• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The invention relates to an acoustic panel (16) for an aircraft propulsion unit, comprising a core (18) and an input layer (22) in contact with the core (18), the input layer (22) comprising lower (34) and upper (36) elements, each having an inner face, an outer face and at least one through opening (30), the inner faces of the lower (34) and upper (36) members being in contact with one another; the other and forming a channel defining a baffle and opening into a cell (24) of the heart (18).
    公开号:FR3069579A1
    申请号:FR1757051
    申请日:2017-07-25
    公开日:2019-02-01
    发明作者:Georges Jean Xavier Riou；Norman Bruno Andre JODET；Jeremy Paul Francisco GONZALEZ
    申请人:Safran Aircraft Engines SAS；
    IPC主号:
    专利说明:

    ACOUSTIC PANEL AND ASSOCIATED PROPULSIVE ASSEMBLY DESCRIPTION
    TECHNICAL AREA
    The present invention relates to an acoustic panel for an aircraft propulsion unit, intended to be arranged at the edge of a fluid flow stream of the propulsion unit.
    The invention also relates to a propulsion unit comprising such an acoustic panel.
    The invention applies to the field of aircraft propulsion systems, and more particularly to acoustic panels arranged in such propulsion systems.
    PRIOR STATE OF THE ART
    It is known to provide a propulsion unit with acoustic panels in order to attenuate the noise generated by a turbomachine present in said propulsion unit. Such noise is, for example, caused by the interaction of a rotor of the turbomachine with its environment.
    In general, such acoustic panels consist of a heart having a honeycomb structure caught between a first plate, intended to be in contact with a fluid flow in the propellant assembly, and a second plate, disposed at the 'opposite of the first plate with respect to the honeycomb structure. In general, the first plate is provided with a plurality of necks, similar to tubes, extending in the cells of the heart perpendicular to the first plate. In addition, the second plate is waterproof and rigid in order to reflect acoustic waves. In this case, each cell in which at least one neck extends forms a Helmholtz resonator, which is capable of ensuring acoustic attenuation by a visco-thermal dissipation effect at the orifices through which the necks open into the cells. In this case, each cell forms a resonant cavity.
    In a Helmholtz resonator, the frequency tuning, i.e. the adjustment of the frequency for which a maximum acoustic attenuation is obtained, is controlled by the volume of the neck (s) as well as by the volume of the associated resonant cavity. Due to the low height of the necks, the frequency tuning of the resonator is mainly controlled by the thickness of the honeycomb structure.
    With such acoustic panels, satisfactory acoustic attenuation, at a given frequency, is obtained when the thickness of the cells is of the order of a quarter of the wavelength corresponding to said frequency.
    However, such acoustic panels are not entirely satisfactory.
    Indeed, new generation turbomachines have a nominal rotation speed and a reduced number of blades compared to turbomachines of previous generations. This results in the fact that the noises generated by the new generation turbomachines have lower frequencies, that is to say greater wavelengths, than the noises generated by the turbomachines of the previous generations.
    In the case of acoustic panels of the prior art, it is necessary to significantly increase the thickness of the acoustic panel when the frequency of the acoustic waves to be attenuated decreases. This leads to an increase in the size and the mass of the acoustic panel, which is not acceptable, in particular in the case of airborne applications.
    An object of the invention is therefore to propose an acoustic panel for which the overall dimensions and the mass depend less on the frequency of the acoustic waves to be attenuated than conventional acoustic panels.
    STATEMENT OF THE INVENTION
    To this end, the subject of the invention is an acoustic panel of the aforementioned type, the acoustic panel comprising a core and an input layer, the core comprising a plurality of cells arranged to form a honeycomb structure, each cell opening, on the one hand, on a first face of the heart and, on the other hand, on a second face of the heart situated opposite the first face, the entry layer comprising a lower element and an upper element , each of the lower element and the upper element comprising a respective plate comprising an internal face and an external face oriented opposite the internal face, each of the lower element and the upper element comprising at least one through opening opening, on the one hand, on the external face and, on the other hand, on the internal face, the internal face of at least one of the lower element and the upper element comprising, for at least one opening t overlapping, a corresponding groove into which the through opening opens, the internal face of the lower element being arranged facing and in contact with the internal face of the upper element, each through opening of one of the upper element and the lower element facing a groove of the other among the upper element and the lower element, so as to form a channel with the groove and the through opening of the other among the upper element and the lower element which opens into the groove, the through openings of each channel being offset in a direction distinct from a thickness direction of the input layer, the input layer extending opposite and in contact from the first face of the heart, for each channel, the through opening of the lower element opening into a cell of the heart, and the through opening of the upper element being intended to open into the fluid flow vein.
