TURBINE MOTOR MODULE WITH ONE PROPELLER AND GUIDE SHAFTS SUITABLE BY TWO HOUSINGS AND ASSOCIATED TURBINE MOTOR

Description

Scope of the invention

[0001] The present invention relates to the field of turbomachinery and in particular to a turbomachine module comprising an unfaired propeller and a stator with stator blades. It also relates to the corresponding turbomachine. Technical background

[0002] Turbomachinery with at least one unducted propeller is known as an "open rotor" or "unducted fan." Within this category, there are those with two unducted, counter-rotating propellers (known as UDFs for "Unducted Dual Fan") and those with a single unducted propeller and a stator with multiple stator blades (known as USFs for "Unducted Single Fan"). The propeller(s) forming the propulsion section can be located at the rear of the gas generator (or engine), making it a pusher type, or at the front of the gas generator, making it a tractor type. These turbomachinery are turboprops, distinguished from turbojets by the use of an external (unducted) propeller instead of an internal fan.This allows for a significantly increased bypass ratio without being negatively impacted by the mass of the housings or nacelles designed to surround the propeller or fan blades. Examples of this type of turbomachine are described in documents EP-A1-3093437, EP-A1-3093443, and EP-A1-3225813.

[0003] Currently, this type of turbomachine, and in particular USF turbomachines, has a considerable length along its longitudinal axis of rotation, which impacts its mass and generates significant noise. This noise originates from the gas generator but primarily from the interaction of the wake and vortex generated by the streamlines winding at the tips of the propeller blades and the stator blades. This noise is even louder when the stator blades are close to the propeller blades. Indeed, the stator blades of turbomachines are generally mounted on an inlet housing that houses the nozzle separating the primary and secondary flows, which circulate respectively in a primary stream and around the inlet housing. However, moving the stator blades of the stator away from the propeller blades goes against the optimization of mass and size; compacting the turbomachine as much as possible is also a challenge. Summary of the invention

[0004] The objective of the present invention is to provide a turbomachine module with stator blades arranged in such a way as to reduce the acoustic impact of unshod turbomachines while avoiding lengthening the turbomachine.

[0005] We achieve this objective in accordance with the invention by means of a turbomachine module with longitudinal axis X, comprising an unfaired propeller intended to be driven in rotation around the longitudinal axis X by a power shaft which is connected at least to a rotor element, at least one rectifier comprising a plurality of stator blades distributed regularly around the longitudinal axis X and extending radially in a secondary airflow, at least a first casing mounted upstream, along the longitudinal axis, of the rotor element and a second casing mounted downstream, along the longitudinal axis, of the rotor element, the first casing and the second casing being separated by the rotor element along the longitudinal axis X and being contiguous, the stator blades each comprising a foot housed in a sleeve which is connected on one side, to the first casing and on the other side, to the second casing.

[0006] Thus, this solution achieves the aforementioned objective. In particular, offsetting the stator blades between a first and a second housing, instead of having them supported by the inlet housing as in the prior art, reduces the noise generated by this type of turbomachine because the distance between the propeller and the stator has been increased. This arrangement, where the stator blades are supported by two housings, facilitates the integration of auxiliary components into the inlet housing (for example, lubricant lines to lubricate and cool a gearbox or a blade pitch control system, etc.). Since the first and second housings are already present in the turbomachine, the arrangement of the stator blade support means between these two housings avoids lengthening the turbomachine.Furthermore, the center of gravity has been shifted downstream of the turbomachine, resulting in less overhang for the turbomachine's suspension on an aircraft. Finally, maintenance of the stator blades and components (such as a compressor, etc.) located in the vicinity of the blades is improved by dismantling and pivoting one or more blades and / or lifting connecting rods, for example.

