Device for cooling a turbomachine annular casing of longitudinal axis, turbomachine assembly, turbine and turbomachine

Abstract

A device (40) for cooling a turbomachine annular casing (46) of longitudinal axis X comprises a manifold housing (42) and a cooling line set (52) extending circumferentially about the longitudinal axis. The line set is connected to the manifold housing such that an internal volume of the manifold housing is in fluidic communication with an internal volume of the line set. The line set comprises ejection orifices (57) which open radially inwards towards the casing (46). The manifold housing comprises a radially inner face (42b) which has an opening (50) intended to be arranged radially facing the casing (46). The opening allows fluidic communication between the internal volume of the manifold housing and the internal volume of the line set. The cooling device further comprises a connection (58) having a generally V-shaped radial section, the vertex of the V being oriented radially outwards.

Description

Description Title: DEVICE FOR COOLING A TURBOMACHINE CASING Technical field

[0001] This document relates to a device for cooling a casing of an aircraft turbomachine, such as for example a dual-flow turbomachine. Prior art

[0002] Figure 1 shows a double-flow, double-spool turbomachine 1. The axis of the turbomachine is referenced X and corresponds to the axis of rotation of the rotating parts. In the following, the terms axial and radial are defined relative to the X axis.

[0003] The turbomachine 1 comprises, from upstream to downstream in the direction of gas flow, a fan 2, a low-pressure compressor 3, a high-pressure compressor 4, a combustion chamber 5, a high-pressure turbine 6 and a low-pressure turbine 7.

[0004] The air from the blower 2 is divided into a primary flow 8 flowing in a primary annular vein 9, and a secondary flow 10 flowing in a secondary annular vein 11 surrounding the primary annular vein 9.

[0005] The low pressure compressor 3, the high pressure compressor 4, the combustion chamber 5, the high pressure turbine 6 and the low pressure turbine 7 are arranged in the primary annular vein 9.

[0006] The rotor of the high-pressure turbine 6 and the rotor of the high-pressure compressor 4 are rotationally coupled via a first shaft 12 so as to form a high-pressure body.

[0007] The rotor of the low pressure turbine 7 and the rotor of the low pressure compressor 3 are coupled in rotation by means of a second shaft 13 so as to form a low pressure body, the fan 2 being able to be connected directly to the rotor of the low pressure compressor 3 or else by means of an epicyclic gear train for example.

[0008] As can be better seen in Figure 2, the low-pressure turbine 7 comprises in particular different axially successive stages comprising moving wheels 14 and distributors 19 formed by rings of fixed blades. The moving wheel comprises a disc 15 at which blades 16 are mounted. The ends of the blades 16 are surrounded by a fixed ring 17 made of abradable material, said fixed ring 17 being fixed to the casing 18 of the turbine. The distributors 19 are located downstream of the moving wheels 14. The distributors 19 and the fixed rings 17 are mounted on the casing by means of flanges or hooks 20 extending from the radially internal surface of the casing 18.

[0009] In order to ensure high efficiency of the turbomachine, it is necessary to limit the flow of air not passing through the moving wheels 14 of the different stages, that is to say to limit the leaks between the radially external ends of the blades 16 and the fixed ring 17 made of abradable material. For this, it is appropriate to check the clearance at this interface, this clearance being dependent on the temperature of the casing 18, and in particular of the areas of said casing 18 comprising the hooks or flanges 20 supporting the fixed ring 17.

[0010] The primary air flow from the combustion chamber 5 has a high temperature and heats the parts located downstream, such as the fixed and moving parts of the turbine 6, 7.

[0011] In order to control the aforementioned clearance and avoid any premature deterioration of the various fixed and moving parts of the turbine, it is necessary to provide effective cooling means that can be easily integrated into the environment of the turbomachine.

[0012] Patent application FR 3 050 228, in the name of the Applicant, relates to a part of a cooling device D of a low-pressure turbine casing C which is shown in Figure 3 and which comprises a collector housing B extending axially.

