TURBOMACHINE WITH IMPROVED OIL RECOVERY DEVICE

Description

Technical field of the invention

[0001] The invention relates to a turbomachine equipped with an improved efficiency oil recovery device. Technical background

[0002] It is known from the prior art, the documents WO 2014 / 199083 A1, EP 2 090 764 A1, EP 3 462 000 A1, FR 3 075 866 A1.

[0003] In a turbomachine of a known type, a rear portion of the low-pressure turbine shaft is mounted to rotate, generally by at least one bearing mounted on a tubular wall of the inter-turbine housing. This bearing is located in a first chamber, called the lubrication chamber, which is delimited, on one side, by the inter-turbine housing and, on the other, by a bearing support integral with the low-pressure turbine shaft. The inter-turbine housing and the bearing support integral with the low-pressure shaft also separate this first chamber from a second, adjacent chamber. The low-pressure shaft is itself integral with a bearing support.

[0004] The lubrication chamber is connected to an oil circuit with an oil inlet pipe, through which oil is pumped into the chamber. It includes an oil recovery device with an oil return pipe, through which the oil returns to the oil circuit to be pumped again.

[0005] Since the inter-turbine casing is fixed and the bearing support attached to the low-pressure shaft is rotating relative to it, the sealing of the enclosure is ensured between these two components at the level of an interface zone which separates the two enclosures.

[0006] The bearing support comprises an outer ring that is rotatably mounted inside an inner ring of the inter-turbine housing, and these two rings define the interface area. This interface area can accommodate an oil evacuation system comprising at least one screw and lunule device. This system can be supplemented by a dynamic sealing system, including a rear labyrinth seal and / or a brush seal.

[0007] Outside the lubrication chamber, the second chamber is pressurized. Pressurization applies positive pressure across the interface zone to prevent oil from escaping from the lubrication chamber. The pressurized chamber also includes an oil drainage system with a drain line that connects to the outside of the turbomachine.

[0008] To ensure the return of the lubricating oil from the bearing to the oil return line, the oil must be guided from the bearing to a wall of the inter-turbine housing that communicates with an inlet of an oil return line. To achieve this, the oil must bypass the interface area without entering it.

[0009] This is why the oil recovery device includes a tubular tongue, commonly called a "dropper," which extends the tubular wall supporting the bearing and extends inside one end of the outer shell of the bearing support.

[0010] This tab is designed to guide the bearing during its assembly to allow precise placement of the low-pressure shaft in order to avoid any contact between the shaft and the inter-turbine housing.

[0011] This tab is also configured to conduct oil to be successively projected from the tab to the outer ferrule of the bearing support, and then from the outer ferrule of the bearing support to the wall of the inter-turbine housing leading to the inlet of the oil return conduit.

[0012] To prevent oil from penetrating the interface zone, the outer shell of the bearing support extends into a tubular section that runs axially around the tubular tab beyond one end of the inner shell of the inter-turbine housing. This section features an annular groove with a circular cross-section and its concavity facing away from the tubular tab. This groove is designed to prevent oil from flowing along the tubular extension and then onto the outer shell of the bearing support in the interface zone.

[0013] In operation, this configuration theoretically allows the oil to bypass the interface area without entering it.

[0014] However, it has been observed that a problem arises when an aircraft equipped with such a turbomachine is parked on the ground and the turbomachine is switched off.

[0015] Indeed, in this case, the interface zone is no longer subjected to the pressurization pressure of the second chamber, and the turbomachine is inclined a few degrees further back than during normal operation. It has been observed that the oil tends to flow by gravity along the drip wand, around the end of the tubular extension, then seeps by capillary action into the circular annular groove and across the interface zone, ultimately penetrating the second chamber. Under certain conditions, oil can then be drained from this second chamber by the oil drainage system and drip onto the tarmac where the aircraft is parked.Oil can even reach a hotter chamber of the turbomachine and cause a release of smoke that would be detrimental to users' perception of the quality of the turbomachine.

[0016] Therefore, there is a real need for a new configuration of the oil recovery device allowing the oil to bypass the interface area under all circumstances.