[0007] The module also includes one or more of the following features, taken alone or in combination: The module comprises a plurality of connecting rods extending between the first and second housings, each connecting rod carrying a sleeve. Each connecting rod has a first end mounted on a first radially external ferrule of the first housing by a ball joint and a second end mounted on a second radially external ferrule of the second housing by a fixed-type connection. Each connecting rod is made in one piece with a sleeve. The stator blades of the rectifier have variable pitch, and the module includes a system for changing the pitch of the stator blades, which is arranged radially outside the second housing. The stator blades of the rectifier are unshrouded. At least one bearing for guiding the rotation of a stator blade root is housed in an internal recess of a sleeve.The first casing is an inlet casing that carries a separation nozzle designed to divide an airflow into a primary airflow and a secondary airflow. The inlet casing comprises a first radially internal shell, a first radially external shell, and between which extends at least one first structural radial arm. The second casing is an inter-compressor casing arranged downstream of a low-pressure compressor, along the longitudinal axis. The inter-compressor casing comprises a second radially internal shell, a second radially external shell, which are coaxial with the longitudinal axis X, and between which extends at least one second structural radial arm. The S / C ratio, corresponding to the distance S between a trailing edge of the propeller blades and a leading edge of a stator blade on the chord C of the propeller blades, is approximately 3. The rotor component is a low-pressure compressor.The stator is located downstream of the propeller. The connecting rods are made of titanium. The propeller blade pitch control system comprises at least one control means having a fixed body and a body that moves axially relative to the fixed body, and a linkage mechanism connecting each stator blade to the moving body of the control means.

[0008] The invention further relates to an aircraft turbomachine comprising at least one module having any one of the preceding characteristics and a gas generator downstream of the propeller. Brief description of the figures

[0009] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent upon reading the detailed explanatory description that follows, of embodiments of the invention given by way of purely illustrative and non-limiting examples, with reference to the accompanying schematic drawings in which: [ Fig. 1 ] There figure 1 is a schematic, axial, partial cross-sectional view of an example of a turbomachine with a single unfaired propeller to which the invention applies; [ Fig. 2 ] There figure 2 represents in perspective an inlet casing connected to an inter-compressor casing by a set of connecting rods, each carrying a sleeve intended to receive the foot of a stator blade of a rectifier according to the invention; Fig. 3 ] There figure 3 illustrates in axial and partial section an embodiment of a stator blade foot of a turbomachine mounted in a sleeve according to the invention; and [ Fig. 4 ] There figure 4 represents in perspective a rear view of an embodiment of an inter-compressor housing according to the invention. Detailed description of the invention

[0010] The invention relates to a turbomachine 1 comprising a single unfaired propeller 2 and a stator 3 downstream of the propeller 2. The turbomachine is intended to be mounted on an aircraft. Such a turbomachine is a turboprop as shown in the figure 1 This turbomachine is known by the English term "Unducted Single Fan," as explained previously. Of course, the invention applies to other types of turbomachinery.

[0011] In the present invention, and generally, the terms "upstream", "downstream", "axial" and "axially" are defined with respect to the gas flow in the turbomachine and here along the longitudinal axis X (and even from left to right on the figure 2 ). Similarly, the terms "radial", "internal" and "external" are defined with respect to a radial axis Z perpendicular to the longitudinal axis X and with respect to the distance from the longitudinal axis X.

[0012] To facilitate its manufacture and assembly, a turbomachine is generally modular, meaning it comprises several modules that are manufactured independently and then assembled together. The modularity of a turbomachine also simplifies its maintenance. In this application, a "turbomachine module" is defined as a module that includes, in particular, a fan and its drive shaft for the propeller.

[0013] On the figure 1The turbomachine 1 comprises a gas generator 4 which typically includes, from upstream to downstream, a low-pressure compressor 5, a high-pressure compressor 6, a combustion chamber 7, a high-pressure turbine 8, and a low-pressure turbine 9. The low-pressure compressor 5 and the low-pressure turbine 9 are mechanically connected by a low-pressure shaft 10 to form a low-pressure housing. The high-pressure compressor 6 and the high-pressure turbine 8 are mechanically connected by a high-pressure shaft 11 to form a high-pressure housing. The high-pressure shaft 11 extends radially outside the low-pressure shaft 10 and they are coaxial.

[0014] In an alternative configuration not shown, the low-pressure unit comprises the low-pressure compressor, which is connected to an intermediate-pressure turbine. A free-running power turbine is mounted downstream of the intermediate-pressure turbine and is connected to the propeller described below via a power transmission shaft to drive its rotation.

[0015] The unfaired propeller 2 is formed of a ring of movable blades 12 extending from a rotating housing 13, which is centered and rotatable about the longitudinal axis X. The rotating housing 13 is mounted movable relative to an internal housing 14 extending downstream of the rotating housing 13. In the example shown of the figure 1The propeller 2 is mounted upstream of the gas generator 4 (tractor or "pull" configuration). Alternatively, the propeller is mounted downstream of the gas generator (pusher configuration). The blades of propeller 2 can have variable pitch by means of a pitch-changing system 15.

