Cooling air injection housing for a turbine rotor disc, including diverter ducts

Abstract

The invention relates to a cooling air injection housing (1) for a turbine rotor disc extending around a longitudinal axis and comprising a radially external wall (4), a radially internal wall (5) and several channels (6a, 6b) distributed around the longitudinal axis, each channel forming an air injector extending axially from an inlet opening (7) opening through the radially external wall to an outlet opening (8) positioned at a downstream end (42) of the radially internal wall, each channel being configured to guide a first airflow from an annular bypass space of a combustion chamber to a ventilation cavity formed between the disc and a sealing flange,the housing comprising at least one diverting conduit (11) positioned circumferentially between two channels and extending radially to divert a portion of a second airflow from a high-pressure compressor towards a purge cavity. Fig. 3.

Description

Title of the invention: Cooling air injection housing for a turbine rotor disc comprising diverter ducts. Technical field

[0001] The present invention relates to the field of ventilation of a high-pressure turbomachine turbine and more particularly to a cooling air injection housing for a rotor disc of such a turbine. Previous technique

[0002] A turbomachine includes a high-pressure turbine which is positioned at the outlet of a combustion chamber to recover energy from the combustion gas flow and thus drive in rotation, a high-pressure compressor, arranged upstream of the combustion chamber and supplying the latter with pressurized air.

[0003] In the following description and claims, the terms "upstream" and "downstream" are to be taken into consideration with respect to the direction of air flow inside the high-pressure turbine, as well as inside the cooling air injection housing.

[0004] Typically, a high-pressure turbine comprises a rotor disc, disposed at the outlet of a combustion chamber and on which turbine blades are mounted, driven in rotation by a flow of gas ejected from this combustion chamber.

[0005] Due to the high temperatures reached by the combustion gases, the rotor disc and the turbine blades it supports are subjected to significant thermal stresses that can induce expansion. To limit the negative impact of these thermal stresses on the lifespan of the turbine blades, the latter are equipped with internal cooling circuits that include ducts through which ventilation air is drawn from the bottom of the combustion chamber.

[0006] This ventilation air is generally supplied to an annular cavity by ventilation air injectors distributed circumferentially around the longitudinal axis of the turbomachine. The injectors are distributed circumferentially around a cooling air injection housing, extend radially under the combustion chamber, and are fluidly connected to an annular cavity that allows ventilation air from the bottom of the compressor to be conveyed to the turbine.

[0007] The ventilation air, exiting the injectors, enters the annular cavity located upstream of the rotor disc, passing through orifices formed in a sealing flange arranged upstream of the rotor disc. The cavity communicates with internal cooling circuits arranged inside the turbine blades.

[0008] Documents FR2943092 and WO2023047055 describe examples of high-pressure turbine and blades.

[0009] Part of the air from the injector also circulates to an upstream purge by first passing through a downstream sealing joint ensuring the seal between the blade and the flange at the location of a radially external part of the turbine.

[0010] Simultaneously, an airflow taken downstream of the last stage of the high-pressure compressor circulates through a first upstream seal and then through a second upstream seal, positioned downstream of the first upstream seal, ensuring the seal between the blade and the flange at the location of a radially internal part of the turbine.

[0011] Conventionally, the first and second upstream seals are labyrinth seals comprising flaps fixed to the rotor and a ring made of abradable material connected to the housing and having a honeycomb structure. This airflow, drawn downstream of the last stage of the high-pressure compressor, mixes with the airflow from the injectors and then vents the upstream purge and the blades. The airflows are injected tangentially to the longitudinal axis.

[0012] However, the airflow from the first and second upstream seals has a higher temperature. This results in a decrease in the effectiveness of this airflow in cooling the blades. Description of the invention

[0013] The invention therefore aims to resolve at least in part these drawbacks by proposing a cooling air injection housing for a rotor disc of a turbine allowing the blades to be cooled more efficiently.

[0014] The invention relates to a cooling air injection housing for a bladed rotor disc of a turbine, in particular a high-pressure turbine, of a turbomachine.