    Indeed, in an acoustic panel according to the invention, each channel which opens into a cell of the honeycomb structure is comparable to a neck of a Helmholtz resonator. Since the grooves are made at the internal face of the lower element and / or of the upper element, it follows that each channel of the acoustic panel according to the invention extends mainly parallel to the input layer, unlike conventional acoustic panels in which the neck of each Helmholtz resonator extends perpendicular to the input layer.
    Thus, with an acoustic panel according to the invention, it is easy to achieve frequency tuning to attenuate the noise generated by the new generation turbomachines, and this without modifying the thickness of the acoustic panel. In fact, the frequency adaptation is done simply by modifying, for example, the dimensions of the grooves, and more particularly the length of the grooves, which does not require an increase in the thickness of the input layer. Such a modification of the dimensions of the grooves results in a modification of the volume of the channel, which indeed leads to a modification of the attenuation frequency of the acoustic panel.
    An acoustic panel according to the invention therefore clearly has a bulk and a mass which are less dependent on the frequency of the acoustic waves to be attenuated than conventional acoustic panels.
    According to other advantageous aspects of the invention, the acoustic panel comprises one or more of the following characteristics, taken alone or in any technically possible combination:
    the internal face of each of the lower element and the upper element comprises, for each through opening, a corresponding groove into which opens the through opening, each channel being formed by two respective grooves of the lower element and of the 'upper element facing each other and through the corresponding through openings of the lower element and the upper element;
    - For each groove, the corresponding through opening opens, on the internal face, into one end of the groove;
    - for each channel, the corresponding grooves are completely opposite one another;
    - The acoustic panel further comprises a reflective layer configured to reflect acoustic waves having a frequency belonging to a predetermined range, the reflective layer extending opposite and in contact with the second face of the heart;
    - for each of the upper element and the lower element, the corresponding internal face comprises a plurality of grooves, the grooves being symmetrical with respect to a plane of symmetry, and, for at least one pair of grooves symmetrical with one another at the plane of symmetry, the corresponding through openings are arranged so as to open into ends of said grooves which are not symmetrical to each other with respect to the plane of symmetry;
    - The internal face of one of the lower element and the upper element comprises at least one stud engaged in an associated cavity of the other of the lower element and the upper element, the cavity and the associated stud having complementary forms;
    - for each of the upper element and the lower element, each groove is rectilinear and extends along a longitudinal axis parallel to a plane locally tangent to the corresponding internal face, and, for each groove, the opening corresponding crossing has an axis orthogonal to the plane locally tangent to the internal face;
    - the furrow has a depth less than or equal to half a length of the furrow, preferably less than or equal to one third of the length of the furrow, the length of the furrow being defined by the extent of the furrow along the axis longitudinal.
    In addition, the subject of the invention is a propulsion unit for aircraft comprising at least one acoustic panel as defined above.
    BRIEF DESCRIPTION OF THE DRAWINGS
    The invention will be better understood with the aid of the description which follows, given solely by way of nonlimiting example and made with reference to the appended drawings in which:
    - Figure 1 is a sectional view of a propulsion unit according to the invention, in a longitudinal plane of the propulsion unit;
    - Figure 2 is a schematic perspective view of an acoustic panel according to the invention;
    - Figure 3 is a top view of a first embodiment of an acoustic panel according to the invention;
    - Figure 4 is a top view of a second embodiment of an acoustic panel according to the invention;
    - Figure 5 is an exploded view in section of an input layer of the acoustic panel of Figure 2, along a plane orthogonal to an external face of the input layer, and containing a longitudinal axis of channels of the input layer;
    - Figure 6 is a sectional view of the input layer of the acoustic panel of Figure 2, along the plane of Figure 5;
    - Figure 7 is a schematic sectional view, along the plane of Figure 5, of the acoustic panel of Figure 2;
    FIG. 8 is an exploded view in section of an input layer of a third embodiment of an acoustic panel according to the invention, along a plane orthogonal to an external face of the input layer, and containing a longitudinal axis of channels of the input layer; and
    FIG. 9 is a sectional view, not exploded, of the input layer of the acoustic panel of FIG. 8, according to the plane of FIG. 8.
    DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS
    A propulsion unit 2 according to the invention is shown in FIG. 1.
    The propulsion unit 2 comprises a nacelle 4 and a turbomachine, for example a turbojet engine 5.
    The nacelle 4 surrounds the turbojet engine 5 and externally delimits a fluid flow stream comprising an air inlet channel 6, a secondary stream 7 and an exhaust channel 8.
    The turbojet engine 5 is intended to generate, during its operation, an air stream 14 flowing from the inlet channel 6 towards the exhaust channel 8. The air stream 14 is illustrated by a set of arrows in figure 1.
    The propulsion unit 2 also comprises at least one acoustic panel 16.
    Each acoustic panel 16 is configured to attenuate acoustic waves whose frequency belongs to a predetermined frequency range.
    Preferably, each acoustic panel 16 is integrated into the nacelle 4 and / or the turbojet engine 5, for example to delimit at least one axial section of at least one of the air inlet channel 6, the secondary stream 7 and the exhaust channel 8.
    Preferably, a set of acoustic panels 16 in ring portion are mounted end to end circumferentially.
    With reference to FIG. 2, the acoustic panel 16 comprises a core 18, a reflective layer 20 and an input layer 22.
    The heart 18 has a honeycomb structure. More specifically, the heart 18 comprises a plurality of cells 24, arranged according to a known honeycomb structure.
    As shown in FIG. 7, each cell 24 opens onto a first face 26 of the heart 18 and onto a second face 28 of the heart 18 situated opposite the first face 26.
    The first face 26 of the heart 18 is that, among the first face 26 and the second face 28, which is intended to be oriented towards the air stream 14. The second face 28 of the heart is that, among the first face 26 and the second face 28, which is intended to be oriented opposite the air stream 14.
    Preferably, the core 18 is such that the distance between the first face 26 and the second face 28 is of the order of a quarter of the wavelength corresponding to a predetermined working frequency.
    The working frequency is a frequency for which maximum acoustic attenuation is desired. The working frequency belongs to the predetermined frequency range.
    For example, the heart 18 is made of metal, for example aluminum. According to another example, the core 18 is made of a composite material, such as a composite material formed of carbon fibers embedded in a hardened resin matrix.
    The reflecting layer 20 is adapted to reflect acoustic waves having a frequency belonging to the predetermined frequency range.
    The reflective layer 20 extends opposite the second face 28 of the heart 18, while being in contact with the second face 28. More specifically, the reflective layer 20 is integral with the second face 28 of the heart 18, for example bonded to the second face 28 of the heart 18.
    For example, the reflective layer 20 is made of metal, for example aluminum. According to another example, the reflective layer 20 is made of a composite material, such as a composite material formed of carbon fibers embedded in a hardened resin matrix.
    The input layer 22 extends opposite the first face 26 of the heart 18, while being in contact with the first face 26. More precisely, the input layer 22 is integral with the first face 26 of the heart 18, for example glued to the first face 26 of the heart 18.
    The input layer 22 is arranged so that a through opening 30 of at least one channel 32 of the input layer 22 opens into a cell 24 of the core 18. The through opening 30 and the channel 32 will be described later.
    The input layer 22 will now be described with reference to FIGS. 3 to 7.
    The input layer 22 comprises a lower element 34 and an upper element 36.
    Each of the lower member 34 and the upper member 36 has a respective plate 38.
    For example, the plate 38 has a thickness of between 0.5 mm (millimeter) and 2 mm.