[0016] An airflow F entering the turbomachine splits into a primary airflow F1 and a secondary airflow F2 at a separation nozzle 16. The latter is carried by an inlet housing 17 centered on the longitudinal axis. The inlet housing 17 is extended downstream by an external housing or inter-flow housing 18. The inlet housing 17, illustrated more precisely in the figure 2, comprises a radially internal ferrule 19 and a radially external ferrule 20 which are centered on the X axis. A plurality of structural arms 21 extend radially between the radially internal ferrule 19 and the radially external ferrule 20. The arms 21 are fixed and are made as a single piece with the internal and external ferrules 19, 20.

[0017] The primary airflow F1 circulates in a primary channel 22 which passes through the gas generator 4. In particular, the primary airflow F1 enters the gas generator 4 through an annular air inlet 23 and exits through a primary nozzle 24 which is disposed downstream of the gas generator 4. The air inlet 23 is radially delimited at least in part by a radially internal wall 16a of the separation nozzle 16 which is annular and centered on the X axis and by a radially external wall 13a of the rotating housing 13.

[0018] The primary vein 22 (into which the air inlet 23 opens) is radially delimited by a radially internal wall 25 and a radially external wall 26. The radially internal wall 25 is formed at least in part by the radially internal ferrule 19 of the inlet housing 17. The radially external wall 26 is formed at least in part by the radially external ferrule 20 of the inlet housing 17. As for the secondary flow F2, it circulates around the inlet housing 17.

[0019] The power shaft or low-pressure shaft 10 (of the free-running power turbine and low-pressure turbine, respectively) drives the propeller 2, which compresses the airflow outside the outer casing and provides most of the thrust. Optionally, a reduction gear 27 is interposed between the propeller 2 and the power shaft, as shown in the figure 1 The reducer 27 can be of the planetary gear type or the epicyclic gear type.

[0020] The stator 3 comprises a plurality of stator vanes 28 (or fixed vanes) known by the English acronym "OGV" for "Outlet Guide Vane". The stator vanes 28 are evenly distributed around the longitudinal axis X and extend radially into the secondary airflow F2. The stator vanes 28 of the stator 3 are arranged downstream of the propeller blades 12 2 so as to straighten the airflow generated by them. Each stator vane 28 comprises a blade 29 that extends radially from a foot 30. We understand, as is also illustrated on the figure 1The stator blades 28 of the stator are unfaired. The turbomachine shown is a USF; there is no fairing on the propeller or the stator. The blades 29 each have a leading edge 31 and a trailing edge 32 that are axially opposed. The stator blades also extend radially outside the inter-flow casing 18. There are between six and fourteen stator blades 28 around the inlet casing 17 and inter-flow casing 18.

[0021] As we can see on the figure 1 The feet 30 of the stator blades of the rectifier are mounted between a first housing and a second housing along the longitudinal axis. In this example, the first housing is the inlet housing 17 and the second housing is an inter-compressor housing 33.

[0022] The inter-compressor housing 33 is arranged downstream of the low-pressure compressor 5. More precisely, the inter-compressor housing 33 extends axially between the low-pressure compressor 5 and the high-pressure compressor 6. More precisely, and with reference to the figure 1 The first casing (inlet casing 17) and the second casing (here, the inter-compressor casing 33) are axially separated by the rotor (here, the low-pressure compressor). Each compressor comprises at least one rotor stage and at least one stator stage arranged along the longitudinal axis X. Furthermore, as shown in the figure 2The inter-compressor housing 33 comprises a radially internal ferrule 34 and a radially external ferrule 35 which are centered on the X-axis and coaxial. Between the radially internal ferrule 34 and the radially external ferrule 35 extends at least one structural radial arm 36. More specifically, several radial arms 36 are attached to the radially internal and external ferrules 34, 35. The radial arms 36 are also regularly distributed around the longitudinal axis X. There are between six and ten radial arms in order to optimize the mechanical strength of the inter-compressor housing 33. These arms 36 are fixed and are formed as a single unit with the internal and external ferrules 34, 36. The radially internal ferrule 34 forms at least partially the radially internal wall 25 of the primary vein 22, while the radially external ferrule 35 forms at least partially the radially external wall 26 of the primary vein 22.The primary flow F1 circulates between the first radial arms 21 of the inlet casing 17 and then the second radial arms 36 of the inter-compressor casing 33.

