Patent Publication Number: US-2022220923-A1

Title: Thrust reverser cascade including acoustic treatment

Description:
TECHNICAL FIELD 
     The invention relates to the acoustic treatment of sound waves emitted by a turbomachine of an aircraft, and more particularly to the treatment of sound waves at the thrust reversers of the turbomachine. 
     PRIOR ART 
     When a turbomachine is in operation, the interaction between the flow and the solid portions of the turbomachine are responsible for the generation of noise which propagates on either side of the turbomachine. 
     One of the means of attenuating this acoustic radiation is to integrated acoustic treatment means in the surfaces in contact with the sound waves. 
     Conventionally, the acoustic treatment of a turbojet, and more precisely of the noise radiated by the interaction of the rotor and its environment, is accomplished by means of absorbing panels positioned at the wetted surfaces of the duct in which the sound waves propagate. What is meant by wetted surfaces are the surfaces in contact with a fluid flow. These panels are generally composite material of the sandwich type confining a honeycomb forming acoustic absorption cells. 
     Known for example in the prior art are acoustic panels with a single degree of freedom, or SDOF, which have a conventional honeycomb acoustic treatment structure lining the walls of the nacelle of a turbomachine. 
     Because of the principle of operation of the technologies of the acoustic treatment panel using resonant cavities, the radial bulk, i.e. the radial thickness, of the acoustic treatment panels depends on the treatment frequency targeted for obtaining the maximum effectiveness in acoustic attenuation. 
     However, engine architectures increasingly have speeds of rotation of the bladed wheels that are slower and slower, and a number of blades on the bladed wheels that are smaller and smaller, which causes a reduction in the dominant frequencies of the noise associated with the module comprising the fan and the straightener stage, or fan-OGV for “outlet guide vane” module. As a result, matching between the optimal thickness of the acoustic panels and the volume available in the nacelles is currently not satisfied. 
     To slow down an aircraft, a turbomachine generally comprises thrust reversers. There exist primarily two technologies of thrust reverser that are based on the action of a cascade. Two types of cascade type thrust reversers are distinguished: fixed cascade type thrust reversers and cascade type thrust reversers with a sliding connection. 
     Schematic section views are shown in  FIGS. 1A and 1B  in a horizontal plane of a turbomachine  1  according to a first known embodiment of the prior art, respectively in a position in which the thrust reversal is inactivated and in a position in which the thrust reversal is activated. 
     The turbomachine  1  comprises a nacelle  2  with axial symmetry around an axis X defining an axial direction D A , a radial direction D R  and a circumferential direction D C , a fan  3 , a primary stream  4 , a secondary stream, a primary straightener stage  5 , a secondary straightener stage  6 , and a cascade type thrust reverser device  7  including a cascade  8 . 
     As illustrated in  FIGS. 1A and 1B , which show a turbomachine provided with a fixed cascade type thrust reverser, in fixed cascade thrust reversers the cascade  8  is embedded in, i.e. secured to an upstream portion  21  of the nacelle  2  and in sliding connection with a downstream portion  22  of the nacelle  2 , upstream and downstream being defined with respect to the flow direction of a gas flow F in the turbomachine  1 . Translating downstream, the downstream portion  22  of the nacelle  2  uncovers the cascade  8  which becomes the only interface between the flow internal to the nacelle  2  and the surrounding medium in which the turbomachine  1  moves. 
     Schematic section views are shown in  FIGS. 2A and 2B  in a horizontal plane of a turbomachine  1  according to a second embodiment of the prior art, respectively in a position in which the thrust reversal is inactivated and in a position in which the thrust reversal is activated. 
     As illustrated in  FIGS. 2A and 2B  which show a turbomachine  1  provided with a cascade type thrust reverser with a sliding connection, in a fixed cascade thrust reverser the cascade  8  is in sliding connection with respect to the upstream portion  21  of the nacelle  2  and in embedded connection with respect to the downstream portion  22  of the nacelle  2 . Translating downstream, the downstream portion  22  of the nacelle  2  drives the cascade  8  out of the nacelle  2  to position it at the interface between the flow internal to the nacelle  2  and the ambient medium. 
     Thrust reversers represent both a cost, a mass and a bulk that are very penalizing for the performance of the propulsive assembly, while they are used only at the end of the landing phase. The volume that they use in the nacelle can in particular not be used in the prior art, for acoustic treatment of the sound waves emitted by the turbomachine. 
