Propulsion system for aircraft
阅读说明:本技术 用于航空器的推进系统 (Propulsion system for aircraft ) 是由 让-路易斯·罗伯特·盖伊·贝斯 叶-邦纳·卡琳娜·马尔多纳多 于 2020-04-10 设计创作,主要内容包括:本发明涉及一种用于航空器的推进系统和航空器。推进系统包括至少一个转子和发动机舱整流罩,所述发动机舱整流罩围绕所述至少一个转子相对于所述转子的旋转轴线延伸,所述发动机舱整流罩包括:前段,其形成所述发动机舱整流罩的入口截面;后段,其末端形成所述发动机舱整流罩的出口截面;以及中间段,其连接所述前段和所述后段;其特征在于,所述后段包括径向内壁和径向外壁,所述径向内壁和所述径向外壁是由可变形的形状记忆材料制成的,并且在于,形成出口截面的末端包括气动或液压的环形驱动器,所述环形驱动器绕所述旋转轴线延伸并且被配置为在预定操纵压力的作用下变形,以使得所述出口截面的外直径在最小直径和最大直径之间变化。(The invention relates to a propulsion system for an aircraft and to an aircraft. The propulsion system includes at least one rotor and a nacelle fairing extending around an axis of rotation of the at least one rotor relative to the rotor, the nacelle fairing including: a forward section forming an inlet cross section of the nacelle fairing; a rear section, the end of which forms an outlet cross section of the nacelle fairing; and a middle section connecting the front section and the rear section; characterized in that said rear section comprises a radially inner wall and a radially outer wall, said radially inner wall and said radially outer wall being made of a deformable shape memory material, and in that the end forming the outlet section comprises a pneumatic or hydraulic annular drive extending around said rotation axis and configured to deform under the action of a predetermined operating pressure so that the outer diameter of said outlet section varies between a minimum diameter and a maximum diameter.)
1. A propulsion system (1, 1') for an aircraft comprising at least one rotor (2) and a nacelle fairing (3), said nacelle fairing (3) extending around a rotation axis (X) of said at least one rotor (2) with respect to said rotor (2), said nacelle fairing (3) comprising:
-a front section (10) forming an inlet section (BA) of the nacelle fairing (3);
-a rear section (20) whose end (21) forms an outlet section (BF) of the nacelle fairing (3); and
-a middle section (30) connecting the front section (10) and the rear section (20);
characterized in that said rear section (20) comprises a radially inner wall (20a) and a radially outer wall (20b), said radially inner wall (20a) and said radially outer wall (20b) being made of a deformable shape-memory material, and in that the end (21) forming the outlet section (BF) comprises a pneumatic or hydraulic annular actuator (23), said annular actuator (23) being arranged around said rotation axis (BF)A line (X) extends and is configured to deform under the action of a predetermined operating pressure so as to cause an outer diameter (D) of the outlet section (BF)BF) At the determined minimum diameter (D)BFc) And maximum diameter (D)BFd) To change between.
2. A propulsion system (1, 1') according to the preceding claim, characterized in that said annular drive employs a radially reinforced elastomeric material comprising fibers.
3. Propulsion system (1, 1') according to claim 1, characterised in that the annular drive (23) comprises an annular pocket (23a) of flexible material inserted in a helical spring (23 b).
4. Propulsion system (1, 1') according to any of the previous claims, further comprising a reinforcing cage (22), said reinforcing cage (22) connecting said radially inner wall (20a) and said radially outer wall (20b) of said rear section (20).
5. Propulsion system (1, 1') according to any of the previous claims, wherein the intermediate section (30) is rigid and connected to the engine (6) of the propulsion system (1, 1') by at least one arm (31).
6. Propulsion system (1, 1') according to any of the previous claims, wherein the front section (10) is made of deformable shape memory material, the front section (10) comprising an outer diameter (D) such that the inlet section (BA)BA) A variant arrangement.
7. Propulsion system (1, 1') according to the previous claim, wherein the outer diameter (D) of the inlet section (BA)BA) Under the action of a pneumatic or hydraulic expansion device.