[0023] With reference to Figures 1 And 2The stator blades 28 are supported by a sleeve 37 which is connected on one side to the inlet housing 17 and on the other side to the inter-compressor housing 33. Each sleeve 37 is supported by a connecting rod 38 which transmits the aerodynamic forces acting on the stator blades 28, as well as the thrust forces transmitted through the inter-compressor housing 33. Each sleeve 37 is cylindrical and extends radially outwards. The base of each sleeve 37 is circular. In particular, each sleeve 37 comprises a cylindrical skirt 39 with axis A parallel to the radial axis Z. The cylindrical skirt 39 extends radially between a first border 40 and a second border 41. Each sleeve 37 comprises a bore 42 which passes through the cylindrical skirt 39 on both sides along its axis A. Each bore 42 forms an internal housing for receiving the foot 30 of a stator blade 28.

[0024] As we can see on the figure 2Each connecting rod 38 is elongated and generally extends along an axis B parallel to the longitudinal axis X. In particular, a connecting rod 38 comprises a first end 43 and a second end 44 which are opposite along its axis B. The first end 43 of each connecting rod 38 is mounted on the radially external ferrule 20 of the inlet housing 17 by a ball joint 45. The ball joint 45 is formed by a spherical head and a shell with a shape complementary to the spherical head, as illustrated in the figure. figure 3In this example, each first end 43 comprises a spherical head 43a. Each head 43a is received in a shell 20a of substantially complementary shape. The shell 20a serves as a housing for the spherical head 43a. The shell 20a is supported by the radially external ferrule 20. The shell 20a extends, in particular, from a radial, annular partition 20b of the radially external ferrule 20. The spherical head 43a is mounted, on one side, to rotate about axis B and, on the other side, to pivot about a predetermined angle of rotation about axis B. The angle of rotation can be between 5° and 30°. The ball joint 45 can, of course, be designed so that the first end 43 comprises the shell and the radially external ferrule 20 supports the spherical head.

[0025] Referencing the figure 3The second end 44 of each connecting rod 38 is connected to the radially external ferrule 35 of the inter-compressor housing 33 via a fixed-type connection 46. In particular, the second end 44 includes a lug 44a that extends the connecting rod along axis B and is defined in a plane perpendicular to the radial axis. This lug is mounted on one side of an upstream annular edge 35a of the radially external ferrule 35 of the inter-compressor housing 33. In other words, this edge 35a and the lug 44a are radially superimposed. Furthermore, fastening elements 47 secure the second end 44 to said edge 35. For this purpose, the lug 44a includes a hole 48 (shown in dashed lines) passing through its wall on both sides along an axis (radial axis Z here) perpendicular to the plane of the lug. The edge 35a includes several radial orifices 49 (represented in dotted lines) which pass through its wall on both sides and are distributed around the X axis.The fasteners 47 in this example include screws 50, each having a head and a shank with a radial axis. Each screw 50 passes through a hole 48 formed in a lug of a connecting rod and the corresponding opening 49 in the edge 35a. The fasteners 47 also include nuts 51 for tightening the assembly.

[0026] The ball joint 45, particularly upstream, allows easy access to the low-pressure compressor compartment for checking its condition with an endoscope, for example, or for repositioning other nearby components such as variable-pitch stator blade rings. Disassembling the second end 44 downstream allows manipulation of the connecting rod 38 by rotating it via the ball joint to access the low-pressure compressor.

[0027] Each sleeve 37 is located axially in the middle of each connecting rod 38. In other words, each connecting rod 38 extends on either side of the cylindrical skirt 39. Similarly, the connecting rods 38 are located approximately one-third of the way up the sleeves 37, measured between their first and second edges 40, 41, and starting from the second edge 41. Thus, the second edge 41 is located radially outside the inlet housing 17 and / or the inter-compressor housing 33. Likewise, we understand that the connecting rods connect the first and second housings via the sleeves. The first and second housings are essentially contiguous. This allows for a more compact design for both the turbomachine module and the turbomachine itself.

[0028] A connecting rod 38 and a sleeve 37 form a single piece. Advantageously, but not exclusively, the connecting rod 38 is formed as a single piece (molded from a single piece of material) with the sleeve 37. Advantageously, this connecting rod-sleeve assembly is produced by an additive manufacturing process. Alternatively, the connecting rod 38 and its sleeve 37 are manufactured separately (for example, by casting or machining) and are then joined by welding or other similar fastening. The connecting rods 38 are made of a metallic material. Advantageously, the connecting rods are made of titanium.

[0029] With the geometry of the connecting rods (here elongated in the shape of a capital I) and its material (titanium), the torsion angles due to the forces of the stator blades 28 are relatively small.

