Assembly forming labyrinth seal for an aircraft turbine engine, turbine engine and aircraft

Abstract

The invention relates to an assembly (1) forming a labyrinth seal for an aircraft turbine engine, comprising: - a rotating part (2) mounted so as to be able to rotate about an axis of rotation (X) and comprising a radially outer face (20) positioned at a radially outer end of the rotating part (2); - a fixed part (3) that extends around the rotating part (2) and comprises a radially inner face (30) positioned at a radially inner end of the fixed part (3); the radially inner face (30) and the radially outer face (20) being separated by a first channel (A) for the circulation of a flow of air circulating in a longitudinal direction corresponding to the axis of rotation (X), characterized in that the assembly (1) further comprises a plurality of second channels (21, 31) comprised of: - rotating second channels (21) formed in the rotating part (2); - fixed second channels (31) formed in the fixed part (3), each of the rotating second channels (21) and fixed second channels (31) being delimited by an inner wall (22, 32) of the rotating part (2) or the fixed part (3) respectively and by a fluidic disturbance island (23, 33).

Description

[0001] DESCRIPTION

[0002] TITLE: Assembly forming labyrinth seal for aircraft turbomachine, corresponding turbomachine and aircraft.

[0003] Scope of the invention

[0004] 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 itself comprising such an assembly.

[0005] The invention applies more particularly to all types of aeronautical turbomachinery, and especially to aircraft turbomachinery such as turbojets and turboprops.

[0006] Prior art

[0007] In the field of turbomachinery, there are different types of sealing systems to ensure sealing between two parts of the turbomachine.

[0008] 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, their ability to prevent excessive air recirculation, primarily impacts the performance of the turbomachine components. 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 leakage during operation.

[0009] Among the known sealing systems, special mention is made of "contactless" sealing systems such as labyrinth seals, which are characterized by an absence of contact between the parts of the turbomachine.

[0010] A labyrinth seal typically comprises a rotating part with fins or vanes, and a static bore covered by a packing of abradable material or a honeycomb structure capable of withstanding high temperatures. When the turbomachine starts, the fins of the labyrinth seal rub lightly against the packing of abradable material, biting into it and resulting in a minimum gap.

[0011] The drawback of this technique is that the scrapers wear down the abradable material lining, making this lining a wear part that requires regular inspection and even replacement. This results in turbomachine downtime, as well as unsatisfactory maintenance costs and time.

[0012] In addition, the friction of the wipers against the lining, even if slight, causes the air circulating at the labyrinth seal to heat up, which can lead to overheating and reduce the performance of the engine and turbomachine.

[0013] Therefore, there is a need to provide a solution that addresses at least some of the drawbacks listed above.

[0014] Description of the invention

[0015] To this end, the invention relates to an assembly forming a labyrinth seal for an aircraft turbomachine comprising: a rotating part mounted movable in rotation 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, the radially internal face and said radially external face being separated by a first channel A for the circulation of an airflow circulating in a longitudinal direction corresponding to the axis of rotation X.

[0016] According to the invention, said assembly further comprises a plurality of second channels distributed between: rotating second 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 for the circulation of an airflow; fixed second 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 for the circulation of an airflow, each of said rotating second channels and fixed second channels being delimited by an internal wall of one of the respective rotating part and fixed part and by a fluidic disturbance island.

[0017] Thus, the solution offers a new and inventive approach that makes it possible to resolve at least some of the drawbacks of the prior art.

[0018] 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.

[0019] 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 Tesla, forming a check valve for the airflow circulating in the first channel.

[0020] 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°.

[0021] 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.

[0022] 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.

[0023] According to a particular aspect of at least one embodiment of the invention, said first portions are substantially parallel to said second portions.

[0024] 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.

[0025] This avoids sharp angles in each of the second channels so as not to disrupt the guidance of the airflow circulating in each of these second channels.

[0026] According to a particular aspect of at least one embodiment of the invention, said second rotating channels are arranged longitudinally in a staggered pattern with said second fixed channels. 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 length, a width L2 greater than or equal to a width L1 of said first airflow channel.