8. Propulsion system (1, 1') according to claim 6, wherein the inlet section (BA) is defined byThe outer diameter (D)BA) The front section (10) also has heat-shrink characteristics, varying under the action of an annular heat lining (13).
9. Propulsion system (1, 1') according to any of the previous claims, wherein the front section (10) comprises a plurality of stiffeners (14) connected by a buckling-resistant device (15).
10. Propulsion system (1, 1') according to claim 6, wherein the outer diameter (D) of the inlet section (BA)BA) Is varied by the action of a jack-driving mechanism (230), said jack-driving mechanism (230) being configured to cooperate with means (240) fixed on an inner surface (12b') of a radially outer wall (12b) of said front section (10).
11. Propulsion system (1, 1') according to claim 6, wherein the outer diameter (D) of the inlet section (BA)BA) Is varied by a pneumatic or hydraulic annular actuator configured to deform radially under a predetermined operating pressure.
12. An aircraft, characterized in that it comprises at least one propulsion system (1, 1') according to any one of claims 1 to 9, said propulsion system (1, 1') being pivotally mounted on the aircraft by means of a pivot axis (4, 4'), said pivot axis (4, 4') being eccentric or through-disposed with respect to the rotor (2).
Technical Field
The present invention relates to the field of aircraft propulsion systems. In particular, the present invention relates to a propulsion system employing a variable section nacelle fairing.
Background
An aircraft propulsion system includes at least one rotor or one propeller comprising a plurality of blades mounted on a rotating shaft.
Aircraft, in particular Vertical Take-Off and Landing aircraft (ADAV: Alronefs a D-deck et VerrissargeVerticaux or VTOL: Vertical Take-Off and Landing in English), are simple rotor propulsion systems when comprising only a single rotor or are contra-rotor propulsion systems when comprising a pair of counter-rotating rotors.
These propulsion systems employ a streamlined rotor (which is then surrounded by an annular nacelle fairing) or a free rotor on which the propulsion system, in particular the rotor (free or streamlined rotor) can be mounted, which enables the propulsion system and the rotor to be oriented between a vertical position and a horizontal position, for example in the vertical direction for take-off or landing, and in the horizontal direction for forward flight or for flight mode.
Streamlined rotors have several advantages, such as:
the acoustic signature directly emitted by the rotor is greatly reduced;
-protecting the blades of the rotor from interference by surrounding obstacles;
improving the performance of the rotor, in particular for hovering or low-speed advancing aircraft.
In fact, at low forward speeds or take-off, associated with the action of the streamlined nacelle on the airflow in front of the rotor, the streamlined nacelle provides the rotor with additional hovering thrust (i.e. the aircraft is stationary in the air, maintaining lift without support or support), also called airflow duct, with reference to the direction of flow of the airflow over the streamlined nacelle. More specifically, when there is no fairing, the airflow behind the rotor is naturally constricted inwardly by the free rotor. In other words, the diameter of the gas flow tube decreases gradually in the backward direction until the diameter is equal to half the cross section of the rotor.
In contrast, for a streamlined rotor, the outlet cross-section of the nacelle fairing defines the shape of the airflow duct, i.e. the outlet of the nacelle fairing, which is of substantially constant cross-section, is cylindrical, thus hindering the natural contraction of the airflow.
The propulsion depends on the outlet cross section of the nacelle fairing, so that the larger the outlet cross section of the nacelle fairing, the greater the propulsion. In fact, the local pressure caused by the deformation of the nacelle fairing caused by the flowing air flow, the thrust increased by the presence of the nacelle fairing, is generated at the leading edge of the nacelle fairing. The greater the air flow permitted in the propulsion system, i.e. the greater the outlet section of the nacelle fairing, the greater this pressure and therefore the greater the thrust produced.
However, the faster the speed, the less efficient the propulsion of the rotor. In fact, as the forward speed of the aircraft increases, the faster the frontal drag due to the presence of the nacelle fairing increases, the lower the performance of the streamlined rotor. Thereby, the propulsive efficiency is reduced according to the rotation state and size of the rotor.