[0013] Pressurized cooling air from the secondary flow is fed from a portion of the turbomachine downstream of the fan to the manifold housing B via a longitudinally extending supply duct connected to a supply opening O of the manifold housing B.

[0014] The device further comprises tubes T extending circumferentially on either side of the collector box B, from lateral faces of the collector box B. A ramp R comprises two of said tubes T formed by curved pipes of circular section, each tube T extending circumferentially around the casing, for example at an angle of 360°.

[0015] Each tube T has an air inlet opening into the channel of the collector box B and a closed distal end. Each tube T also has a cylindrical wall provided with air ejection orifices facing the casing C, so that cooling air can enter the collector box B then into the tubes T before opening through the orifices opposite the casing C, so as to cool it. This is particularly referred to as impact cooling since the air impacts the casing C.

[0016] It was found that the areas of the casing located opposite the housing B have stronger cooling than the rest of the circumference of the casing C.

[0017] Indeed, the cooling air exiting the housing through its internal face impacts the crankcase but is not evacuated as well as the impact air exiting the tubes. Thus, the housing creates a partial obstruction which prevents the cooling air after impact from flowing radially outwards, i.e. out of the cooling device.

[0018] This local confinement causes cooling heterogeneity around the circumference of the casing and premature wear of the casing which reduces the service life of the various fixed and moving parts of the low pressure turbine due to difficulty in controlling clearances at the blade tips. Summary

[0019] To this end, the present document relates to a device for cooling an annular casing of longitudinal axis X of a turbomachine, comprising a collector housing and a cooling ramp extending circumferentially around the longitudinal axis, the ramp being connected to the housing in such a way that an internal volume of the housing communicates fluidically with an internal volume of the ramp which comprises ejection orifices which open radially inwards towards the casing, characterized in that the housing comprises a radially internal face which has an opening intended to be arranged radially opposite the casing, the opening allowing fluid communication between the internal volume of the housing and the internal volume of the ramp.

[0020] The terms axial, radial, annular and circumferential are defined relative to the longitudinal axis of the turbomachine.

[0021] In this document, the term "box" means the term "collector box".

[0022] In operation, the cooling device allows cooling air in the internal volume of the manifold housing to flow through the opening into the internal volume of the ramp.

[0023] This cooling air is then ejected from the internal volume of the ramp through the ejection ports which open radially inwards towards the casing.

[0024] The cooling air impacts the casing circumferentially in a uniform manner, which allows for better temperature control. This makes it possible to better control the thermal stresses experienced by the casing, leading to an increase in its lifespan. By positioning the opening of the housing on one of its radially internal faces, uneven air circulation around the casing is avoided.

[0025] The ramp can be arranged radially between the housing and the housing opening.

[0026] In other words, the entire ramp can be arranged radially inside a circle tangent to the radially internal surface of the housing. In such a configuration, the opening of the collector housing is located radially outside relative to the ramp with which it allows fluid communication.

[0027] The air gap between the housing opening and the casing may be greater than the air gap between the corresponding ramp and the casing.

[0028] By air gap between a first element and a second element is meant the radial distance relative to the longitudinal axis separating said two elements.

[0029] The air gap between the ramp and the casing is understood as the air gap between an ejection orifice of said ramp and a radially external surface of the casing.

[0030] The air gap between the opening of the collector box and the casing can be between 2mm and 10mm.

[0031] The air gap between the ramp and the casing can be between 2mm and 10mm.

[0032] Such a configuration of the cooling device allows cooling air to first exit from the ejection ports opening radially towards the casing and then, after impact on the casing, to be evacuated radially towards the outside, out of the cooling device.

[0033] More specifically, this configuration allows for the evacuation of cooling air that has impacted the casing and is located in a space radially between the housing and the casing.

[0034] The ramp may comprise two branches extending circumferentially in opposite directions on either side of the housing.

[0035] The branches can be cylindrical tubes.

[0036] The branches can extend circumferentially around the longitudinal axis, at an angle between 45° and 360°, and also between 90° and 180°.

[0037] The branches of a single ramp may extend so that the two branches taken together extend around the entire circumference of the casing.

[0038] In other words, the ramp may be an annular ramp extending around the longitudinal axis.