[0027] This allows a major part of the airflow circulating in said first circulation channel of an airflow to be taken in order to disrupt the flow and limit the flows passing through the whole.

[0028] 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.

[0029] According to a particular aspect of at least one embodiment of the invention, said outlets have a funnel shape widening towards the first airflow channel A.

[0030] 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.

[0031] According to a particular aspect of at least one embodiment of the invention, the junction wall extends in a direction tangential to said axis of rotation X, and has a height h whose dimension ensures the mechanical strength of the fluidic disturbance islands.

[0032] The invention also relates to a turbomachine comprising an assembly according to one of the aforementioned embodiments.

[0033] The invention also relates to an aircraft comprising a turbomachine according to the aforementioned embodiment.

[0034] Presentation of the figures

[0035] The invention, and its various advantages, will be more easily understood in light of the following description of illustrative and non-limiting embodiments thereof, and the accompanying drawings, among which:

[0036] [Fig. 1] illustrates a schematic longitudinal cross-sectional view of an aircraft turbomachine according to the invention;

[0037] [Fig. 2] is a partial longitudinal cross-sectional view of an aircraft turbomachine, illustrating an assembly forming a labyrinth seal;

[0038] [Fig. 3] is a detailed view of figure 2;

[0039] [Fig. 4] is a perspective view of figure 3;

[0040] [Fig. 5] is a partial perspective view of a rotor-stator assembly including a labyrinth seal assembly, and [Fig. 6] is another partial perspective view of a rotor-stator assembly including a labyrinth seal assembly.

[0041] Detailed description of an embodiment of the invention

[0042] Throughout the description, it is noted that the upstream and downstream terms are to be considered in relation to a pressure delta in the turbomachine, which in the illustrated embodiment corresponds to a main direction 5, shown in Figure 1, of normal gas flow (from upstream to downstream) for an aircraft turbomachine.

[0043] With reference first to Figure 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.

[0044] 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 fan 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 fan 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).

[0045] 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 flows into a secondary channel 14b, radially delimited outwards by an engine casing, surrounded by a nacelle 9.

[0046] Compressors and turbines are notably composed of a succession of rotor and stator stages. As previously discussed, 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 specifically an assembly forming a labyrinth seal.

[0047] We now present, in relation to figures 2 to 6, a preferred embodiment of the invention.

[0048] As illustrated in these figures, the assembly 1 forming a labyrinth seal comprises a rotating part 2 and a fixed part 3. The rotating part 2 is mounted to rotate freely about 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 face 30 and radially external face 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 airflow 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 whole.

[0053] To achieve this, the assembly 1 forming a labyrinth seal further comprises a plurality of second channels distributed between: rotating second 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 airflow channel A; fixed second 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 airflow channel A.

[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 airflow circulation channel A at the outlet 311 formed 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 relative to the rotation axis 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] For their part, 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 junction walls 220, 320 have a height h whose function is to ensure mechanical stability 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 specifically, 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 pattern with the second fixed channels 31.

[0068] This staggered arrangement prevents interference between the second rotating channels 21 and the second fixed channels 31 because the inlets of the second rotating channels are longitudinally offset from the inlets of the second fixed channels, and the outlets of the second rotating channels are longitudinally offset from the outlets of the second fixed channels. Furthermore, in this embodiment, each of the second rotating channels 21 and second fixed channels 31 has a width L2 across its entire length that is greater than or equal to the width L1 of the first airflow channel A.

[0069] Here, the second rotating and fixed channels have a similar width. However, depending on certain variations, the second channels could have different dimensions.

[0070] 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.

[0071] In this embodiment, the first portions 212 are substantially parallel to the second portions 213.

[0072] According to an alternative, the first portions could be non-parallel to the second portions.

[0073] 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.

[0074] 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.

[0075] 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 [Claim 1] 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 between: 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) for the 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 air flow, 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).; [Claim 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°. [Claim 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). [Claim 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). [Claim 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). [Claim 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. [Claim 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. [Claim 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. [Claim 9] Turbomachine comprising an assembly according to one of the preceding claims. [Claim 10] Aircraft comprising a turbomachine according to claim 9.

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