Assembly forming labyrinth seal for aircraft turbomachine, turbomachine and corresponding aircraft.

Abstract

The invention relates to an assembly (1) forming a labyrinth seal for an aircraft turbomachine comprising: a rotating part (2) mounted movably to rotate about an axis of rotation (X) and comprising a radially external face (20) positioned at a radially external end of said rotating part (2); a fixed part (3) extending around the rotating part (2) and comprising a radially internal face (30) positioned at a radially internal end of the fixed part (3); said radially internal face (30) and said radially external face (20) being separated by a first channel (A) for the circulation of an airflow circulating in a longitudinal direction corresponding to said axis of rotation (X), characterized in that said assembly (1) further comprises a plurality of second channels (21, 31) distributed among: rotating second channels (21) formed in said rotating part (2);of the second fixed channels (31) formed in said fixed part (3), each of said second rotating channels (21) and second fixed channels (31) being delimited by an internal wall (22, 32) of one of the respective of said rotating part (2) and fixed part (3) and by a fluidic disturbance island (23, 33).;

Description

Title of the invention: Assembly forming labyrinth seal for aircraft turbomachine, corresponding turbomachine and aircraft. Scope of the invention

[0001] The present invention relates to the field of turbomachinery, and more particularly to the general field of labyrinth seal systems designed to ensure sealing between two elements of a turbomachine rotating relative to each other. More specifically, it relates to an assembly forming a labyrinth seal for a turbomachine, as well as the turbomachine comprising such an assembly.

[0002] The invention applies more particularly to any type of aeronautical turbomachine, and especially to aircraft turbomachines such as turbojets and turboprops. Prior art

[0003] In the field of turbomachinery, there are different types of sealing systems to ensure sealing between two parts of the turbomachine.

[0004] Such sealing is required, for example, under a turbomachine compressor rectifier, or more generally at the clearances between the rotating blades and the turbine and compressor housings, but also at the clearances between the fixed blade roots and the rotating parts. Indeed, the permeability of the various cavities, that is to say, their ability to prevent excessive air recirculation, primarily impacts the performance of the turbomachine components. However, the difficulty in ensuring a good level of sealing is linked to the fact that the two parts of the turbomachine involved, which can be turbine distributors or compressor rectifiers—namely, a fixed part and a rotating part—undergo relatively significant mechanical and thermal deformations during typical engine operation, thus creating clearance and a leakage rate during operation.

[0005] Among the known sealing systems, special distinction is made of "contactless" sealing systems of the labyrinth seal type, which are characterized by an absence of contact between the parts of the turbomachine.

[0006] A labyrinth seal therefore classically comprises a rotating part with fins, or vanes, with a static bore covered with a packing of abradable material or a honeycomb structure capable of withstanding high temperatures.

[0007] When the turbomachine starts, the flaps of the labyrinth seal rub slightly against the abradable material lining, biting into the latter, which results in a minimum gap.

[0008] The drawback of such a technique is that the scrapers are designed to wear down the abradable material lining, which is therefore a wear part that must be checked and even replaced regularly. This results in turbomachine downtime, as well as unsatisfactory maintenance costs and time.

[0009] In addition, the friction of the wipers against the lining, even if slight, causes the air circulating at the level of this labyrinth seal to heat up, which can cause overheating and reduce the performance of the engine and the turbomachine.

[0010] There is therefore a need to provide a solution that will at least partially resolve these drawbacks listed above. Description of the invention

[0011] To this end, the invention relates to an assembly forming a labyrinth seal for an aircraft turbomachine comprising: - a rotating part mounted to rotate about an axis of rotation X and comprising a radially external face positioned at a radially external end of said rotating part; - a fixed part extending around the rotating part and comprising a radially internal face positioned at a radially internal end of the fixed part,

[0012] the radially internal face and the said radially external face being separated by a first channel A for the circulation of an airflow circulating along a longitudinal direction corresponding to the axis of rotation X.

[0013] According to the invention, said assembly further comprises a plurality of second channels distributed among: - of the second rotating channels formed in said rotating part and extending from an inlet formed on said radially external face to an outlet provided on said radially external face downstream of said inlet and opening into said first channel A of circulation of an airflow; - of the second fixed channels formed in said fixed part and extending from an inlet formed on said radially internal face to an outlet provided on said radially internal face downstream of said inlet and opening into said first channel A of circulation of an airflow,

[0014] each of said second rotating channels and second fixed channels being delimited by an internal wall of one of the respective of said rotating part and fixed part and by a fluidic disturbance island.

[0015] Thus, the solution proposes a new and inventive approach that makes it possible to resolve at least in part some of the drawbacks of the prior art.

[0016] In particular, and because the fixed part and the rotating part are separated by the first airflow channel A, there is no wear of the part by contact between the fixed part and the rotating part.

