Patent Application
20230089038
The present invention relates to a thrust reverser for an aircraft turbofan propulsion system, a related turbofan propulsion system, and a related thrust reversal method, adapted to allow an at least partial reversal of the thrust provided by the turbofan propulsion system.
In the field of aircraft propulsion systems, and particularly with application to turbofan propulsion systems, the use of movable blocker doors to provide thrust reversal is generally known. This architecture relies on blocking the outflow of air through one or more blocker doors—often also known as “petals”—that are positioned to completely or partially occlude an air outflow duct. These petals are typically driven by a series of rods, which may be located in the outflow duct of the engine or embedded in the structure of the propulsion system. Generally, the thrust reverser system is composed of two parts, a fixed one and a translating one, which are connected by beams that have runners adapted to allow the relative movement of the translating structure with respect to the fixed structure. The relative movement of the two parts provides, through the rotation of a blocker door, the at least partial occlusion of the outflow duct, and, simultaneously, opens an outflow circumferential opening to the environment outside the propulsion system. It is also known to associate a plurality of guiding structures, i.e., a “cascade,” aimed at guiding the aerodynamic flow out of said circumferential opening to said circumferential opening.
An example of such a thrust reverser system is shown in U.S. Patent Application US 2019/0032600 A1.
Propulsion systems comprising thrust reverser systems according to the prior art just described, however, have several disadvantages.
First, the presence of so many movable components, arranged inside the outflow duct, and therefore having stringent structural constraints, makes the known thrust reverser systems heavy, expensive, difficult to make, and moreover makes rather frequent maintenance necessary.
In addition, the presence of blocker doors causes a plurality of aerodynamic discontinuities, transverse and inclined with respect to airflow.
Lastly, these known systems require a non-negligible amount of space, and their bulk makes any maintenance work on the substructure, systems, or the propulsion system engine itself inconvenient and slow. In particular, with the known thrust reverser systems it is not possible to open and inspect the fixed and movable structures of the thrust reverser system when the bypass duct has an O or ring cross section.
The object of the present invention is to provide a thrust reverser system for a turbofan propulsion system that does not have the disadvantages of the prior art.
A further object of the invention is to provide a turbofan propulsion system comprising a thrust reverser system that does not have the disadvantages of the prior art.
A further object of the invention is to provide a method for thrust reversal of an aircraft turbofan propulsion system that does not have the disadvantages of the prior art.
Further objects of the invention are to provide a thrust reverser system and a turbofan propulsion system comprising a thrust reverser system that is improved with respect to the prior art, and/or having fewer components, and/or wherein any bleeding of the occluded air stream is minimized, and/or wherein the acoustically treatable surface area is maximized, so as to significantly reduce acoustic emission with respect to the prior art.
This and other objects are fully achieved according to the present invention by a thrust reverser system as defined in the appended claim 1, by a turbofan propulsion system as defined in claim 11, and by a method for thrust reversal of a turbofan propulsion system of an aircraft as defined in the appended claim 17.
Advantageous embodiments of the invention are specified in the dependent claims, the content of which is to be understood as an integral part of the description that follows.
In summary, the invention is based on the idea of providing a thrust reverser system comprising a movable mechanism for making an opening adapted to allow the outflow of air to the external environment and an iris mechanism adapted to at least partially occlude the air passage.
In summary, according to a further aspect of the invention, the invention is based on the idea of providing a turbofan propulsion system comprising a thrust reverser system having a movable mechanism for making an opening adapted to allow the outflow of air to the external environment and an iris mechanism adapted to at least partially occlude the air passage.
Lastly, in summary, according to a further aspect of the invention, the invention is based on the idea of providing a method of thrust reversal in a turbofan propulsion system having a bypass duct, wherein the thrust reversal is provided by an outflow of air from the bypass duct to the external environment by means of a radial opening in conjunction with the at least partial occlusion of the bypass duct by means of an iris mechanism.
Advantageously, the thrust reverser system is configured in such a way that the movement of the translating structure between the stowed position and the opening position and the movement of said plurality of blades of the iris mechanism between said rest configuration and said deployed configuration are driven in a coordinated manner.
Preferably, the thrust reverser system further comprises a plurality of outflow guides, preferably arranged integral in translation with the translating structure, and adapted to guide the outflow of air from the bypass duct to the external environment through the circumferential opening defined between a translating structure and a fixed structure when the translating structure is in an opening position.
