Turbine with improved oil recovery device

Abstract

The present application discloses a turbomachine (10) having an oil recovery device comprising a tubular tab (54) of a first member (14) between first and second members (14, 16) rotatable relative to each other, the tubular tab being surrounded by a tubular extension (56) of a shell layer (42) of the second member, the tubular extension defining an interface region with a shell layer (44) of the first member (14), the tubular extension (56) comprises an outer groove (60) opposite the tab (54), characterized in that the extension (56) axially surrounds the tubular tab (54) beyond the axial half length (l) of the tab (54), the inner diameter (d72, d74, d76) of the extension being equal to the inner diameter (d42) of the outer shell layer (42) of the second component (16), the outer diameter (D72, D74, D76) of the extension being less than or equal to the outer diameter (D42) of the outer shell layer (42), and the cross-section of the annular groove of the extension being rectangular.

Description

Technical Field

[0001] The present invention relates to a turbomachine equipped with an oil recovery device having improved efficiency. Background Art

[0002] The prior art includes documents WO 2014 / 199083 A1, EP 2 090 764 A1, EP 3 462 000 A1 and FR 3 075 866 A1.

[0003] In known types of turbines, the rear part of the low-pressure turbine shaft is usually rotatably mounted by at least one bearing mounted on the tubular wall of the inter-turbine housing. The bearing is arranged in a first enclosure, referred to as the lubrication enclosure, which is delimited on the one hand by the inter-turbine housing and on the other hand by a bearing support fixed to the shaft of the low-pressure turbine shaft. Furthermore, the inter-turbine housing and the bearing support fixed to the low-pressure shaft separate this first enclosure from a second enclosure adjacent to the first. The low-pressure shaft is also fixed to the bearing support.

[0004] The lubricating enclosure is connected to an oil circuit including an oil inlet conduit through which oil is pumped into the enclosure. The turbine includes an oil recovery device including an oil return conduit through which oil is returned to the oil circuit to be pumped again.

[0005] Since the inter-turbine casing is stationary and the bearing support fixed to the low-pressure shaft rotates relative to the low-pressure shaft, the sealing of the enclosure between these two components is ensured at the interface region separating the two enclosures.

[0006] The bearing support comprises an outer shell rotatably mounted within an inner shell of the turbine housing, the two shells defining an interface region. The interface region may be equipped with an oil flushing system comprising at least one spinning crescent device. The system may be supplemented by a dynamic sealing system comprising a rear labyrinth seal and / or a brush seal.

[0007] Outside the lubricating enclosure, the second enclosure is pressurized. Pressurization enables a positive pressure to be applied on the interface area to prevent oil from escaping from the lubricating enclosure. The pressurized enclosure also includes an oil drain device, which includes an oil drain conduit communicating with the outside of the turbine.

[0008] In order to ensure that the lubricating oil is returned from the bearing to the oil return pipe, the oil must be guided from the bearing to the wall of the turbine housing that is connected to the inlet of the oil return pipe. To achieve this, the oil must bypass the interface area and will not pass through the interface area.

[0009] To this end, the oil recovery device comprises a tubular tab (commonly referred to as a "drip tube emitter") extending from a tubular wall supporting the bearing and extending within one end of the outer shell layer of the bearing support.

[0010] The tab is configured to guide the bearing when installing it so that the low-pressure shaft can be accurately positioned to avoid any contact between the shaft and the inter-turbine casing.

[0011] The tab is also configured to guide the oil so that the oil is ejected from the tab in turn to the outer shell layer of the bearing support and then from the outer shell layer of the bearing support to the wall of the inter-turbine housing leading to the inlet of the oil return conduit.

[0012] In order to prevent the oil from passing through the interface area, the outer shell of the bearing support is extended by a tubular extension, which extends axially beyond one end of the inner shell of the inter-turbine casing around the tubular tab and in which an outer annular groove is formed, the cross section of the outer annular groove is circular and the concave surface of the outer annular groove faces away from the tubular tab. The groove is intended to prevent the oil from spreading along the tubular extension and then spreading to the outer shell of the bearing support in the interface area.

