Aircraft engine nacelle air inlet lip with passive exhaust device shutoff device

Abstract

Aircraft engine nacelle air inlet lip provided with a passive communication port closure device The invention relates to an aircraft engine nacelle (10) air inlet lip (12) provided with a passive closure device (22) for exhaust devices (20). The passive closure device (22) is capable of taking a closure position (P1) in which it closes the exhaust devices (20) and an open position (P2) in which it releases the exhaust devices (20) depending on the temperature felt by the passive closure device (22). Thus, the exhaust devices (20) are closed in all flight phases where de-icing of the air inlet lip is not necessary. Figure for abstract: Fig. 3

Description

Title of the invention: Aircraft engine nacelle air inlet lip provided with a passive exhaust device closure device Field

[0001] The present invention relates to an aircraft engine nacelle air inlet lip provided with a passive exhaust device closing device.

[0002] If necessary (prevention of frost formation or elimination of frost already formed), the leading edge of the air intake lip of aircraft engines is de-iced by heating with pressurized hot air, taken from said engine and brought to said leading edge by a pressurized hot air circulation circuit. An example of such a de-icing device is shown in patent EPI 186533.

[0003] For this purpose, such an air inlet lip comprises, in a known manner, a hollow leading edge delimiting an internal annular peripheral chamber, closed by an internal partition (or frame) and provided with at least one orifice putting said internal chamber into communication with the exterior. In addition, a hot air supply pipe is connected, on the rear side opposite said leading edge, to a pressurized hot air circulation circuit and, on the front side towards the leading edge, to an injector injecting a flow of said pressurized hot air into the annular chamber.

[0004] Thus, said hot air flow circulates in said annular chamber, heating it before escaping to the outside through said communication orifice. Several orifices are provided in said leading edge for the evacuation into the open air of the hot air having circulated inside the leading edge.

[0005] As shown schematically in [Fig.l], an aircraft engine nacelle 1 comprises an air inlet lip 2. The lip 2 comprises a hollow leading edge 3 in which the hot air taken from the engine circulates.

[0006] The nacelle 1 further comprises an internal duct 4, provided at its rear end, directed towards the body of the engine (not shown), with a connecting element 5 and at its front end, housed in the hollow leading edge 3 of the air inlet 2, with an injector 6. Hot air under pressure is taken from the engine and is injected, via the internal duct 4 and the injector 6 into the hollow leading edge 3 of the air inlet lip 2.

[0007] The injector 6 injects into the inner duct of the lip 2, a flow of hot air 7 which it receives from the duct 4. The hot air 7 circulates inside the leading edge 3 and heats it, which makes it possible to defrost said leading edge.

[0008] A hot air exhaust device is used to evacuate the hot defrosting air outside the leading edge 3 and not exceed the thermal capacity of the materials constituting said edge 3. This device is in the form of orifices 8 distributed in the leading edge 3 of the lip 2 for the evacuation into the open air (arrow 7a) of the hot air having circulated inside said leading edge 3. The orifices 8 can be calibrated to allow the evacuation to the outside of only a part of the flow of hot air circulating in the hollow leading edge 3, the other part of said flow being caused to recirculate in said leading edge 3.

[0009] These orifices 8, due to their size, their location and the pressure difference between the inside and the outside of the lip 2, are detrimental to the performance of the aircraft, in particular during the takeoff, climb, descent or landing phases because they cause parasitic drag. In addition, these orifices generate aerodynamic disturbances resulting in additional and unpleasant acoustic effects during the aforementioned flight phases.

[0010] However, it is generally not necessary to defrost the air inlet lip during these flight phases.

[0011] There is therefore a need for a hot air exhaust device for evacuating hot deicing air from the leading edge circulating in the air intake lip which has less impact on the performance of the aircraft and which has a reduced acoustic footprint.

[0012] The present invention aims to remedy all or part of the drawbacks of the prior art. SUMMARY

[0013] For this purpose, the invention relates to an air intake lip for an aircraft engine nacelle provided with a hollow leading edge delimiting an internal annular peripheral chamber closed by an internal partition in which hot air circulates under pressure, said hollow leading edge being provided with at least one hot air exhaust device to allow the evacuation to the outside of all or part of said hot air flow circulating in said annular chamber and at least one passive closing device for said at least one exhaust device, said at least one passive closing device being remarkable in that it is movable between a closing position in which said at least one passive closing device closes said at least one exhaust device and an open position in which said at least one passive closing device releases said at least one exhaust device,said at least one passive sealing device being made of a shape memory material.