The features and advantages of this invention will be clarified by the detailed description that follows, given purely by way of non-limiting example in reference to the accompanying drawings, wherein:
In general, in the present description and the appended claims, terms such as “axial,” “axial direction,” “axially,” and the like, refer to the direction indicated by the axis of the core engine of the turbofan propulsion system according to the invention. Similarly, terms such as “radial,” “radially,” “transverse,” or the like refer to a direction lying in a plane substantially perpendicular to the direction of said engine axis.
In general, in the present description and the appended claims, terms such as “thrust reversal” and “thrust reverser” are to be understood as generally used in the relevant technical field, namely that of aircraft thrusters, and also include conditions, or systems designed to achieve such conditions, wherein the thrust reversal is only partial, i.e., not directed in the direction opposite to the direction of operation but also only directed in a non-axial direction relative to the thruster.
With reference to the figures, in general, the turbofan propulsion system according to an aspect of the invention is indicated by the reference numeral 30, and the thrust reverser system according to a further aspect of the invention is indicated by the reference numeral 60.
The turbofan propulsion system 30 essentially comprises a core engine 200, an engine nacelle 40, a bypass duct 430, and the thrust reverser system 60.
In a manner known per se, the core engine 200 is made as a conventional core engine of a turbofan propulsion system, so that it extends along an axial direction 10 and defines within it a first air flow path, typically a so-called “hot flow” of the turbofan propulsion system 30. Inside the core engine 200, in a conventionally known manner, there are arranged at least one compression stage, a combustion chamber, one or more expansion stages, and the exhaust nozzle 70.
The engine nacelle 40 comprises a front portion of the engine nacelle 50, downstream of which the thrust reverser system 60 is arranged.
The engine nacelle 40 is arranged at least partially around the core engine 200, and jointly defines therewith the bypass duct 430. In a manner known per se, the bypass duct 430 preferably has a cross-sectional area, in a plane transverse to the axial direction 10, that is either O-shaped or ring-shaped, or may comprise a pair of side-by-side C-shaped sections. The bypass duct 430 defines a second flow path for air, typically a so-called “cold flow” of the turbofan propulsion system 30.
The turbofan propulsion system 30 further comprises at least one fan arranged upstream of the core engine 200 and bypass duct 430 (known per se, and thus not shown in the figures) so as to provide one or more stages of compression of the incoming air flow.
As stated previously, the thrust reversal system 60 is arranged downstream of the front portion of the engine nacelle 50 and is connected thereto.
The thrust reverser system 60 comprises a fixed structure 80, which is mounted integral with the front portion of the engine nacelle 50 or is made integrally thereto, and a translating structure 90. The fixed structure 80 and the translating structure 90 are made as an ideal continuation of the front portion of the engine nacelle 50 to define therewith a flow path for air. The fixed structure 80 and the translating structure 90 are thus adapted to define therewith a sequential flow path for air. Both the fixed structure 80 and the translating structure 90 may, advantageously, be made in two portions, for example in two semi-annular halves, or in two C-shaped halves, to allow easy opening for inspection or maintenance.
The fixed structure 80 preferably has a connection ring 14 for connecting to a housing of the core engine 200 or the front portion of the engine nacelle 50, said connection ring 14 being arranged to support loads in the axial direction 10.
As seen in particular in
The translating structure 90 may comprise, in a manner similar to the fixed structure 80, an outer translating panel 390 and an inner translating panel 300 (preferably acoustically treated).
The translating structure 90 is arranged slidable, or translatable, parallel to the axial direction 10 between a stowed position and an opening position. In the stowed position, the translating structure 90 is connected in a fluid-tight connection, advantageously by means of a dedicated gasket, with said fixed structure 80, substantially so as to define therewith, and with the front portion of the engine nacelle 50 connected thereto, a flow path for air. In the opening position, the translating structure 90 is, on the other hand, spaced apart from said fixed structure 80 in the axial direction 10. In this way, when the translating structure 90 is in the opening position, there is defined in the space between said fixed structure 80 and said translating structure 90 a circumferential opening 12, adapted to allow the outflow of air from said bypass duct 430 toward the external environment along a flow path at least partially non-parallel to the axial direction 10.
This sliding movement of the translating structure 90 with respect to the fixed structure 80 is driven by a first actuator mechanism 120, which is arranged to move the translating structure 90 from the stowed position to the opening position and vice versa. According to a preferred embodiment, said first actuator mechanism 120 comprises at least one conventional, hydraulic or electric linear actuator, preferably a pair of linear actuators, even more preferably a plurality of linear actuators, adapted to drive a translational movement along an axis of the actuator 100.