    The plate 38 comprises an internal face 40 and an external face 42 oriented opposite the internal face.
    The plate 38 is, for example, made of a composite material, such as a composite material formed of carbon fibers embedded in a hardened resin matrix.
    As shown in FIG. 4, the internal face 40 of the plate comprises at least one groove 44. Each groove 44 has two opposite ends 46.
    Preferably, each groove 44 is rectilinear and extends along a respective longitudinal axis X-X parallel to a plane locally tangent to the internal face 40.
    The respective longitudinal axes of the grooves 44 may or may not be parallel to each other.
    Preferably, each groove 44 has a depth less than or equal to half the length of the groove, preferably less than or equal to one third of the length of the groove. The length of the groove 44 is defined as the extent of the groove 44 along the longitudinal axis X-X.
    Preferably, the grooves 44 are regularly arranged on the internal face 40 of the plate 38, as appears in FIGS. 4 and 5.
    Each groove 44 is associated with a corresponding through opening 30.
    Each through opening 30 opens, on the one hand, on the internal face 40 into one end of the corresponding groove 44 and, on the other hand, on the external face of the plate 38.
    Preferably, for each groove 44, the corresponding through opening 30 has an axis Y-Y which is orthogonal to the plane locally tangent to the internal face 40.
    The grooves 44 and the through openings 30 are, for example, obtained by machining or stamping the plate 38, or even during the production of the plate 38 by molding.
    Advantageously, the internal face 40 of the plate 38 has a plane of symmetry P. The plane of symmetry P is such that the grooves 44 are symmetrical with respect to the plane of symmetry P.
    In addition, for at least one pair of grooves 44 which are symmetrical to one another with respect to the plane of symmetry P, the corresponding through openings 30 are arranged so as to open into ends 46 which are not symmetrical to one another by relation to the plane of symmetry P.
    For example, and as it appears in FIG. 3, with a plane of symmetry P which is orthogonal to the longitudinal axis XX of the grooves 44, the through openings 30 are all arranged on the same side of the plate 38, c ' i.e. on the left side in Figure 3.
    According to another example, illustrated by FIG. 4, with a plane of symmetry P locally orthogonal to the internal face 40 and parallel to the longitudinal axis XX of the grooves 44, the through openings 30 which are on one side of the plane of symmetry P (top in Figure 4) are all arranged on the same first side of the plate 38 (right in Figure 4), and the through openings 30 which are on the other side of the plane of symmetry P (below in FIG. 4) are all arranged on the same second side of the plate 38 (on the left in FIG. 4), opposite the first side.
    Advantageously, the internal face 40 comprises a keying device 50.
    The polarizing device 50 comprises at least one cavity 52 associated with a corresponding stud 54.
    The cavity 52 and the associated stud 54 have complementary shapes.
    In addition, on the internal face 40, the position of the cavity 52 and the position of the associated stud 54 are symmetrical with respect to the plane of symmetry P.
    To form the entry layer 22, the internal face 40 of the lower element 34 is arranged opposite the internal face 40 of the upper element 36, as illustrated in FIG. 5.
    Then, the internal face 40 of the lower element 34 is brought into contact with the internal face 40 of the upper element 36, so that at least one groove 44 of the upper element 36 is arranged opposite a groove 44 corresponding to the lower element 34, to form the channel 32.
    More specifically, the edges of the grooves 44 arranged opposite one another are completely superimposed.
    In addition, the through opening 30 of the groove 44 of the upper element 36 and the through opening 30 of the groove 44 of the lower element 34 are arranged respectively at opposite ends of the channel 32, as illustrated in FIG. 6. In other words, each through opening 30 of one of the lower element 34 and the upper element 36 is located opposite a solid part of a bottom of the groove 44 corresponding to the other of the lower element 34 and upper element 36.
    Thus, in a plane orthogonal to the respective internal faces 40 of the elements 34, 36 forming the input layer 22, each channel 32 defines a baffle, as it appears in FIGS. 6 and 7.
    More generally, the through openings 30 of a given channel 32 are offset with respect to each other in a direction distinct from a thickness direction of the input layer 22.