[0015] The housing extends around a longitudinal axis and comprises a radially external wall, a radially internal wall and several channels distributed around the longitudinal axis, each channel forming an air injector extending axially and partly along the radially internal wall from an inlet opening through the radially external wall to an outlet opening positioned at a downstream end of the radially internal wall, each channel being configured to guide a first airflow from an annular bypass space of a turbine combustion chamber to a ventilation cavity formed between the rotor disc and a sealing flange positioned upstream of the rotor disc.

[0016] The housing includes at least one diverter conduit which is positioned circumferentially between two channels and which extends in a generally radial direction, from a radially internal inlet to a radially external outlet, the diversion duct being configured to divert a portion of a second airflow from a high-pressure compressor of the turbine and guide said portion of the second airflow to a turbine purge cavity delimited on one side by the radially internal wall and on the other side by the radially external wall.

[0017] The invention thus provides a cooling air injection housing for a rotor disc of a turbine allowing the blades to be cooled more efficiently.

[0018] The diversion duct allows the portion of air from the second airflow to bypass the outlet of the channel and arrive in the purging cavity of the turbine.

[0019] The temperature of the air intended to cool the blades is reduced by approximately 15°C compared to prior art solutions as described in document WO2023047055A1.

[0020] Furthermore, this housing configuration eliminates the first upstream seal, and more specifically a disc, flanges, an abradable cartridge, and an abradable support, thus resulting in a weight reduction. Removing the disc also reduces the tensile forces applied to the rotor shaft.

[0021] This solution also makes it possible to minimize the air flow taken from the high-pressure compressor in order to improve the overall performance of the turbomachine.

[0022] This solution is also simple to implement.

[0023] In some embodiments, the circumferentially adjacent channels are separated by inter-channel connecting sections, each inter-channel connecting section being traversed by a single diversion conduit having an oblong cross-section, the diversion conduit extending circumferentially between a first channel and a second channel.

[0024] In some embodiments, circumferentially adjacent channels are separated by inter-channel connecting sections, each inter-channel connecting section comprising at least one, preferably three, diversion conduit(s), each diversion conduit having a circular cross-section.

[0025] In some embodiments, the diversion conduits are arranged circumferentially in a regular manner around the longitudinal axis.

[0026] In certain embodiments, the housing includes a downstream end ring which extends radially in projection from the radially internal wall, the downstream end ring being delimited axially, on the one hand, by a downstream end wall of the ring and, on the other hand, by an upstream end wall of the ring opposite the downstream end wall of the ring, the outlet openings of the channels opening through the downstream end ring.

[0027] In certain embodiments, each diversion conduit extends through the downstream end ring from the radially internal inlet which opens through a radially internal face of the downstream portion of the radially internal wall to the radially external outlet which opens through a radially external face of the downstream end ring.

[0028] In certain embodiments, the radially internal wall comprises a first annular abradable element intended to cooperate with at least one first slat connected to a radially internal part of the sealing flange to form a first sealing device, and a second annular abradable element intended to cooperate with at least one second slat connected to the first slat to form a second sealing device, the first and second abradable elements extending radially in projection from the radially internal wall and being intended to ensure sealing between the radially internal wall of the housing and the radially internal part of the sealing flange, the radially internal inlet of the diverter conduit opening between the first and second abradable elements.

[0029] In certain embodiments, the downstream end ring comprises a third annular abradable element intended to cooperate with a third slat connected to a radially external part of the sealing flange to form a third sealing device ensuring sealing between the radially internal wall of the housing and the radially external part of the sealing flange, the third abradable element extending radially outwards from the downstream end ring.

[0030] In certain embodiments, the radially internal wall comprises an upstream portion along which a primary section of the channel extends from the inlet opening and a downstream portion along which a secondary section of the channel extends to the outlet opening, the upstream portion being connected to the downstream portion by a curved portion in which the diversion conduits are formed.

[0031] In some embodiments, the bypass conduits are positioned axially upstream of the curved portion.

[0032] In some embodiments, the outlet openings of the channels have a tangential orientation.

[0033] The invention also relates to a turbine for a turbomachine comprising a casing as defined above.

[0034] The aforementioned features and advantages, as well as others, will become apparent from the following detailed description and examples of housing embodiments. This detailed description refers to the attached drawings. Brief description of the drawings

[0035] The attached drawings are schematic and are intended primarily to illustrate the principles of the exposition.

[0036] On these drawings, from one figure to another, identical elements (or parts of elements) are identified by the same reference signs.