[0013] In operation, this configuration enables oil to bypass the interface region without entering the interface region.

[0014] However, it has been found that problems arise when an aircraft equipped with such a turbine is parked on the ground with the turbine switched off.

[0015] In this case, the interface area is no longer subjected to the pressurization pressure of the second enclosure and the turbine is tilted back several degrees more than in normal operation. It has been found that the oil tends to flow by gravity along the dropper emitter tab, around the end of the tubular extension, then by capillary action into the annular groove with circular cross section and through the interface area, in particular through the interface area by capillary action, and finally into the second enclosure. Under certain conditions, the oil can then be discharged from this second enclosure through the oil drain device and flow onto the apron where the aircraft is parked. The oil may even reach the hotter enclosure of the turbine and cause smoke release, which will be detrimental to the user's perception of the quality of the turbine.

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

[0017] More generally, there is a real need for a new oil recovery device configuration that enables optimization of the flow of oil from a tab known as a "dropper emitter" that is located close to the interface area between two components that rotate relative to each other. It should therefore be understood that the invention is not limited to the configurations described in this specification. Summary of the invention

[0018] The object of the present invention is a turbine equipped with an oil recovery device which overcomes the above-mentioned drawbacks. According to the invention, these objects are achieved by proposing an improvement of the outer shell layer of the bearing support opposite the tubular tab, which has an extension of larger dimensions and an outer groove with a rectangular cross section instead of a circular one.

[0019] To this end, the invention proposes a turbine, comprising a first inner member and a second inner member, and at least one guide bearing, the first inner member and the second inner member being rotatable relative to each other about an axis X, the at least one guide bearing being mounted between respective first and second tubular walls of the first and second members having the axis X,

[0020] The first member also comprises a third wall substantially transverse to the axis X,

[0021] The second member comprises a fourth wall surrounded by said third wall and substantially transverse to the axis X,

[0022] The third wall and the fourth wall separate two enclosures, which are respectively a first enclosure and a second enclosure. The first enclosure is used to lubricate the bearing.

[0023] the fourth wall is defined by the outer shell of the second member, and the third wall is defined by the inner shell of the first member, the inner shell surrounding the outer shell, and the inner shell and the outer shell defining an interface region between the enclosures,

[0024] The turbine further includes an oil recovery device, the oil recovery device including a tubular tab extending the first tubular wall of the first member and extending axially within one end of the outer shell layer of the second member, the tab being configured to guide the oil to be injected sequentially from the tab to the outer shell layer of the second member and then from the outer shell layer of the second member to the third wall,

[0025] The inner shell of the second member is extended by a tubular extension that axially extends beyond one end of the inner shell of the first member around the outside of the tubular tab and has an outer groove formed therein that faces away from the tubular tab,

[0026] It is characterized in that the extension part axially extends beyond the axial half length of the tubular tab around the outside of the tubular tab, the inner diameter of the extension part is equal to the inner diameter of the outer shell layer of the second component, the outer diameter of the extension part is less than or equal to the outer diameter of the outer shell layer, and the cross-section of the annular groove of the extension part is rectangular.

[0027] Advantageously, the tubular extension enables oil flowing from the tubular tab to be directed to a considerable axial distance from the interface region, and the rectangular shape of the recess in the extension enables oil to be prevented from forming capillary bridges and reaching the interface region.