[0017] More generally, there is a real need for a new configuration of an oil recovery device that optimizes oil flow from a so-called "dropper" located near an interface between two components rotating relative to each other. It will therefore be understood that the invention is not limited to the configuration described herein. Summary of the invention

[0018] The present invention relates to a turbomachine equipped with an oil recovery device that remedies the aforementioned drawback. These objectives are achieved, according to the invention, by proposing a modification of the outer shell of the bearing support opposite the tubular tongue, with a larger extension and an outer groove with a rectangular rather than a circular cross-section.

[0019] To this end, the invention proposes a turbomachine comprising first and second internal moving parts rotating relative to each other around an X-axis, and at least one guide bearing mounted between the respective first and second tubular walls of the first and second parts, the first component further comprising a third wall substantially transverse with respect to the X axis, the second component comprising a fourth wall substantially transverse with respect to the X axis surrounded by said third wall, said third and fourth walls separating two enclosures, respectively a first bearing lubrication enclosure, and a second enclosure, the fourth wall being bordered by an outer shell of the second component and the third wall being bordered by an inner shell of the first component, the inner shell surrounding the outer shell and said inner and outer shells delimiting an interface zone between said enclosures, said turbomachine further comprising an oil recovery device comprising a tubular tab which extends the first tubular wall of the first component and which extends axially inside one end of the outer shell of the second component,This tab being configured to conduct oil to be successively projected from the tab to the outer ferrule of the second component, and then from the outer ferrule of the second component to the third wall, said inner ferrule of the second component extending by a tubular extension which surrounds the outside of the tubular tab axially beyond one end of the inner ferrule of the first component, and in which is formed an external groove of concavity facing away from the tubular tab, characterized in that the extension surrounds the outside of the tubular tab axially beyond half an axial length of said tubular tab, has an internal diameter equal to an internal diameter of the outer ferrule of the second component and an external diameter less than or equal to an external diameter of the outer ferrule, and in that its annular groove has a rectangular cross-section.

[0020] The tubular extension advantageously allows the oil dripping from the tubular tongue to be diverted to a significant axial distance from the interface area, and the rectangular shape of the groove of this extension prevents the oil from forming a capillary bridge and reaching the interface area.

[0021] According to other characteristics of the turbomachine, the tubular extension comprises successively, starting from the outer shell of the second component: a first section, extending the outer shell of the second component, and having the same inner and outer diameters as the inner and outer diameters of said outer shell in the interface zone, a second section, contiguous to the first section, with an inner diameter equal to the inner diameter of the outer shell, and an outer diameter less than the outer diameter of the outer shell, and a third section, contiguous to the second section, with an inner diameter equal to the inner diameter of the outer shell in the interface zone, and a determined outer diameter equal to the outer diameter of the outer shell in the interface zone, the annular groove being delimited by an outer wall with axis X of the second section and by transverse walls of the first and third sections at their junction with the second section, the first lubrication chamber of the bearing contains lubricating oil,the external wall along axis X of the second section determines a width L of the groove, the transverse wall of the third section determines a height H of the groove, and the groove is configured such that its height H is an interval affine function of its width L, according to a relation H = mx L + p of which coefficients m and p are associated with determined characteristics of said lubricating oil. The characteristics of the lubricating oil include an operating temperature below 120°C, a viscosity between 20 and 30 centistokes at 40°C and 4.9 to 5 centistokes at 100°C with a density between 0.9 and 1.05 kg / L. Advantageously, the turbomachine is such that: for a width interval L greater than or equal to 4 mm and less than 6 mm, m = -0.6 and p = 7; for a width interval L of 6 to 7 mm, m = -0.2 and p = 4.6; for a width L greater than 7 mm, m = 0 and p = 3.2. The first and second sections, on the one hand,and the second and third sections, on the other hand, are connected at the bottom of the groove by a radius of curvature R less than or equal to 0.6 mm, the third section has an axial thickness greater than or equal to 1.2 mm, the first component is an inter-turbine housing, the second component is a bearing support integral with a low-pressure shaft, the first bearing lubrication chamber communicates with an oil recovery duct connected to an oil circuit of the turbomachine, and the second chamber is a pressurized chamber communicating with an oil drain duct connected to the outside of the turbomachine, the interface area is a receiving area for an oil expulsion system comprising a front spiral and front lunules and a rear spiral and rear lunules interposed between the inner and outer shells, the interface area receives behind said oil expulsion system a dynamic sealing system comprising at least one dynamic seal. Brief description of the figures