[0037] [Fig-1] Fig. 1 schematically represents an axial cross-sectional view of a turbomachine according to the invention;

[0038] [Fig.2] Fig.2 schematically represents an axial cross-sectional view of a part of a high-pressure turbine of the turbomachine comprising a cooling air injection housing, according to an embodiment of the invention;

[0039] [Fig.3] The [Fig.3] schematically represents a perspective view of an angular portion of the housing;

[0040] [Fig.4] Fig.4 schematically represents a view of the inside of the housing of the [Fig.3];

[0041] [Fig.5] The [Fig.5] schematically represents a radially internal face of the radially internal wall of the housing of the [Fig.4];

[0042] [Fig.6] Fig.6 schematically represents a perspective view of an angular portion of a cooling air injection housing, according to another embodiment of the invention;

[0043] [Fig.7] The [Fig.7] schematically represents a radially internal face of a radially internal wall of the housing of the [Fig.6]. Description of the implementation methods

[0044] To make the explanation more concrete, an example of a housing 1 is described in detail below, with reference to the accompanying drawings. It should be noted that the invention is not limited to this example.

[0045] The invention applies to turbines 3, particularly high-pressure turbines, of a twin-spool turbomachine, such as the high-pressure turbine of an aircraft turbojet 40 shown in [Fig. 1]. The turbojet 40 extends around a longitudinal axis X, corresponding to the axis of revolution of the turbojet 40 and the axis of rotation of the rotor.

[0046] The turbojet 40 comprises, from left to right, i.e. from upstream to downstream with reference to the gas flow which flows during operation in the turbomachine: a fan 37, a high-pressure compressor 38, a combustion chamber 36, the high-pressure turbine 3 and a low-pressure turbine 3'. The high-pressure turbine 3 is equipped with blades 39.

[0047] In a known manner, the high-pressure turbine 3 is positioned at the outlet of the combustion chamber 36 to recover energy from a combustion gas stream originating from this chamber and drive in rotation the high-pressure compressor 38 located upstream of the chamber and supplying the latter with pressurized air.

[0048] The turbine 3 comprises a rotor disc 2 centered on the longitudinal axis X and which is disposed at the outlet of the combustion chamber 36. The turbine blades 39 are mounted on the rotor disc 2 and driven in rotation by the flow of gas ejected by this combustion chamber 36.

[0049] The turbine 3 also includes a sealing flange 10 which is centered on the longitudinal axis X and disposed upstream of the rotor disc 2. This sealing flange 10 is rotationally movable and rotates with the rotor disc 2.

[0050] Furthermore, the sealing flange 10, together with the rotor disc 2, defines an annular ventilation cavity 9 designed to receive ventilation air and direct it to internal cooling circuits for the blades 39. For this purpose, channels 6a, 6b, forming ventilation air injectors, are regularly distributed around the longitudinal axis X, along the circumferential direction. The channels 6a, 6b are connected upstream to an annular bypass space 12 around the combustion chamber 36, also called the combustion chamber bottom, to convey ventilation air from the high-pressure compressor 38 to the ventilation cavity 9. The annular space 12 extends around the combustion chamber 36.

[0051] As shown in Figures 2 to 5, the turbine 3 comprises an annular cooling air injection housing 1 extending around the longitudinal axis X and including a radially external wall 4 and a radially internal wall 5 serving as a stiffener. The housing 1 is fixed to the stator of the turbine 3. The sealing flange 10 is rotatably mounted relative to the stator. The housing 1 is positioned between the annular space 12 and the sealing flange 10.

[0052] The radially external wall 4 has the function of separating the annular bypass space 12 located below the combustion chamber 36 from cavities, such as the ventilation cavity 9, intended to cool the blades 39.

[0053] The radially internal wall 5 extends downstream from the radially external wall 4. The radially internal wall 5 is connected to the radially external wall 4 at an upstream end 60 of the housing 1. More specifically, the radially internal wall 5 comprises an upstream portion 25, which extends along the longitudinal axis X from a radially internal face 52 of the radially external wall 4 to a curved portion 29, inclined relative to the upstream portion 25. The curved portion 29 extends downstream from the upstream portion 25. The radially internal wall 5 comprises a downstream portion 26, which extends downstream from the curved portion 29 along the longitudinal axis X.