[0028] According to other features of the turbine, the tubular extension comprises, starting from the outer shell layer of the second member,:

[0029] a first section which prolongs the outer shell of the second component and has an inner diameter and an outer diameter which are identical to the inner diameter and the outer diameter of the outer shell in the interface region,

[0030] a second section connected to the first section, the second section having an inner diameter equal to the inner diameter of the outer shell and an outer diameter smaller than the outer diameter of the outer shell, and

[0031] a third section connected to the second section, the inner diameter of the third section being equal to the inner diameter of the outer shell in the interface region and the specific outer diameter of the third section being equal to the outer diameter of the outer shell in the interface region, the annular groove being delimited by the outer wall of the second section having the axis X and by the transverse walls of the first section and the third section at their junction with the second section,

[0032] - a first lubricating capsule for lubricating the bearing contains a lubricating oil, the outer wall of the second section with the axis X determines the width L of the groove, the transverse wall of the third section determines the height H of the groove, and the groove is configured so that the height H of the groove is an affine function of the interval of the width L of the groove according to the relationship H=m×L+p, the coefficients m and p of the relationship being associated with given characteristics of the lubricating oil.

[0033] - the lubricating oil's characteristics include an operating temperature of less than 120°C, a viscosity between 20 and 30 centistokes at 40°C and between 4.9 and 5 centistokes at 100°C, a density between 0.9 and 1.05 Kg / L,

[0034] - Advantageously, the turbine is such that:

[0035] o For the interval where the width L is greater than or equal to 4 mm and less than 6 mm, m = -0.6 and p = 7,

[0036] o For the interval of width L from 6 mm to 7 mm, m = -0.2 and p = 4.6,

[0037] o For widths L greater than 7 mm, m = 0 and p = 3.2,

[0038] On the one hand, the first section and the second section are connected at the bottom of the groove by a radius of curvature R less than or equal to 0.6 mm, and on the other hand, the second section and the third section are connected at the bottom of the groove by a radius of curvature R less than or equal to 0.6 mm.

[0039] - the axial thickness of the third section is greater than or equal to 1.2 mm,

[0040] - the first component is an inter-turbine casing, the second component is a bearing support fixed to the low-pressure shaft, the first bearing lubrication enclosure is in communication with an oil recovery duct connected to the oil circuit of the turbine, and the second enclosure is a pressurized enclosure in communication with an oil drain duct connected to the outside of the turbine,

[0041] the interface region is a region for receiving an oil flushing system comprising a front spin and a front crescent and a rear spin and a rear crescent between the inner shell and the outer shell,

[0042] The interface area receives a dynamic sealing system behind said oil flushing system, the dynamic sealing system comprising at least one dynamic seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Other features and advantages of the present invention will become apparent from the following detailed description, for which reference is made to the accompanying drawings, in which:

[0044] [ Figure 1 ] Figure 1 is an axial cross section of the rear part of a turbine according to the prior art,

[0045] [ Figure 2 ] Figure 2 yes Figure 1 An axial cross-sectional view of an extension of the outer shell of a bearing support of a turbine,

[0046] [ Figure 3 ] Figure 3 is a cross-sectional view of the rear portion of a turbine according to the prior art, showing the path of the lubricating oil,

[0047] [ Figure 4 ] Figure 4 is an axial cross-sectional view of an extension of the outer shell layer of a bearing support of a turbine according to the invention,

[0048] [ Figure 5 ] Figure 5 is a cross-sectional view of the rear portion of a turbine according to the invention, showing the path of the lubricating oil,

[0049] [ Figure 6 ] Figure 6 is a perspective view of the end of the outer shell layer of the bearing support and its extension. DETAILED DESCRIPTION

[0050] Figure 1 The rear part 12 of a turbine 10 made according to the prior art is shown. In a known manner, the turbine comprises respective first and second inner members 14, 16, rotatably movable relative to each other about an axis X, and at least one guide bearing 20 mounted between them.

[0051] In the present case, the invention relates in particular to the case of an inter-turbine casing 14 which rotatably receives a low-pressure shaft 15 internally via a bearing support 16 fixed to the low-pressure shaft 15. The low-pressure shaft also comprises a rear end carrying a trunnion 19 of a low-pressure turbine 18.