[0014] Thus, the present invention makes it possible to close the exhaust devices during the flight phases during which the de-icing of the air inlet lip is not active. and to allow the evacuation of hot air under pressure only during flight phases requiring de-icing of the air intake lip. In doing so, parasitic drag and the acoustic footprint are significantly reduced.

[0015] According to particular embodiments, the tool comprises other remarkable characteristics taken separately or in combination:

[0016] In a particularly simple embodiment, said at least one passive closure device is in the form of a part complementary to that of the at least one exhaust device.

[0017] Said at least one passive sealing device is capable of deforming from a predetermined transition temperature TD.

[0018] Said at least one passive shutter device is capable of occupying the shutter position as soon as the temperature in the internal annular peripheral chamber is lower than the predetermined transition temperature TD.

[0019] Said at least one passive closure device is capable of occupying the open position as long as the temperature in the internal annular peripheral chamber is higher than the predetermined transition temperature TD + A°C.

[0020] Said at least one exhaust device is in the form of an exhaust orifice capable of evacuating the hot air under pressure from the internal annular peripheral chamber.

[0021] Said at least one exhaust device is in the form of an exhaust grille comprising several exhaust orifices capable of evacuating the hot air under pressure from the internal annular peripheral chamber.

[0022] It will be noted that, within the framework of the present invention, said at least one passive closure device may have the form of a blade arranged opposite each exhaust orifice.

[0023] Said at least one passive closure device comprises as many blades as there are exhaust orifices.

[0024] Said at least one passive sealing device is in the form of a single plate whose dimensions are adapted to cover all of the exhaust orifices of the exhaust grille.

[0025] Preferably, said at least one passive sealing device comprises at least one protrusion adapted to seal said at least one exhaust device. Thus, the passive sealing device effectively seals the exhaust device and prevents any air leakage causing external flow disturbance when the passive sealing device is in the sealing position.

[0026] The invention also relates to an aircraft comprising an air intake according to one of the preceding characteristics.

[0027] Other features and advantages of the device according to the invention will become more apparent on reading the description given below, for informational but non-limiting purposes, with reference to the appended drawings in which:

[0028] [Fig. 1] represents an aircraft engine air intake nacelle according to the prior art.

[0029] [Fig.2] represents a sectional view of an aircraft engine air intake nacelle comprising a passive shutter device according to the invention, the passive shutter device being in the shutter position.

[0030] [Fig.3] represents a sectional view of an aircraft engine air intake nacelle comprising a passive shutter device according to the invention, the passive shutter device being in the open position.

[0031] [Fig.4] represents an enlarged view of a passive shutter device according to a variant of the invention.

[0032] [Fig.5] represents a graph of the deformation of the passive shutter device according to the invention.

[0033] [Fig.6] represents a top view of a particular embodiment of the closure device according to the invention, adapted to an exhaust device different from that represented in the preceding figures.

[0034] [Fig.7] represents a first variant embodiment of the passive shutter device according to the invention.

[0035] [Fig.8] represents a second variant embodiment of the passive shutter device according to the invention.

[0036] [Fig. 2] shows an aircraft engine nacelle 10 provided with an air inlet lip 12. The air inlet lip 12 has a hollow leading edge 14 delimiting an internal annular peripheral chamber 16 closed by an internal partition 18 in which hot air under pressure circulates. This hot air under pressure is taken from the aircraft engine and brought by any means known to those skilled in the art into the internal annular peripheral chamber 16 of the air inlet lip 12.

[0037] The purpose of the hot air taken from the engine is, when the operating conditions of the aircraft require it, to de-ice the leading edge 14 of the air inlet lip 12, this hot air having to be evacuated to reduce the thermal stresses on the materials constituting the leading edge 14.

[0038] To this end, the hollow leading edge 14 is provided with at least one exhaust device 20 to allow the evacuation to the outside of all or part of said hot air flow circulating in said annular chamber 16. The leading edge 14 may have several exhaust devices 20 distributed over the entire periphery of the leading edge 14 or distributed only over a portion of said leading edge. In the example shown in [Fig.l], a single exhaust device 20 is shown: it is produced in the wall of the air inlet lip 12, between a first portion 12a and a second portion 12b of the lip 12. In this example, the exhaust device 20 is in the form of an exhaust orifice 20a.