[0054] Each channel 6a, 6b extends axially, that is, globally along the direction of the longitudinal axis X, from an inlet opening 7 opening through the radially external wall 4 to an outlet opening 8 positioned at one end downstream 42 of the casing 1, opposite the upstream end 60. Each channel 6a, 6b extends partly along a radially external face 23 of the radially internal wall 5, opposite a radially internal face 15 of the radially internal wall 5.

[0055] The housing 1 comprises a downstream end ring 30 positioned at the downstream end 42 of the housing 1 and extending radially outward from the radially inner wall 5. The downstream end ring 30 is delimited axially by a downstream end wall of the ring 46 and an upstream end wall of the ring 59, opposite the downstream end wall of the ring 46, and radially by the downstream portion 26 of the radially inner wall 5 and a radially outer wall of the ring 33, opposite the downstream portion 26. The outlet openings 8 of the channels 6a, 6b open through the downstream end wall of the ring 46. The downstream end wall of the ring 46 and the upstream end wall of the ring 59 extend radially, that is, orthogonally with respect to the longitudinal axis X.

[0056] The housing 1 includes a flange 32 extending radially from an upstream end 60 of the radially internal wall 5 and towards the longitudinal axis X.

[0057] The downstream end ring 30 is positioned opposite the flange 32.

[0058] The radially external wall of the annular crown 33 is positioned radially above a downstream portion of the channels 6a, 6b and extends axially over a length equivalent to approximately 1 / 3 of the length of the channels 6a, 6b, for example. The radially external wall of the crown 33 extends axially from the downstream end wall of the crown 46 to the upstream end wall of the crown 59.

[0059] Each channel 6a, 6b is traversed by a first ventilation airflow DI from the annular bypass space 12 of the combustion chamber 36 to supply air to the ventilation cavity 9.

[0060] More specifically, the ventilation air exiting the channels 6a, 6b enters the ventilation cavity 9 by passing through orifices 41 formed in the sealing flange 10. The ventilation cavity 9 communicates with the internal cooling circuits arranged inside the blades 39.

[0061] As shown in [Fig.4], each channel 6a, 6b comprises a primary section 27 extending along the upstream portion 25 of the radially internal wall 5 along the longitudinal axis X from the inlet opening 7 to a bend 61 positioned in the curved portion 29 of the radially internal wall 5 and a secondary section 28 extending along the downstream portion 26 of the bend 61 to the outlet opening 8.

[0062] Channels 6a, 6b are inclined as described in application WO2023047055.

[0063] The channels 6a, 6b comprise a bottom 34 delimited by the radially internal wall 5.

[0064] The inlet opening 7 has an oblong section, preferably generally rectangular, and a central axis parallel to the longitudinal axis X. The outlet opening 8 also has an oblong section, preferably generally rectangular.

[0065] The secondary section 28 exhibits a gradual change in its orientation along a tangential direction Y between the elbow section 61 and the outlet opening section 8. "Gradual change in orientation" means a change in the orientation of a vector normal to the center of a section of the channel 6a, 6b and originating at the center of said section. The tangential direction Y is perpendicular to the longitudinal axis X and to the radial direction Z.

[0066] Preferably, the outlet section of the outlet opening 8 of each channel 6a, 6b extends tangentially in a plane perpendicular to the longitudinal axis X. In addition, the elbow 61 is advantageously oriented so that the airflow exiting the outlet opening 8 flows tangentially in the same direction as the direction of rotation of the rotor disc 2 facing it.

[0067] Each channel 6a, 6b includes a neck 31 forming a reduction in cross-section. The neck 31 corresponds to the point in the channel 6a, 6b that has the smallest cross-section. The neck 31 extends from the elbow 61 to the outlet opening 8.

[0068] The throat 31 forms a calibrating section in the sense that it is this section that calibrates the flow rate through the channels 6a, 6b. The throat 31 also has an orientation along a tangential component with respect to the longitudinal axis X. This allows the air passing through the channels 6a, 6b to obtain a tangential velocity close to the rotational speed of the rotor. The more inclined the throat 31, the higher the tangential velocity. The cross-sectional ratio between the inlet opening 7 and the throat 31 is at least 2.

[0069] The downstream end crown 30 is axially traversed by the channels 6a, 6b and includes the neck 31.