Advantageously, the thrust reverser system 60 further comprises at least one, and preferably a plurality of, outflow guides 110, also known as a “cascade.” Said at least one outflow guide 110 is made, for example, as a slat, or a metal sheet. Preferably, the outflow guides 110 are arranged translationally integral with the translating structure 90, whereby, when the translating structure 90 is moved toward the opening position, said outflow guides 110 occupy at least partially the space between the translating structure 90 and the fixed structure 80, to guide the outflow of air from the bypass duct 430 to the external environment through the opening 12. Alternatively, the outflow guides 110 may be arranged integral with the fixed structure 80. Preferably, when the translating structure 90 is in the closed configuration, the outflow guides 110 are housed in a defined compartment between the fixed outer panel 380, the fixed inner panel 290, and a front frame 310.
The thrust reverser system 60 further comprises an iris mechanism 190, adapted to at least partially, and advantageously, completely, occlude the bypass duct 430; however, even in the case of “complete” occlusion of the bypass duct 430, a small air bleeding may exist in the radially innermost portion of the bypass duct 430, or the portion abutting the core engine 200, for a thickness generally less than a few millimeters. To this end, the iris mechanism 190 comprises a plurality of blades 140, said blades 140 being arranged for joint movement between a rest configuration, in which the free cross-sectional area of the bypass duct 430, or the free cross-sectional area of the bypass duct 430 in a plane substantially perpendicular or transverse to the axial direction 10, is at a maximum, and thus the blades 140 of the plurality of blades 140 jointly define an air passage; and a deployed configuration, in which the plurality of blades 140 is adapted to occlude at least partially the bypass duct 430, or said air passage, or is positioned to occlude the bypass duct 430 at least partially, and, advantageously, completely. Obviously, the invention is not limited to an iris mechanism 190 comprising the number of blades 140 shown in the figures, but may include any number of blades 140, even very different from that described or illustrated in the figures, without thereby departing from the scope of the invention as defined by the appended claims. For example, the iris mechanism 190 may include four blades, or eight blades, or even thirty-two blades, it being understood that such numbers are described herein by way of non-limiting example only.
Said iris mechanism 190 is, in the embodiment shown in the figures, mounted integral in translation with the translating structure 90 of the thrust reverser system 60. Alternatively, the iris mechanism 190 may be mounted integral with the fixed structure 80 of the thrust reverser system 60.
Alternatively, and more advantageously, in an embodiment, the iris mechanism 190 may be permanently constrained to the pylon coupling system 160 (which will be described later) and engageably coupled to one of either the fixed structure 80 or the translating structure 90, or it is adapted to be coupled to one of either the fixed structure 80 or the translating structure 90 to make it integral in translation with said structure. By virtue of this latter configuration, it is possible, even in the case of a bypass duct with an O-shaped or ring-shaped cross section, to arrange the plurality of blades 140 in such a way that they are adapted, in the deployed configuration, to completely occlude the passage (unless, possibly, there is a minimal leakage in the radially innermost section), and at the same time to make both the translating structure 90 and the fixed structure 80 in two half-shells, or in two portions, for example in two semi-annular halves, or in two C-shaped halves, hinged on the same side, to allow easy opening for inspection or maintenance, as shown in
As may be seen in the figures, in particular in
As is particularly visible in
Even if the blade structure 140 shown in the figures is planar, in an alternative embodiment of the invention, the blades 140 have a non-planar shape. For example, the iris mechanism 190 may be made in the form of a dome, preferably a spherical segment, and each blade 140 of the plurality of blades 140 may be made in the form of a curved panel adapted to cover only a portion of said dome. Again, in a further alternative embodiment, the iris mechanism 190 may be made in the form of a cone, having the apex of the cone oriented in the direction of, or in the direction opposite to, the airflow exit section from the bypass duct 430, in which case each blade 140 of the plurality of blades 140 of the iris mechanism 190 is made in the form of a curved panel adapted to cover a portion of said truncated cone.
In order to provide greater structural strength at least in the deployed configuration, in an advantageous embodiment, the adjacent blades 140 of the plurality of blades 140 overlap at least partially.
In order to provide greater structural strength, in a further advantageous embodiment, the blades 140 of the plurality of blades 140 of the iris mechanism 190 are made with a sandwich structure, even more preferably with a sandwich structure with composite materials. Alternatively, depending on the structural design requirements, the blades 140 may also be made as, or from, simple sheet metal structures.