[0039] In this particular example, the ramp could extend over 360° and in this way, the cooling applied to the casing is homogeneous over the entire casing (i.e. over its total circumference): this avoids premature wear of the entire casing and improves its lifespan.

[0040] The device may include at least one three-line connection, a first line of which is connected to a first branch of the ramp, a second line of which is connected to a second branch of the ramp, and a third line of which is connected to the opening.

[0041] In this embodiment, a single opening of the housing is fluidically associated with a ramp, the fluidic connection between the housing and the ramp being then ensured by the connection to three pipes.

[0042] In addition, this helps to limit the size of the device: a single opening is necessary to ensure the fluid connection for two branches of a ramp.

[0043] Obviously, it would still be possible to have a first opening associated with a first branch of the corresponding ramp and a second opening distinct from the first opening, said second opening being associated with a second branch of the corresponding ramp. In this case, two openings provide the fluid connection for two branches of the same ramp.

[0044] The connection could be an add-on part so that the first ramp and the second ramp are assembled indifferently to the first pipe or the second pipe.

[0045] The connection may have a radial section in the general shape of a T.

[0046] The connection may have a radial section in the general shape of a V with the apex oriented radially outwards.

[0047] The connection allows the manifold box to supply cooling air to the boom branches with reduced pressure loss.

[0048] In fact, the pressure losses due to the geometry of the connection through which the cooling air flows are reduced: the generally V-shaped radial section ensures a gradual transition of the direction of flow of the cooling air, from a radial direction to a circumferential (tangential) direction.

[0049] The connection may have symmetry with respect to a plane comprising the longitudinal axis of the turbomachine X and the axis of the opening of the housing.

[0050] Such symmetry allows cooling air to be distributed evenly in each branch.

[0051] In fact, the flow of cooling air passing through an opening of the housing flows into the first conduit of the connection and is divided into a first and a second flow circulating in the first and the second branches respectively, so that the first and the second flows have identical flow rates.

[0052] Distributing the cooling air evenly in each branch improves the uniformity of crankcase cooling.

[0053] The cooling device may comprise a plurality of cooling ramps. The radially inner face may have a plurality of openings each intended to be arranged radially opposite the casing. The device may comprise a plurality of three-pipe connections, each ramp being associated with a corresponding opening and connection.

[0054] The plurality of openings may be arranged along the longitudinal axis X.

[0055] In this way, the casing is cooled on its outer surface opposite the ejection ports of the plurality of cooling ramps. Cooling is improved because the circumferential cooling of a single cooling ramp is repeated along the longitudinal axis by the plurality of cooling ramps.

[0056] This document also relates to a turbomachine assembly comprising an annular turbomachine casing and a cooling device of the aforementioned type, mounted on said casing and surrounding said casing.

[0057] This document also relates to a turbine, such as a low pressure turbine, comprising the turbomachine assembly of the aforementioned type.

[0058] In this way, in operation, the uniform cooling of the annular casing by the cooling device makes it possible to reduce the radial clearances between turbine blades and a radially internal surface of the casing and to improve the engine performance.

[0059] This document also relates to a turbomachine comprising at least one turbine of the aforementioned type.

[0060] The turbomachine can be an aircraft turbomachine.

[0061] Said aircraft may be an airplane or a rotary-wing aircraft.

[0062] The turbomachine can be an aircraft turbojet or turboprop. Brief description of the drawings

[0063] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analyzing the attached drawings, in which: - [Fig. 1] is an axial sectional view of a prior art dual-flow turbojet engine, - [Fig. 2] is an axial sectional view of a part of the prior art turbojet engine, illustrating in particular the low pressure turbine, - [Fig. 3] is a perspective view of a portion of the prior art cooling device, - [Fig. 4A] is a perspective view of a portion of the cooling device according to an embodiment of the present document, - [Fig. 4B] is an axial sectional view of the embodiment of Figure 4A, - [Fig. 4C] is a perspective view of the embodiment of Fig. 4A, and - [Fig. 5] is a detailed view of a part of the cooling device according to an embodiment of the present document. Description of the embodiments

[0064] Figures 4A, 4B and 4C represent a part of a device for cooling a turbomachine casing according to an embodiment of the present document.