[0070] The radially internal face 15 of the radially internal wall 5 supports a first annular abradable element 16 intended to cooperate with at least one first lip 19 connected to a radially internal portion 22 of the sealing flange 10 to form a first sealing device. More specifically, the first abradable element 16 is carried by the upstream portion 25 of the radially internal wall 5.

[0071] The radially internal face 15 also supports a second annular abradable element 17 intended to cooperate with at least one second lip 20 connected to the first lip 19 to form a second sealing device. More specifically, the second abradable element 17 is carried by the downstream portion 26 of the radially internal wall 5 and therefore by the downstream end ring 30. The second abradable element 17 is positioned radially below the neck 31.

[0072] The first and second sealing devices are contiguous and ensure sealing between the radially internal wall 5 of the housing 1 and the radially internal part 22 of the sealing flange 10.

[0073] The radially external wall of the crown 33 of the downstream end crown 30 has a radially external surface 63 supporting a third abradable annular element 18 intended to cooperate with a third slat 21 connected to a radially external part 24 of the sealing flange 10 to form a third sealing device ensuring the seal between the radially internal wall 5 of the housing 1 and the radially external part 24 of the sealing flange 10.

[0074] The collar 31 is positioned radially between the second and third abradable elements 17, 18.

[0075] The third abradable element 18 is positioned radially above the neck 31, at the downstream end 42 of the downstream end ring 30 and runs along the downstream end wall of the ring 46 of the downstream end ring 30.

[0076] The first, second and third sealing devices are labyrinth seals.

[0077] The first, second, and third abradable elements 16, 17, 18 have an annular shape, extend radially outward from the radially internal wall 5, and are formed of an abradable material, in particular a honeycomb structure, in contact with the slats 19, 20, 21. The first, second, and third abradable elements 16, 17, 18 may each comprise one or more tiers. The slats 19, 20, 21 may be straight or inclined and / or tiered.

[0078] In the example of Figures 2 to 5, the first sealing device comprises a first abradable element 16 having two first abradable surfaces 43 in a stepped arrangement, i.e., offset from each other along the radial direction Z, each cooperating with a first blade 19 inclined with respect to the first abradable surfaces 43. The second sealing device comprises a second abradable element 17 having two second abradable surfaces 44 in a stepped arrangement, each cooperating with a second blade 20 inclined with respect to the second abradable surfaces 44. The first and second blades 19, 20 are supported by a first arm 45 connected to the radially internal part 22 of the sealing flange 10.

[0079] The third sealing device comprises a single third abradable surface 47 in contact with the third slit 21. The third slit 21 is straight, i.e. orthogonal to the third abradable surface 47.

[0080] The third lick 21 is supported by a second arm 48 connected to the radially external part 24 of the sealing flange 10.

[0081] The turbine 3 includes a fourth sealing device comprising three inclined fourth blades 49 supported by the second arm 48 and cooperating with a fourth abradable element 51 supported by a radially internal face 52 of the radially external wall 4. The fourth abradable element 51 is stepped and comprises three fourth abradable surfaces 50 offset from each other along the radial direction Z. Each fourth abradable surface 50 is in contact with one of the fourth blades 49 which is inclined with respect to the fourth abradable surface 50.

[0082] The fourth sealing device ensures the seal between the radially external part 24 of the sealing flange 10 and the radially external wall 4 of the housing 1.

[0083] In another embodiment, all the sealing devices can be brush seals.

[0084] The housing 1 includes at least one diverting conduit 11 positioned circumferentially between two channels 6a, 6b and extending radially with respect to the two channels 6a, 6b, in a general radial direction Z, from a radially internal inlet 55 to a radially external outlet 56.

[0085] The diverter duct 11 is configured to guide a portion of a second airflow D2 from the high-pressure compressor 38 of the turbine 3 to a purge cavity of the turbine 3. The diverter duct 11 forms an air passage through which a diverted ventilation airflow D2' from the second airflow D2 flows. The diverted ventilation airflow D2' flows in the radial direction Z.

[0086] Each diversion conduit 11 extends radially through the downstream end ring 30 from the radially internal inlet 55 opening through a radially internal face 62 of the downstream portion 26 of the radially internal wall 5 to the radially external outlet 56 opening through a radially external face 64 of the downstream portion 26 of the radially internal wall 5. The radially internal face 62 and external face 64 are radially opposite.