     In the propulsive assembly architectures using door type thrust reversers which are deployed inside the secondary flow to deflect the flow upstream outside the nacelle, a known practice for integrated the conventional acoustic treatment consists of integrating acoustic panels in the cavities of the reverser doors. This practice consists simply of integrating conventional absorbing panels into the available volumes, as is done in the fan casing. 
     DISCLOSURE OF THE INVENTION 
     The invention seeks to supply a cascade type thrust reverser which allows both reorienting a flow of air upstream of the turbomachine outside the nacelle and minimizing the head losses through the cascade when the thrust reversal is activated, and maximizing the effectiveness of acoustic absorption when the thrust reversal is inactive. 
     One object of the invention proposes a cascade type thrust reverser device for a turbomachine of an aircraft, the device comprising a thrust reverser cascade and a casing. The cascade extends in a first plane defining a first direction and a second direction and includes first cavities. The casing comprises an opening extending in a plane orthogonal to said first direction and defining a housing in which said cascade can be inserted in said first direction. The casing and the cascade are in relative translation with respect to one another in the first direction between a first position of the thrust reverser device in which the cascade is entirely positioned in the housing and a second position of the thrust reverser device in which said cascade is at least partially outside said housing. 
     According to a general characteristic of the invention, the casing comprises an acoustic treatment panel including second cavities extending in a second plane parallel to the first plane, each first cavity facing a second cavity when the thrust reverser device is in the first position to form an acoustic treatment cell. 
     The thrust reverser cascade can be formed by an annular one-piece cascade or by a plurality of cascade sections which can be assembled together to form a hollow cylinder with a circular or polygonal base. 
     Likewise, the acoustic treatment panel can be formed by a single-piece annular panel or by a plurality of panel sections which can be assembled together to form a hollow cylinder with a circular or polygonal base. 
     A thrust reverser cascade is usually characterized by a metallic structure, dimensions to as to withstand the aerodynamic load to which it is subjected during the thrust reversal phase. This structure also generates head losses. A cell is a volume consisting of four walls through which a fluid can circulate. Having too great a density of cells can impair the effectiveness of the thrust reverser due to the fact of too great a resistance to the passage of air. 
     On the other hand, acoustic panel structures are not subjected to aerodynamic loads. The partitions which constitute them are very thin and their low volume allows optimizing the tuning of the panel, i.e. the maximum attenuation frequency. 
     The two functions of thrust reversal and acoustic treatment therefore call on very different cell structures. 
     When the cascade type thrust reverser device is mounted on a turbojet, the first direction corresponds to an axial direction of the turbojet and the second direction corresponds to a circumferential direction of the turbojet when the cascade is at least partially annular or to a direction tangent to the circumferential direction of the turbojet when the cascade is flat, in other words not curved. 
     When the thrust reverser device is in its first position in which the thrust reversal is inactive, the first cavities of the cascade thus continue the second cavities of the acoustic treatment panel, the second cavities being resonant cavities. The superposition of the first cavities and the second cavities in a direction orthogonal to the first plane, for example in a radial direction, allows forming acoustic treatment cells the height of which is greater than the height of the second cavity in the direction orthogonal to the first plane. The acoustic treatment cell thus formed by the superposition of a second and of a first cavity comprises a treatment height allowing, on the one hand, increasing the absorption of acoustic waves and, on the other hand, absorbing acoustic waves of lower frequencies than with only the acoustic treatment panel. 
     In a first aspect of the thrust reverser device, the thrust reverser cascade can comprise first partitions positioned successively in a first direction and parallel to one another and first transverse partitions intersecting said first partitions and each extending in planes parallel to one another and parallel to the first direction. The acoustic treatment panel can comprise second partitions positioned successively in the first direction and parallel to one another and second transverse partitions intersecting said second partitions and each extending in planes parallel to one another and parallel to the first direction, the first cavities each being defined by two first partitions and two first transverse partitions, the second cavities each being defined by two second partition and two second transverse partitions. Each first partition can be positioned in the continuation of a second partition in a direction intersecting the first plane and each first transverse partition can be positioned in the continuation of a second transverse partition in said direction intersecting the first plane when the thrust reverser device is in said first position. 
     The first partitions are intended to be oriented in a direction intersecting the flow direction of a gas flow inside a turbomachine including a thrust reverser device provided with a cascade of this type. When the cascade is mounted on a thrust reverser device on a turbomachine, the first partitions, oriented in an azimuthal or radial direction of the turbomachine, are indispensable for guaranteeing the functionality of thrust reversal. In fact, it is due to these first partitions that the flow of air circulating in a stream, inside the nacelle in which the thrust reverser device is mounted, can be captured and reoriented upstream of the turbomachine, with respect to the flow direction of the flow inside the nacelle, outside the nacelle. 