[0065] The cooling device 40 comprises a collector housing 42 extending along the longitudinal axis X of the turbomachine 1, hollow and delimiting an internal volume 44.

[0066] The X axis refers to the longitudinal axis of the turbomachine in Figure 1.

[0067] An X' axis parallel to the X axis of the turbomachine is illustrated in the figures. The X and X' axes are included in the same radial plane.

[0068] The collector housing 42 comprises an upper face 42a (radially external with respect to the longitudinal axis X), a lower face 42b (also called radially internal face 42b with respect to the longitudinal axis X) matching the shape of the casing 46 and two lateral faces 42c, 42d, the lateral faces 42c, 42d providing a connection between the circumferential ends of the upper 42a and lower (radially internal) 42b faces.

[0069] The upstream and downstream ends of the housing 42 are connected to lugs 43a, 43b for fixing the housing 42 to a stator of the turbomachine.

[0070] The upper face 42a comprises a first portion 42a-1 oblique with respect to the longitudinal axis X, a downstream end of which is connected to a second portion 42a-2 parallel to the longitudinal axis X, the two portions forming an angle α with respect to each other.

[0071] The first portion 42a-1 of the upper face 42a of the collector housing 42 has a supply orifice 48 (also called a supply orifice 48) capable of receiving pressurized cooling air coming from upstream of the turbomachine 1.

[0072] As described in the prior art, this supply of cooling air may, for example, be carried out by a duct, not illustrated, extending longitudinally from the supply orifice 48 of the manifold housing 42 and opening into a part of the turbomachine downstream of the fan 2, for example into the secondary flow 10 flowing in the part of the turbomachine downstream of the fan 2.

[0073] The collector housing 42 further comprises a plurality of openings 50 distributed along the longitudinal axis X on the radially internal face of the housing 42, which is therefore arranged radially opposite the casing 46.

[0074] This plurality of openings 50 is connected to a plurality of ramps 52 by a plurality of connections 58 so that each opening 50 is associated with a ramp 52 and a connection 58 to form a triplet.

[0075] The plurality of ramps 52 is arranged radially between the opening 50 of the collector housing 42 and the casing 46, thus an air gap E1 between an opening 50 of the collector housing 42 and the casing 46 is greater than an air gap E2 between the associated ramp 52 of the triplet and the casing 46.

[0076] Each ramp 52 comprises a first and a second branch 52a, 52b extending circumferentially on either side of the collector housing 42 around the casing 46, as well as ejection orifices 57 distributed along the branches 52a, 52b and arranged radially opposite the casing 46.

[0077] Each connection 58 comprises three pipes as shown in particular in Figure 5.

[0078] A first pipe 58a and a second pipe 58b are connected, on the one hand, to the first and second branches 52a, 52b respectively, and, on the other hand, to a third pipe 58c of the connection 58.

[0079] The third pipe 58c is connected, on the one hand, to the opening of the collector box 42 by a radially external end 58c-1 and, on the other hand, to the first and second pipes 58a, 58b by a radially internal end 58c-2.

[0080] In operation, the cooling air flow arrives in the internal volume of the collector housing 42 via the supply orifice 48 (arrow 61 a), then flows through the plurality of openings 50 and their associated connection 58 (arrow 61 b).

[0081] Arriving at the radially internal end 58a-1 of the first pipe 58a of the connection 58, the cooling air flow is divided into two flows, a first flow (arrow 61c) flowing in the internal volume of the first branch 52a and a second flow (arrow 61d) flowing in the internal volume of the second branch 52b.

[0082] The first and second flows then circulate circumferentially in the branches 52a, 52b and are ejected through the ejection orifices 57, the cooling air then impacts the casing 46.

[0083] The post-impact cooling air is then evacuated and discharges radially outwards (arrow 61 e) through gaps 62 between the circumferentially adjacent ramps 52.