Advantageously, each blade 140 of the iris mechanism 190 may have an arrangement of pins and recesses adapted to cooperate with a similar arrangement of blades 140 directly adjacent thereto, in such a way to allow locking adjacent blades 140 in the deployed configuration, with obvious advantages in terms of structural strength. In particular, as may be seen clearly in
Advantageously, at least one blade 140 of the plurality of blades 140 of the iris mechanism has a control hole, which is adapted to allow controlling the aerodynamic transient during the movement of the iris mechanism 190 between the rest configuration and the deployed configuration.
In an embodiment, at least one blade 140 of the plurality of blades 140 of the iris mechanism has a service hole adapted to allow wiring or other structures or installations to pass through.
To drive the joint movement of the plurality of blades 140 of the iris mechanism 190 from the rest configuration to the deployed configuration, and vice versa, the thrust reverser system 60 further comprises a second actuator mechanism 170.
In the most preferred embodiment of the invention, the first actuator mechanism 120 and the second actuator mechanism 170 are arranged for coordinated drive such that:
In an even more preferred embodiment of the invention, the first actuator mechanism 120 and the second actuator mechanism 170 are arranged for synchronized actuation such that the movement of the first actuator mechanism 120 causes the concurrent movement of the second actuator mechanism 170, and, consequently, the movement of the translating structure 90 of the thrust reverser system 60 from the stowed position to the opening position is matched by the similar movement of the plurality of blades 140 of the iris mechanism 190 from the rest configuration to the deployed configuration, and vice versa.
As may also be inferred from a comparison between
In a particularly preferred embodiment of the invention, the first actuator mechanism 120 comprises a runner 280 and a pin 180. The runner 280 has a first portion 280a extending parallel to said axial direction 10, and a second portion 280b extending non-parallel to said first portion 280a from said first portion 280a, as a continuation thereof. The pin 180, which may also be made in the form of a roller, is arranged integral in translation with the translating structure 90 of the thrust reverser system 60 and is mounted slidable inside the runner 280. In the same embodiment, the second actuator mechanism 170 comprises an actuation ring 250 adapted to rotatably draw said plurality of blades 140 of the iris mechanism 190 between said rest configuration and said deployed configuration. In this way, the pin 180 is arranged to rotatably draw said actuation ring 250 when the pin 180 is slid within said second portion 280b of said runner 280, for example when it is moved along the axial direction 10 by the action of the first actuator mechanism 120, and in particular of a linear actuator preferably part of said first actuator mechanism 120. Preferably, the runner 280 further comprises a third portion 280c, extending along a direction parallel to, and spaced apart from, said first portion 280a, from said second portion 280b, as a continuation thereof. In this way, the pin 180 may reach a locked end position when it has reached the end portion 280, or the third portion 280c of the runner 280, while ensuring that the angular position of the actuation ring 250, which defines the rest or deployed configuration of the plurality of blades 140, is stably maintained. Obviously, in an equivalent way, the second portion 280b of the runner 280 may also not be straight, and extend, for example, along a curve or a circumferential arc. Similarly, although in
Alternatively, the mechanical connection between the first actuator mechanism 120 and the second actuator mechanism 170 may be provided by means of other types of transmission means, such as by gear or belt or chain mechanisms or other known mechanisms.
Alternatively, the first actuator mechanism 120 and the second actuator mechanism 170 may be made or constructed separately, i.e., without a mechanical connection between them, but rather arranged to be controlled simultaneously by the same electronic control unit (not shown, known per se), according to a coordinated or synchronized actuation program in ways similar to those just described.
In a further alternative embodiment, the first actuator mechanism 120 and the second actuator mechanism 170 may be arranged to be controlled by a common hydraulic, or pneumatic actuation, known per se and not further described in detail, advantageously so as to achieve coordinated or synchronized control in ways similar to those described above.
As shown in detail in
The iris mechanism 190 further comprises a plurality of actuation pins 240, each actuation pin 240 being mounted slidably in a respective blade guide 230 and mounted integral with a respective blade 140.
Thus, as is evident to the person skilled in the art, the rotation of the actuation ring 250 about the axial direction 10, caused by the second actuator mechanism 170, corresponds to a rotation of each blade 140 of the plurality of blades 140 about the respective hinge 150. The joint and complete rotation of the plurality of blades 140 causes the iris mechanism to move between the aforementioned two rest and deployment configurations.