     The first transverse partitions are intended to be oriented in the direction of the gas flow inside a turbomachine including a thrust reverser device provided with a cascade of this type. When the cascade is mounted on a thrust reverser device on a turbomachine, the first transverse partitions, oriented in an axial direction of the turbomachine, are not indispensable for the functionality of thrust reversal. On the other hand, they allow the formation of resonant cavities allowing attenuating acoustic waves generated by the turbomachine. 
     In a second aspect of the thrust reverser device, the second partitions of the acoustic treatment panel can comprise a first end facing said thrust reverser cascade and a second end opposite to the first end. And for each second partition, the tangent to the second partition at the second end of the second partition can form a first angle with a plane parallel to said first plane when the thrust reverser device is in said first position, the first angle being comprised between 60° and 120°. 
     This orientation of the second partitions of the acoustic treatment panel to an end opposite to the end facing the thrust reverser cascade allows defining a substantially radial orientation of the acoustic treatment cells, to avoid penalizing the operation of the resonator due to undesired acoustic reflections on the partitions. 
     The second partitions of the acoustic treatment panel can thus be curved with possibly one or more inflection points. The use of second curved partitions in the acoustic treatment panel allows maximizing the effectiveness of the acoustic treatment without degrading the functionality of the thrust inversion of the cascade regardless of the positioning of the panel with respect to the cascade in the direction orthogonal to the first plane. 
     The second end of the second partitions can thus either be at the inlet to the acoustic treatment cell or at the outlet of the acoustic treatment cell, depending on the positioning of the acoustic treatment panel with respect to the thrust reverser cascade in a direction perpendicular to the first plane, i.e. in the radial direction. 
     In a third aspect of the thrust reverser device, the first partitions of the thrust reverser cascade can comprise a first end facing the acoustic treatment panel and a second end opposite to the first end. And for each first partitions, the tangent to the first partition at the first end of the first partition can form a second angle with the tangent to the second partition at the first end of the second partition when the thrust reverser device is in said first position, the second angle being comprised between −20° and +20°. 
     This orientation of the first partitions of the thrust reverser cascade and one end facing the acoustic treatment panel allows defining a relatively small gap regarding the orientation of the cells at the interface between the thrust reverser cascade and the acoustic treatment panel, and thus avoiding penalizing the operation of the resonator due to undesired acoustic reflections on the partitions, without perturbing the functionality of thrust reversal. 
     In a fourth aspect of the thrust reverser device, the first partitions of the cascade can comprise a first curvature in the direction orthogonal to said first plane and the second partitions of the panel can comprise a second curvature in the direction orthogonal to said first plane distinct from the first curvature. The acoustic treatment cells formed in the first position of the thrust reverser device can comprise two undulated walls orthogonal to the first direction and each formed by a first partition and a second partition in the continuation of one another. 
     Said two walls of an acoustic treatment cell thus have an undulation, i.e. a curve with an inflection point which allows maximizing the acoustic absorption by the cell while still retaining the effectiveness of the thrust reversal of the thrust reverser cascade when the latter is used for thrust reversal. 
     In a fifth aspect of the thrust reverser device, the first cavities and the second cavities can have the same shape in a section plane parallel to said first plane. 
     In a sixth aspect of the thrust reverser device, the casing can also comprise a porous interface with a thickness comprised between 0.5 and 20 mm, formed of at least one layer of porous material and positioned at the interface between the acoustic treatment panel and the cascade when the thrust reverser device is in the first position, the thickness extending in a direction perpendicular to said first plane. 
     The addition of a porous interface allows improving the interface between the two cellular structures, namely the acoustic treatment panel and the thrust reverser cascade, while ensuring better sealing at the junctions between the partitions of the acoustic treatment panel and the partitions of the thrust reverser cascade, while still offering useful clearance to improve the sliding of the thrust reverser cascade at the time when the thrust reverser function is used, i.e. when the device is in the second position. 
     In a seventh aspect of the thrust reverser device, the acoustic treatment cells can comprise a height comprised between 10 and 100 mm, the height being measured in a direction perpendicular to the first plane. 
     In an eighth aspect of the thrust reverser device, the casing can comprise a perforated wall and an acoustically reflecting wall each extending parallel to said first plane, the cascade and the acoustic treatment panel being positioned between the perforated wall and the acoustically reflecting wall when the thrust reverser device is in the first position. 