[0087] Inter-channel connecting sections 13 are formed between circumferentially adjacent channels 6a, 6b, each inter-channel connecting section 13 comprising at least one diversion conduit 11.

[0088] In the example shown in Figures 2 to 5, each inter-channel connecting section 13 comprises a single diverting conduit 11 extending circumferentially from a first channel 6a to a second channel 6b. More specifically, each diverting conduit 11 extends circumferentially from a first circumferential end wall 53a of the first channel 6a to a second circumferential end wall 53b of the second channel 6b. The circumferential end walls 53a separate each diverting conduit 11 from a channel 6a, 6b.

[0089] The circumferential length of the diversion conduits 11 is as large as possible while maintaining a sufficient circumferential end wall thickness 53a, 53b. The thickness of the circumferential end walls 53a, 53b separating each diversion conduit 11 from a channel 6a, 6b is at least 0.5 mm.

[0090] Preferably, there are as many diversion ducts 11 as there are channels 6a, 6b. The number of channels 6a, 6b must be sufficient to deliver the necessary airflow to the blades for cooling and to avoid generating large pressure heterogeneities downstream of the downstream end ring 30.

[0091] The diversion ducts 11 are positioned on a ventilation ring 14 extending circumferentially around the longitudinal axis X. The diversion ducts 11 pass radially through the ventilation ring 14 and the channels 6a, 6b pass axially through the ventilation ring 14. The downstream end ring 30 comprises the ventilation ring 14.

[0092] The ventilation ring 14 and therefore the diversion ducts 11 are positioned in the curved portion 29 connecting the upstream portion 25 to the downstream portion 26 of the radially internal wall 5.

[0093] The radial projection of the ventilation ring 14 towards the longitudinal axis is positioned between the first and second abradable elements 16, 17.

[0094] As shown in [Fig.5], the diversion conduits 11, and more specifically the radially external inlets 55, open between the first and second abradable elements 16, 17. The first and second abradable elements 16, 17 are axially spaced and the diversion conduit 11 opens radially between the two abradable elements 16, 17.

[0095] In other words, the diversion conduits 11 extend around a central axis A which is positioned between the first and second abradable elements 16, 17. Each diversion conduit 11 extends from the radially internal inlet 55 which is in fluidic communication with the last stage of the high-pressure compressor 38 of the turbine 3 to the radially external outlet 56 which is in fluidic communication with the purge cavity of the turbine 3.

[0096] The first and second abradable elements 17 are separated by an annular groove 57, as shown in [Fig. 5]. The radially external inlets 55 open into the annular groove 57.

[0097] The axial width of the diversion channels 11 corresponds substantially to the spacing between the first and second abradable elements 16, 17. The spacing between the first and second abradable elements 16, 17 is on the order of 5 mm, for example.

[0098] The channels 6a, 6b extend through the ventilation ring 14 forming channel portions 58, each positioned between two diversion ducts 11. The ventilation ring 14 has a set of diversion ducts 11 and channel portions 58. The channel portions 58 are delimited radially by a part of the downstream portion 26 of the radially internal wall 5 and a part of the radially external wall of the ring 33 and circumferentially by the first and second circumferential end walls 53a, 53b.

[0099] The ventilation ring 14 is formed by an alternation of diversion ducts 11 and portions of channel 58.

[0100] Each diversion conduit 11 is circumferentially delimited by the first and second circumferential end walls 53a, 53b and axially by the upstream end wall of the ring 59 of the downstream end ring 30 and by a downstream wall 54, opposite the upstream end wall of the ring 59. The first and second circumferential end walls 53a, 53b are curved.

[0101] According to another example shown in Figures 6 and 7, the housing la includes diverter conduits lia which have a circular cross-section. The housing la includes at least one diverter conduit 1 la of circular cross-section between two channels 6a, 6b.

[0102] Preferably, each inter-channel link segment 13 includes at least one diversion conduit 1 of circular cross-section.

[0103] In the example of Figures 6 and 7, each inter-channel connecting section 13 comprises three circular-section diverter conduits lia. Each set of three diverter conduits 1la is positioned between two channels 6a, 6b.

