcing, stall, and/or flutter in response to the engine 10 operating in particular speed ranges.
In order to compensate for these forces acting on the fan blades 22, the control system 99 is configured to rotate the first plurality of variable leading edge outlet guide vanes 30, in particular the segments 32, 42, to an arrangement of pitch angles in order to reduce the incidence between the outlet guide vane assembly 28 and the fan exit air received from the fan blades 22 and return the flow to generally axial flow. This reduction in the incidence between the outlet guide vane assembly 28 and the fan exit air received from the fan blades 22 can improve the operating range of the fan blades 22 relative to forcing, stall, and/or flutter. Moreover, the control system 99 is configured to reset a desired incidence of air flow into the first plurality of variable leading edge outlet guide vanes 30 in response to swirl in the inlet flow. This produces an averaging effect that improves engine performance and efficiency. These arrangements of the vanes 30 can also recover the losses created by flow separation, flow distortions, vortices, and/or swirl.
The control system 99 is operable to control the first plurality of variable leading edge outlet guide vanes 30 in a variety of configurations and arrangements in order to compensate for inlet pressure distortion, vortices and swirl, thus reducing the forcing, stall, flutter, flow separation, and any other undesirable effects in the fan rotor or outlet vanes. For example, in some embodiments, the control system 99 is configured to rotate each vane 30 of the first plurality of guide vanes 30 in unison. In other words, all of the segment 32, 42 of the first plurality of guide vanes 30 move to the same pitch angle. In such embodiments, the each segment 32, 42 of the vane 30 may be mechanically connected to each other via the first and second annular rings 162, 164.
In some embodiments, the control system 99 is configured to rotate at least two different groups of variable leading edge outlet guide vanes 30. For example, the control system 99 may be configured to selectively rotate each group of vanes 30 to create non-uniform backpressure that drives the fan inlet distortion flows within the fan to change or redistribute around the circumference of the fan. This locally reduces loading on fan blades 22 within a lip separated flow with low local pressure to reduce forcing and/or improve the uniformity of flow in general through the fan to reduce forcing. In particular, fully opening (allowing full flow through the guide vanes) at least one group of vanes 30 and fully closing at least one further group of vanes 30 (allowing no flow through the guide vanes) reduces a tendency for a local stall of the fan blades 22 that could lead to early overall stall in the fan. In some embodiments, the control system 99 is configured to rotate a large group of vanes 30 which counters bulk swirling flows or local changes to improve localized intake swirl gradients to improve fan performance and operability.
In at least one additional embodiment, the plurality of variable leading edge outlet guide vane 30 are broken into unique groups of vanes 30, as shown in
In some embodiments, the first plurality of variable leading edge outlet guide vanes 30 includes a first group of tip and/or hub segments 32, 42 of first vanes 30 and a second group of tip and/or hub segments 32, 42 of first vanes 30 different from the first group of guide vanes 30. The control system 99 is configured to rotate the first group of tip and/or hub segments 32, 42 of first vanes 30 to a first angles and the second group of tip and/or hub segments 32, 42 of first vanes 30 to a second angle that is different from the first angle. The groups of vanes 30 may be individually controlled or each group may be ganged together. For example, in some embodiments, one half of the first plurality of outlet guide vanes 30 is the first group and the other half of the first plurality of outlet guide vanes 30 is the second group.
In some embodiments, the control system 99 utilizes predetermined arrangements of the plurality of variable leading edge outlet guide vanes 30 that are based on predetermined measurements and data taken in predetermined engine operating conditions and predetermined airflow characteristics. As such, the control system 99 is configured to rotate the vanes 30 to specific predetermined arrangements based on the operating condition and/or airflow characteristic(s) of the fan exit air 15 or the inlet air that the engine 10 and fan assembly 12 are operating in, or based on projected operating conditions and/or airflow characteristic(s) that will be encountered by the engine 10 during a mission.
In some embodiments, the predetermined arrangements of the plurality of variable leading edge outlet guide vanes 30 can be based on previously acquired test data corresponding to specific flight conditions. In a more complex arrangement, the control system 99 could be coupled to measurement systems, such as the at least one sensor 92 described below, that detect flow instabilities associated with impending fan stall to direct vane geometry changes to extend margins. The control system 99 may be more effective near stall as the vanes 30 can redistribute flow conditions to minimize local stall cells. Having smaller ganged vane 30 groups are efficient as well in that such groups only reduce losses locally to extend operability and performance.