     In a ninth aspect of the thrust reverser device, the perforated wall can be directly assembled by gluing, i.e. directly glued on, to said cascade or said one acoustic treatment panel. 
     In a tenth aspect of the thrust reverser device, the acoustic treatment panel can be positioned between the perforated wall and the thrust reverser cascade when the thrust reverser device is in the first position. 
     In an eleventh aspect of the thrust reverser device, the acoustic treatment panel can be positioned between the acoustically reflecting wall and the thrust reverser cascade when the thrust reverser device is in the first position. 
     In a twelfth aspect of the thrust reverser device, the cascade can be movable and the casing fixed to use the thrust reverser device in a turbomachine provided with a cascade type thrust reverser with a sliding connection, or the cascade can be fixed and the casing movable to use the thrust reverser device in a turbomachine provided with a fixed cascade thrust reverser. 
     In another object of the invention, a turbomachine is proposed which is intended to be mounted on an aircraft, the turbomachine comprising an axially symmetrical nacelle defining an axial direction and a radial direction, the nacelle including a thickness in the radial direction and a housing extending in the axial direction in its thickness to accommodate a cascade of a cascade type thrust reverser device. 
     According to a general feature of this object of the invention, the turbomachine can comprise a cascade type thrust reverser device as defined above, the cascade being positioned, when the thrust reversal is not required, in the corresponding housing of the nacelle of the turbomachine. 
     In another object of the invention, an aircraft is proposed comprising at least one turbomachine as defined above. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be better understood upon reading performed hereafter, by way of indication and without limitation, with reference to the appended drawings in which: 
         FIGS. 1A and 1B , already described, show schematic section views in a longitudinal plane of a turbomachine according to a first known embodiment of the prior art, respectively in a position in which the thrust reversal is inactive and in a position in which the thrust reversal is activated. 
         FIGS. 2A and 2B , already described, show schematic section views in a longitudinal plane of a turbomachine according to a second known embodiment of the prior art, respectively in a position in which the thrust reversal is inactive and in a position where the thrust reversal is activated. 
         FIG. 3  shows a schematic section view in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device in a position in which the thrust reversal is inactive according to a first embodiment of the invention. 
         FIG. 4  shows a schematic section view in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device in a position in which the thrust reversal is activated according to a first embodiment of the invention. 
         FIG. 5  illustrates schematically a section view in a plane comprising the axial direction and the circumferential direction of a cascade of the thrust reverser device. 
         FIG. 6  illustrates schematically a section view in a plane comprising the axial direction and the circumferential direction of an acoustic treatment panel of the thrust reverser device. 
         FIG. 7  shows a schematic section view in a plane comprising the axial direction and the radial direction of a thrust reverser device in a position in which the thrust reversal is inactive according to a second embodiment of the invention. 
         FIG. 8  shows a schematic section view in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device in a position in which the thrust reversal is activated according to a second embodiment of the invention. 
         FIG. 9  is a zoom of  FIG. 7  illustrating the arrangement of the first partitions and the second partitions in the first position of the device. 
         FIG. 10  shows a schematic section view in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device in a position in which the thrust reversal is inactive according to a third embodiment of the invention. 
         FIG. 11  shows a schematic section view in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device in a position in which the thrust reversal is activated according to a third embodiment of the invention. 
         FIG. 12  is a zoom of  FIG. 10  illustrating the arrangement of the first partitions an of the second partitions in the first position of the device. 
         FIG. 13  shows a schematic section view in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device in a position in which thrust reversal is inactive according to a fourth embodiment of the invention. 
         FIG. 14  shows a schematic section view in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device in a position in which the thrust reversal is activated according to a fourth embodiment of the invention. 
         FIG. 15  shows a schematic section view in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device in a position in which the thrust reversal is in active according to a fifth embodiment of the invention. 
         FIG. 16  shows a schematic section view in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device in a position in which the thrust reversal is activated according to a fifth embodiment of the invention. 
         FIG. 17  shows a schematic section view in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device in a position in which thrust reversal is inactive according to a sixth embodiment of the invention. 
         FIG. 18  shows a schematic section view in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device in a position in which the thrust reversal is activated according to a sixth embodiment of the invention. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     In  FIGS. 3 to 12 , the turbomachine  1  comprises a thrust reverser device  70  which can operate according to the operation described in  FIGS. 2A and 2B . The turbomachine comprises a nacelle with axial symmetry around an axis X defining an axial direction D A , a radial direction D R  and a circumferential direction D C . 
     Shown in  FIGS. 3 and 4  are schematic section views in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device mounted on an aircraft turbomachine according to a first embodiment of the invention and respectively in a position in which the thrust reversal is inactive and in a position in which the thrust reversal is activated. 
