Patent Application
20250163819
The invention relates to a drainage cavity dedicated to collecting oil liable to leak through a seal that this cavity juxtaposes, in a sealing system incorporating this seal and this cavity.
On
The primary flow passes through a low-pressure compressor 4 and then a high-pressure compressor 5 before arriving in a combustion chamber 6, after which it expands through a high-pressure turbine 7 and then a low-pressure turbine 8 before being discharged towards the downstream end AV. As for the secondary flow, this is propelled directly downstream by the fan 3 in a duct delimited by the casing 9 to generate a thrust.
Such an engine includes a rotor rotating about its longitudinal axis AX, and including a plurality of discs each carrying at its periphery a series of blades or vanes, these discs corresponding to the fan, to the compressors and to the turbines.
In the case of a twin-spool turbojet engine, the high-pressure compressor and the high-pressure turbine form part of a high-pressure spool that surrounds a low-pressure shaft and rotates at a speed different from the latter, this low-pressure shaft carrying the low-pressure compressor and the low-pressure turbine. The shaft and the high-pressure spool are carried by bearings housed in lubrication chambers that isolate them from the rest of the engine.
Such a chamber is delimited by walls rotating with respect to each other with a seal between these walls, which limits the cross section of oil leakage. In a complementary manner, such a chamber is said to be pressurised, which in practice means that the interior of the chamber is at a pressure lower than that of its environment. Thus the oil is distanced from the seal by means of a stream of air continuously entering through this seal, from the outside towards the inside of the chamber.
On
The grooves 13 and 17 delimit a drainage cavity 18 connected to the drain 14 to form with the seal 12 a sealing system for a chamber E1 located upstream of this system. This drainage cavity 18 juxtaposes the seal 12 to collect oil liable to leak through this seal 12 while circulating from upstream AM to downstream AV from the chamber E1, to prevent it reaching a space E2 external to the chamber E1.
When the engine is horizontal, as in
If the engine is inclined as on
As can be seen on
Leaks can also occur in situations where the chamber is not sufficiently pressurised, during a transient operating phase, for example when the engine is ticking over or stopped, or in the case of failure of the seal.
The aim of the invention is to provide a sealing system solution for reducing or even preventing leaks, towards the external space, of oil collected in the drainage cavity.
For this purpose, the object of the invention is a system for sealing and draining leaks of oil for a turbine-engine bearing chamber, this bearing comprising a stator carrying a rotor rotating about a rotation axis, this system comprising a seal carried by the stator and surrounding the rotor, an external circumferential groove carried by the stator while being contiguous with the seal to collect leaking oil travelling along the rotor through the seal and which is centrifuged by the rotor towards this circumferential groove, a drain located at the bottom part of the turbine engine for collecting the oil recovered by the circumferential groove, this circumferential groove being open towards the rotation axis while being delimited by a bottom extended by two lateral walls, the lateral wall opposite to the seal terminating in a gutter opening towards the bottom.
By virtue of the gutter carried by the lateral wall opposite to the seal, the oil centrifuged towards the bottom of the axial groove is necessarily collected by this gutter instead of falling onto the rotor to risk continuing its progress beyond the sealing system.
The invention thus makes it possible to best guide the leaks of oil towards the drain so that they do not pollute the rest of the engine, and this by adapting an already existing part.
The invention also relates to a sealing system thus defined, wherein the gutter is absent at the bottom part of the circumferential groove.
The invention also relates to a sealing system thus defined, wherein the bottom is formed by a frustoconical wall the inside diameter of which decreases on moving away from the seal.
The invention also relates to a sealing system thus defined, comprising an internal circumferential groove formed in the rotor facing the external circumferential groove, this internal circumferential groove having a length along the rotation axis that is less than the length of the external circumferential groove along the rotation axis.
The invention also relates to a sealing system thus defined, wherein the internal circumferential groove has a frustoconically shaped bottom the inside diameter of which decreases on moving away from the seal.
The invention also relates to a sealing system thus defined, wherein the rotor includes a circumferential rib terminating the internal circumferential groove.
The invention also relates to a sealing system thus defined, including knife-edge seals secured to the rotor sliding along a radially internal face of the gutter that is provided with abradable elements, to form a labyrinth seal.
The invention also relates to a turbine engine comprising a bearing chamber that is equipped with a sealing system thus defined.
Invention also relates to a turbine engine comprising a bearing chamber that is equipped with a sealing system thus defined.
The idea at the basis of the invention is improving the external groove so that it better captures the oil leaking through the seal.
On
This system 21, which constitutes a sealing barrier, includes a seal 25 carried by the stator 22 and surrounding the rotor 23, which is here a segmented radial seal, and an external groove 26 carried by the stator 22 while being located immediately downstream of the seal 25, this external groove 26 being open towards the axis AX.