Thus, by using a streamlined rotor, noise shielding and rotor perimeter safety are achieved by sacrificing propulsion efficiency while the aircraft is cruising, i.e., traveling at high speeds.
Furthermore, depending on the flight conditions of the aircraft, in particular at takeoff or when the aircraft is flying vertically stationary (or VTOL mode) or at low speed near above a surface such as the ground, the direction of flow of the airflow around the aircraft, in particular around the nacelle cowling of the propulsion system of the aircraft. In fact, under these conditions, the air flow ejected behind the rotor can cause damage to the surface under the aircraft, which deviates the trajectory of the air flow and alters the direction of flow of the air flow around the aerodynamic profile that constitutes the nacelle fairing. Thus, the aerodynamic characteristics of the streamlines vary depending on the position of the cruise flight or flight away from the obstacle. When an aircraft is flying vertically, at rest or at low speed, sufficiently close above a surface, the surface affects the airflow flow circulation around the aircraft, particularly around the nacelle fairing. This phenomenon is called the "ground effect".
For the desired aerodynamic performance, it is advantageously possible to adapt to the shape of the aerodynamic profile constituting the nacelle fairing under the various flight conditions of the aircraft, in particular when the "ground effect" is important.
In the prior art, various solutions have been proposed for adapting to the shape of the aerodynamic profile of an aircraft under various flight conditions, but most of these solutions are directed to the wing of the aircraft, which solutions cannot be transferred to or adapted to axisymmetric elements such as the nacelle fairing of a propulsion system (for example a turbojet or an electronic impeller).
Dual-flow turbojet engines have been proposed which are capable of locally varying the geometry of the secondary jet, or turbojet engines whose nacelle cowlings have a variable inlet section.
However, none of these proposed solutions proposes adapting the outlet or inlet section of the nacelle fairing of the propulsion system (in particular in rotor VTOL mode) to the various flight conditions of the aircraft.
Therefore, in view of the above problems, it is desirable to provide a simple and efficient solution.
The invention aims to provide a scheme capable of simply and quickly adapting a propulsion system of an aircraft, so that the aerodynamic and acoustic properties of the propulsion system are improved, and the safety of a rotor is guaranteed at each flight phase of the aircraft.
Disclosure of Invention
To this end, the invention relates to a propulsion system for an aircraft comprising at least one rotor and a nacelle fairing extending around an axis of rotation of the at least one rotor with respect to the rotor, the nacelle fairing comprising:
-a front section forming an inlet section of a nacelle fairing;
-a rear section, the end of which forms the outlet section of the nacelle fairing; and
-a middle section connecting the front section and the rear section;
characterized in that said rear section comprises a radially inner wall and a radially outer wall, said radially inner wall and said radially outer wall being made of a deformable shape memory material, and in that the end forming the outlet section comprises a pneumatic or hydraulic annular drive extending around said rotation axis and configured to deform under the action of a predetermined operating pressure so that the outer diameter of said outlet section varies between the determined minimum diameter and maximum diameter.
The propulsion system of the invention thus makes it possible to obtain simply and rapidly, according to the needs of the aircraft, a nacelle fairing shape adapted to the flight conditions of the aircraft, ensuring optimum propulsion efficiency, while minimizing the acoustic hazards posed by the rotor of the propulsion system, and the presence of the nacelle fairing ensuring the safety of this rotor. In other words, an advantage of the propulsion system is that the presence of the nacelle fairing enables the nacelle fairing to be adapted according to the flight conditions of the aircraft.
An inlet cross-section of an engine compartment fairing of the propulsion system may correspond to a leading edge of the fairing. The outlet cross section of the fairing may correspond to the trailing edge of said fairing. Thus, the outer diameter of the trailing edge may correspond to the outer diameter of the outlet cross section of the propulsion system.
Preferably and advantageously, the annular drive is of radially reinforced elastomeric material containing fibres.
According to another embodiment, the annular drive comprises an annular pocket of flexible material inserted in the helical spring.
Advantageously, the propulsion system further comprises a reinforcement shroud connecting the radially inner wall and the radially outer wall of the rear section and such as to ensure a substantially constant clearance between the radially inner wall and the radially outer wall of the rear section, in particular from a convergent position to a divergent position or vice versa of the rear section of the nacelle fairing of the propulsion system.