    In addition, the length of the channel 32, that is to say the spatial extent of the channel 32 in the longitudinal direction of the corresponding grooves 42, is advantageously greater than or equal to the thickness of the input layer 22.
    In addition, the part of the baffle defined by the channel 32 which has the greatest length corresponds to the part delimited by the grooves 44, that is to say the part of the channel 32 extending parallel to the respective internal faces 40 elements 34, 36, along the longitudinal axis of said grooves 44.
    Preferably, the lower element 34 and the upper element 36 are made integral with one another, for example by gluing.
    Preferably, the channel 32 has a cross section between 0.1 mm 2 (square millimeter) and 10 mm 2 , for example between 0.2 mm 2 and 7 mm 2 .
    Preferably, the lower element 34 has a symmetry such as that described above, and the lower element 34 and the upper element 36 are similar. In this case, the upper element 36 is such that, by operating a 180 ° rotation of the upper element 36 around an axis belonging both to the internal face 40 of the upper element 36 and to the plane of symmetry P, the upper element 36 merges perfectly with the lower element 34.
    In this case, each pair of symmetrical grooves 44 of the lower element 34 is arranged opposite the same pair of symmetrical grooves 44 of the upper element 36.
    Preferably, at least one pad 54 of the internal face 40 of the plate 38 of one of the lower element 34 and the upper element 36 is engaged in an associated cavity 52, having a shape complementary to said stud 54, formed in the other among the lower element 34 and the upper element 36.
    In the case where the lower element 34 has a symmetry such as that described above, has a polarizing device 50 and is similar to the upper element 36 ,, the stud 54 of the polarizing device 50 of the upper element 36 is engaged in the cavity 52 of the polarizer 50 of the lower element 34, and the stud 54 of the lower element 34 is engaged in the cavity 52 of the upper element 36.
    With such an acoustic panel 16, the working frequency, noted f 0 and expressed in hertz, is connected, as a first approximation (that is to say when the effects of the grazing flow are not taken into account), to parameters of the acoustic panel 16 by the following relation:
    where C is the speed of the sound, in meters per second;
    S is a section of channel 32, in square meters;
    V is a volume of cell 24, in cubic meters; and and I 'is a corrected length of channel 32, in meters.
    The corrected length Γ of channel 32 is given by the following relation: l = l + 1.7r (l-0.7Vô) where I is the length of channel 32, equal, in the case where channel 32 is formed by two grooves 44 perfectly superimposed, along the length of one of the grooves 44, in meters;
    r is a diameter of a corresponding through opening, in meters; and σ is a perforation rate of the lower element 34, only taking into account the through openings 30 associated with a channel 32 for which there is a corresponding through opening 30 in the upper element 36. The perforation rate σ is equal to the result of dividing the total area of the through openings 30 by the area of the portion of the external face 42 of the lower element 34 provided with the through openings 30.
    Each channel 32 is formed by a single through opening 30 respectively of the upper and lower elements 34, 36, and the corresponding grooves 44. In addition, each channel 32 does not communicate with any other channel 32 of the input layer 22.
    According to a variant illustrated by Figures 8 and 9, at least one through opening 30 of at least one of the lower element 34 and the upper element 36 does not open into any groove of the same element. More specifically, said through opening 30 opens directly on the external face 42 of the element considered, on the one hand, and on the internal face 40 of said element, on the other hand. In this case, when the lower element 34 and the upper element 36 are assembled, said through opening 30 opening directly both on the external face 42 and on the internal face 40 is arranged opposite a groove 44 corresponding to the other element from among the lower element 34 and the upper element 36, advantageously at a distance from the through opening 30 formed in this other element and opening into this last groove 44.
    For example, in the case of a through opening 30 leading directly both to the external face 42 and to the internal face 40 of the lower element 34, the channel 32 is formed by said through opening 30 of the lower element 34, the corresponding groove 44 of the upper element 36, the through opening 30 formed in the upper element 36 and opening into said groove 44, and the part of the internal face 40 of the lower element 34 which is located in look of the groove 44.