[0039] However, these exhaust devices 20 are not necessary throughout the flight. They impair the performance of the aircraft, in particular during the takeoff, climb, descent or landing phases and even generate unpleasant noise pollution for residents living near airports.

[0040] To avoid these inconveniences, the hollow leading edge 14 is provided with at least one passive closure device 22 movable between a closure position PI (shown in [Fig.2]) in which the passive closure device 22 closes the exhaust device 20 and an opening position P2 (shown in [Fig.3]) in which the passive closure device 22 releases said exhaust device 20.

[0041] The passive sealing device 22 is fixed to the hollow leading edge 14 by any known and suitable fixing means 24. The fixing means 24 may be fixed to the first portion 12a or to the second portion 12b of the lip 12.

[0042] The passive closure device 22 is made of a shape memory material, that is to say that the device 22 can memorize and recover its original shape after significant deformation following a particular external stimulus such as temperature. The shape of the device 22 can therefore alternate between two previously memorized shapes when its temperature varies around a predetermined transition temperature TD: a first so-called rest shape which corresponds to the closure position PI and a second so-called deformation shape which corresponds to the opening position P2. In other words, the device 22 changes shape according to the temperature to which it is subjected. The NiTi material, an alloy of nickel and titanium, has such characteristics. Nitinol ® having these characteristics can be used to manufacture the passive closure device 22.

[0043] The predetermined transition temperature TD is calculated as a function of the maximum temperature prevailing in the internal annular peripheral chamber 16. The transition between the position PI and the position P2 may take place quickly or gradually depending on the need for evacuating the hot air. All these parameters are linked to the characteristics of the shape memory material (percentage of titanium and nickel for example) and are known to those skilled in the art.

[0044] The predetermined transition temperature TD may be between 70°C and 90°C, preferably of the order of 80°C.

[0045] Accordingly, in situations where defrosting of the leading edge 14 is not necessary, the temperature in the inner annular peripheral chamber 16 will be the ambient temperature inside the leading edge 14. In this situation, it is advantageous to close the exhaust devices 20 so as not to generate parasitic drag or noise. The passive closing device 22 will therefore occupy the position PI closure. In this configuration shown in [Fig.2], the device 22 closes the exhaust orifice 20a.

[0046] Conversely, when the aircraft encounters icing conditions requiring deicing of the leading edge 14 of the lip 12, hot air under pressure taken from the engine is brought by any known and suitable means to the internal annular peripheral chamber 16 and injected into it. In doing so, the temperature in the annular chamber 16 increases. This increase in temperature acts on the passive closure device 22, causing it to change shape. The closure device 22 passes from its so-called rest shape to its so-called deformation shape. Thus the shape of the device 22 is modified; it moves away from the exhaust device 20 and releases it, allowing the evacuation of the hot air under pressure present in the annular chamber 16 (arrow F). The passive closure device 22 then occupies the open position P2 shown in [Fig. 3]. In this configuration shown in [Fig.3], the device 22 releases the exhaust orifice 20a.

[0047] The passive closing device 22 is in the form of a part complementary to that of the exhaust devices 20 so as to close the latter when the device 22 is in the closing position PL

[0048] According to a particular embodiment, the passive closing device 22 has the shape of a blade 22a whose dimensions are adapted to close the exhaust devices 20 when the device 22 is in the closing position PL. The shape of the blade 22a is complementary to that of the exhaust devices 20. In the closing position PI, the blade 22a is positioned on the exhaust devices 20 so as to close them.

[0049] According to another embodiment of the invention described in [Fig. 4], the passive closure device 22 comprises a protrusion 22b adapted to close said exhaust devices 20. The protrusion 22b is dimensioned so as to adapt to the geometry of each exhaust device 20. The dimensions of the protrusion 22b are also calculated so that it does not protrude from the wall of the lip 12, this in order not to disturb the flow of the aerodynamic flow seen by the lip 12 (arrow FA). Thus, the passive closure device 22 effectively closes the exhaust device 20 and prevents any air leakage when the closure device 22 is in the closure position PL

[0050] The protrusion 22b can be made of a deformable material in order to closely match the shape of the exhaust devices 20. Nitinol®, for example, can be used to manufacture the protrusion 22b.

[0051] When the ambient temperature of the inner annular peripheral chamber 16 is lower than the predetermined transition temperature TD, the leading edge 14 of the lip 12 does not require defrosting. No hot air is evacuated under pressure is then required. Consequently, the passive shut-off device 22 is not deformed, it retains its original shape and occupies the shut-off position PI: it therefore shuts off the exhaust devices 20.