Advantageously, the intermediate section is rigid and connected to the engine of the propulsion system by at least one arm.
This gives the nacelle cowling of the propulsion system a rigid structure to ensure the screening function.
Preferably and advantageously, the front section is made of a deformable shape memory material and comprises means for varying the outer diameter of the inlet section of the propulsion system.
In this way, the nacelle fairing of the propulsion system of the invention can be easily adapted according to the flight phase of an aircraft equipped with this propulsion system.
According to one embodiment, the outer diameter of the inlet section is varied by a pneumatic or hydraulic expansion device.
The advantage of this solution is that it does not require a large amount of energy for its implementation.
According to another embodiment, the outer diameter of the inlet section is varied by the annular thermal liner and the front section further has thermal contraction characteristics.
The technical scheme is simple to realize and has smaller volume and mass.
According to another embodiment, the outer diameter of the inlet section is varied under the action of a jack drive mechanism configured to cooperate with means fixed on the inner surface of the radially outer wall of the front section.
According to another embodiment, the outer diameter of the inlet section is varied under the action of a pneumatic or hydraulic annular actuator configured to deform radially under the action of a predetermined control pressure.
Advantageously, the front section comprises a plurality of stiffeners connected by a buckling-resistant device. This makes it possible to maintain a uniform aerodynamic profile of the inlet section of the nacelle fairing of the propulsion system of the invention.
The invention also relates to an aircraft characterised in that it comprises a propulsion system having at least one of the features described above, which is pivotally mounted on the aircraft by means of a pivot axis which is eccentric or through-disposed with respect to the rotor.
As mentioned above, the nacelle fairing of the propulsion system of the invention can be easily adapted according to the flight phase of the aircraft equipped with this propulsion system, and according to the translational or vertical flight mode of the aircraft.
Drawings
Other features and advantages of the present invention will become apparent upon reading the following detailed description and upon reference to the accompanying drawings.
In the drawings:
FIG. 1a is a perspective view of a first embodiment of a propulsion system having a nacelle mounted on an eccentric pivot shaft, the propulsion system being in a horizontal position;
FIG. 1b is a view similar to FIG. 1a and showing the propulsion system in a vertical position;
FIG. 1c is a perspective view of a second embodiment of a propulsion system having a nacelle mounted on a through pivot shaft, the propulsion system being in a horizontal position;
FIG. 2 is a cross-sectional view of the propulsion system of the present invention with the aft section of the nacelle fairing in a converging position;
FIG. 3 is a view similar to FIG. 2 and showing the propulsion system of the present invention with the aft section of the nacelle fairing in an intermediate position;
FIG. 4 is a view similar to FIG. 2 and showing the propulsion system of the present invention with the aft section of the nacelle fairing in a diverging position;
FIG. 5a is a partial cross-sectional view of the nacelle fairing of the propulsion system of the present invention and showing the inlet of the nacelle fairing in a neutral position;
FIG. 5b is a view similar to FIG. 5a and showing the inlet of the nacelle fairing in a converging position;
FIG. 5c is a longitudinal cross-sectional view of the forward section of the nacelle fairing shown in a converging position;
FIG. 6a is a cross-sectional view of an inlet of a nacelle fairing of the propulsion system, the inlet being in a neutral position;
FIG. 6b is a view similar to FIG. 6a and showing the inlet of the nacelle fairing of the propulsion system in a converging position;
FIG. 6c is a partial view of the front of the inlet of the nacelle fairing of the propulsion system;
FIG. 7a is a front view of one embodiment of the ring driver of the present invention;
FIG. 7b is a cross-sectional view of an embodiment of the ring drive of the present invention, shown in the rest position;
figure 7c is a cross-sectional view of an embodiment of the ring driver of the present invention shown in a converging position.
Detailed Description
The terms "axial", "inner" and "outer" are used herein with reference to the axis of rotation of the propulsion system of the present invention.