[0084] In the volume 64 located radially between the radially internal face 42b of the collector housing 42 and the casing 46, the cooling air after impact can then be evacuated without being confined by the space created by the collector housing 42.

[0085] Reference is now made to Figure 5 which illustrates one embodiment of a connection zone.

[0086] In this particular example, the connection 58 is symmetrical with respect to a plane P comprising the longitudinal axis X of the turbomachine and an axis Y of the associated opening 50, said axis Y of the opening 50 being a radial axis (orthogonal to the longitudinal axis X).

[0087] The second and third conduits 58b, 58c are therefore symmetrical with respect to this plane P and form a recess 66 oriented radially outwards. The recess 66 is included in the plane of symmetry P.

[0088] The connection 58 therefore has a radial section in the general shape of a V, the point 68 of which is oriented radially outwards in the direction of the opening 50 of the collector box 42.

[0089] In operation, the cooling airflow 60 passes through the opening 50 and flows radially inwardly through the radially outer end 58a-2 of the first conduit 58a of the connection 58.

[0090] This cooling airflow 60 then moves through the first conduit 58a and is divided into a first and a second flow 60a, 60b flowing to the internal volumes of the first and second branches 52a, 52b respectively.

[0091] This division is carried out by a point 67 of the internal volume of the connection 58, said point 67 being a counterform of the recess 66.

[0092] The symmetry of the connection 58 with respect to the plane P makes it possible to distribute the cooling air uniformly in the first and second branches 52a, 52b of the associated ramp 52 (arrows 61c, 61d respectively).

Claims

Claims

1. Cooling device (40) for an annular casing (46) of longitudinal axis X of a turbomachine, comprising a collector housing (42) and a cooling ramp (52) extending circumferentially around the longitudinal axis X, the ramp (52) being connected to the collector housing (42) so that an internal volume of the collector housing (42) communicates fluidically with an internal volume of the ramp (52), the ramp (52) comprising ejection orifices (57) which open radially inwards towards a radially external face of the casing (46), characterized in that the collector housing (42) comprises a radially internal face (42b) which has an opening (50) intended to be arranged radially opposite the radially external face of the casing (46), the opening (50) allowing fluid communication between the internal volume of the collector box (42) and the internal volume of the ramp (52),wherein the cooling device (40) further comprises a connection (58) having a generally V-shaped radial section whose apex is oriented radially outwards.,

2. Cooling device (40) according to the preceding claim, in which the ramp (52) is intended to be arranged radially between the radially external face of the casing (46) and the opening (50) of the collector housing (42).

3. Cooling device (40) according to one of the preceding claims, in which the ramp (52) comprises a first and a second branch (52a, 52b) extending circumferentially in opposite directions, on either side of the collector housing (42).

4. Cooling device (40) according to the preceding claim, wherein the connection (58) is to three conduits (58a, 58b, 58c), of which a first conduit (58a) is connected to the first branch (52a) of the ramp (52), a second conduit (58b) is connected to the second branch (52b) of the ramp (52) and a third conduit (58c) is connected to the opening (50).

5. Cooling device (40) according to claim 1, in which the connection (58) has a symmetry with respect to a plane P comprising the longitudinal axis of the turbomachine X and a direction passing through the axis Y of the opening (50) of the collector housing (42).

6. Cooling device (40) according to claim 4, comprising a plurality of cooling ramps (52), the radially internal face (42b) of the collector housing (42) having a plurality of openings (50) each intended to be arranged radially opposite the radially external surface of the casing (46), the device (40) comprising a plurality of connections (58) to three conduits (58a, 58b, 58c), each ramp (52) being associated with a corresponding opening (50) and connection (58).

7. Cooling device (40) according to the preceding claim, wherein the plurality of openings (50) is arranged along the longitudinal axis X.

8. A turbomachine assembly comprising an annular turbomachine casing (46) and a cooling device (40) according to one of the preceding claims, mounted on said casing (46) and surrounding said casing.

9. Turbine, such as a low pressure turbine (7), comprising the turbomachine assembly according to the preceding claim.

10. Turbomachine comprising at least one turbine (7) according to the preceding claim.

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