[0052] The behavior of the passive shutter device 22 will now be described in detail, with reference to [Fig. 5]. When the aircraft encounters conditions requiring de-icing of the leading edge 14 of the lip 12, hot air under pressure is taken from the engine, brought by any known and suitable means to the internal annular peripheral chamber 16 and injected into it. The temperature in the chamber 16 increases progressively in order to de-ice the leading edge 14. In doing so, the passive shutter device 22 is subjected to the increase in ambient temperature and begins to deform. When the ambient temperature becomes higher than the predetermined transition temperature TD + A°C, the passive shutter device 22 deforms and exhibits its so-called deformation shape. It therefore occupies the open position P2.As long as the ambient temperature of the chamber 16 remains above the predetermined transition temperature TD + A°C, the device 22 maintains its open position P2. If the operating conditions of the aircraft no longer require deicing, the hot air tapping under pressure on the engine ceases, and the ambient temperature in the annular chamber 16 gradually decreases until it falls below the predetermined transition temperature TD. The passive closure device 22 then returns to its original, so-called rest, shape. It then occupies the closure position PL.

[0053] The A°C value can be between 0°C and 30°C.

[0054] According to a first variant embodiment, the passive closure device 22 comprises a return spring 22c capable of returning said device to the closure position PI ([Fig.7]). The stiffness of the spring 22c is calculated so that said spring does not hinder the deformation of the blade 22a during its transition from the closure position PI to the opening position P2. Conversely, during the transition of the closure device 22 from the opening position P2 to the closure position PI, the spring 22c exerts a return force promoting this transition and thus helping the closure device 22 to return to its closure position PL.

[0055] According to a second embodiment variant shown in [Fig. 8], the passive closure device 22 consists of two blades 23a and 23b integral with each other and formed from a shape memory material having different transition temperatures. The advantage of such a configuration is to accelerate the closure of the exhaust devices 20, once the ambient temperature in the annular chamber 16 has fallen below the predetermined transition temperature TD.

[0056] The predetermined transition temperature TDa of the blade 23a is lower than the predetermined transition temperature TDb of the blade 23b. For example, for a transition temperature TDb of the order of 80°C of the blade 23b, the transition temperature TDa of the blade 23a will be of the order of 70°C. Thus, when the ambient temperature in the annular chamber 16 increases until it reaches TDa, the blade 23a begins to deform before the blade 23b, however causing the deformation of the blade 23b. When the temperature in the annular chamber 16 reaches TDb, the blade 23b begins to deform in turn, accelerating the deformation of the closure device 22 and therefore the transition from the closure position P1 to the opening position P2. As previously explained, the device 22 remains in the open position P2 as long as the ambient temperature in the internal annular peripheral chamber 16 is greater than TDb+ A°C.

[0057] Conversely, when the temperature in the annular chamber 16 decreases and falls below TDb, the blade 23b deforms again to return to its initial so-called resting shape, just like the blade 23a when the temperature becomes lower than TDa, thus helping the closure device 22 to return to its closure position PL.

[0058] In this configuration, the blade 23b is fixed to the air inlet 12 when the passive shutter device 22 is in the shutter position PI and the blade 23a is positioned above the blade 23b.

[0059] According to another configuration, it is the blade 23a which is fixed to the air inlet 12 when the passive closing device 22 is in the closing position PI, the blade 23b being positioned above the blade 23a.

[0060] In the embodiment where the exhaust device has the shape of an exhaust orifice 20a, the passive closure device 22 may comprise a protrusion 22b arranged opposite said orifice 20a. This exemplary embodiment is shown in [Fig. 4]. The protrusion 22b may be added to the closure device 22 at the same time as the manufacture of the device 22 or it may be added subsequently and fixed to said device 22 by any fixing means known to those skilled in the art.

[0061] In an alternative embodiment schematically shown in [Fig. 6], the leading edge 14 of the air inlet 12 comprises at least one exhaust device 20 in the form of an exhaust grille 20b comprising several exhaust orifices 20c for evacuating the hot air from the annular chamber 16. In this case, the passive closure device 22 (shown on the side for the sake of clarity) comprises as many blades 22a as there are exhaust orifices 20c making up the exhaust grille 20b.