     The thrust reverser device  70  comprises a plurality of cascades  80  assembled to form a cascade ring. The ring can have a cylindrical base or a polygonal base, the cascades  80  extending respectively either in a curved plane comprising the axial direction D A  and the circumferential direction D C  of the turbomachine, or in a straight plane comprising the axial direction D A  and a direction tangent to the circumferential direction D C . 
     In the embodiments illustrated, the cascades  80  are curved to facilitate the explanation and the labels, and extend mainly in a curved plane, hereafter called the first plane, comprising the axial direction D A  and the circumferential direction D C . 
     As shown in  FIG. 5 , which is a section view of a cascade  80  in a section plane parallel to the first plane, each cascade  80  comprises a frame  81  inside which extend first partitions  82  in the circumferential direction D C  and first transverse partitions  83  in the axial direction D A . The frame  81 , the first partitions  82  and the first transverse partitions  83  have a height in the radial direction D R  comprised between 5 mm and 50 mm. 
     The thickness of the first partitions  82  is comprised between 0.5 mm and 5 mm to be sufficiently thick to withstand the loads to which they are subjected, but also as thin as possible to minimize the mass and the head losses in the cascade. 
     The first partitions  82  are azimuthal partitions intended to orient the gas flow F toward the outside of the nacelle  2  and upstream of the turbomachine  1  for the reversal of thrust when the thrust reverser device is activated. The first transverse partitions  83  are axial partitions intended to define, with the first partitions  82 , first cavities  84  for the absorption of acoustic waves generated by the turbomachine, when the thrust reverser device is inactive. 
     The distance in the circumferential direction D C  separating two first transverse partitions  83  adjacent to one another is equal to the distance in the axial direction D A  separating two first partitions  82 , to thus favor acoustic propagation in plane waves inside the cavities. 
     The cascade  80  comprises, in the axial direction D A  of the turbomachine  1  on which the device  70  is mounted, a first axial end  810  and a second axial end  812 . As illustrated in  FIGS. 3 and 4 , in the embodiments illustrated in  FIGS. 3 to 12  and being able to operate according the operation described in  FIGS. 2A and 2B , the second axial end  812  of the cascades  80  is fixed to a downstream portion  22  of the nacelle  2  movable with respect to an upstream portion  21  of the nacelle  2 . 
     Housed in the upstream portion  21  of the nacelle  2  of the turbomachine  1 , the thrust reverser device  70  comprises a plurality of casings  71  assembled to form a panel ring. The ring can have a cylindrical base or a polygonal base, the casings  71  extending respectively either in a curved plane comprising the axial direction D A  and the circumferential direction D C  of the turbomachine  1 , or in a straight plane comprising the axial direction D A  and a direction tangent to the circumferential direction D C . 
     In the embodiments illustrated, the casing&#39;s  71  are curved to facilitate the explanation and the labels, and extend mainly in a curved plane comprising the axial direction D A  and the circumferential direction D C . 
     Each casing  71  includes a perforated wall  72 , an acoustically reflecting wall  73  and an acoustic treatment panel  74 . The casing  71  comprises successively in the radial plane D R  moving away from the axis of revolution of the turbomachine  1 , the perforated wall  72 , the acoustic treatment panel  74 , a housing  75  configured to accommodate the cascade  80 , and the acoustically reflecting wall  73 . 
     The casing  71  also comprises an opening  76  communicating with the housing  75 , the opening extending in a plane comprising the radial direction D R  and the circumferential direction D C  at an axial end of the casing  71  facing the downstream portion  22  of the nacelle  2 . 
     When thrust reversal is inactive, the thrust reverser device  70  is in a first position illustrated in  FIG. 3  in which the cascade  80  is positioned in the housing  75  of the casing  71 . 
     When thrust reversal is activated, the thrust reverser device  70  is in a second position illustrated in  FIG. 4  in which the cascade  80  is extracted from the casing  71  in the axial direction D A  in translation with the downstream portion  22  of the nacelle, leaving the housing  75  free, at least in part. 
     The acoustic treatment panel  74  is positioned in the casing  71  in a second plane parallel to the first plane in which the cascade  80  extends, and the acoustic panel  74  glued to the perforated wall  72 . 
     The acoustic treatment panel  74  of each casing  71  comprises second partitions  742  and second transverse partitions. 
     As shown in  FIG. 6 , which is a section view of an acoustic treatment panel  74  in a section plane parallel to the first plane, each acoustic treatment panel  74  comprises a frame  741  inside which extend second partitions  742  in the circumferential direction D C  and second transverse partitions  743  in the axial direction D A . 
