AIR INTAKE OF AN AIRCRAFT NACELLE INCORPORATING HOT AIR INJECTION MEANS FOR OPTIMIZED ICE TREATMENT

Abstract

Aircraft nacelle air intake incorporating optimized hot air injection means for de-icing. The invention relates to an aircraft nacelle air intake (100) comprising hot air injection means (108) including a manifold (112) connected to a hot air supply, a duct (114) delimited by an inner wall (116) and an outer wall (118), and fluidly connected to said manifold (112), and comprising a plurality of fins (124) distributed in said duct (114). These injection means allow hot air to be injected with a single injection vector, which makes the mixture of hot air with ambient air more homogeneous, while eliminating the risk of creating hot spots. Figure 6

Description

Title of the invention: AIR INTAKE OF AN AIRCRAFT NACELLE INTEGRATING HOT AIR INJECTION MEANS FOR OPTIMIZED ICE TREATMENT technical field

[0001] The present invention relates to an air intake for an aircraft nacelle incorporating hot air injection means optimized for de-icing. PRIOR TECHNOLOGY

[0002] In a known manner, as illustrated in [Fig.1], a propulsion unit 10 of an aircraft, for example connected under the wing of the aircraft by means of a mast (not shown), comprises a nacelle 14 in which a motor 11 is arranged in a substantially concentric manner. The longitudinal axis of the nacelle 14 is referenced X in [Fig.1].

[0003] The nacelle 14 includes an air inlet 16 upstream of the motor 11, side covers 14.1, 14.2 arranged around the motor 11, and a thrust reverser and an exhaust 14.3 downstream of the motor 11.

[0004] The terms “upstream” or “front” and “downstream” or “rear” are to be considered in relation to a direction of forward movement of the aircraft 10 during the operation of the engine 11 (direction of gas flow from the intake of gases (air) into the engine to the exhaust of gases (combustion gases)), this direction being schematically represented by the arrow FIL

[0005] The air inlet 16 has a leading edge 17 (also known as a “D-duct” in English terminology) consisting of a lip 19 and an inner wall, called the front frame 18. The leading edge 17 defines an air inlet duct 21 that channels air towards the engine. Air entering the duct 21 towards the engine when the aircraft is operating in icing conditions can cause frost or ice to form on the leading edge 17.

[0006] The present invention relates more particularly to a nacelle incorporating a frost treatment process using hot air taken from the engine.

[0007] According to an embodiment illustrated in [Fig. 2], a nacelle 14 has an air inlet 16, which includes a lip 19 and a front frame 18 which, together with the lip 19, defines a duct 20 extending around the entire circumference of the nacelle 14 and having a substantially D-shaped cross-section through which hot air circulates. The leading edge 17 of the air inlet 16 is therefore hollow and is defined by the lip 19 and closed from the rear side by the front frame 18, so as to form the conduit 20.

[0008] The air inlet 16 includes an internal conduit 16.1, provided at its rear end directed towards the motor 11, with a connecting element 16.2 and at its front end, housed in the conduit 20, with an injection means 22.

[0009] Furthermore, on a compressor stage 11.1 of the engine 11, a pressurized hot air intake 11.2 is arranged which is connected to a pipe 11.3, provided, opposite the connection element 16.2 of the pipe 16.1, with a complementary connection element 11.4. Thus, when the complementary connection elements 16.2 and 11.4 are connected to each other, pressurized hot air taken from 11.2 on the engine 11 is conveyed by the pipes 11.3 and 16.1 to the injection means 22.

[0010] The injection means 22 passes through the front frame 18 and opens into the conduit 20, parallel to the leading edge.

[0011] This duct 20 is supplied with hot air by the injection means 22 (which has the function of mixing the air). The hot air injected by the injection means 22 travels through the duct 20 over 360°, in order to heat the leading edge 17, before being expelled through an exhaust 24 to the open air (arrow F24). The hot air injected by the injection means 22 mixes with the air already present in the duct 20. The hot air injected by the injection means 22 corresponds to a portion of the air circulating in the duct 21 from the air inlet 16, and which is channeled through the air inlet 16 towards the motor 11. This airflow is therefore heated by the motor 11, as explained above, before being drawn in and conveyed to the injection means 22, via the ducts 16.1, 11.3. This hot airflow circulating in the duct 20 helps to raise the temperature of the outer skin 34 of the lip 19 of the air inlet, and thus to limit ice buildup on the lip 19.