[0017] Furthermore, the implementation of an assembly with two parts separated by a first channel and each carrying second channels so as to take a part of the flow from the first channel and recirculate it into the first channel, that is to say the implementation of an assembly integrating a valve system commonly called a "Tesla valve" after its inventor Nikola TES LA, forming a check valve for the airflow circulating in the first channel.

[0018] According to a particular aspect of at least one embodiment of the invention, each of said second rotating channels and second fixed channels is inclined with respect to said longitudinal direction at an angle between 5 and 60°.

[0019] According to a particular aspect of at least one embodiment of the invention, said second rotating channels and second fixed channels are at an angle to said first channel A of circulation of an airflow.

[0020] According to a particular aspect of at least one embodiment of the invention, each of said second rotating channels and second fixed channels comprises a first portion extending from said inlet and a second portion extending to said outlet.

[0021] According to a particular aspect of at least one embodiment of the invention, said first portions are substantially parallel to said second portions.

[0022] According to a particular aspect of at least one embodiment of the invention, for each of said second rotating channels and second fixed channels, said first portion and said second portion are separated by a curvilinear portion, said curvilinear portion delimiting a rounded downstream end of said fluidic disturbance island.

[0023] This makes it possible to avoid having a sharp angle in each of the second channels so as not to disturb the guidance of the airflow circulating in each of these second channels.

[0024] According to a particular aspect of at least one embodiment of the invention, said second rotating channels are arranged longitudinally in a staggered arrangement with said second fixed channels.

[0025] According to a particular aspect of at least one embodiment of the invention, each of said second rotating channels and second fixed channels has over its entire extent a width L2 greater than or equal to a width L1 of said first airflow circulation channel.

[0026] This makes it possible to take a major part of the airflow circulating in said first circulation channel of an airflow in order to disrupt the flow and limit the flows through the whole.

[0027] According to a particular aspect of at least one embodiment of the invention, each of said inlets is delimited at least partially by an upstream end of said fluidic disturbance island, said upstream end forming an acute angle.

[0028] According to a particular aspect of at least one embodiment of the invention, said outlets have a funnel shape widening towards the first channel A of circulation of an airflow.

[0029] According to a particular aspect of at least one embodiment of the invention, each of said fluidic disturbance islands is connected to said respective internal wall of one of said respective rotating part and fixed part by a junction wall.

[0030] According to a particular aspect of at least one embodiment of the invention, the junction wall extends in a tangential direction to said axis of rotation X, and has a height h whose dimension ensures the mechanical stability of the fluidic disturbance islands.

[0031] The invention also relates to a turbomachine comprising an assembly according to one of the aforementioned embodiments.

[0032] The invention also relates to an aircraft comprising a turbomachine according to the aforementioned embodiment. Presentation of the figures

[0033] The invention, as well as its various advantages, will be more easily understood in the light of the following description of illustrative and non-limiting embodiments thereof, and the accompanying drawings, among which:

[0034] [Fig-1] illustrates a schematic longitudinal cross-sectional view of a turbomachine aircraft according to the invention;

[0035] [Fig.2] is a partial longitudinal cross-sectional view of an aircraft turbomachine, illustrating an assembly forming a labyrinth seal;

[0036] [Fig.3] is a detailed view of [Fig.2];

[0037] [Fig.4] is a perspective view of [Fig.3];

[0038] [Fig. 5] is a partial perspective view of a rotor-stator assembly comprising a assembly forming a labyrinth seal, and

[0039] [Fig.6] is another partial perspective view of a rotor stator assembly comprising an assembly forming a labyrinth seal.

[0040] Detailed description of an embodiment of the invention

[0041] Throughout the description, it is noted that the terms upstream and downstream are to be considered in relation to a pressure delta in the turbomachine, which in the illustrated embodiment corresponds to a main direction 5, represented on [Fig.1], of normal gas flow (from upstream to downstream) for an aircraft turbomachine.

[0042] With reference first to [Fig. 1], an aircraft turbomachine T is shown, according to a preferred embodiment of the invention. This is a twin-spool, turbofan engine. However, it could be a turbomachine of another type, for example a turboprop, without departing from the scope of the invention.

[0043] The turbomachine T has a central longitudinal axis X around which its various components extend. It comprises, from upstream to downstream along the main direction 5 of gas flow through this turbomachine, a blower 90, a low-pressure compressor 4, a high-pressure compressor 6, a combustion chamber 11, a high-pressure turbine 7 and a low-pressure turbine 8. The blower 90 can be driven directly by a low-pressure unit comprising the compressor 4 and the turbine 8, or indirectly by a reduction gear (not shown).