     The second partitions  742  are azimuthal partitions and the second transverse partitions  743  are axial partitions. The second partitions  742  and the second transverse partitions  743  define between them second cavities  744  for the absorption of acoustic waves generated by the turbomachine, when the thrust reverser device is in its first position. 
     The distance in the circumferential direction D C  separating two second transverse partitions  743  adjacent to one another is equal to the distance in the axial direction D A  separating two second partitions  742 , to thus favor acoustic propagation in plane waves inside the cavities. 
     In addition, at the interface between the acoustic treatment panel  71  and the cascade  80 , each casing  70  comprises a porous interface  77  formed of several layers of porous material and having a thickness E in the radial direction D R  comprised between 0.5 mm and 20 mm to improve the interface between the two cellular structures by ensuring better sealing between the different partitions while still facilitating the sliding of the cascade  80  in the housing  75  during translations. 
     When the thrust reverser device  70  is in its first position, as illustrated in  FIG. 3 , the first cavities  84 , the first partitions  82  and the first transverse partitions  83  are superimposed respectively with the second cavities  744 , the second partitions  742  and the second transverse partitions  743 , and thus form resonant cavities  710 , or acoustic treatment cells, the volume of each of which corresponds to the sum of the volume of a first cavity  84  and the volume of a second cavity  744 . The acoustic treatment cells  710  thus extend at a height H in the radial direction D R  corresponding to the sum of the height of the acoustic treatment panel  74 , the thickness E of the porous interface  77  and the height of the cascade  80 . The height H of the acoustic treatment cells is comprised between 10 mm and 100 mm. 
     In the first embodiment illustrated in  FIGS. 3 and 4 , the first cavities  84  and the second cavities  744  have an identical shape in a section plane comprising the axial direction D A  and the circumferential direction D C , with first partitions  82  and second partitions  742  each extending purely radially. Thus, in the first position of the thrust reverser device  70 , each of the first transverse partitions  83  is not only in the continuation of one of the second transverse partitions  743 , but more precisely is aligned with one of the second transverse partitions  743 . 
     Shown in  FIGS. 7 and 8  are schematic section views in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device  70  mounted on an aircraft turbomachine according to a second embodiment of the invention and respectively in a position in which the thrust reversal is inactive and in a position in which the thrust reversal is activated. 
     The thrust reverser device  70  of the second embodiment illustrated in  FIGS. 7 and 8  differs from the first embodiment illustrated in  FIGS. 3 and 4  in that the first transverse partitions  83  of the cascade  80  and the second transverse partitions  743  of the acoustic treatment panel  70  each have a curvature in a section plane comprising the radial direction D R  and the axial direction D A  unlike the first embodiment where the partitions are rectilinear in the radial direction D R , i.e. where they extend radially. 
     As illustrated in  FIG. 9 , which is a zoom of  FIG. 7  illustrating the arrangement of the first partitions  82  and of the second partitions  742  in the first position of the thrust reverser device  70  in the second embodiment, the curvature of the second partitions  742  of the acoustic treatment panel  74  is shown in  FIG. 9  by a first curve C 1 , and the curvature of the first partitions  82  of the cascade  80  is shown by a second curve C 2 . 
     If it is considered that each partition  742  and  82  is formed by the radial stacking of an infinity of cross sections, taken in a plane orthogonal to the radial direction D R , it is possible to define a curve passing through the center of each cross section and extending over the entire height H of the acoustic treatment cell  710  which is formed by the assembly of the first curve C 1  with the second curve C 2  over the height H of the acoustic treatment cell  7 . 
     The second partitions  742  of the acoustic treatment panel  74  comprise a first end  7420  facing said thrust reverser cascade  80  and a second end  7425  opposite to the first end  7420  and facing the porous wall  72 . 
     And the first partitions  82  of the cascade  80  each comprise a first end  820  facing the acoustic treatment panel  74  and a second end  825  opposite to the first end  820  and facing the acoustically reflecting wall  73 . 
     The second end  7425  of the second partitions  742  is thus at the inlet of the acoustic treatment cell  710 . 
     In addition, for each second partition  742 , in a section plane comprising the axial direction D A  and the radial direction D R , the tangent T 11  to the second partition  742  taken at the second end  7425  forms a first angle A with a plane parallel to said first plane comprised between 60° and 120°, the perforated wall  72  extending in said first plane to the second end  7425  of the second partition  742 . 