    For example, in the case of a through opening 30 opening directly onto the external face 42 and the internal face 40 of the upper element 36, the channel 32 is formed by said through opening 30 of the upper element 36, the groove 44 corresponding to the lower element 34, the through opening 30 formed in the lower element 34 and opening into said groove 44, and the part of the internal face 40 of the upper element 36 which is located opposite the groove 44 .
    An acoustic panel 16 according to the invention allows the implementation of acoustic attenuation for low frequencies associated with new generations of turbomachinery, without a significant increase in the mass or size of the acoustic panel 16. This effect is obtained by the implementation of an input layer 22 in which the channels 32, comparable to the necks of the usual Helmholtz resonators, extend in a longitudinal direction relative to the acoustic panel 16. Thanks to such a geometry, the lengthening of the channel 32, dictated by the need to attenuate a lower frequency, does not lead to a significant increase in the thickness of the acoustic panel 16.
    The symmetry of the upper and lower elements 34, 36 leads to a reduction in manufacturing costs, the lower and upper elements 34, 36 being identical and obtained by the same process. Such symmetry in fact ensures that the grooves of the lower element 34 overlap with the grooves of the upper element 36 to form the channels 32 of the input layer 22.
    The presence of the polarizing device 50 allows precise positioning of the lower element 34 relative to the upper element 36, and facilitates mounting operations.
    权利要求:
    Claims (10)
    [1" id="c-fr-0001]
    1. Acoustic panel (16) for propulsion unit (2) of an aircraft, intended to be arranged at the edge of a fluid flow stream of the propulsion unit (2), the acoustic panel (16) comprising a core (18) and an entry layer (22), the core (18) comprising a plurality of cells (24) arranged to form a honeycomb structure, each cell (24) opening, on the one hand, on a first face (26) of the core (18) and, on the other hand, on a second face (28) of the core (18) situated opposite the first face (26), the input layer ( 22) comprising a lower element (34) and an upper element (36), each of the lower element (34) and the upper element (36) comprising a respective plate (38) comprising an internal face (40) and an external face (42) oriented opposite the internal face (40), each one of the lower element (34) and the upper element (36) comprising at least one through opening (30) on the one hand, on the external face (42) and, on the other hand, on the internal face (40), the internal face (40) of at least one of the lower element (34) and the 'upper element (36) comprising, for at least one through opening (30), a corresponding groove (44) into which opens the through opening (30), the internal face (40) of the lower element (34) being disposed facing and in contact with the internal face (40) of the upper element (36), each through opening (30) of one of the upper element (36) and the lower element (34) being in look of a groove (44) of the other among the upper element (36) and the lower element (34), so as to form a channel (32) with the groove (44) and the through opening ( 30) on the other among the upper element (36) and the lower element (34) which opens into the groove (44), the through openings (30) of each channel (32) being offset in a distinct direction d 'a thickness direction of the input layer (22), the input layer (22) extending opposite and in contact with the first face (26) of the core (18), for each channel (32), the through opening (30) of the lower element (34) opening into a cell (24) of the heart (18), and the through opening (30) of the upper element (36) being intended to open into the fluid flow vein.
    [2" id="c-fr-0002]
    2. Acoustic panel (16) according to claim 1, in which the internal face (40) of each of the lower element (34) and the upper element (36) comprises, for each through opening (30), a groove (44) corresponding in which opens the through opening (30), each channel (32) being formed by two grooves (44) respective of the lower element (34) and the upper element (36) facing the one from the other and by the corresponding through openings (30) of the lower element (34) and the upper element (36).
    [3" id="c-fr-0003]
    3. Acoustic panel (16) according to claim 1 or 2, wherein, for each groove (44), the corresponding through opening (30) opens, on the internal face (40), in one end of the groove (44) .
    [4" id="c-fr-0004]
    4. Acoustic panel (16) according to claim 3 when it depends on claim 2, wherein, for each channel (32), the corresponding grooves (44) are integrally opposite one another.
    [5" id="c-fr-0005]
    5. Acoustic panel (16) according to any one of claims 1 to 4, further comprising a reflective layer configured to reflect acoustic waves having a frequency belonging to a predetermined range, the reflective layer extending opposite and in contact with the second face (28) of the heart (18).