[0022] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the attached drawings in which: [ Fig. 1 ] There figure 1 is an axial cross-sectional view of a rear part of a turbomachine according to the prior art, [ Fig. 2 ] There figure 2 is an axial cross-sectional view of an extension of an outer shell of a bearing support of the turbomachine of the figure 1 , [ Fig. 3 ] There figure 3 is a cross-sectional view of the rear part of a turbomachine according to the prior art, illustrating the path of the lubricating oil, [ Fig. 4 ] There figure 4 is an axial cross-sectional view of an extension of an outer shell of a bearing support of a turbomachine according to the invention, [ Fig. 5 ] There figure 5is a cross-sectional view of the rear part of the turbomachine according to the invention illustrating the path of the lubricating oil; [ Fig. 6 ] There figure 6 is a perspective view of the end of the outer ferrule of the bearing support and its extension. Detailed description of the invention

[0023] We represented at the figure 1 a rear part 12 of a turbomachine 10 made in accordance with the prior art. In a known manner, the turbomachine comprises first and second internal components 14, 16 respectively, which are movable in rotation relative to each other about an axis X, and at least one guide bearing 20 mounted between the first and second components.

[0024] In the present case, the invention relates particularly to the case of an inter-turbine housing 14 internally receiving in rotation a low pressure shaft 15 via a bearing support 16 integral with this low pressure shaft 15. The low pressure shaft also includes a rear end carrying a trunnion 19 of a low pressure turbine 18.

[0025] It will be understood that this provision which is the subject of this description is not limiting of the invention and that the invention may be applicable to other components mounted in rotation relative to each other, such as bearing supports attached to trunnions of low pressure turbine and high pressure turbine.

[0026] A segmented radial joint 22 is also mounted between the inter-turbine housing 14 and the low-pressure shaft 15.

[0027] The inter-turbine casing 14, which here forms the first component, is a substantially annular casing through which a primary gas stream 24 of the turbomachine passes. Turbine discs 26, integral with the low-pressure turbine journal 16, are also placed in the gas stream 24, and their blades 28 are arranged alternately with stator blades 30.

[0028] The inter-turbine housing 14 has a first tubular wall 32 with axis X and the bearing support 16 has a second tubular wall 33, the bearing 20 being mounted between these walls 32, 33.

[0029] The inter-turbine casing 14 also includes a third wall 36, substantially transverse with respect to the X axis

[0030] The bearing support 16, which here forms the second component, has a fourth wall 34, substantially transverse with respect to the X axis, which is surrounded by the third wall 36 of the inter-turbine housing 14. The fourth wall 34 therefore rotates inside the third wall 36, which is fixed.

[0031] The inter-turbine housing 14, the low-pressure shaft 15 and the bearing support 16 define a first bearing lubrication chamber 38 containing lubricating oil inside the rear part 12 of the turbomachine 10. Furthermore, these fourth and third walls 34, 36 separate the first bearing lubrication chamber 38 from a second chamber 40, outside the first chamber 38.

[0032] The fourth wall 34 is bordered by an outer ferrule 42, thus also forming part of the bearing support 16, and the third wall 36 is bordered by an inner ferrule 44, thus forming part of the inter-turbine housing 14.

[0033] The two ferrules 42, 44 are arranged opposite each other, the inner ferrule 44 surrounding the outer ferrule 42. As a result, the two outer ferrules 42 and inner ferrule 44 delimit an interface zone 46 between the two enclosures 38, 40.

[0034] Conventionally, the second chamber 40 is a pressurized chamber supplied with pressurized air drawn from a connection on one of the turbomachine's compressors. This chamber 40 is pressurized so as to exert positive pressure on the interface zone 46, in which, by way of non-limiting the invention, an oil expulsion system comprising at least one auger and crescents may be housed, which may be supplemented, within or outside the interface zone 46, by a dynamic sealing system such as a labyrinth or brush seal ensuring a seal between the lubrication chamber 38 and the second chamber 40.

[0035] Since none of these systems are limiting to the invention, in the remainder of this description it will be considered that the interface area 46 comprises only a system for expelling oil.

[0036] The purpose of pressurizing enclosure 40 is to confine the lubricating oil of bearing 20 inside the lubrication enclosure 38. In addition, this second enclosure 40 has an oil drain channel 41, which communicates with the outside of the turbomachine.