[0104] As in the previous example, each diversion conduit lia extends through the downstream end ring 30 from the radially internal inlet 55 opening through the downstream portion 26 of the radially internal wall 5 to the radially external outlet 56 opening through the radially external wall of the ring 33.

[0105] The diversion conduits 1 extend circumferentially and are equidistant from each other in the same interchannel connecting section 13.

[0106] The diameter of the diversion conduits 1 is as large as possible and corresponds approximately to the spacing between the first and second abradable elements 16, 17. The spacing between the first and second abradable elements 16, 17 is on the order of 5 mm, for example.

[0107] The diversion ducts 1 la are positioned on a ventilation ring 14 extending circumferentially around the longitudinal axis X. The diversion ducts lia cross radially the ventilation ring 14 and the channels 6a, 6b cross axially the ventilation ring 14.

[0108] The ventilation ring 14 and therefore the circular diversion ducts 1 are positioned in the curved portion 29 connecting the upstream portion 25 to the downstream portion 26 of the internal radial wall 5.

[0109] The ventilation ring 14 is positioned between the upstream portion 25 of the radially internal wall 5 and the downstream end ring 30. The radial projection of the ventilation ring 14 towards the longitudinal axis is positioned between the first and second abradable elements 16, 17.

[0110] As shown in [Fig.7], the diversion conduits 1la, and more specifically the radially external inlets 55, open radially between the first and second abradable elements 16, 17. In other words, the diversion conduits 1la of circular cross-section extend around a central axis A positioned radially between the first and second abradable elements 16, 17. Each diversion conduit 1la extends from the radially internal inlet 55, which is in fluidic communication with the last stage of the high-pressure compressor 38 of the turbine 3, to the radially external outlet 56, which is in fluidic communication with the purge cavity of the turbine 3.

[0111] The channels 6a, 6b extend through the ventilation ring 14 forming channel portions 58 positioned between two sets formed of three diversion ducts lia.

[0112] The following describes the circulation of airflows in the ventilation circuits of turbine 3, regardless of the example presented previously.

[0113] As shown in [Fig.2], each channel 6a, 6b is traversed by the first ventilation airflow DI from the annular bypass space 12 of the combustion chamber 36.

[0114] The second airflow D2 from the last stage of the high-pressure compressor 38 of the turbine 3 passes through the first sealing device formed by the first abradable element 16 and the first two blades 19.

[0115] The second airflow D2 then splits into two airflows, between the first and second sealing devices, including a diverted airflow D2' through the diverting ducts 11 and a third airflow D3 through the second sealing device formed by the second abradable element 17 and the two second flaps 20. The diverted airflow D2' represents between 95% and 80% of the second airflow D2, and preferably 90%.

[0116] The third airflow D3 then mixes with the first airflow DI to form an airflow that divides into a fourth airflow D4 and a fifth airflow D5. The fifth airflow D5 represents between 5% and 15% of the airflow generated by the mixing of the third airflow D3 and the first airflow DI.

[0117] The fourth airflow D4 passes through the orifices 41 formed in the sealing flange 10 to enter the ventilation cavity 9. The ventilation cavity 9 communicates with the internal cooling circuits arranged inside the blades 39. The fourth airflow D4 therefore supplies air to the internal cooling circuits of the blades 39.

[0118] The fifth airflow D5 then passes through the third sealing device formed by the third abradable element 18 and the third lick 21 to mix with the diverted airflow D2', generating a sixth airflow D6 supplying the turbine purge cavity 3 to cool it.

[0119] The fourth airflow D4 according to the invention has a higher tangential velocity and a lower temperature than an airflow generated only by mixing the second airflow D2 and the first airflow DI according to the prior art, leading to a lower temperature of the air cooling the blades 39. The cooling efficiency of the turbine 3 ventilation circuit is therefore improved.

[0120] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than a restrictive sense.