In some embodiments, the control system 99 includes at least one sensor 92 configured to take real-time measurements of the air flow within the fan duct passage 24 and of forces acting on the fan assembly components, as shown in
In some embodiments, the control system 99 includes a neural network configured to perform machine learning such that the control system 99 can iterate over the predetermined arrangements in order to calculate new arrangements that are applicable to new variations in the operating condition and/or airflow characteristics that are unaccounted for by the predetermined settings and arrangements.
In some embodiments, the control system 99 further includes a subsystem control that is integrated with other engine controls to further control reduction of losses created by undesirable variations in the air flow and improve engine performance and efficiency. For example, if rotation of vanes 30 resulted in a fan flow drop, the subsystem control is configured to compensate for this by increasing the fan speed in order to maintain thrust, and/or by changing the exhaust area of the engine 10 in order to further reduce the losses and improve engine efficiency.
In some embodiments, the at least one sensor 92 may be located proximate to the fan blades 22, proximate to the plurality of variable leading edge outlet guide vanes 30, or both, as shown in
In the illustrative embodiment, the functionality of the control system 99 described herein may be implemented in various processing and computing devices, and may be located within the engine 10 or outside of the engine 10. Moreover, the functionality may be configured to operate on executable software provided on the processing and computing devices.
Furthermore, the functionality disclosed herein may be implemented in various configurations using computer-readable media for carrying or having computer-executable instructions or data structures stored thereon. Such computer-readable media can be any available media that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, such computer-readable media can comprise physical storage and/or memory media such as RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer. Computer-executable instructions comprise, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing device to perform a certain function or group of functions.
As shown in
As shown in
The winglet 90 further includes a forward edge 96 that is curved. In some embodiments, the forward edge 96 is curved to match the rotational path, or path of movement, of the leading edge 33, 43 of the tip and hub segments 32, 42. In particular, the forward edge 96 may include a radius of curvature 97 that matches the rotational path of the tip and hub segments 32, 42, as shown in
As can be seen in
A person skilled in the art will understand that all features and components of all embodiments described herein, including the guide vane assembly 28 described above and the outlet guide vane assemblies described below can be interchanged and modified to include some elements of some embodiments and other elements of other embodiments. For example, even though some embodiments are shown without a static central segment, these embodiments may include such a central segment, as described herein. Similarly, although some embodiments described two tip segments and two hub segments, some embodiments can include one tip and two hub segments, two tip and one hub segments, each with or without a static central hub section, or other combinations thereof. Similarly, the actuation assemblies can be interchanged, with some embodiments and configurations including pass-through actuation assemblies, two assemblies arranged at the tip and hub, different configurations of segmented and full annular rings, and the like.
Another embodiment of an outlet guide vane assembly 128 is shown in
Similar to the outlet guide vane assembly 28 described above, the outlet guide vane assembly 128 includes first tip and hub segments 132, 142. In this embodiment, the first variable leading edge outlet guide vane 130 further includes a central segment 148 arranged between the first tip segment 132 and the first hub segment 142 such that the first tip segment 132 and the first hub segment 142 are radially spaced apart. In some embodiments, the central segment may be coupled to and extend axially away from the axially forward side 153 of the fixed aft portion 150. The central segment 148 is static and does not rotate.
As can be seen in
Unlike the outlet guide vane assembly 28, the assembly 128 does not include a single actuation rod, but instead includes two actuation assemblies 170, 180 each having its own unique actuation rod 178, 188. The first actuation assembly 170 is configured to rotate the first tip segment 132, and the second actuation assembly 180 is configured to rotate the first hub segment 142. Although two actuation assemblies 170, 180 are shown in
As can be seen in
The components of the first actuation assembly 170, including the first actuation arm 174, the first actuation head 176, the first actuation rod 178, and the gears 157, 158, may be arranged similarly to the first actuation arm 74, first actuation head 76, first actuation rod 78, and gears 57, 58 described above. In particular, the first actuation assembly 170 is arranged radially outward of the fixed aft portion 150 such that the first actuation head 176 is arranged at least partially within the fan duct outer casing 19.
As can be seen in
Similar to the first actuation rod 178, the second actuation rod 188 is configured to be selectively rotated by pivoting movement of the actuation arm 184, and thus rotation of the actuation head 186, about the central axis of the actuation rod 188 so as to selectively rotate the gears 160, 161. Rotation of the gears 160, 161 causes rotation of the first hub segment 142 about the leading edge pitch axis 139 to a second pitch angle relative to the incoming fan exit air 15. The second pitch angle can be the same or different than the first pitch angle.