[0037] The lubricating oil is pumped under pressure into the lubrication chamber 38 through an oil inlet pipe 48 and is recovered by an oil recovery device which allows the oil to be discharged from the lubrication chamber through a pipe 50, so that it can be recovered and then pumped back into the chamber 38. To reach the pipe 50, as shown by the arrows of the figure 1 , the lubricating oil from bearing 20 must first reach an internal face 52 of the third wall 36 of the inter-turbine casing 14 from where it is conveyed to the inlet of conduit 50.

[0038] It should be noted that in the plan of the figure 1 , conduit 50 has been represented in dotted lines.

[0039] To that end, as illustrated in more detail by the figure 3 , the oil recovery device also includes a tubular tongue 54 which extends the first tubular wall 32 of the inter-turbine housing 14 and extends axially towards the outer shell 42 of the bearing support 16, and more particularly inside one end 43 of it.

[0040] This tab 54 is intended to guide the bearing 20 during its assembly to allow precise placement of the low pressure shaft 15 in order to avoid any contact between the shaft 15 and the inter-turbine housing 14.

[0041] As is known, when the turbomachine is in operation, oil is successively projected from the tab 54 to the outer ferrule 42 of the bearing support 16, and then from the outer ferrule 42 of the bearing support 16 to the inner surface 52.

[0042] As is known, the end 43 of the inner ferrule 42 of the bearing support 16 extends into a tubular extension 56 which extends axially and partially around the tubular tab 54. This extension 56 extends beyond one end 58 of the inner ferrule 44 of the inter-turbine housing 14, and is therefore not arranged within the interface zone 46, but is located outside of it. In this extension 56, an external groove 60 is formed, the concavity of which is oriented away from the tubular tab 54.

[0043] An extension 56 of this type, conforming to the prior art, was represented at the figure 2 As can be seen, the extension 56 has approximately the same inner and outer diameters as the outer ferrule 42 of the bearing support 16, and its groove 60 has a determined width L and depth P. The groove 60 has a circular cross-section.

[0044] However, in such a configuration, it has been observed that, when the turbomachine is stopped, for certain angles of inclination, corresponding for example to an inclination of the turbomachine of about 4°, which is typically an inclination of an under-wing turbomachine in the aircraft parking position, the oil from the tubular tongue 54 drops on the inner wall 62 of the extension 56 and then, flowing down its end face 64, does not limit itself to dripping from the end face 64 but also tends to penetrate by capillary action into the groove 60 to form a lubricant bridge from which it spreads against an outer wall 66 of the inner ferrule 42 of the support 16 until it reaches the interface area 46.When the interface area 46 is equipped with a system for expelling oil such as a double system comprising a front screw 67 and front lunules 69 and a rear screw 68 and rear lunules 68, the oil can pass through this system and then enter the second enclosure 40 from where it can be evacuated through the drainage conduit 41.

[0045] The invention proposes a modification of extension 56 to remedy this problem.

[0046] To this end, as illustrated by the figures 2 And 5 , the extension 56 extends firstly beyond half an axial length I of the tubular tongue 54.

[0047] Furthermore, as illustrated by the figure 5, the extension 56 surrounds the outside of the tubular tongue 54 axially beyond half an axial length I of the tubular tongue 54. It has an internal diameter equal to an internal diameter of the outer ferrule 42 of the second organ 16 and an external diameter less than or equal to an external diameter of the outer ferrule, and its annular groove 60 has a rectangular cross-section.

[0048] The free end of the extension 56 thus forms a return which, combined with the rectangular shape of the section of the outer annular groove 60, prevents the oil from forming a bridge by capillary action through this annular groove 60 to reach the interface area 46. Indeed, unlike a groove with a circular section, a groove with a rectangular section makes it possible to break the continuity of the oil film and prevent its propagation through the annular groove 60.

[0049] More specifically, as illustrated by the figure 5, the tubular extension 56 comprises successively, from the outer ferrule 42 of the support 16, a first section 72, a second section 74 and a third section 76.

[0050] The first section 72 extends the outer ferrule 42 of the support 16, and has the same inner diameter d 72 and outer diameter D 72 as the inner diameter d 42 and outer diameter D 42 of the outer ferrule 42 in the interface area 46.

[0051] Then the tubular extension includes a second section 74, joined to the first section 72. The second section 74 has an internal diameter d 74 equal to the internal diameter d 42 of the outer shell 42 in the interface zone 46, and an external diameter D 74 less than the external diameter D 42 of the outer shell 42 in the interface zone 46.