The rotor 23 has a shape of revolution including a cylindrical portion 27 at the seal 25 that is extended towards downstream AV by a conical portion or shoulder 28 delimiting a reduction in diameter, to the downstream of which an internal groove 29 extends, located radially facing the external groove 26 of the stator. Downstream of the groove 29, the rotor 23 includes a circumferential rib 31 advantageously followed by a sealing portion provided with three knife-edge seals 32.
The external groove 26 includes a bottom 33 extended by an upstream lateral wall 34 running along the seal 25 and a downstream lateral wall 35 opposite to the seal 25, the bottom and the lateral walls conjointly delimiting a corresponding shape similar to that of the letter U that is open in the direction of the axis AX.
In a complementary manner, a drain 36 located at the lowest point of the bottom 33 emerges in this bottom, so as to collect any oil that could accumulate in the bottom part of the groove 26, so as to return it for example to a dedicated recovery box.
The downstream lateral wall 35 includes a body 37 having the form of a ring with an orientation normal to the axis AX, and the radially internal edge of which is extended by an internal skirt 38 extending in the direction of the bottom 33. This internal skirt 38 includes in the example of the figures a cylindrical portion 39 running along the knife-edge seals 32 and which terminates in a conical portion 41 bringing it radially close to the bottom 33, so that it has a roughly annular shape that is splayed in the direction of the chamber E1.
The internal face of the cylindrical portion 39 includes abradable elements so as to constitute, with the knife-edge seals 32, a labyrinth seal 42 opposing the passage of oil towards the space E2. Other forms of the sealing portion that comprises the knife-edge seals 32 can be envisaged. It is also possible to dispense with such a sealing portion, or even to dispense with the labyrinth seal 42 overall, if the passage of oil towards the space E2 remains minimal and tolerable.
The internal skirt 38 delimits, with the downstream lateral wall 35, a gutter 43 extending in the groove 26. In the example of
In the case of a fault, or of operation with a pressure in the space E2 insufficient to prevent a leak of oil out of the chamber, the oil H that passes through the seal 25 while running along the external face of the cylindrical portion 27 of the rotor travels in the downstream direction AV, i.e. towards the groove 29, in the direction of the drainage cavity 24 juxtaposing this seal. When it travels towards or in the groove 29, this oil H is centrifuged by the rotation of the rotor 23, so that it is collected by the groove 26, at the bottom 33 thereof and/or at the lateral walls 34, 35 thereof.
As can be seen on
At the top part of the engine, the oil collected by the conical bottom 33 is thus conveyed by the effect of gravity in the downstream direction AV in the direction of the lateral wall 35. After having joined the lateral wall 35, this oil descends in the gutter 43 by gravity effect, and then trickles circumferentially in this gutter 43 downwards. Once it has reached the bottom part of the engine, this oil leaves the gutter 43 to fall onto the bottom 33 and be recovered in the drain 36, which is located at the lowest point of the groove 26.
At the bottom part of the engine, the oil collected by the bottom 33 trickles along this bottom 33, until it reaches the drain 36, through which it is discharged.
On
This angular extent with no gutter ensures that any oil that may have accumulated on the rib 31 of the rotor can trickle by gravity directly towards the bottom 33 when the engine is inclined. This avoids this oil being collected by the upstream face of the conical portion 41, which could then convey it downstream in the direction of the labyrinth seal 42.
As illustrated on the figures, the groove 26 can be provided in the form of a circular profiled member that is attached to the internal face of the stator 22, this profiled member including a portion with no gutter 43. Advantageously, this profiled member is provided with positive angular location so as to enable it to be angularly positioned suitably to ensure that the portion with no gutter 43 is located at the bottom part of the engine.
The invention makes it possible to limit losses of oil also when the engine is inclined, for example during a takeoff phase, as illustrated on
The oil that passes through the seal 25 at the bottom part of the engine for its part is collected almost directly by the bottom 33 and by the downstream lateral wall 35 to be recovered in the drain 36.
As can be seen in the bottom part of
In a complementary fashion, in order to limit the quantity of oil present on the gutter 23, the bottom of the internal groove 29 has a conical shape, the diameter of which decreases in the downstream direction, so that any oil liable to be present in this groove is directed upstream by centrifugal effect. Under these conditions, this oil is naturally directed towards the upstream face of the groove 29, which is normal to the axis AX, so that it is spontaneously centrifuged to be collected by the bottom 33 of the external groove 26. The internal groove 29 thus constitutes a drip step at its upstream face.
More generally, the internal groove 29 has, along the axis AX, a length less than that of the external groove 26 while being located facing this external groove, to ensure that the oil captured in this internal groove is centrifuged into the wider external groove. This centrifugation occurs either at the upstream face of the internal groove or at the rib 31 delimiting the downstream face of this internal groove.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2201525 | Feb 2022 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2023/050244 | 2/21/2023 | WO |