In a manner known per se, the turbofan propulsion system 30 may be coupled to an aircraft wing for support by means of a pylon 20. Said pylon 20 defines within it a cavity, in which, preferably, said runner 280 is fully accommodated.
Within said cavity of the pylon 20 is also housed a system for coupling to the pylon 160, adapted to suspend the thrust reverser system 60 to the pylon 20, and to allow at least a translational movement, along a direction parallel to the axial direction 10, of the translating structure 90 of the thrust reverser system 60 and of the components of the system integral to the structure.
The pylon coupling system 160 is constrained to the pylon 20 through fixed interfaces provided by a front pylon coupling 360 and a rear pylon coupling 370. The fixed structure 80 is constrained to the pylon coupling system 160 by means of a first hinge of the fixed structure 320 and a second hinge of the fixed structure 330. The translating structure 90 is constrained to the pylon coupling system 160 by means of a first hinge of the translating structure 340 and a second hinge of the translating structure 350. The iris mechanism 190 may be, in a non-limiting example, constrained to cylindrical guides of the pylon coupling system 160 so as to slide freely along them.
As mentioned previously, a method for reversing the thrust of the turbofan propulsion system 30 of an aircraft forms part of the invention. The method is applicable to the turbofan propulsion system 30 according to the invention, and comprises the steps of:
Preferably, the sliding movement of the translating structure 90 of the thrust reverser system 60 of said step a) and the joint movement of the plurality of blades 140 of the iris mechanism 190 of said step b) are performed in a coordinated manner. In this way, it is ensured that:
In an even more preferable embodiment of the method according to the latter further aspect of the invention, the movement of the first actuator mechanism 120 and the movement of the second actuator mechanism 170 are performed synchronously so that the movement of the translating structure 90 of the thrust reverser system 60 from the stowed position to the opening position is matched by the similar movement of the plurality of blades 140 of the iris mechanism 190 from the rest configuration to the deployed configuration, and vice versa.
As may be seen from the foregoing description, due to the thrust reverser system and the related turbofan propulsion system according to the invention, the objects of the above-described invention may be fully achieved, resulting in several advantages.
In particular, the invention provides a thrust reverser system improved with respect to the prior art.
Firstly, by virtue of the configuration of the iris mechanism, the thrust reverser system may occlude the bypass duct in the best way possible and reduce any airflow leakage to a minimum, or substantially to zero.
Further, by virtue of the advantageous ability to actuate in a coordinated, and even more preferably synchronized, manner, the movement of the translating structure of the thrust reverser system between the stowed and opening positions and the joint movement of the blades of the plurality of blades of the iris mechanism between the rest and deployed configurations, a more precise and better-timed thrust reversal effect may be achieved than in the prior art.
In addition, the reduction of the number of components, the number and complexity of aerodynamic discontinuities, and, most importantly, the weight of the thrust reverser system benefits the production, maintenance, and operation costs of a turbofan propulsion system, and allows for a significant reduction in the noise emission of such a propulsion system compared to the prior art by virtue of the increase in acoustically treatable surface area.
Moreover, such a configuration makes it possible to comply with safety requirements regarding unintentional actuation of the thrust reverser system. Indeed, by virtue of the configuration of the iris mechanism and the first actuator mechanism and the second actuator mechanism, it is easy for the person skilled in the art to integrate locking mechanisms in both the first and second actuator mechanisms, as well as in the fixed ring of the iris mechanism or in the runner or pin operatively connected thereto (in a way that is known per se and therefore not shown).
In addition, the possibility of accommodating the guide and the pylon coupling system entirely within a hollow space obtained inside the pylon connecting the turbofan propulsion system to the aircraft wing allows the aerodynamic shape of the engine nacelle to be improved and facilitates maintenance operations.
Lastly, constraining the iris mechanism permanently to the pylon coupling system and engageably to one of the fixed and translating structures makes it possible to simultaneously create a 360° iris mechanism, or one capable of occluding a bypass duct with an O-shaped or ring-shaped cross section, and, at the same time, to create both the translating and fixed structures in two half-shells, or in two portions, for example in two half-annular halves, or in two C-shaped halves, to facilitate opening for inspection or maintenance, as shown in
Without prejudice to the principle of the invention, the embodiments and the details of construction may be widely varied with respect to that which has been described and illustrated purely by way of non-limiting example, without thereby departing from the scope of the invention as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 102020000013846 | Jun 2020 | IT | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2021/055056 | 6/9/2021 | WO |