The propulsion system generally comprises:
-an engine compartment;
-an engine and its steering control system; and
in the case of propeller or rotor propulsion, a propeller or rotor.
The nacelle is an element that can be integrated with the engine of an aircraft, the nacelle comprising:
nacelle cowlings (enabling the engine to be inverted, streamlining the rotor, directing the air flow according to the operation of the aircraft, generating thrust actions, reversing the thrust of the propulsion system, etc.);
engine-mounted devices (e.g. Engine mounts for converged electric, hydraulic, pneumatic networks, i.e. Engine built-Up, EBU); and
-a suspension system suspended to the aircraft.
Fig. 1a and 1b show in a simplified manner a first embodiment of a
Here, the
The
Fig. 1c shows a second embodiment of the propulsion system 1' of the aircraft of the invention, wherein the propulsion system ' may be mounted on a pivot axis 4' extending through the
Referring to fig. 2 to 5, the nacelle fairing 3 of the
-a
-a
an
The
The material comprising the
More precisely, with reference to fig. 5a to 6c, the
The aim of the invention is to enable the air inlet cross section of the nacelle fairing 3 of the
FIGS. 5a and 5b schematically show the outer diameter D of the inlet section BABAChange between a neutral position (fig. 5a) and a convergent position (fig. 5 b). Outer diameter DBAHaving a minimum value D at neutral positionBAminAnd has a maximum value D at the convergence positionBAmax. Thus, the outside diameter D at the convergent positionBAmaxGreater than the outside diameter D at neutral positionBAminAnd an inlet of the nacelle cowl 3: (Or as the front section 10) is said to be convergent. In other words, the jet air flow is varied so that the radial dimension of the air inlet section is greater than the radial dimension of the air outlet section. Thus, fluid rather than geometric definition is used herein for convergence.
According to a first advantageous embodiment, in order to obtain the outside diameter D of the inlet section BABAVarying between the neutral position and the convergent position or vice versa, the
The annular thermal coating 13 is heated in a known manner, for example by means of a resistive circuit arranged in the coating 13.
The radially inner wall 12a and the radially outer wall 12b of the annular rear portion 12 of the
According to a second advantageous embodiment, shown in fig. 5c, in order to straighten the outside of the inlet section BADiameter DBAVarying between a neutral position and a convergent position, and vice versa, the
More precisely, the jack arm 230 'of the jack-actuating mechanism 230 is configured to be extended or retracted under a predetermined manipulation to act on the device 240 and to radially move the device 240, exerting a pressure on the radially inner surface 12b' of the radially outer wall 12b and thus causing the outer diameter D of the inlet section BABAAnd (4) changing. The jack drive mechanism 230 may be an electric, hydraulic, pneumatic, or screw-nut system.
For example, the device 240 is embedded in the radially inner surface 12b' of the radially outer wall 12b (e.g. by vulcanization) and is moved radially under the action of the jack drive mechanism 230.
According to an embodiment, the device 240 comprises a plurality of prisms (for example triangular in section) distributed in at least one annular column, driven by at least one jack through at least one annular element 250.
Prism 240 and ring member 250 are formed of a rigid material, such as a metal material.
In fig. 5c, the
Actuation of the jack drive mechanism 230 drives the jack arms 230' to extend, thereby driving the annular member 250 to move axially (in the direction of arrow F5 in fig. c) and thus the prism columns 240 to move radially (in the direction of arrow F6). The annular element 250 moves on the face of the prism 240 between a neutral position of the front section of the nacelle fairing 3 (in a position flush with the inner surface 12b' of the inner wall 12b) and a convergent position of the
When the jack drive mechanism 230 is actuated to retract the jack arm 230', the elements move in opposite directions to reduce the diameter of the entry section BA. The radially inner wall 12a and the radially outer wall 12b of the
Advantageously but not limitatively, each annular row comprises at least four prisms 240, the four prisms 240 being equi-angularly distributed along the radially inner surface 12b' of the radially outer wall 12b of the
It is also conceivable that the
According to another embodiment, not shown, the annular crown is directly connected to the jack arm 230' of each drive mechanism 230. Each annular crown then slides directly (converges to rest) on the inner surface 12b' of the outer wall 12 b. Advantageously, the inner surface 12b' of the outer wall 12b is then provided with an anti-friction coating.