[0052] It will be appreciated that this arrangement, which is the subject of this description, is not limiting of the invention, which may be applied to other components mounted to rotate relative to each other, such as bearing supports fixed to the low-pressure turbine trunnions and the high-pressure turbine trunnions.

[0053] A segmented radial seal 22 is also installed between the turbine inter-casing 14 and the low-pressure shaft 15 .

[0054] The turbine housing 14 forming the first component here is a substantially annular housing through which the main gas flow path 24 of the turbine passes. A turbine disk 26 fixed to the low-pressure turbine trunnion 16 is also arranged in the gas flow path 24, and the blades 28 of the turbine disk are arranged alternately with stator blades 30.

[0055] The inter-turbine casing 14 comprises a first tubular wall 32 having an axis X, and the bearing support 16 comprises a second tubular wall 33 , between which the bearing 20 is mounted.

[0056] The inter-turbine casing 14 also comprises a third wall 36 which is substantially transverse to the axis X.

[0057] The bearing support 16, which here forms the second component, comprises a fourth wall 34, substantially transverse to the axis X, which is surrounded by a third wall 36 of the turbine wheel casing 14. The fourth wall 34 thus rotates within the third wall 36, which is stationary.

[0058] The turbine housing 14, the low-pressure shaft 15 and the bearing support 16 define a first lubricating enclosure 38 for lubricating the bearings, which contains lubricating oil, in the rear part 12 of the turbine 10. Furthermore, these fourth wall 34 and third wall 36 separate the first lubricating enclosure 38 for lubricating the bearings from a second enclosure 40, which is outside the first enclosure 38.

[0059] The fourth wall 34 is delimited by an outer shell layer 42 which also forms part of the bearing support 16 , and the third wall 36 is delimited by an inner shell layer 44 which forms part of the inter-turbine casing 14 .

[0060] The two shells 42, 44 are arranged opposite one another, wherein the inner shell 44 surrounds the outer shell 42. The outer shell 42 and the inner shell 44 thus define an interface region 46 between the two enclosures 38, 40.

[0061] Typically, the second enclosure 40 is a pressurized enclosure supplied with pressurized air taken from a tap on one of the compressors of the turbomachine. This enclosure 40 is pressurized so as to exert a positive pressure on the interface region 46, wherein, in a manner not limiting the invention, it is possible to house an oil flushing system comprising at least one spinning crescent, which system may be supplemented inside or outside the interface region 46 by a dynamic sealing system, for example a labyrinth or brush seal, which ensures sealing between the lubricating enclosure 38 and the second enclosure 40.

[0062] Since neither of these systems is a limitation of the present invention, the remainder of this description will consider the interface region 46 to include only an oil flushing system.

[0063] The purpose of pressurizing the enclosure 40 is to confine the lubricating oil from the bearing 20 within the lubricating enclosure 38. The second enclosure 40 also includes an oil drain conduit 41 communicating with the exterior of the turbine.

[0064] Lubricating oil is pumped under pressure into the lubrication enclosure 38 via an oil inlet conduit 48 and is recovered by an oil recovery device which allows the oil to be discharged from the lubrication enclosure via a conduit 50 so that the oil can be recovered and then pumped back into the enclosure 38. Figure 1 As shown by the arrows in , in order to reach the duct 50 , the lubricating oil from the bearing 20 must first reach the inner surface 52 of the third wall 36 of the inter-turbine casing 14 , from which the lubricating oil is transported to the inlet of the duct 50 .

[0065] Note that Figure 1 In the plan view shown, the duct 50 is indicated by a dotted line.

[0066] For this reason, Figure 3 As shown in more detail in , the oil recovery device also comprises a tubular tab 54 extending from the first tubular wall 32 of the inter-turbine casing 14 and axially into the outer shell 42 of the bearing support 16 , more specifically into one end 43 of the outer shell.