[0030] In an alternative not shown, each connecting rod has a Y-shaped or triangular shape. Similarly, other types of fixed joints can be considered.

[0031] With reference to the figure 3The stator blades 28 are advantageously variable-pitch to optimize the performance of the turbomachine. To this end, the turbomachine 1 includes another pitch-changing system 55 for the stator blades 28. We can see that the foot 30 of each blade 28 is typically in the form of a pivot 56 which is pivotally mounted about an axis C in the internal housing of the sleeve 37. The axes A and C are coaxial. The pivot 56 of the foot 30 is pivotally mounted by means of at least one guide bearing 57 in the internal housing of each sleeve 37. In this example, two guide bearings 57, 57' are superimposed about the radial axis Z (or axis A of the sleeve 37). These bearings 57, 57' are preferably, but not exclusively, roller bearings.Bearings 57, 57' can have a larger diameter than usual due to the space available in sleeves 37 and their location in an annular space between the inlet housing and the inter-compressor housing 33.

[0032] Each bearing 57, 57' comprises an inner ring 58 rotationally fixed to the pivot 56 and an outer ring 59 surrounding the inner ring 58. The bearings include rolling elements 60 installed between the inner surfaces of the inner and outer rings, which form raceways. The rolling elements 60 here comprise balls. The bearings 57, 57' advantageously retain the blades 28 in the housing of the sleeves 37.

[0033] A cylindrical bushing 61 with a radial axis is installed in a bore 42 of each sleeve 37 so as to connect the inner ring 58 of each bearing to the root of each stator blade 28. The bushing 61 is centered on the alignment axis C of the stator blades 28. Each bushing 61 also has internal splines arranged on an inner cylindrical face, designed to mate with external splines provided on an external surface of the pivot 56 of each stator blade root 28. A spacer 62 is also arranged radially between each bearing to ensure the radial spacing of the bearings. Indeed, the bearings must resist both forces and moments. Consequently, two spaced bearings are required to resist the bending moment. This spacer 62 is advantageously, but not exclusively, positioned between two inner rings of the bearings.Sealing elements are provided in each bore 42 to prevent lubricant from leaking out of the bearings.

[0034] As we can also see on the figure 3 Two rings are arranged between the inner wall of each sleeve 37 and the lateral sides of the bearings 57, 57'. A first ring 63 has an L-shaped axial cross-section with a branch that radially overlaps the bearing 57' (radially superior), and a second ring 64 has an I-shaped axial cross-section (capital I) with an axial bulge. The bearing 57 (radially inferior with respect to the radial axis Z and along the figure 3 The bearing rests on the axial bulge. Advantageously, the first and second frets 63, 64 each have an annular shape and fit into one another. The frets 63, 64 allow for radial locking of the bearings.

[0035] The pitch change system 55 comprises at least one control means 66 and at least one linkage mechanism 65 connecting each stator blade 28 to the control means 66. The pitch change system 55 is arranged in a defined annular space within the inter-vein housing 18. In particular, the pitch change system 55 is located radially outside the inter-compressor housing 33. More precisely, the control means 66 is located downstream of the sleeves 37 and connecting rods 38. At this location, there is indeed more space to install such a mechanism and the means for securing the blade feet 30. We understand that the sleeves are also located within this annular space of the inter-vein housing 18, and as shown in the figure 1 .

[0036] On the figure 3The pivot 56 of each foot 30 comprises an arm 67 forming an eccentric at its lower free end. Advantageously, but not exclusively, the pivot 56 includes a radial bore opening at its free end. A fastener 68, such as a screw, is received in the radial bore to fix the arm 67 to the foot of the stator blade 28. In the example shown, there are as many arms as there are stator blades 28. The arm 67 is connected to one end of a connecting rod (shown in dashed lines) which forms the linkage mechanism 65. The first end of the connecting rod is provided with a ball joint through which a pivot axis carried by the arm 67 passes. The pivot axis is parallel to the radial axis Z. The second end of the connecting rod (opposite the first end) is connected to the control means 66.

[0037] The control means 66 is advantageously an actuator such as a hydraulic cylinder. The actuator comprises a fixed body and a movable body relative to the first fixed body. The first fixed body is connected to a fixed ferrule of the turbomachine so as to be immobile in translation and rotation. The fixed ferrule is mounted, in particular, on the fixed inter-line housing. The movable body moves axially in translation relative to the fixed body along the longitudinal axis X. The movable body comprises an axial rod whose free end is connected to the other end of the connecting rod. The actuator is connected to a fluid supply source to supply pressurized oil to chambers (not shown) of the fixed body. In this example, the radially external ferrule 35 of the inter-compressor housing 33 comprises a plurality of ports 69 passing through its wall on both sides and along the longitudinal axis X.At least a portion of each axial rod is designed to pass through a slot 69. There are as many slots 69 as there are rods or connecting rods. The control means 66 is located downstream of the inter-compressor housing 33.