[0012] As shown in [Fig. 3], the injection means 22 (also called an “O-ring” in English terminology) comprises a hot air inlet tube 26 projecting from the front frame 18, and an annular conduit 28 fluidically connected to the tube 26. The annular conduit 28 defines an orifice 30 for the passage of air circulating in the conduit 20, and a plurality of injection nozzles 32 arranged around the periphery of the annular conduit 28 and adapted to inject hot air. Each injection nozzle 32 diffuses hot air along a vector and an injection cross-section (represented by arrows F1, F2, and F3) specific to it.This hot air injected by the injection nozzles 32 mixes both with the air passing through the orifice 30, and with the air circulating around the annular conduit 28, so as to obtain a mixed airflow, the temperature of which is lower than the temperature of the hot air injected by the injection nozzles 32, but higher than the temperature of the airflows surrounding the injection means 22.

[0013] However, these means of injecting hot air do not fully provide sa- satisfaction.

[0014] Indeed, the hot air from the injection nozzles 32 is directed towards the outer side of the air inlet referenced 34 in [Fig. 2]. This results in the creation of hot spots, and therefore the defrosting or anti-icing capacity of the air inlet is not uniform around its circumference. There is thus a discontinuity in the frost treatment. Furthermore, the positioning and orientation tolerances of the injection nozzles are therefore difficult to guarantee.

[0015] Furthermore, such an injection method is produced by molding or three-dimensional (3D) printing and requires a post-machining step, i.e., re-machining of the inside of the injection nozzles. This re-machining is complex and costly.

[0016] The present invention also aims to overcome the drawbacks of the prior art by providing an aircraft nacelle air intake using hot air for de-icing, incorporating optimized hot air injection means. Summary of the invention

[0017] For this purpose, the invention relates to an air inlet of an aircraft nacelle comprising a duct extending over the circumference of said air inlet and means for injecting hot air in a localized manner into said duct ensuring the circulation of hot air in the duct along its circumference.

[0018] According to the invention, the injection means comprise a manifold connected to a hot air supply and extending in projection into the conduit, a cylindrical conduit delimited by an internal wall and an external wall, said conduit being fluidly connected to said manifold at the level of its external wall at a first end of said conduit, said conduit being substantially orthogonal to said manifold, and an orifice allowing the airflow circulating in the conduit to pass through it, said orifice being delimited by the internal wall of said conduit.

[0019] According to the invention, the conduit comprises a plurality of fins distributed at a second end of said conduit around the orifice.

[0020] Advantageously, with such hot air injection means in the air intake duct, the hot air is injected into the duct with a single injection vector, while being mixed with the air already present in the duct. This allows for proper homogenization of the temperature of the air circulating around the circumference of the duct, while eliminating the risk of hot spots appearing around the circumference of the air intake. There is thus continuous frost treatment along the circumference of the air intake. The invention therefore makes it possible to optimize the mixing of the hot air injected into the duct, to mix it more homogeneously with the air already present in the duct, and to eliminate the need to manage injection vectors induced by the machining of the injection nozzles (as in the prior art).

[0021] According to one feature, the fins are inclined along the duct at an angle between 10° and 45°. This advantageously directs the flow of hot air exiting the duct and entering it, thus giving it a helical motion, with a cyclonic effect. This improves the mixing between the hot air injected into the duct and the air already present in the duct, making it more homogeneous.

[0022] According to another feature, the fins are regularly distributed in the conduit around the orifice.

[0023] According to another feature, the fins are arranged on the inner wall of the pipe, and extend along said pipe towards the outer wall of said pipe.

[0024] Alternatively, the fins are arranged on the outer wall of the pipe, and extend along said pipe towards the inner wall of said pipe.

[0025] According to another feature, the duct comprises between six and fifteen fins distributed in said duct around the orifice. Advantageously, the duct shall have sufficient fins to direct the flow of hot air, but without unduly slowing down said flow of hot air.