[0067] The tab 54 is configured to guide the bearing 20 when the bearing 20 is installed, so that the low-pressure shaft 15 can be accurately positioned to avoid any contact between the shaft 15 and the inter-turbine casing 14 .

[0068] In a known manner, when the turbine is operating, oil is sprayed from the tabs 54 in turn to the outer shell layer 42 of the bearing support 16 and then from the outer shell layer 42 of the bearing support 16 to the inner surface 52 .

[0069] In a known manner, the end 43 of the inner shell 42 of the bearing support 16 is extended by 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 shell 44 of the inter-turbine casing 14 and is therefore not arranged in the interface region 46 but outside it. An outer groove 60 is formed in this extension 56, the concave surface of which faces away from the tubular tab 54.

[0070] exist Figure 2 2 shows an extension 56 of this type according to the prior art. It can be seen that the extension 56 has substantially the same inner and outer diameters as the outer shell 42 of the bearing support 16, and the groove 60 of the extension 56 has a specific width L and depth P. The groove 60 has a circular cross section.

[0071] In such a configuration, it has been observed that, when the turbine is at rest, for certain inclination angles (for example corresponding to an inclination angle of about 4° of the turbine, which is usually the inclination angle of an underwing turbine in the parking position of an aircraft), the oil coming from the tubular tab 54 drips onto the inner wall 62 of the extension 56, then flows onto the end face 64 of the extension, not only dripping from the end face 64 but also tending to penetrate into the groove 60 by capillary action to form a lubricant bridge from which the oil spreads along the outer wall 66 of the inner shell 42 of the support 16 until it reaches the interface zone 46. When the interface zone 46 is equipped with an oil flushing system (for example a double system comprising a front spin 67 and a front crescent 69 and a rear spin 68 and a rear crescent 68), the oil can pass through this system and then enter the second enclosure 40, from which the oil can be discharged via the oil drain duct 41.

[0072] The present invention proposes a modification of the extension 56 so as to be able to overcome this problem.

[0073] For this reason, Figure 2 and Figure 5 As shown, the extension 56 first extends beyond the axial half length l of the tubular tab 54 .

[0074] In addition, if Figure 5As shown, the extension 56 surrounds the outside of the tubular tab 54 and axially exceeds the axial half length l of the tubular tab 54. The inner diameter of the extension is equal to the inner diameter of the outer shell 42 of the second member 16, the outer diameter of the extension is less than or equal to the outer diameter of the outer shell, and the cross section of the annular groove 60 of the extension is rectangular.

[0075] Thus, the free end of the extension 56 forms a return portion which, in combination with the rectangular shape of the cross section of the outer annular groove 60, prevents the oil from bridging through the annular groove 60 by capillary action to reach the interface region 46. Unlike a groove having a circular cross section, a groove having a rectangular cross section makes it possible to break the continuity of the oil film and prevent the oil film from spreading through the annular groove 60.

[0076] More specifically, if Figure 5 As shown, the tubular extension 56 includes a first section 72 , a second section 74 and a third section 76 in order from the outer shell layer 42 of the support member 16 .

[0077] The first section 72 extends the outer shell 42 of the support 16 and has an inner diameter d ... 42 and outer diameter D 42 Same inner diameter d 72 and outer diameter D 72 .

[0078] The tubular extension then comprises a second section 74 connected to the first section 72. The inner diameter d of the second section 74 is 74 is equal to the inner diameter d of the shell layer 42 in the interface region 46 42 , the outer diameter D of the second section 74 74 smaller than the outer diameter D of the outer shell 42 in the interface region 46 42 .

[0079] Finally, the inner diameter d of the third section 76 connected to the second section 74 is 74 Equal to the inner diameter d of the outer shell 42 42 , specific outer diameter D 76 Equal to the outer diameter D of the outer shell 42 42 .