The second actuation assembly 180 is arranged radially inward of the fixed aft portion 150 such that the second actuation head 186 is arranged at least partially within the inner wall 23.
Similar to the first actuation assembly 170, the second actuation assembly 180 can include a second annular ring 164, or annular ring segments or individually actuators arranged radially inward of the fan duct 24, as shown in
In some embodiments, the outlet guide vane assembly 128 may include a single or multiple air manipulating members 190, 190S arranged in the small radial gaps between the tip segment 132 and central segment 148 and between the hub segment 142 and central segment 148, as shown in
In some embodiments, one of the air manipulating members 190, 190S may be formed as a winglet while the other is formed as a seal. In some embodiments, both of the air manipulating members 190, 190S are formed as a seal. In some embodiments, both of the air manipulating members 190, 190S are formed as a winglet. In embodiments in which the tip and hub segments 132, 142 are rotationally attached to the central segment 148 via hinge rods similar to those described above, the air manipulating members 190, 190S can include a cutout (not shown but similar to the cutout 98) to allow the hinge rods to pass therethrough. In other arrangements in which the tip and hub segments 132, 142 are entirely spaced apart from the central segment 148, the cutout would not be necessary.
As can be seen in
Another embodiment of an outlet guide vane assembly 228 is shown in
Similar to the outlet guide vane assemblies 28, 128 described above, the outlet guide vane assembly 228 includes first tip and hub segments 232A, 242A and a central segment 248. Unlike the assemblies described above, the outlet guide vane assembly 228 further includes a second tip segment 232B and a second hub segment 242B arranged radially between the first tip segment 232A and the central segment 248 and between the first hub segment 242A and the central segment 248, respectively. The additional second tip segment 232B and second hub segment 242B allow for additional variations of the fan exit air 15 flowing over the vane 230.
In order to move all four segments 232A, 232B, 242A, 242B, the assembly 228 includes a first actuation assembly 270 configured substantially similarly to the actuation assemblies 70, 170. Specifically, instead of two gear assemblies arranged on a single actuation rod 278, such as the gear assemblies 56, 59 described above, the first actuation assembly 270 includes four gear assemblies 256A, 256B, 259A, 259B each associated with a respective segment 232A, 232B, 242A, 242B, as shown in
Similar to the outlet guide vane assembly 128, in some embodiments, the outlet guide vane assembly 228 may include a central segment 248 that is static and formed similarly to the central segment 148 described above. Moreover, in some embodiments, the outlet guide vane assembly 228 may include a single or multiple air manipulating members 290 arranged in the small radial gaps between the segment 232A, 232B, 242A, 242B and central segment 248, as shown in
In some embodiments, one of the air manipulating members 290 may be formed as a winglet while the others are formed as seals. In some embodiments, one of the air manipulating members 290 may be formed as a seal while the others are formed as winglets. In some embodiments, two of the air manipulating members 290 may be formed as winglets while the others are formed as seals. In some embodiments, all of the air manipulating members 290 are formed as seals. In some embodiments, all of the air manipulating members 290 are formed as winglets.
As can be seen in
Another embodiment of an outlet guide vane assembly 328 is shown in
The outlet guide vane assembly 328 is similar to the outlet guide vane assemblies 28, 128 described above, in particular including first tip and hub segments 332, 342 that are rotated via actuation mechanisms. Unlike the outlet guide vane assemblies 28, 128, 228, the assembly 328 does not include gears or the actuation assemblies described above, but instead includes a hydraulic actuation assembly 354, as shown in
The hydraulic actuation assembly 354 can include a first hydraulic actuator 355 and a second hydraulic actuator 365. The two actuators 355, 365 can be formed substantially similarly and used interchangeably for the first tip and hub segments 332, 342. As such, although only the first hydraulic actuator 355 is shown in
As can be seen in
The hydraulic actuator 355, 365 may be fluidically coupled to a hydraulic fluid supply 390, which is controlled by the control system 99 to supply a fluid to the cylinder 356, 366 so as to control movement of the piston 357, 367. The first hydraulic actuator 355 can be fluidically connected to the hydraulic fluid supply 390 via a first fluid line 391, and the second hydraulic actuator 365 can be coupled to the hydraulic fluid supply 390 via a first fluid line 392.