[0044] Conventionally, after passing through the blower 90, the air splits into a central primary flow 12a and a secondary flow 12b which surrounds the primary flow. The primary flow 12a flows into a main gas circulation channel 14a passing through the compressors 4, 6, the combustion chamber 11 and the turbines 7, 8. The secondary flow 12b, on the other hand, flows into a secondary channel 14b delimited radially outwards by an engine casing, surrounded by a nacelle 9.

[0045] Compressors and turbines are notably composed of a succession of rotor and stator stages. As previously developed, for example under a turbomachine compressor rectifier, or more generally at the level of the clearances between the blades and the housings of the rotor or stator stages of turbines and compressors, it is necessary to ensure sealing between two parts of the turbomachine, and more particularly an assembly forming a labyrinth seal.

[0046] A preferred embodiment of the invention is now presented in relation to Figures 2 to 6.

[0047] As illustrated in these figures, the assembly 1 forming a labyrinth seal comprises a rotating part 2 and a fixed part 3.

[0048] The rotating part 2 is mounted to rotate freely around the axis of rotation X and includes a radially external face 20 positioned at a radially external end of this rotating part 2.

[0049] As for the fixed part 3, it extends around the rotating part 2 and includes a radially internal face 30 positioned at a radially internal end of this fixed part 3.

[0050] In other words, the radially internal faces 30 and radially external faces 20 are positioned opposite each other.

[0051] This radially internal face 30 and this radially external face 20 are separated by a first channel A for the circulation of an air flow F circulating along a longitudinal direction corresponding to the axis of rotation X.

[0052] It is the airflow F circulating in this first circulation channel A that the solution proposes to reduce or even stop in order to guarantee a seal of the assembly.

[0053] To achieve this, the assembly 1 forming a labyrinth seal further comprises a plurality of second channels distributed between: - of the second rotating channels 21 formed in the rotating part 2 and extending from an inlet 210 formed on the radially external face 20 to an outlet 211 provided on the radially external face 20 downstream of the inlet 210 and opening into the first channel A of circulation of an air flow; - second fixed channels 31 formed in the fixed part 3 and extending from an inlet 310 formed on the radially internal face 30 to an outlet 311 provided on the radially internal face 30 downstream of the inlet 310 and opening into the first channel A of circulation of an airflow.

[0054] Each of these second rotating channels 21 and second fixed channels 31 is delimited by an internal wall 22, 32 of one of the respective rotating part 2 and fixed part 3 and by a fluidic disturbance island 23, 33.

[0055] In other words, each of the rotating channels 21 extends from an inlet 210 formed on the radially external face 20, then extends into the rotating part, being delimited on one side by an internal wall 22 and on the other side by a fluidic disturbance island 23 formed by a portion of the rotating part remaining from the excavation of the rotating channel 21, and opens into the first channel A of circulation of an air flow at the outlet 211 formed on the radially external face 20 downstream of the inlet 210.

[0056] Furthermore, each of the fixed channels 31 extends from an inlet 310 formed on the radially internal face 30, then extends into the fixed part, being delimited on one side by an internal wall 32 and on the other side by a fluidic disturbance island 33 formed by a portion of the fixed part 3 remaining from the excavation of the fixed channel 31, and opens into the first channel A of circulation of an air flow at the level of the outlet 311 provided on the radially internal face 30 downstream of the inlet.

[0057] Here each of the inlets 210, 310 is delimited at least partially by an upstream end of the fluidic disturbance island 23, 33, the upstream end forming an acute angle.

[0058] In addition, each of the outlets 211,311 has a funnel shape widening towards the first channel A of circulation of an airflow.

[0059] In this embodiment, each of the fluidic disturbance islands has an elongated shape extending in an oblique direction with respect to the axis of rotation X.

[0060] In addition, each of the fluidic disturbance islands 23, 33 is connected to the respective internal wall 22, 32 of one of the respective rotating part 2 and fixed part 3 by a junction wall 220, 320 extending in a direction tangential to the axis of rotation X.

[0061] In other words, the fluidic disturbance islands 23 connected to the internal wall 22 formed in the rotating part 2 are connected to the rotating part by a junction wall 220 extending in a direction tangential to the axis of rotation X.

[0062] On their side, the fluidic disturbance islands 33 connected to the internal wall 32 formed in the fixed part 3 are connected to the fixed part 3 by a junction wall 320 extending in a direction tangential to the axis of rotation X.

[0063] These connecting walls 220, 320 have a height h whose function is to ensure mechanical support of the disturbance islands.

[0064] Such a height h thus makes it possible to maintain the fluidic disturbance island and to resist mechanical stresses while not obstructing the passage of air in the second respective channel.

[0065] In this embodiment, each of the second rotating channels 21 and second fixed channels 31 is inclined with respect to the longitudinal direction at an angle between 5° and 60°.