[0080] Therefore, it should be understood that the second section 74 and the third section 76 thus form a recess that extends axially outside the tubular tab 54 beyond the axial half length l of the tubular tab 54. Therefore, the axial dimensions of the first to third sections 72, 74, 76 determine the coverage of the tubular extension 56 around the tubular tab 54 beyond the axial half length l.

[0081] It should also be understood that the annular groove 60 of rectangular cross section is defined by an outer wall 74a of the second segment 74 having the axis X, which is sandwiched between the respective transverse walls 72a and 76a of the first segment 72 and the third segment 76 at their junction with the second segment 74.

[0082] The size of the groove 60 plays a decisive role in its ability to prevent lubricant bridges from forming thereon. The outer wall 74a of the second section 74 having the axis X determines the width L characteristic of the groove 60 and the transverse wall 76a of the third section 76 determines the height H characteristic of the groove 60 .

[0083] According to the invention, the groove 60 is configured such that its height H is an affine function of the interval of its width L according to a relationship of the type H=m×L+p, the coefficients m and p of which are associated with specific properties of the lubricating oil.

[0084] In the context of the present invention, the properties of the lubricating oil used to lubricate the bearing 20 include an operating temperature of less than 120°C, a viscosity between 20 and 30 centistokes at 40°C and between 4.9 and 5 centistokes at 100°C, and a density between 0.9 Kg / L and 1.05 Kg / L.

[0085] According to the present invention, for such lubricating oil, the coefficients m and p of the affine function that determines the height H of the groove 60 according to the width L of the groove 60 vary according to the following three intervals:

[0086] - for the interval of width L greater than or equal to 4 mm and less than 6 mm, m=-0.6 and p=7,

[0087] - for the interval of width L from 6 mm to 7 mm, m=-0.2 and p=4.6,

[0088] Finally, for a width L greater than 7 mm, m=0 and p=3.2, which corresponds to a constant height H of the groove 60 .

[0089] Another important parameter of the groove 60 is the radius of curvature of the sections 72 to 76. In order to break the oil film, the radius of curvature connecting these sections must be as small as possible in order to provide a groove 60 with a cross section that is as close to a perfect rectangle as possible. On the one hand, the first section 72 and the second section 74 are connected at the bottom of the groove by a radius of curvature R less than or equal to 0.6 mm, and on the other hand, the second section 74 and the third section 76 are connected at the bottom of the groove by a radius of curvature R less than or equal to 0.6 mm.

[0090] It is also important that the third section 76 has a minimum thickness E 76To prevent oil from flowing through the free end 78 of the third section. To this end, the thickness E of the third section 76 is 76 Greater than 1.2mm.

[0091] Advantageously, the extension 56 may be arranged radially relative to the tubular tab 54 with a reduced clearance making it possible to limit the oil flow rate.

[0092] Advantageously, the invention makes it possible to prevent oil from passing through the interface zone 46 at a given inclination angle of up to 4° when the turbine is at rest, regardless of whether this zone is configured to receive an oil flushing system or another system such as the spins 67, 68 and the crescents 69, 70. The invention thus prevents oil from escaping onto the apron via the oil drain duct 41 or from penetrating into other hotter enclosures of the turbine, such as the enclosure 80, with the attendant risk of smoke generation, which would be detrimental to the user's perception of the quality of the turbine.