The actuation piston 357, 367 can be directly coupled to the first tip or hub segment 332, 342, or an actuation rod 358, 368 can extend between an end of the piston 357, 367 and the first tip or hub segment 332, 342, as shown in
In operation, the hydraulic actuators 355, 365 are actuated via control by the control system 99 or other known means by controlling a fluid flow to the actuators 355, 365 via the hydraulic fluid supply 390 and the fluid lines 391, 392. In this way, the first tip segment 332 can be selectively rotated about the leading edge pitch axis 339 to a first pitch angle relative to the incoming fan exit air 15. Similarly, the first hub segment 342 can be selectively rotated about the leading edge pitch axis 39 to a second pitch angle or the same first pitch angle relative to the incoming fan exit air 15. As shown in
Another embodiment of an outlet guide vane assembly 428 is shown in
Similar to the outlet guide vane assembly 28 described above, the outlet guide vane assembly 428 includes first tip and hub segments 432, 442 as well as first and second gear assemblies 456, 459. In this embodiment, the first tip and hub segments 432, 442 include first and second gears 455, 466 fixedly coupled to the radially outer and radially inner hub members 19H, 23H of the tip and hub members 432, 442, and arranged within the radially outer and radially inner hub receiving recesses 19R, 23R, as shown in
The first and second gears 455, 466 are configured to engage with the teeth of the gears of the gear assemblies 456, 459 in order to rotate the first tip and hub segments 432, 442. Similar to the gear assemblies 55, 59 described above, the gear assemblies 456, 459 each include two gears 457, 458, 460, 461. However, in such embodiments as that shown in
The first actuation rod 478 is fixedly coupled to the axially aftmost gear (gears 458, 461 as shown in
A method can include arranging a fan duct 20 circumferentially around a central axis 11, providing a fan 21 comprising a plurality of fan blades 22 that extend radially outward relative to the central axis 11 and that are adapted to rotate about the central axis 11 to force fan exit air 15 toward an aft end of the fan duct 20, and arranging an outlet guide vane assembly 28 in the fan duct 20 axially downstream of the fan 21 and configured to adjust a direction of incoming fan exit air 15 received from the plurality of fan blades 22 and reduce incidence between the outlet guide vane assembly 28 and the fan exit air 15, the outlet guide vane assembly 28 including a first variable leading edge guide vane 30 that extends radially relative to the central axis 11 and includes a leading edge portion 31 and a fixed aft portion 50, the leading edge portion 31 including a first tip segment 32 configured to rotate about a leading edge pitch axis 39 and a first hub segment 42 located radially inward of and separate from the first tip segment 32, the first hub segment 32 configured to independently rotate about the leading edge pitch axis 39 relative to the first tip segment 32, the first tip segment 32 including a first plurality of gear teeth 55 arranged thereon, the first hub segment 42 including a second plurality of gear teeth 66 arranged thereon.
The method can further include arranging a first actuation assembly 70 relative to the first variable leading edge guide vane 30, the first actuation assembly 70 including a first actuation rod 78, coupling a first gear assembly 56 to the first actuation rod 78, the first gear assembly 56 in engagement with the first plurality of gear teeth 55 arranged on the first tip segment 32, and selectively coupling a second gear assembly 59 to the first actuation rod 78 radially spaced apart from the first gear assembly 56, the second gear assembly 59 in engagement with the second plurality of gear teeth 66 arranged on the first hub segment 42. The first actuation rod 78 is configured to be selectively rotated so as to rotate the first and second gear wheel assemblies 56, 59. Rotation of the first gear wheel assembly 56 causes rotation of the first tip segment 32 about the leading edge pitch axis 39 to a first pitch angle relative to the incoming fan exit air 15, and rotation of the second gear wheel assembly 59 causes rotation of the first hub segment 42 about the leading edge pitch axis 39 to a second pitch angle relative to the incoming fan exit air 15.
While the disclosure has been illustrated and described in detail in the foregoing drawings and description, the same is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments thereof have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected. Moreover, each of the embodiments described herein, including the specific features and characteristics of each embodiment, may be combined with other embodiments as would be understood by one of ordinary skill in the art.
This application claims the benefit under 35 U.S.C. § 119(e) of U.S. Provisional Application Ser. No. 63/452,895, filed on Mar. 17, 2023, the entire disclosure of which is incorporated herein by reference.
Embodiments of the present disclosure were made with government support under Contract No. FA8650-19-F-2078 awarded by the U.S. Air Force. The government may have certain rights.
| Number | Date | Country | |
|---|---|---|---|
| 63452895 | Mar 2023 | US |