[0066] More particularly, in this embodiment, the second rotating channels 21 and second fixed channels 31 are arranged in a herringbone pattern.

[0067] As can be seen, moreover, the second rotating channels 21 are arranged longitudinally in a staggered fashion from the second fixed channels 31.

[0068] Such a staggered arrangement thus makes it possible not to create disturbances between the second rotating channels 21 and the second fixed channels 31 because the inputs of the second rotating channels are longitudinally offset with the inputs of the second fixed channels and the outputs of the second rotating channels are longitudinally offset from the outputs of the second fixed channels.

[0069] Furthermore, in this embodiment, each of the second rotating channels 21 and second fixed channels 31 has over its entire extent a width L2 greater than or equal to a width L1 of the first channel A of circulation of an airflow.

[0070] Here, the second rotating and fixed channels have a similar width. However, according to certain variations, second channels with different dimensions could be provided.

[0071] The second rotating channels 21 here comprise a first portion 212 extending from the inlet 210 and a second portion 213 extending to the outlet 211.

[0072] In this embodiment, the first portions 212 are substantially parallel to the second portions 213.

[0073] According to an alternative, the first portions could be non-parallel to the second portions.

[0074] Furthermore, the first portion 212 and the second portion 213 of each of these rotating channels 21 are separated by a curvilinear portion 214, this curvilinear portion 214 delimiting a rounded downstream end of the fluidic disturbance island 23.

[0075] Furthermore, in this embodiment, the second fixed channels 31 comprise a first portion 212 extending from the inlet 210 and a second portion 313 extending to the outlet 311, the first portions 312 being substantially parallel to the second portions 313.

[0076] Furthermore, the first portion 212 and the second portion 213 of each of these fixed channels 31 are separated by a curvilinear portion 214, this curvilinear portion 214 delimiting a rounded downstream end of the fluidic disturbance island 23.

Claims

Demands

1. Assembly (1) forming a labyrinth seal for an aircraft turbomachine, comprising: - a rotating part (2) mounted to rotate about an axis of rotation (X) and comprising a radially external face (20) positioned at a radially external end of said rotating part (2); - a fixed part (3) extending around the rotating part (2) and comprising a radially internal face (30) positioned at a radially internal end of the fixed part (3); said radially internal face (30) and said radially external face (20) being separated by a first channel (A) for the circulation of an airflow circulating along a longitudinal direction corresponding to said axis of rotation (X), characterized in that said assembly (1) further comprises a plurality of second channels (21, 31) distributed between: - of the second rotating channels (21) formed in said rotating part (2) and extending from an inlet (210) formed on said radially external face (20) to an outlet (211) provided on said radially external face (20) downstream of said inlet (210) and opening into said first channel (A) of circulation of an airflow; - of the second fixed channels (31) formed in said fixed part (3) and extending from an inlet (310) formed on said radially internal face (30) to an outlet (311) provided on said radially internal face (30) downstream of said inlet (310) and opening into said first channel (A) of circulation of an airflow, each of the said second rotating channels (21) and second fixed channels (31) being delimited by an internal wall (22, 32) of one of the respective of the said rotating part (2) and fixed part (3) and by a fluidic disturbance island (23, 33).

2. Assembly (1) according to claim 1, characterized in that each of said second rotating channels (21) and second fixed channels (31) is inclined with respect to said longitudinal direction at an angle between 5° and 60°.

3. Assembly (1) according to any one of the preceding claims, characterized in that each of said second rotating channels (21) and second fixed channels (31) comprises a first portion (212, 312) extending from said inlet (210, 310) and a second portion (213, 313) extending to said outlet (211, 311).

4. Assembly (1) according to claim 3, characterized in that for each of said second rotating channels (21) and second fixed channels (31), said first portion (212, 312) and said second portion (213, 313) are separated by a curvilinear portion (214, 314), said curvilinear portion (214, 314) delimiting a rounded downstream end of said fluidic disturbance island (23, 33).

5. Assembly (1) according to any one of the preceding claims, characterized in that said second rotating channels (21) are arranged longitudinally in a staggered fashion with said second fixed channels (31).

6. Assembly (1) according to any one of the preceding claims, characterized in that each of said second rotating channels (21) and second fixed channels (31) has over its entire extent a width (L2) greater than or equal to a width (L1) of said first channel (A) of circulation of an airflow.

7. Assembly (1) according to any one of the preceding claims, characterized in that each of said inlets (210, 310) is delimited at least partially by an upstream end of said fluidic disturbance island (23, 33), said upstream end forming an acute angle.

8. Assembly (1) according to any one of the preceding claims, characterized in that said outlets (211,311) have a funnel shape widening towards said first channel (A) of circulation of an airflow.

9. Turbomachine comprising an assembly according to any one of the preceding claims.

10. Aircraft comprising a turbomachine according to claim 9.

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