Claims

Demands

1. Cooling air injection housing (1, la) for a bladed rotor disc (2) of a turbine (3), in particular a high-pressure turbine of a turbomachine, the housing (1, la) extending about a longitudinal axis (X) and comprising a radially external wall (4), a radially internal wall (5) and several channels (6a, 6b) distributed about the longitudinal axis (X), each channel (6a, 6b) forming an air injector extending axially and partly along the radially internal wall (5) from an inlet opening (7) opening through the radially external wall (4) to an outlet opening (8) positioned at a downstream end (42) of the radially internal wall (5), each channel (6a,6b) being configured to guide a first airflow (D1) from an annular bypass space (12) of a combustion chamber (36) of the turbine (3) to a ventilation cavity (9) formed between the rotor disc (2) and a sealing flange (10) positioned upstream of the rotor disc (2), the housing (1, 1a) comprising at least one divert duct (11) which is positioned circumferentially between two channels (6a, 6b) and which extends in a generally radial direction from a radially internal inlet (55) to a radially external outlet (56), the divert duct (11) being configured to divert a portion of a second airflow (D2) from a high-pressure compressor (38) of the turbine (3) and to guide said portion of the second airflow (D2) to a purge cavity of the turbine (3) delimited, on the one hand, by the wall radially internal (5) and, on the other hand, by the radially external wall (4).

2. Carter (1, la) according to claim 1, wherein the circumferentially adjacent channels (6a, 6b) are separated by inter-channel connecting sections (13), each inter-channel connecting section (13) being traversed by a single diverter conduit (11) having an oblong cross-section, the diverter conduit (11) extending circumferentially between a first channel (6a) and a second channel (6b).

3. Carter (1, la) according to claim 1, wherein the circumferentially adjacent channels (6a, 6b) are separated by inter-channel connecting sections (13), each inter-channel connecting section (13) comprising at least one, preferably three, diversion conduit(s) (11), each diversion conduit (11) having a circular cross-section.

4. Carter (1, la) according to any one of claims 1 to 3, wherein the diversion conduits (11) are arranged circumferentially in a regular manner around the longitudinal axis (X).

5. Carter (1, la) according to any one of claims 1 to 4, comprising a downstream end ring (30) which extends radially in projection from the radially internal wall (5), the downstream end ring (30) being axially delimited, on the one hand, by a downstream end wall of the ring (46) and, on the other hand, by an upstream end wall of the ring (59) opposite the downstream end wall of the ring (46), the outlet openings (8) of the channels (6a, 6b) opening through the downstream end ring (30).

6. Carter (1, la) according to claim 5, wherein each diversion conduit (11) extends through the downstream end ring (30) from the radially internal inlet (55) which opens through a radially internal face (62) of the downstream portion (26) of the radially internal wall (5) to the radially external outlet (56) which opens through a radially external face (64) of the downstream end ring (30).

7. Housing (1, 1a) according to any one of claims 1 to 6, wherein the radially internal wall (5) comprises a first annular abradable element (16) intended to cooperate with at least one first lip (19) connected to a radially internal portion (22) of the sealing flange (10) to form a first sealing device, and a second annular abradable element (17) intended to cooperate with at least one second lip (20) connected to the first lip (19) to form a second sealing device, the first and second abradable elements (16, 17) extending radially in projection from the radially internal wall (5) and being intended to provide sealing between the radially internal wall (5) of the housing (1, 1a) and the radially internal portion (22) of the sealing flange (10), the radially internal inlet (55) of the conduit diversion (11) opening between the first and second abradable elements (16, 17).

8. Housing (1, la) according to any one of claims 5 or 6, or claim 7 taken in relation to claim 5 or 6, wherein the downstream end ring (30) comprises a third annular abradable element (18) intended to cooperate with a third slat (21) connected to a radially external part (24) of the sealing flange (10) to form a third sealing device ensuring sealing between the radially internal wall (5) of the housing (1, la) and the radially external part (24) of the sealing flange (10), the third abradable element (18) extending radially outwards from the downstream end ring (30).

9. Carter (1, la) according to any one of claims 1 to 8, wherein the radially internal wall (5) comprises an upstream portion (25) along which extends a primary section (27) of the channel (6a, 6b) from the inlet opening (7) and a downstream portion (26) along which extends a secondary section (28) of the channel (6a, 6b) to the outlet opening (8), the upstream portion (25) being connected to the downstream portion (26) by a curved portion (29).

10. Carter (1, la) according to claim 9, wherein the bypass conduits (11) are positioned axially upstream of the curved portion (29).

11. Turbine (3) for a turbomachine comprising a casing (1, la) as defined according to any one of claims 1 to 10.

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