Claims

1. A turbomachine (10) comprising a first inner member and a second inner member (14, 16) capable of rotational movement relative to each other about an axis X and at least one guide bearing (20), the first inner member and the second inner member being mounted between a first tubular wall and a second tubular wall (32, 33) of the first member and the second member (14, 16) respectively having the axis X, The first member (14) comprises a third wall (36) substantially transverse to the axis X, The second member (16) comprises a fourth wall (34) substantially transverse to the axis X, surrounded by the third wall (36), The third wall and the fourth wall (34, 36) separate two enclosures (38, 40), the two enclosures being a first enclosure (38) and a second enclosure (40), the first enclosure being used for lubricating the bearing (20). The fourth wall (34) is defined by an outer shell (42) of the second member (16), and the third wall (36) is defined by an inner shell (44) of the first member (14), the inner shell (44) surrounding the outer shell (42), and the inner shell and the outer shell (42, 44) defining an interface region (46) between the enclosures, The turbine further comprises an oil recovery device, the oil recovery device comprising a tubular tab (54) extending the first tubular wall (32) of the first member (14) and extending axially within one end (43) of the outer shell (42) of the second member (16), the tab (54) being configured to guide the oil to be injected sequentially 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), The inner shell (42) of the second member (16) is extended by a tubular extension (56) which extends axially beyond one end (58) of the inner shell (44) of the first member (14) around the outside of the tubular tab (54) and has an outer groove (60) formed therein facing away from the tubular tab (54), It is characterized in that The extension (56) axially extends beyond the axial half length (l) of the tubular tab (54) around the outside of the tubular tab (54), and the inner diameter (d 72 , d 74 , d 76 ) is equal to the inner diameter (d 42 ), the outer diameter of the extension (D 72 , D 74 , D 76 ) is less than or equal to the outer diameter (D 42 ), and the cross-section of the annular groove of the extension portion is rectangular.

2. The turbine (10) according to the preceding claim, characterized in that The tubular extension (56) includes, starting from the outer shell layer (42) of the second member (16), a first section (72) which extends the outer shell (42) of the second component (16) and has an inner diameter (d 72 ) and outer diameter (D 72 ) and the inner diameter (d 42 ) and outer diameter (D 42 )same, - a second section (74) connected to the first section (72), the inner diameter (d 74 ) is equal to the inner diameter (d ) of the outer shell (42) in the interface region (46) 42 ), and the outer diameter of the second section (D 74 ) is smaller than the outer diameter (D 42 ),as well as - a third section (76) connected to the second section (74), the inner diameter (d 74 ) is equal to the inner diameter (d 42 ), and the specific outer diameter (D 76 ) is equal to the outer diameter (D 42 ), The annular groove is defined by an outer wall (74a) of the second section having the axis X and by transverse walls (72a, 76a) of the first and third sections (72, 74) at their junction with the second section (74).

3. The turbine (10) according to the preceding claim, characterized in that A first lubricating capsule (38) for lubricating the bearing (20) contains lubricating oil, an outer wall (74a) of the second section (74) having an axis X determines a width L of the groove (60), a transverse wall (76a) of the third section (76) determines a height H of the groove, and the groove is such that the height H of the groove is an affine function of the interval of the width L of the groove according to the relationship H=m×L+p, the coefficients m and p of the relationship being associated with given characteristics of the lubricating oil.

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

5. Turbine (10) according to the preceding claim, characterized in that - for the interval of width L greater than or equal to 4 mm and less than 6 mm, m=-0.6 and p=7, - for the interval of width L from 6 mm to 7 mm, m=-0.2 and p=4.6, - For widths L greater than 7 mm, m=0 and p=3.

2.

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

7. The turbine (10) according to any one of claims 4 to 6, characterized in that The axial thickness (E) of the third section (76) 76 ) is greater than or equal to 1.2mm.

8. A turbine (10) according to any one of the preceding claims, characterised in that The first component (14) is a turbine inter-casing, the second component (16) is a bearing support fixed to a low-pressure shaft (15), the first bearing lubrication enclosure (38) is in communication with an oil recovery conduit (50) connected to an oil circuit of the turbine, and the second enclosure (40) is a pressurized enclosure in communication with an oil drain conduit (41) connected to the outside of the turbine (10).

9. Turbine according to the preceding claim, characterized in that The interface region (46) is a region for receiving an oil flushing system including a front spin (67) and front crescent (69) and a rear spin (68) and rear crescent (70) between the inner and outer shell layers (44, 46).

10. The turbine according to claim 8 or 9, characterized in that The interface region (46) is a region for receiving a sealing system including at least one dynamic seal.

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