[0038] According to another embodiment illustrated on the figure 4 The control means 66 advantageously comprises several actuators such as hydraulic cylinders. Each actuator is connected to a connecting rod which passes at least partially through a slot.

[0039] Thus, the stator blades 28 are positioned away from the propeller blades 2 without affecting the length of the turbomachine or increasing its overall size, particularly for installing a pitch control system 55 for the stator. The connecting rods 38 allow the transmission of thrust forces from the upstream side of the turbomachine, through the inlet casing 17 and then the inter-compressor casing 33, as well as the aerodynamic forces acting on the blades 28. Thanks to this configuration, no additional component is required.

[0040] To this end, the S / C ratio, corresponding to the distance S between a trailing edge of the propeller blades 2 and the leading edge 31 of the stator blades 28 along the chord C of the propeller blades 2, is improved. This ratio is approximately 3, whereas in the prior art this ratio is between 1 and 2. The minimum ratio for compliance with acoustic standards is indeed 1.

Claims

1. A turbine engine module of longitudinal axis X, comprising an unducted propeller (2) intended to be driven in rotation about the longitudinal axis X by a power shaft (10, 11) which is connected to at least one rotor member (5, 6), at least one straightener (3) comprising a plurality of stator vanes (28) evenly distributed around the longitudinal axis X and extend radially into a secondary air flow (F2), at least one first casing (17) mounted upstream along the longitudinal axis of the rotor member (5, 6) and a second casing (33) mounted downstream along the longitudinal axis of the rotor member (5, 6), the first casing (17) and the second casing (33) being separated by the rotor member (5) along the longitudinal axis X, and being contiguous, characterised in that the stator vanes (28) each comprise a root (30) housed in a sleeve (37) which is connected on the one hand to the first casing (17) and on the other hand to the second casing (33).

2. The turbine engine module according to the preceding claim, characterised in that a plurality of connecting rods (38) extend between the first casing (17) and the second casing (33), each connecting rod (38) carrying a sleeve (37).

3. The turbine engine module according to the preceding claim, characterised in that each connecting rod (38) comprises a first end (43) mounted on a first radially external shroud (20) of the first casing (17) by a ball joint type connection and a second end (44) mounted on a second radially external shroud (35) of the second casing (33) by an embedded type connection.

4. The turbine engine module according to one of claims 2 and 3, characterised in that each connecting rod (38) is made in one-piece with a sleeve (37).

5. The turbine engine module according to any one of the preceding claims, characterised in that the stator vanes (28) of the straightener (3) are of variable pitch setting and in that it comprises a pitch change system (55) for changing the pitch of the blades of the stator vanes (28) which is arranged radially outside the second casing (33).

6. The turbine engine module according to any one of the preceding claims, characterised in that at least one rotational guide bearing (57, 57') for guiding in rotation a root (30) of a stator vane (28) is housed in an internal housing of a sleeve (37).

7. The turbine engine module according to one of the preceding claims, characterised in that the first casing (17) is an inlet casing which carries a splitter nose (16) for dividing an air flow into a primary air flow and the secondary air flow, the inlet casing comprising a first radially internal shroud (19), the first radially external shroud (20) and between which extends at least a first radial structural arm (21).

8. The turbine engine module according to one of claims 3 to 7, characterised in that the second casing is an inter-compressor casing arranged downstream of a low-pressure compressor, along the longitudinal axis, the inter-compressor casing comprising a second radially internal shroud (34), the second radially external shroud (35) which are coaxial with the longitudinal axis X and between which extends at least one second radial structural arm (36).

9. The turbine engine module according to one of the preceding claims, characterised in that the ratio S / C corresponding to the distance S between a trailing edge of the vanes of the propeller (2) and a leading edge (31) of a stator vane (28) on the chord C of the vanes of the propeller (2) is of the order of 3.

10. The turbine engine module according to one of the preceding claims, characterised in that the stator vanes (28) of the straightener are unducted.

11. An aircraft turbine engine comprising at least one turbine engine module according to any one of the preceding claims and a gas generator (4) downstream of the propeller (2).