[0052] Finally, the third section 76, joined to the second section 74, has an internal diameter d 74 equal to the internal diameter d 42 of the outer ferrule 42, and an external diameter D 76 determined equal to the external diameter D 42 of the outer ferrule 42.

[0053] It will therefore be understood that the second and third sections 74, 76 thus form a step which extends axially outside the tubular tongue 54 beyond the axial half-length I of this tubular tongue 54. The axial dimensions of the first to third sections 72, 74, 76 therefore determine the coverage of the tubular extension 56 around the tubular tongue 54 beyond the axial half-length I.

[0054] It will also be understood that the annular groove 60 of rectangular section is delimited by an external wall 74a of axis X of the second section 74 taken between respective transverse walls 72a and 76a of the first and third sections 72, 76 at their junction with the second section 74.

[0055] The dimensions of the groove 60 are crucial in preventing the formation of a lubricant bridge across it. The outer wall 74a along axis X of the second section 74 determines a characteristic width L of the groove 60, and the transverse wall 76a of the third section 76 determines a characteristic height H of the groove 60.

[0056] According to the invention, the groove 60 is configured such that its height H is an interval affine function of its width L, according to a relationship of the type H = mx L + p of which coefficients m and p are associated with determined characteristics of the lubricating oil.

[0057] Within the framework of the invention, the characteristics of the lubricating oil used for the lubrication of bearing 20 include an operating temperature below 120°C, a viscosity between 20 and 30 centistokes at 40°C and 4.9 to 5 centistokes at 100°C with a density between 0.9 and 1.05 Kg / L.

[0058] For such a lubricating oil, according to the invention, the coefficients m and p of the affine function determining the height H of the groove 60 as a function of its width L vary according to three intervals: for a width interval L greater than or equal to 4 mm and less than 6 mm, m = -0.6 and p = 7, for a width interval L from 6 to 7 mm, m = -0.2 and p = 4.6, and finally, for a width L greater than 7 mm, m = 0 and p = 3.2, which corresponds to a height H of the groove 60 which is constant.

[0059] Another important parameter of the groove 60 is the radius of curvature of the sections 72 to 76. To break the oil film, the radius of curvature at the joint of these sections must be as small as possible, resulting in a groove 60 with a cross-section as close as possible to a perfect rectangle. Therefore, the first and second sections 72 and 74, and the second and third sections 74 and 76, are joined at the bottom of the groove by a radius of curvature R less than or equal to 0.6 mm.

[0060] It is also essential that the third section 76 has a minimum thickness E 76, in order to prevent the oil from passing through its free end 78. For this purpose, the third section 76 has a thickness E 76 which is greater than 1.2 mm.

[0061] Advantageously, the extension 56 can be arranged radially with respect to the tubular tongue 54 with a reduced clearance, a reduced clearance allowing the speed of the oil flow to be limited.

[0062] The invention advantageously prevents, at a predetermined angle of inclination of the turbomachine up to 4°, oil from passing through the interface zone 46 when stationary, whether this zone is designed to receive an oil removal system such as the augers 67, 68 and lunules 69, 70 or another system. It therefore prevents oil from spilling onto the tarmac via the drainage duct 41 or from seeping into other, hotter enclosures of the turbomachine, such as an enclosure 80, with the associated risk of smoke emissions, which would be detrimental to users' perception of the turbomachine's quality.