     This orientation of the second partitions  742  of the acoustic treatment panel  74  at their second end  7425 , which faces the flow circulating inside the nacelle, allows defining a substantially radial orientation of the acoustic treatment cells  710 , to avoid penalizing the operation of the resonator due to undesired acoustic reflections on the partitions. 
     The second partitions  742  of the acoustic treatment panel are therefore curved. The use of curved second partitions  742  in the acoustic treatment panel  74  allows maximizing the effectiveness of the acoustic treatment without degrading the functionality of thrust reversal of the cascade regardless of the positioning of the panel with respect to the cascade in the direction orthogonal to the first plane. 
     In addition, for each first partition  82 , in a section plane comprising the axial direction D A  and the radial direction D R , the tangent T 2  to the first partition  82  at its first end  820  forms a second angle B with the tangent T 1  to the second partition  742  at the first end  7420  when the thrust reverser device  70  is in said first position. The second angle B is comprised between −20° and +20°. 
     The first curve C 1  defines a first angle A with the first plane. The first angle A is formed between the first plane and the tangent to the end of the first curve C 1  opposite to the end facing the second curve C 2 . 
     This orientation of the first partitions  82  of the thrust reverser cascade  80  and of the second partitions  742  at the location where they face one another, i.e. at the interface between the cascade and the panel  74 , allowing having continuity of the acoustic treatment cells  710  and thus avoid penalizing the operation of the resonator due to undesired acoustic reflections on the partitions, without perturbing the functionality of thrust reversal. 
     The first partitions  82  of the thrust reverser cascade  80  all having the same shape and the second partitions  742  of the acoustic treatment panel  74  also all having the same shape, the acoustic treatment cells  710  all have the same profile, this profile following the profile of the first and second partitions  82  and  742 . 
     The first and second curves C 1  and C 2  define the second angle B. The second angle B is formed between the tangent to the first curve C 1  at the end of the first curve C 1  facing the second curve C 2  and the tangent to the second curve C 2  at the end of the second curve C 2  facing the first curve C 1 . 
     In  FIGS. 10 and 11  are shown schematic section views in a plane comprising the axial direction and the radial direction of a cascade type thrust reverser device  70  mounted on an aircraft turbomachine  14  according to a third embodiment of the invention and respectively in a position in which the thrust reversal is inactive and in a position in which the thrust reversal is activated. 
     The thrust reverser device  70  of the third embodiment illustrated in  FIGS. 10 and 11  differs from the second embodiment illustrated in  FIGS. 7 and 8  in that the positions in the radial direction D R  of the acoustic treatment panel  74  and of the cascade  80  are reversed. 
     In the third embodiment, the cascade  80  is, in the radial direction D R , inside the acoustic treatment panel  74 . Thus, in the first position of the thrust reverser device  70  illustrated in  FIG. 10 , the cascade  80  extends in the radial direction D R  between the perforated wall  72  of the casing  71  and the acoustic treatment panel  74 , the porous interface  77  extending between the panel  74  and the cascade  80  in the radial direction D R . 
     As for the second embodiment, the first transverse partitions  83  of the cascade  80  and the second transverse partitions  743  of the acoustic treatment panel  70  each have a curvature in a section plane comprising the radial direction D R  and the axial direction D A . 
     As illustrated in  FIG. 12 , which is a zoom of  FIG. 10  illustrating the arrangement of the first partitions  82  and of the second partitions  742  in the first position of the thrust reverser device  70  in the second embodiment, the curvature of the second partitions  742  of the acoustic treatment panel  74  is shown in  FIG. 12  by a first curve C 1 , and the curvature of the first partitions  82  of the cascade  80  is shown by a second curve C 2 . 
     If it is considered that each partitions  742  and  82  is formed by the radial stacking of an infinity of cross sections, taken in a plane orthogonal to the radial direction D R , it is possible to define a curve passing through the center of each cross section and extending over the entire height H of the acoustic treatment cell  710  which is formed by the assembly of the first curve C 1  with the second curve C 2  to the height H of the acoustic treatment cell  7 . 
     The second partitions  742  of the acoustic treatment cell  74  comprise a first end  7420  facing said thrust reverser cascade  80  and a second end  7425  opposite to the first end  7420  and facing the acoustically reflecting wall  73 . 
     And the first partitions  82  of the cascade  80  each comprise a first end  820  facing the acoustic treatment panel  74  and a second end  825  opposite to the first end  820  and facing the porous wall  72 . 
     The second end  825  of the first partitions  82  is thus at the inlet of the acoustic treatment cell  710 . 