The transition of the
According to a third advantageous embodiment, not shown, in order to obtain the outside diameter D of the inlet section BABAThe inlet section BA of the
More precisely, the annular actuator is configured to deform radially under the action of a predetermined operating pressure, so as to cause the outer diameter D of the inlet section BABABetween a neutral position and a convergent position of the
Preferably and advantageously, the annular actuator is made of a radially reinforced elastomeric material, for example comprising fibres. For example, the annular drive 40 employs a polymeric material that contains external devices or inclusions to strengthen the polymeric material in a radial direction.
According to another embodiment, the annular actuator comprises an annular pocket of flexible material and inserted into the helical spring, so as to limit the diametral expansion of the section of the flexible pocket. Another embodiment can use an anisotropic material with a greater elastic modulus in the radial direction relative to the azimuthal direction.
The annular driver is configured such that, upon an increase in pressure experienced, the expansion of the inner cross-sectional diameter of the annular driver is substantially less than the expansion of the outer diameter of the annular driver. In other words, the increased pressure inside the annular driver (or flexible bag) is expressed as a directional angular expansion that increases the outer diameter of the annular driver.
In fact, the gradual increase of the operating pressure generated by the pneumatic or hydraulic automatic means causes a gradual change of the outer diameter of the annular actuator, so as to deform the radially inner wall 12a and the radially outer wall 12b of the deformable shape-memory material of the
Likewise, the progressive reduction of the operating pressure generated by the pneumatic or hydraulic automatic means causes the progressive transformation of the
The transition of the
According to another embodiment, not shown, the outer diameter D of the inlet section BA is made such thatBAThe means capable of varying between a neutral position and a convergent position or vice versa comprise pneumatic expansion means. Thus, pressurized air is injected inside the annular front wing 11, so that it moves outwards in a radial direction, driving the retraction of the radially outer wall 12b and the extension of the radially inner wall 12a of the annular rear portion of the
Thus, the outer diameter D of the inlet section BA of the
The
Referring to fig. 6a to 6c, a plurality of
These stiffeners, for example metal stiffeners, have an aerodynamic profile with a C-shaped cross section, corresponding to the aerodynamic shape of the inlet section BA of the
According to the example shown, the
The
Referring to FIG. 6a, the
Referring to FIG. 6b, the
However, in order to obtain the outer diameter D of the inlet section BABAIn a variation, such
The
The
The
The
The radially
The radially
The shape memory material constituting the radially
The thickness of the radially
The
In addition, to ensure a substantially constant gap between the radially inner and
The
Indeed, another aspect of the inventionThe aim is to enable the shape of the air outlet cross-section of the nacelle fairing 3 of the
In other words, for a streamlined rotor, the outlet air profile of the
For this purpose, the
The
More precisely, the
Preferably and advantageously, the
According to the embodiment shown in fig. 7a to 7c, the
The
Fig. 2 shows a
Fig. 3 shows a
Fig. 4 shows a
In fact, produced by pneumatic or hydraulic automatic meansThe gradual increase in the actuating pressure causes the outer diameter D of the
Likewise, the progressive reduction of the operating pressure generated by the pneumatic or hydraulic automatic means causes the progressive transformation of the
The transition of the
The aerodynamic profiles of the inlet and outlet sections of the nacelle fairing 3 can therefore advantageously be optimized between a diverging configuration and a converging configuration according to the aerodynamic and mechanical constraints obtained during the working phase of the aircraft, so as to form a diverging or converging flow respectively around the nacelle fairing.
The
The advantage of an aircraft equipped with the
Indeed, the variation of the inlet section combined with the variation of the outlet section makes it possible to vary the jet of the propulsion system and thus to significantly improve the aerodynamic performance of the aircraft.
Furthermore, the outer diameter D of the inlet cross-section BA (or leading edge) of the nacelle fairing 3BAIt can also be varied between a neutral position and a convergent position, further improving the aeromechanical performance of the aircraft.