[0026] According to another feature, the fins have a length between 25% and 35% of the length of the pipe.

[0027] According to another feature, the duct has a frustoconical shape that narrows from its first end to its second end. This accelerates the flow of hot air in the duct, and thus allows the hot air to be injected at a higher speed into the duct, thereby improving the mixing of this hot air with the air already present in the duct.

[0028] According to another feature, the conduit has a closed annular surface at its first end and an open annular surface at its second end.

[0029] The invention also relates to an aircraft nacelle which includes an air inlet according to the invention. Brief description of the drawings

[0030] Other features and advantages will become apparent from the following description of the invention, given by way of example only, with reference to the accompanying drawings, among which:

[0031] [Fig. 1] is an exploded perspective view of an aircraft nacelle,

[0032] [Fig.2] is a perspective view illustrating part of an air inlet of a aircraft nacelle, incorporating a means for injecting hot air according to a prior art embodiment,

[0033] [Fig.3] is a perspective view of a means of injecting hot air according to a mode of the realization of prior art,

[0034] [Fig.4] is a perspective view illustrating part of an air inlet of a aircraft nacelle, incorporating means for injecting hot air according to an embodiment of the invention,

[0035] [Fig. 5] is a perspective view of the means for injecting hot air according to a mode of the realization of the invention,

[0036] [Fig.6] is another perspective view of the hot air injection means according to a method of embodiment of the invention,

[0037] [Fig.7] is a side view of the hot air injection means according to a mode of publication of the invention,

[0038] [Fig.8] is a front view of the hot air injection means according to a mode of publication of the invention, and

[0039] [Fig.9] is a top view of part of the hot air injection means according to a method of embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] Figure 4 shows an air inlet 100 of an aircraft nacelle. The inlet Air 100 allows to channel towards the motorization (not shown on [Fig.4]) an air flow referenced by arrow 102. This air flow extends along the longitudinal axis X, which is the longitudinal direction of the nacelle.

[0041] By convention, the longitudinal direction X is parallel to the axis of rotation of the engine and to a longitudinal axis of the aircraft. The transverse direction Y of the nacelle is also defined, which is horizontal when the aircraft is on the ground and perpendicular to the axis of rotation of the engine; as is the vertical direction Z, also called vertical height, which is vertical when the aircraft is on the ground and perpendicular to the axis of rotation of the engine. These three directions X, Y, and Z are orthogonal to each other.

[0042] The front portion of the air inlet 100 describes a substantially circular shape extending in a plane that may be substantially perpendicular to the longitudinal axis X (i.e., in the YZ plane), or not perpendicular, with the upper front portion slightly projecting beyond the lower front portion. However, other air inlet shapes may be considered.

[0043] The invention relates more particularly to a nacelle incorporating a frost treatment consisting of using hot air taken from the engine.

[0044] The nacelle includes an air inlet 100, which has a leading edge 101 comprising a lip 103 and a front frame 104 which, together with the lip 103, defines a duct 106 extending around the entire circumference of the nacelle and having a D-shaped cross-section. This duct 106 includes means 108 for injecting hot air from in a localized manner. The injection means 108 are here arranged in a lower part of the conduit 106, but could be arranged in a port or starboard side portion, or in an upper part of the conduit 106. In addition, the conduit 106 includes an exhaust 110, visible in [Fig. 4]. According to the example illustrated in [Fig. 4], the injection means 108 generate a flow F in the conduit 106 in a counterclockwise direction. Of course, the injection means 108 could be arranged to generate a flow in the conduit 106 in a clockwise direction.

[0045] As shown more precisely in Figures 5 to 9, the injection means 108 include a hot air inlet manifold 112 projecting from the front frame 104 into the duct 106. In position in the air inlet 100 of [Fig.4], the manifold 112 therefore extends longitudinally along the longitudinal direction X. The manifold 112 here has a general cylindrical shape. The manifold 112 is fluidly connected to a hot air supply (not shown in the figures) and fixed by any suitable means to the front frame 104 (for example by means of a collar 122 screwed to the front frame 104) in line with an opening (not shown in the figures) provided in the front frame 104. In particular, a hot air supply opens at this opening at the rear of the front frame 106. Alternatively, the manifold 112 can pass through the front frame 106 and be fluidly connected directly to a hot air supply.The hot air supply is not described in further detail as it is known to those skilled in the art. Preferably, the hot air is drawn from the engine and conveyed to the air intake via one or more ducts, as described previously.