     In addition, for each second partition  742 , in a section plane comprising the axial direction D A  and the radial direction D R , the tangent T 11  to the second partition  742  taken at the second end  7425  forms a first angle A with a plane parallel to said first plane comprised between 60° and 120°, the acoustically reflecting wall  73  extending in said first plane to the second end  7425  of the second partition  742 . 
     The first curve C 1  defines the first angle A with the first plane. The first angle A is formed between the first plane and the tangent to the end of the first curve C 1  opposite to the end facing the second curve C 2 . 
     This orientation of the second partitions  742  of the acoustic treatment panel  74  at their second end  7425  allows defining a substantially radial orientation of the acoustic treatment cells  710 , to avoid penalizing the operation of the resonator due to undesired acoustic reflections on the partitions. 
     In addition, for each first partition  82 , in a section plane comprising the axial direction D A  and the radial direction D R , the tangent T 2  to the first partition  82  at its first end  820  forms a second angle B with the tangent T 1  to the second partition  742  at the first end  7420  when the thrust reverser device  70  is in said first position. The second angle B is comprised between −20° and +20°. 
     The first and second curves C 1  and C 2  define the second angle B. the second angle B is formed between the tangent to the first curve C 1  at the end of the first curve C 1  facing the second curve C 2  and the tangent to the second curve C 2  at the end of the second curve C 2  facing the first curve C 1 . 
     In  FIGS. 13 to 18 , the turbomachine  1  comprises in this case a thrust reverser device  70  which can operate according to the operation described in  FIGS. 1A and 1B . 
     In  FIGS. 13 and 14  are shown schematic section views in a plane comprising the axial direction D A  and the radial direction D R  of a cascade type thrust reverser device mounted on an aircraft turbomachine  1  according to a fourth embodiment of the invention and respectively in a position in which the thrust reversal is inactive and in a position in which the thrust reversal is activated. 
     The fourth embodiment differs from the first embodiment in that the cascade  80  is secured to the upstream portion  21  of the nacelle  2  of the turbomachine  1  and the casing  71  is made in the downstream portion  22  of the nacelle  2 . Thus, as illustrated in  FIGS. 14, 16 and 18 , in the embodiments illustrated in  FIGS. 13 to 18  and being able to operate according to the operation described in  FIGS. 1A and 1B , the first axial end  810  of the cascades  80  is fixed to an upstream portion  21  of the nacelle  2 , movable with respect to a downstream portion  22  of the nacelle  2 . 
     The casing  71  comprises an opening  76  communicating with the housing  75 , the opening extending in a plane comprising the radial direction D R  and the circumferential direction D C  at an axial end of the casing  71  facing the upstream portion  21  of the nacelle  2 . 
     When the thrust reversal is inactive, the thrust reverser device  70  is in a first position illustrated in  FIG. 13  in which the cascade  80  is positioned in the housing  75  of the casing  71 . 
     When the thrust reversal is activated, the thrust reverser device  70  is in a second position illustrated in  FIG. 14  in which the cascade  80  is extracted from the casing  71  in the axial direction DA, the casing  71  being in translation with the downstream portion  21  of the nacelle  2 , leaving the housing  75  at least partially free. 
     Shown in  FIGS. 15 and 16  are schematic section views in a plane comprising the axial direction D A  and the radial direction D R  of a cascade type thrust reverser device mounted on an aircraft turbomachine  1  according to a fifth embodiment of the invention and respectively in a position in which the thrust reversal is inactive and in a position in which the thrust reversal is activated. 
     The fifth embodiment differs from the second embodiment in that the cascade  80  is secured to the upstream portion  21  of the nacelle  2  of the turbomachine  1  and the casing  71  is made in the downstream potion  22  of the nacelle  2 . 
     Shown in  FIGS. 17 and 18  are schematic section views in a plane comprising the axial direction D A  and the radial direction D R  of a cascade type thrust reversal device mounted on an aircraft turbomachine  1  according to a sixth embodiment of the invention and respectively in a position in which the thrust reversal is inactive and in a position in which the thrust reversal is activated. 
     The sixth embodiment differs from the third embodiment in that the cascade  80  is secured to the upstream portion  21  of the nacelle  2  of the turbomachine  1  and the casing  71  is made in the downstream portion  22  of the nacelle  2 . 
     The invention thus supplies a cascade type thrust reverser device which allows both reorienting an air flow upstream of the turbomachine outside the nacelle and minimizing the head losses through the cascade when the thrust reversal is activated, and maximizing the effectiveness of acoustic absorption when the thrust reversal is inactive.