    [6" id="c-fr-0006]
    6. Acoustic panel (16) according to any one of claims 1 to 5, in which, for each of the upper element (36) and the lower element (34), the corresponding internal face (40) has a plurality of grooves (44), the grooves (44) being symmetrical with respect to a plane of symmetry, and, for at least one pair of grooves (44) which are symmetrical with respect to the plane of symmetry, the corresponding through openings (30) are arranged so as to open into ends of said grooves (44) which are not symmetrical to each other with respect to the plane of symmetry.
    [7" id="c-fr-0007]
    7. Acoustic panel (16) according to any one of claims 1 to 6, wherein the internal face (40) of one of the lower element (34) and the upper element (36) comprises at least one stud engaged in an associated cavity of the other among the lower element (34) and the upper element (36), the cavity and the associated stud having complementary shapes.
    [8" id="c-fr-0008]
    8. Acoustic panel (16) according to any one of claims 1 to 7, in which, for each of the upper element (36) and the lower element (34), each groove (44) is rectilinear and s' extends along a longitudinal axis parallel to a plane locally tangent to the corresponding internal face (40), and, for each groove (44), the corresponding through opening (30) has an axis orthogonal to the plane locally tangent to the internal face (40).
    [9" id="c-fr-0009]
    9. Acoustic panel (16) according to claim 8, in which the groove (44) has a depth less than or equal to half a length of the groove (44), preferably less than or equal to one third of the length of the groove (44), the length of the groove (44) being defined by the extent of the groove (44) along the longitudinal axis.
    [10" id="c-fr-0010]
    10. Propulsion unit (2) for aircraft comprising at least one acoustic panel (16) according to any one of claims 1 to 9.
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    同族专利:
    公开号 | 公开日
    US20200173362A1|2020-06-04|
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    EP3635229A1|2020-04-15|
    CN110998077A|2020-04-10|
    WO2019020933A1|2019-01-31|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    FR2376994A1|1977-01-11|1978-08-04|Snecma|IMPROVEMENTS TO RESONANT CAVITY DEVICES FOR THE REDUCTION OF NOISE IN A DUCT IN THE PRESENCE OF A GAS FLOW|
    US20040045766A1|2002-09-10|2004-03-11|Airbus France|Acoustically resistive layer for an acoustical attenuation panel, panel using such a layer|
    US20100206664A1|2007-07-12|2010-08-19|Rolls-Royce Plc|Acoustic panel|
    FR3080151B1|2018-04-13|2020-11-20|Safran Aircraft Engines|ACOUSTIC TREATMENT PANEL FOR TURBOREACTOR|
    FR3102882B1|2019-10-31|2021-11-12|Safran Nacelles|Acoustic attenuation panel and its manufacturing processes|
    DE102020116396A1|2020-06-22|2021-12-23|Kaiser GmbH|Sound absorber|
    法律状态:
    2019-02-01| PLSC| Search report ready|Effective date: 20190201 |
    2019-06-21| PLFP| Fee payment|Year of fee payment: 3 |
    2020-06-23| PLFP| Fee payment|Year of fee payment: 4 |
    2021-06-23| PLFP| Fee payment|Year of fee payment: 5 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1757051A|FR3069579B1|2017-07-25|2017-07-25|ACOUSTIC PANEL AND ASSOCIATED PROPULSIVE ASSEMBLY|
    FR1757051|2017-07-25|FR1757051A| FR3069579B1|2017-07-25|2017-07-25|ACOUSTIC PANEL AND ASSOCIATED PROPULSIVE ASSEMBLY|
    US16/633,249| US20200173362A1|2017-07-25|2018-07-25|Acoustic panel and associated propulsion unit|
    EP18782479.2A| EP3635229A1|2017-07-25|2018-07-25|Acoustic panel and associated propulsion unit|
    CN201880049386.1A| CN110998077A|2017-07-25|2018-07-25|Acoustic panel and associated propulsion unit|
    PCT/FR2018/051899| WO2019020933A1|2017-07-25|2018-07-25|Acoustic panel and associated propulsion unit|
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