Claims

1. A turbomachine (10) comprising first and second internal members (14, 16) which are movable in rotation relative to each other about an axis X, and at least one guide bearing (20) mounted between respective first and second tubular walls (32, 33) of axis X of the first and second members (14, 16), the first member (14) comprising a third wall (36) substantially transverse to the axis X, the second member (16) comprising a fourth wall (34) substantially transverse to the axis X surrounded by said third wall (36), said third and fourth walls (34, 36) separating two enclosures (38, 40), respectively a first enclosure (38) for lubricating the bearing (20), and a second enclosure (40), the fourth wall (34) being bordered by an outer shell (42) of the second member (16) and the third wall (36) being bordered by an inner shell (44) of the first member (14), the inner shell (44) surrounding the outer shell (42) and said inner and outer shells (42, 44) delimiting an interface area (46) between said enclosures, said turbomachine further comprising an oil-recovery device comprising a tubular tab (54) which extends the first tubular wall (32) of the first member (14) and which extends axially inside one end (43) of the outer shell (42) of the second member (16), this tab (54) being configured to conduct oil to be projected successively from the tab (54) to the outer shell (42) of the second member (16), and then from the outer shell (42) of the second member (16) to the third wall (36), said inner shell (42) of the second member (16) being extended by a tubular extension (56) which surrounds the outside of the tubular tab (54) axially beyond one end (58) of the inner shell (44) of the first member (14), and wherein is formed an outer concave groove (60) facing away from the tubular tab (54), characterised in that the extension (56) surrounds the outside of the tubular tab (54) axially beyond an axial half-length (l) of said tubular tab (54), has an inner diameter (d72, d74, d76) equal to an inner diameter (d42) of the outer shell (42) of the second member (16) and an outer diameter (D72, D74, D76) less than or equal to an outer diameter (D42) of the outer shell (42), and in that its annular groove is rectangular in cross-section.

2. The turbomachine (10) according to the preceding claim, characterised in that the tubular extension (56) comprises successively, starting from the outer shell (42) of the second member (16): - a first section (72), extending the outer shell (42) of the second member (16), and having the same inner diameter (d72) and outer diameter (D72) as the inner diameter (d42) and outer diameter (D42) of said outer shell (42) in the interface area (46), - a second section (74), joined to the first section (72), with an inner diameter (d74) equal to the inner diameter (d42) of the outer shell (42) in the interface area (46), and with an outer diameter (D74) smaller than the outer diameter (D42) of the outer shell (42) in the interface area (46), and - a third section (76), joined to the second section (74), with an inner diameter (d74) equal to the inner diameter (d42) of the outer shell (42), and with a specific outer diameter (D76) equal to the outer diameter (D42) of the outer shell (42), the annular groove being delimited by an external wall (74a) of axis X of the second section and by transverse walls (72a, 76a) of the first and third sections (72, 74) at their junction with the second section (74).

3. The turbomachine (10) according to the preceding claim, characterised in that the first lubrication enclosure (38) for lubricating the bearing (20) contains lubricating oil, in that the external wall (74a) of axis X of the second section (74) determines a width L of the groove (60), in that the transverse wall (76a) of the third section (76) determines a height H of the groove, and in that the groove is such that its height H is an affine function by intervals of its width L, according to a relationship H = m x L + p whose coefficients m and p are associated with given characteristics of the lubricating oil.

4. The turbomachine (10) according to the preceding claim, characterised in that the characteristics of the lubricating oil comprise an operating temperature of less than 120°C, a viscosity of between 20 and 30 centistokes at 40°C and 4.9 to 5 centistokes at 100°C with a density of between 0.9 and 1.05 Kg / L.

5. The turbomachine (10) according to the preceding claim, characterised in that: - for an interval of width L greater than or equal to 4mm and less than 6mm, m = -0.6 and p = 7, - for an interval of width L of 6 to 7mm, m = -0.2 and p = 4.6, - for a width L greater than 7mm, m = 0 and p= 3.2.

6. The turbomachine (10) according to one of claims 4 or 5, characterised in that the first and second sections (72, 74) on the one hand, and the second and third sections (74, 76) on the other hand, are connected at the bottom of the groove (60) by a radius of curvature R less than or equal to 0.6 mm.

7. The turbomachine (10) according to one of claims 4 to 6, characterised in that the third section (76) has an axial thickness (E76) greater than or equal to 1.2 mm.

8. The turbomachine (10) according to one of the preceding claims, characterised in that the first member (14) is an inter-turbine casing, in that the second member (16) is a bearing support secured to a low-pressure shaft (15), in that the first bearing lubrication enclosure (38) communicates with an oil-recovery duct (50) connected to an oil circuit of the turbomachine, and in that the second enclosure (40) is a pressurised enclosure communicating with an oil drainage duct (41) connected to the outside of the turbomachine (10).

9. The turbomachine according to the preceding claim, characterised in that the interface area (46) is an area for receiving a system for flushing oil comprising a front spin (67) and front lunulae (69) and a rear spin (68) and rear lunulae (70) interposed between the inner and outer shells (44, 46).

10. The turbomachine according to one of claims 8 or 9, characterised in that the interface area (46) is a area for receiving a sealing system comprising at least one dynamic seal.