[0046] The hot air injection means 108 comprise a cylindrical conduit 114 delimited by an internal wall 116 and an external wall 118, between a first and a second end 114a, 114b. The pipe 114 is fluidically connected at one of its ends 114a to the manifold 112 at its outer wall 118. Thus, the internal volume of the manifold 112 is fluidically connected to the internal volume (between the inner wall 116 and the outer wall 118) of the pipe 114. The pipe 114 extends substantially orthogonally to the manifold 112. In position within the air inlet 100 of [Fig. 4], the pipe 114 therefore extends longitudinally along the transverse direction Y. The pipe 114 can be cylindrical with an annular base, or frustoconical in shape as shown in Figures 5 to 9.The duct 114 has a circular crown-shaped surface SI 14a which is closed at its first end 114a and a circular crown-shaped surface SI 14b which is open to the duct 106 at its second end 114b. In position in the air inlet 100 of [Fig. 4], the surfaces SI 14a, SI 14b extend along a plane XZ. The hot air flow from the manifold 112 thus passes through the duct 114, between the external and internal walls 118, 116 of the duct 114, from the first to the second ends 114a, 114b of the duct. conduit 114, before exiting into conduit 106. When conduit 114 is frustoconical in shape, the external wall 118 has a section that reduces between the first end 114a and the second end 114b of conduit 114. This advantageously allows the speed of the hot air flow to be increased between its inlet and outlet of conduit 114, at the level of the surface SI 14b, and allows the ratio of hot air (via the injection section) injected into conduit 106 (i.e. into the D-shaped section), which will be mixed with the surrounding air, to be managed.

[0047] The inner wall 116 of the conduit 114 defines a through orifice 120 for the passage of air circulating in the conduit 106. The orifice 120 here has a cylindrical shape with a circular base.

[0048] According to one embodiment, the conduit 114 comprises a plurality of fins 124 arranged on the inner wall 116 of the conduit 114, extending longitudinally along the inner wall 116 and projecting towards the outer wall 118 of the conduit 114. The fins 124 are arranged at the second end 114b of the conduit 114, near the surface SI 14b. The fins 124 are distributed regularly around the orifice 120. For example, six fins 124 are shown in Figures 5 to 9, the fins being distributed every 60°. The fins 124 have a length L124 between 25% (¼) and 35% (approximately Es) of the length L114 of said pipe 114.

[0049] The fins 124 are inclined along the pipe 114. More specifically, the fins 124 comprise a first part 126 which extends along the length of the pipe 114, and a second part 128 connected to the first part 126 of the fin 124, and which forms an angle A with respect to said first part 126. The angle A is between 10° and 45°. The second section 128 of the fin 124 is closer to the SI surface 14b than the first section 126 of the fin 124. This inclination of the fins 124 directs the hot air flow in a different direction, thus improving the cyclonic effect of the hot air exiting the duct 114. To optimize the mixing of the injected hot air with the air already circulating in the duct 106, the fins 124 are oriented in this way to direct the hot air flow. There is therefore a single injection vector for the hot air in the duct 106.The hot air flow exiting surface SI 14b, represented by arrow Fl 14, thus has a helical motion around the air flow passing through orifice 120, represented by arrow F120, and relative to the air flow circulating around the injection means 108, represented by arrow F106. These air flows mix before circulating in duct 106 and being expelled through exhaust 110. The mixing of the injected hot air is thus optimized, since it is mixed more homogeneously with the air already present in duct 106. In particular, the shape of duct 114 allows the airflow to have a cyclonic / vortex effect, without the need for a mixer. Indeed, the air passing through... the orifice 120, and the air passing around the pipe 114, naturally mix with the hot air injected through the pipe 114.

[0050] Preferably, the duct 114 has at least six fins 124, in order to improve the mixing between the hot air flow and the surrounding air flow of the duct 106. And preferably, the duct 114 has a maximum of fifteen fins 124, in order not to slow down the hot air flow too much.