[0062] These blades 22a may comprise protrusions 22b (shown in dotted lines) in order to more effectively close the exhaust orifices 20c. In this variant embodiment, the blades 22a comprise as many protrusions 22b as there are exhaust orifices 20c.

[0063] Each blade 22a of the passive shutter device 22 is fixed to the leading edge 14 via fixing means 24.

[0064] In an alternative embodiment, the passive sealing device 22 comprises a single plate whose dimensions are adapted to cover all of the exhaust orifices 20c of the exhaust grille 20b.

[0065] The single plate may comprise protrusions 22b arranged opposite each exhaust orifice 20c of the exhaust grille 20b. As in the previous embodiment, the plate comprises as many protrusions 22b as there are exhaust orifices 20c.

[0066] Whatever the embodiment, each passive closure device 22 is capable of covering the exhaust device 20 opposite which it is fixed.

[0067] The advantages of such a passive shutter device 22 are numerous: - This shutter device 22 is passive, it does not require a specific energy source, nor an active system such as a jack or control command, - It is easy to use, assemble and disassemble, - It allows the evacuation of hot air under pressure circulating in the annular peripheral chamber when conditions require it, - This device 22 greatly minimizes the drag and parasitic noise generated by the devices of the prior art.

Claims

Claims

1. Air inlet lip (12) of an aircraft engine nacelle (10) provided with a hollow leading edge (14) delimiting an internal annular peripheral chamber (16) closed by an internal partition (18) in which hot air circulates under pressure, said hollow leading edge (14) being provided with at least one hot air exhaust device (20) to allow the evacuation to the outside of all or part of said hot air flow circulating in said annular chamber (16) and at least one passive closing device (22) of said at least one exhaust device (20), said at least one passive closing device (22) being characterized in that it is movable between a closing position (PI) in which said at least one closing device (22) closes said at least one exhaust device (20) and an open position (P2) in which said at least one passive shutter device (22) releases at least one exhaust device (20),said passive sealing device (22) being made of a shape memory material.,

2. Air inlet lip (12) of an aircraft engine nacelle (10) according to claim 1 characterized in that said at least one passive closing device (22) is in the form of a part complementary to that of the at least one exhaust device (20).

3. Air inlet lip (12) of an aircraft engine nacelle (10) according to any one of the preceding claims, characterized in that said at least one passive closure device (22) is capable of deforming from a predetermined transition temperature (TD).

4. Air inlet lip (12) of an aircraft engine nacelle (10) according to the preceding claim, characterized in that said at least one passive closure device (22) is capable of occupying the closure position (PI) as soon as the temperature in the internal annular peripheral chamber (16) is lower than the predetermined transition temperature (TD).

5. Air inlet lip (12) of an aircraft engine nacelle (10) according to any one of claims 3 or 4, characterized in that said at least one passive closure device (22) is capable of occupying the open position (P2) as long as the temperature in the inner annular peripheral chamber (16) is higher than the predetermined transition temperature (TD)+ A°C.

6. Air inlet lip (12) of an aircraft engine nacelle (10) according to any one of the preceding claims, characterized in that at least one exhaust device (20) is in the form of an exhaust orifice (20a) capable of evacuating the hot air under pressure from the internal annular peripheral chamber (16).

7. Air inlet lip (12) of an aircraft engine nacelle (10) according to any one of the preceding claims, characterized in that at least one exhaust device (20) is in the form of an exhaust grille (20b) comprising several exhaust orifices (20c) capable of evacuating the hot air under pressure from the internal annular peripheral chamber (16).

8. Air inlet lip (12) of an aircraft engine nacelle (10) according to claim 6 characterized in that said at least one passive closing device (22) has the shape of a blade (22a) arranged opposite each exhaust orifice (20a, 20c).

9. Air inlet lip (12) of an aircraft engine nacelle (10) according to the preceding claim, characterized in that said at least one passive closing device (22) comprises as many blades (22a) as there are exhaust orifices (20a, 20c).

10. Air intake lip (12) of an aircraft engine nacelle (10) according to claim 7 characterized in that said at least one passive closing device (22) is in the form of a single plate whose dimensions are adapted to cover all of the exhaust orifices (20c) of the exhaust grille (20b).

11. Air inlet lip (12) of an aircraft engine nacelle (10) according to any one of the preceding claims, characterized in that said at least one passive closing device (22) comprises at least one protrusion (22b) adapted to close said at least one exhaust device (20, 20a, 20c).

12. Aircraft comprising an air intake lip (12) according to one of the preceding claims.

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