[0051] According to another embodiment (not shown in the figures), the fins 124 are arranged on the outer wall 118 of the conduit 114, and extend longitudinally along the outer wall 118 and project outwards towards the inner wall 116 of the conduit 114.

[0052] According to another embodiment (not shown in the figures), fins 124 are arranged on the inner wall 116 of the conduit 114 and fins are arranged on the outer wall 118 of the conduit 114. The position of the fins 124 can thus be alternated between the inner wall 116 and the outer wall 118 of the conduit 114.

[0053] According to another embodiment (not shown in the figures), the fins 124 are distributed irregularly on one of the internal 116 or external 118 walls of the conduit 114.

[0054] The injection means 108 are produced by molding or 3D printing. The injection means 108 are made of Inconel. These injection means can therefore be produced using the same manufacturing processes as those used to produce the injection means of the prior art (and therefore at the same cost).

[0055] In addition, the SI 14b hot air injection surface in the duct 106 is substantially equal to the sum of the hot air injection surfaces at each injection nozzle 32 of the prior art.

[0056] Regardless of the embodiment, an air inlet duct 106 equipped with these injection means 108, which allow the injection of hot air with a single injection vector, advantageously carries a flow of hot air homogeneously mixed with the ambient air circulating in said duct, without risk of hot spots forming in said duct. These injection means thus optimize the heat exchange between the air and the surface of the lip 103 of the air inlet, thereby preventing frost formation on the leading edge 101 of the air inlet, and ensuring temperature homogeneity within the duct 106.

Claims

Claims

1. Air inlet (100) of an aircraft nacelle comprising a duct (106) extending around the circumference of said air inlet (100) and hot air injection means (108) in a localized manner in said duct (106) ensuring the circulation of the hot air in the duct (106) along its circumference, characterized in that said injection means (108) comprise a manifold (112) connected to a hot air supply and extending projecting into said duct (106), a cylindrical duct (114) delimited by an inner wall (116) and an outer wall (118), said duct (114) being fluidically connected to said manifold (112) at its outer wall (118) at a first end (114a) of said duct (114), said duct (114) being substantially orthogonal to said manifold (112), and an orifice (120) allowing the air flow circulating in the conduit (106) to pass through it,said orifice (120) being delimited by the internal wall (116) of said conduit (114), and in that said conduit (114) comprises a plurality of fins (124) distributed at a second end (114b) of said conduit (114) around the orifice (120).,

2. Air inlet (100) of an aircraft nacelle according to claim 1, characterized in that the fins (124) are inclined along said duct (114) with an angle of between 10° and 45°.

3. Air inlet (100) of an aircraft nacelle according to one of claims 1 or 2, characterized in that the fins (124) are regularly distributed in said duct (114) around the orifice (120).

4. Air inlet (100) of an aircraft nacelle according to one of claims 1 to 3, characterized in that the fins (124) are arranged on the internal wall (116) of said duct (114), and extend along said duct (114) towards the external wall (118) of said duct (114).

5. Air inlet (100) of an aircraft nacelle according to one of claims 1 to 3, characterized in that the fins (124) are arranged on the external wall (118) of said duct (114), and extend along said duct (114) towards the internal wall (116) of said duct (114).

6. Air inlet (100) of an aircraft nacelle according to one of claims 1 to 5, characterized in that the duct (114) comprises between six and fifteen fins (124) distributed in said duct (114) around the orifice (120).

7. Air inlet (100) of an aircraft nacelle according to one of claims 1 to 6, characterized in that the fins (124) have a length (L124) of between 25% and 35% of the length (L114) of said duct (114).

8. Air inlet (100) of an aircraft nacelle according to one of claims 1 to 7, characterized in that the duct (114) has a frustoconical shape which reduces from its first end (114a) to its second end (114b).

9. Air inlet (100) of an aircraft nacelle according to claim 8, characterized in that the duct (114) has an annular surface (SI 14a) closed at its first end (114a) and an annular surface (SI 14b) open at its second end (114b).

10. Aircraft nacelle characterized in that said nacelle comprises an air inlet (100) according to one of the preceding claims.

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